A COURSE ON 'FAULT CALCULATIONS'

MODULE 3.0: FAULT CALCULATIONS & APPLICATIONS IN INDUSTRIES

COURSE DESCRIPTION

The application of Fault Calculations is the third phase in the design of the industrial power system. Without Fault Calculations, the design can never be considered complete. Module 3.0 covers in satisfactory details how electrical systems are designed from the point of view of abnormal conditions, such as faults. The course will likewise present how the interrupting ratings of circuit breakers & power fuses as well as the withstand ratings of switchgears & cables are selected.

Often not fully understood, applications of fault calculations in industrial plants or power generation complexes are frequently taken-for-granted, as sizing system equipment & components are usually selected on the basis of normal conditions, only. But during abnormal conditions, faults cause disintegration of system components & ignite full-blown fires - in many cases, explosions.

As the presence of the threat of major faults is 24/7 throughout the lifetime of the plant, understanding the nature and behavior of faults must therefore be given emphasis if preservation of lives, properties and continuity of plant operation are of prime importance. How to understand this behavior and how to control fault magnitudes are the mainstreams of this course.

The course covers the following specific subjects of applications:

1) Establishment of Three-Phase Short Circuit Duties at any point of the system (whether power plants, industrial plants or commercial buildings) as bases for circuit breaker interrupting ratings, power fuses as circuit protection and for switchgear short-time withstand ratings, among others.

2) For existing plants, the output of fault calculations will trigger power system audits to confirm if the operating equipment or devices in the system can withstand abnormal conditions within their operating limits without injury and damage to itself.

3) The course also covers Single-Line-to-Ground Fault Calculations necessary in sizing Neutral Grounding Impedances for generators and substations in the end view of limiting and/or controlling destructive fault current magnitudes. A substantial treatment culminating in Grounding Transformers is covered in the course for the engineer to appreciate the value of this specific application.

4) The output of Fault Calculations will also carry the fundamental reference in arming up protective relays or other protective devices wherever they are placed in the system.

COURSE OBJECTIVES

At the end of the module, the participants are expected be able to:

a) Understand the behavior of the system in events of faults,

b) Calculate the Three-Phase Fault Duties at any point of an industrial plant electrical system,

c) Calculate the Single-Line to Ground Fault Duties at any point of an industrial plant electrical system,

d) Select and apply the proper protective devices such as circuit breakers and power fuses,

e) Select and apply the proper sizes of Neutral Grounding Impedances for Power Transformers and Generators to control the magnitude of fault currents,

f) Select equipment and components that can withstand the maximum available fault current at any point of the system,

g) Establish benchmarks for Power System Audit that may be conducted after establishing the fault duties in an industrial system.

WHAT CAN CESEEPS ACCOMPLISH IN THE GLOBALIZATION
OF THE FILIPINO ELECTRICAL ENGINEER?

 Completing the five-course Training Program will catapult the electrical engineer to higher dimensions in the practice of electrical engineering,

 Completing the five-course Training Program will transform the electrical engineer into a world-class practitioner applying IEEE/ANSI and IEC standards of design & practice,

 The application of the skills derived from this program will not only hasten productivity of the engineer but also result to a safer, reliable and much better electrical environment.

SCHEDULE OF MODULE 3.0 SEMINARS

September 5, 6 & 7, 2007: Ormoc City (Exclusive to PNOC EDC Engineers)
September 12, 13 & 14, 2007: Mandaue City, (Open to All)

A BRIEF ENCOUNTER WITH AN ICON

A BRIEF ENCOUNTER WITH AN ICON

“DOODS. Dominico “Doods” Amora is a Professional Electrical Engineer, one of very few in the Philippines. Engineering is his true passion, but boxing is a beloved mistress.” (SunStar Daily, Second Overtime, Aug. 22, 2007)

There went the lines of a renowned sports columnist in one of his SunStar Daily postings. The words were uncomplicated - nimble as a butterfly but stinging like a bee. The usual patent of Homer Sayson.

Somehow, my wife liked it. I myself loved it… My friends too, in concurrence.

The morning before these words came off the press, I happened to have an unexpected overseas call direct from Chicago, Illinois, USA. We talked for about an hour as if we had long been good old friends lost in the vastness of the globe.

Unbelievable my friends, it was MR. HOMER SAYSON, the engineers’ favorite sports columnist, himself! I couldn’t believe my ears!

And there never was a dull moment…

His voice was youthful, humble and kind - his speech friendly, truthful, straight-forward and witty – continuously flowing akin to the energy of the beer bottle filling machines of a brewery in Mandaue City. Much to my delight, the compliment was mutual. From the very first line of our conversation, I knew I was talking to an exceptionally talented man.

He had read the article, “A SUNDAY IN HISTORY” which was posted at CESEEPS Blogsite. He called because he wanted to “feel the face” of the writer just as he enjoyed much the piece. “I just can’t call anybody overseas if I don’t have good reason to do it”, said he. Those mere words alone were enough for me to swoon. Disarmed, I stammered, unsure of what to say along the way… I was talking to an icon…!

HOMER SAYSON. Yes, a Cebuano, a full-bloodied Bisaya whose unique delivery and mastery of the English prose must have brought multitudes of English–speaking Caucasians envious. To countless buffs, Homer is the best! I had been following his “Second Overtime” at SunStar Daily with faithful adulation for years. My only yearning was, “I wish I could do a mere fraction of his talent in writing”. I am just an engineer, without any journalistic training…

But then he said, “Writing can be self-taught. Yet fundamentally the flare should be there and the learnings can be achieved later”. To his conviction, improvements to one’s work are endless. It’s up for me to discover.

Sounded familiar, I recalled my own lectures… something about an open-ended, never-ending exercise…

I wanted to discern the underlying secrets, and I found myself browsing the SunStar archives. And for several times, again and again…, I savored and relished his previous works; and to share a few excerpts of them are as follows:

“… and her smile was just like the afternoon ocean breeze, soft and warm…and as she leaned slightly forward, her twin assets threatened to spill.

Her legs were long, deliciously thick and round. And they’re white as the sandy beach. Hazel Reyes in real life, Ms. Ara Mina has been all over the news lately. But for the wrong reasons…” How can anyone else introduce Ms. Ara Mina in a better fashion?

In another piece of work, “When I first saw him in Sacramento during the World Cup of Boxing two weeks ago, Bert Batawang looked ashen, as though life had just been sucked out of his vibrant 30-year-old spirit.

… The flood of bad news was enough to send Batawang to jump from the nearest bridge or the tallest building. He, however, took his fate like a man, confident that in the mystery of God’s ways, things will play itself out for the better.” …

And in tribute to Edito Villamor,

… He is one of the most valuable pieces of the ALA boxing empire, a tireless team player with selfless goals and an unbridled, unceasing love for the sport.

But every time the lambent lights of recognition gleam on the ALA boxers, he is rarely seen or heard. Not a shadow, not even a whisper.

He isn’t mute, or acting hard to get. He just doesn’t want to be found. Or heard.

But on the heels of our success last week at the World Cup in Sacramento, where our pugs drilled the Mexicans, 5-1, it’s high time to unmask this unsung hero.

Given his patent discomfort with publicity, writing this piece was, shall we say, quite a challenge. I felt like a rookie dentist trying to pluck a reluctant molar from a stubborn, defiant patient…”

With the above lines read and re-read, I felt hypnotized. I couldn’t help expressing to myself, my awe.

Outside, there was heavy downpour. A brief thunderstorm ensued - as if boldly reminding me that I’m in the verge of committing the sin of idolatry.

Then I thought of his advice: “Develop further your metaphors. And you will find the big difference. Go back to your past works and rewrite them as if they are as recent as today. Then you will discover the diversity.”

I groped my past, seeking where could I have heard the word “metaphor”. It couldn’t be in college, I’m sure. Similar to other engineering students, those were the days where my cronies and I used to hop our English classes in favor of that bubbly brownish elixir concoction served in “garapons” popularly known as South Terminal I & II courses. (The engineers knew what it was! Hehehe… remember the good old times, guys?)

I now suppose, it should have been my High School English. I remembered I had two excellent teachers way back high school days. But then, without any clear directions at the time, youthful fancies used to derail and drown a confused soul from the right roadmap.

Now I discovered, my beloved mistress could have been writing.

Unofficially today, everyone knows that I have written five books which stood as training materials for CESEEPS Re-Engineering program. But they are technical books. And I suppose, mine is more of a Technical English.

Again, writing could be my other love. But I should have done my homework long before…

I hope it's not too late to be a trace of HOMER SAYSON.

DOODS A. AMORA, PEE
August 27, 2007

SYSTEM DIMENSIONING (Second of Two Parts)

SYSTEM DIMENSIONING
(2nd of Two Parts)

THE LOAD FACTOR: Load factor is the ratio of the Average Load (AL) over that of the Peak Load (MD). Some time in 1996, Meralco & NPC declared rebates to industrial customers because of “improved heat rates due to improved system load factor”. Prior to this event, there was a campaign by utility companies urging customers to implement “Demand Side Management” – the purpose of which was to improve the over-all load factor. That brings us the question, what in real business & engineering sense, does “Load Factor” means?

If a plant for instance in Mindanao has a monthly load factor of, say 40%, why is an identical plant in Pasig City, 70%? Why is another identical plant in Cebu registering for instance, 65%? Experts in electrical engineering say that a load factor of 70% is ideal and a 60% for an industrial plant is already very good. What does it mean then to an industrial plant?

Load factor is a measure how the peaks and valleys of the system load behave. A low load factor means high peaks but at the same time, very low off-peak loads. It should be understood that the Average Load for a certain period is the energy consumed in kW-H divided by the number of hours inclusive of the period. If the kW-H consumption is low (so with the average load in KW), and if the peak is very high (the highest load within the period), the ratio between them is very low, too. To the generating plant, this scenario is a nightmare because the power plant has to run several generating units to watch and serve the peaks, plus the required spinning reserve capacity of at east equal to the capacity of the largest unit in operation. In the end, this makes the power plant operating in a very costly mode (requiring more fuel BTU per kW-H). With the utility rates regulated by ERC (Energy Regulatory Commission), the power plant will have to absorb the inefficiencies. While it is true that the utility company charges the customer a “demand charge” this alone can not pay nor offset the inefficiencies.

To the industrial plant, a ‘low’ Load Factor means that the peak MW is way above the average MW for the month or period. This means paying for higher demand charges. If the peaks can be controlled like proper scheduling of operation so as not to superimpose large loads, the peaks can be brought to the minimum, hence improving the load factor. Similar to the generating company’s predicament, a low load factor requires bigger substation capacities in preparation for large peaks while under-utilizing the system most of the time.

On top of the above, load factor is a reflection of the operation and ‘not-so-good-looking’ plant capacity utilization. For instance, if a manufacturing plant is only yielding 40% of plant production capacity, the plant operating loads may only be significant during the first three days of the work week. The rest of the week is off-peak, thereby bringing down the average load for the month. Please note that had the manufacturing plant operated 6 days a week, the peak demand would have been the same but the average load becomes higher because the wide valleys are eliminated thus, made narrow, i.e., during weekends only. If the plant is operating six (6) days a week, the load factor could be 70%. If the plant operates all the time even on Sundays, then the load factor becomes more than 80%. Hence, ‘high’ Load Factor bespeaks of good business, while a ‘low’ Load Factor means not-so-good business.

Load Factor therefore is influenced by the following circumstances:

a) OPERATING BEHAVIOR OF THE MANUFACTURING PLANT

 If the manufacturing plant operates at or near its full production capacity, then the Load Factor will be close to 70%. High Load Factor, after all, means good business. Controlling the superimposing large loads can greatly help in making the load factor high. Test running a large motor for a few minutes after undergoing maintenance during production weekdays may not be desirable because it may mean PhP 100,000 penalty in terms of added demand charge. Typical Load Factors of brewery plants with large motors in its system viz-a-viz plant production rates can be seen as the following:

Plant Production Rate / Plant Load Factor

... 30% ... 0.35
... 40% ... 0.40
... 50% ... 0.48
... 60% ... 0.55
... 70% ... 0.60
... 80% ... 0.65
... 90% ... 0.68
... 100% ... 0.70


THE “DIVERSITY FACTOR” OR
“NON-SIMULTANEITY FACTOR”

“Diversity Factor” or “Non Simultaneity Factor” – is the ratio of the arithmetical sum of the maximum demands of all group loads over that of the system peak loads as seen by the main source. Diversity Factors normally end up greater than unity. Its reciprocal, the “Simultaneity or Coincidence Factor” must be less than unity. Diversity Factor means that the system peak load of an industrial plant is not the sum of the peaks of all departments or process plants. This is because the peaks of these group loads do not individually happen at the same time. Should the peaks occur at the same time, the “Coincidence Factor” or “Simultaneity Factor” or “Diversity Factor” should have been unity, which is in real scenario; this condition is statistically very difficult to happen.

The over-all peak DiF typical between main distribution feeders of medium size industrial plants is established to be in the vicinity of 1.15 - 1.35, as seen by the main substation or by the island generation power plant. This factor should be known for use in sizing the main substation or a power plant for that kind of specific industry. Please note that adding up all the individual maximum demands of load centers will end up to a very large size substation or power plant which is neither desired.

THE LOAD GROWTH FACTOR (LGF)

Electrical Engineering Practitioners usually consider load growth in sizing the system. It normally starts with the size of the sub-feeders & feeders to the transformers and substation. In the US, it is not unusual to provide a load growth factor of some 25-35% envisioned for the next five or seven years. As such, transformers are always oversized for same practical reasons.

b)THE PRESENCE OF LARGE MOTORS THAT INFLUENCE THE PEAKS

 A Bottling Plant typically registers a 68% to 70% load factor, while a refrigeration plant at 49%. This is so because motor starts-up in a Bottling Plant, mostly by small motors (and a few 20 hp motors), as seen by the demand meter only represents ripples. While the entry of a large compressor into a system influences the peso value of the demand charge that the manufacturing plant is paying for. More often than not, the size of the substation or a power plant serving a beverage plant is greatly influenced by the block loads brought by the size by large refrigeration compressor motors. Note that a 1,000 Hp compressor is even larger than a Bottling Line or a Pharmaceutical or an Automotive Harness Plant, electrically. Starting up one thousand pieces of one hp motor is very different from starting up a single – 1,000 Hp motor.

Power Plant Generators and Substation Transformers react to large motor starting as manifested in voltage dips. In general terms, transformers in an electrical system are usually larger than the maximum demands they serve, in some instances even larger than the connected loads. In the industrial plant scenario, the obvious reason at first glance for this apparent oversizing is the anticipation for future load growth. Fine…

But more often than not, sizing the transformer with extra kVA capacity unwittingly addresses voltage sag problems, not for load growth for which it is intended originally. That’s why for newly constructed plants where load growth is not yet there, the problem of starting significantly large motors may not surface out. Why? Because the extra kVA capacity intended for load growth is taking care of it. (See related article of this topic in this blogsite).

For systems with large motors:

TRAFO KVA = (Maximum Demand kVA of Small Group Motors) + (Maximum Demand kVA of Other Loads Including Load Growth) + (kVA Ratings of all Large Motors) + (Additional Trafo kVA Capacity necessary to accommodate the inrush of the largest motor)

DOODS A. AMORA, PEE
(August 19, 2007)

SYSTEM DIMENSIONING

SYSTEM DIMENSIONING
(First of Two Parts)

SYSTEM RELATIONS

Let us step farther away and look at the forest. The industrial complex under a design concept needs to consider & integrate system voltages, voltage transformations; behavior of loads, load distribution, load growths, transformer KVA sizes, transformer connections, device & equipment sizes, grounding, switching schemes, and protection systems among others; that would serve best the manufacturing and/or industrial processes the plant is intended to. This integration usually ends up in the Substation that will eventually link the industry with the power distributor company.

This task is what is known in the industry as “System Dimensioning”. And the designer must see to it that the system to be built will last for years in the entire lifetime of the industrial plant.

The whole power system exists to serve the load. The behavior of the load therefore commands the shape of the power system. Incidentally, the character of the load is very capricious for which the electrical system has to readily react to load situations instant by instant to accommodate its peaks and valleys. It is worthwhile to mention that unlike any other systems in the planet, the production, consumption & sale of electricity all happen at the same time, at an instance. The design, installation and the operation of the system must therefore be best suited to the requirements of the load that varies from time to time.

To further illustrate, a few terminology needs to be understood, as follows:

 Connected Load (CL) – the arithmetical sum total of the continuous nominal power consuming ratings of all equipment in a system. In Europe, it is known as “Installed Power or Installed kVA”. In real terms, all of this amount of power can not be used or consumed at any given time. Thus the “Installed Power” or “Connected Load” can not be reached.

 Maximum Demand (MD) - the highest or peak load in a certain time frame of a system. It is also known as 15-Minute Demand KW or KVA. For instance in a system connected load of 1,000 KVA, if only 60% of maximum power found drawn as metered, then the same system has a Maximum Demand of only 60% or 600 KVA. IEC lingo termed it as “Maximum Utilized Power”. This is so because even in operating motors, the actual load of these motors can not reach the “Installed Power KVA” because they are not most likely operating at fully loaded condition all at the same time. The maximum demand usually is the demand kW reflected in monthly utility billings.

 Average Load (AL) - the equivalent average load of a variable load in a certain time frame. As the actual load with respect to time could be seen as a “mountain range curve”, there exists an imaginary straight line equivalent to this mountainous curve. That straight line represents the average load. For instance, in a variable load for the month, the meter read-out is 1,000,000 kW-H, the Average Load for the month will be: AL = 1,000,000 kW-H /(30 days per month x 24 hr per day) 1,388.89 KW. This means that the actual variable load for the month is likened to a uniform 1,388.89 KW load all the time for 30 days. Normally, the average load can be derived from the kW-hr consumption of the period divided by the hours of the period. It thus can be likened that the plant has an average KW or MW at any given time for the subject period.

SYSTEM LOAD METRICS IN INDUSTRIAL APPLICATIONS

In order for the design engineer to further understand the meaning of the relevant design factors, the following is an attempt to provide more explanation using the experience of the author in brewery operations. Note however, that load metrics for different types of plants differ from each other. Load Metrics are reflections of the actual behavior of plants. It is now up to the plant engineer, to interpret and establish them into the real scenario of his plant. It is thus desired that the engineer should create his own statistics in his supposed field of expertise.

THE DEMAND FACTOR: Let us recall that Demand Factor is the ratio of the Maximum Demand or Peak Load over that of the Connected Load. For instance, for a connected load of 100 KW, if the actual peak load is only 50 KW, the Demand Factor is supposed to be 50%. If we say that the Demand Factor of a typical Beer Filtration Plant is 54.5%, could it mean that the plant is operating only half of its capacity? … Not quite!

For the sake of explanation, about 35% of the connected loads in a Beer Cellaring/Filtration Plant are destined not to operate during normal production days. These specific loads referred to as the CIP (Cleaning-In-Place) systems don’t run during production operation. They are meant to operate only when the system ceases to produce and cleaning/sterilizing of the equipment, pipelines, etc with caustic soda are required for every shutdown to prepare the system for another round of production schedule. These types of loads are the so-called “Non-Coincidental Loads”. The effect of non-coincidental loads in an operation is a good example how the demand factor takes shape for every type of operation. It must be appreciated that the CIP system in this example is included in the inventory of the “Installed KVA” but in reality doesn’t influence the size of the power center in concept. It must be understood therefore that demand factors depend on the mode & type of industrial plant operation. Again the engineer must define his own turf.

In like manner that in an industrial plant, there are a number of installed spare units as compressors, boilers and system auxiliaries. These are typical in Steam & Refrigeration Plants, where a number of installed spare units are included in the connected load inventory but are meant to operate only when needed – that is, in case of breakdowns of the operating units. Moreover, a running motor usually doesn’t operate at full load. Remember, the peak loads discussed here are real-time values captured by a demand meter, while the connected loads are based on nameplate ratings. Most motors in any industrial plant are in fact running at 75% to 90% load only – this further shapes the demand factor of a specific plant.

(To be continued…)

DOODS A. AMORA, PEE
(August 17, 2007)

A SUNDAY IN HISTORY

A SUNDAY IN THE HISTORY

OF PHILIPPINE BOXING

PROLOGUE

The temperature outside was typical yet the air seemed to have retired somewhere. Despite inside an air-conditioned living room, the heat appeared intense - most likely from the radiation constantly detonating from my very own spirit….

It was a very different Sunday morning … my heart throbbed inconsistently. Although full of joyful expectations, I was worried, uneasy and excited, in other terms. With the strange ambiance, I knew vehicular traffic in the entire archipelago had been immobilized to a standstill. Malls, markets and streets; all deserted. I imagined my friends and buddies were likewise glued to their seats – this time no leisurely activities in Mactan white beaches. At home, no telephone calls from the outside world. Invitations no matter how tempting were neither allowed nor accepted, in other words, no disturbance please…, at least for the moment.

I skipped the Sunday morning mass and breakfast was not part of my intentions. I was hungry, yet I didn’t feel like eating. Chilled canned beers or a series of ice-cold whisky waiting to be engulfed seemed more appealing. Just as I wanted to be powered, I wanted to talk and chatter lengthily but I was in a sense, alone. I didn’t have any audience as my wife busied herself somewhere, doing something else – as if distancing from me in a different zeal. Of course, that’s understandable. But she must have noticed that early in the day, a 2000 lumens multi-media projector had been hooked up with the boob tube with 1200 watts powered mixer with speakers reverberating decibels ready to herald in full might the event of the day! Something I don’t normally do. Then she knew it was THE WORLD CUP IN BOXING…

I texted my good old reliable fellow electrical engineer buddy in my hometown in Northern Mindanao to confirm if he was collaborating with me in my fray. “Shoot! Botchoy Gorres is our town-mate and everybody in Nasipit is rooting & praying for him!” Hehehe… soothing, with his reply, at least I had a cohort.

THE WORLD CUP UNFOLDING

The second edition of the so-called “World Cup in Boxing” this time between the Philippines and Mexico had slowly been unfolding on the big screen in front of me. The WAR happening in The Arco Arena in Sacramento, California was the ‘moment of truth’ much more in magnitude than the Cebu episode in a recent past.

To recall, the first World Cup in Boxing was Mexico vs. Thailand where Mexico in utter domination scored 5-1, in a near sweep! This time, it’s war between the Philippines and Mexico. “Go Philippines!”, “Mahal ko ang Pilipinas!” as the battle cry goes. What else could make a Filipino like me and you quiver? “Four–Two” for the Philippines will be great. By then we would be the Champion Team!

Unfortunately or fortunately, my home DSL was down. PLDT promised to come but I knew they couldn’t, probably not until the war was over. In previous occasions, I had always been ahead round by round – texting advance information to my fellow electrical engineers hours earlier than any TV transmission – all courtesy of the Internet. This time, I had to make do of ABS-CBN. But as the event went by, even with the annoying commercials, the more electrifying it became. As I came to realize, in times like this; no internet, the better.

THE MOMENTS OF TRUTH

The first TV scene saw Korina Sanchez announcing a 2–0 score for the Philippines as Michael Domingo and Dado Gabi gloriously won over their respective opponents by UD. By not showing the two earlier bouts deprived me of the two parts of the menu. The video synopses that followed only increased the urgent appetite for more action.

I realized that fighting for the country brought along the national pride within me. The feeling of being a Filipino touched me – reminding me despite the personal frustrations on the political misadventures in the country, boxing indeed is one avenue to the “Pagkakaisa sa Sambayanang Pilipino” - as every soft-core or hard-core politician loves to utter, Manny Pacquiao, included. Later, the sight of our “kababayans” pitted with the macho mexicano warriors made my pulse beat faster. I wished I could not see disturbing moments...

The moment of truth had begun but with a different emotion from the “Moment of Truth” episode in Cebu last December and the recent Penalosa-De Leon combat. Those two occasions were falsehoods! Whether or not these falsehoods could be changed in Sacramento is something worthy to be anxious of. We have just witnessed the lapses of our very own Rodel Mayol in the attempt to grab the championship off Ulyses Solis. And who can forget Czar Amonsot battling the Australian Michael Katsidis in a bloody episode?

But Dado and Michael had already done their shares. This time I prayed for Boom-Boom, Gerry, Botchoy (my townmate in Nasipit Agusan) and AJ Banal – that all of them would make it! Two more to go… Lord God, please give the Philippines , a break…

Then came the Bazooka (14-0-1, 11 KO’s) on screen. The first round was so good for AJ that it signaled the texture of the entire bout. Indeed, with AJ controlling the fight, an explosive counter right hook to the chin in the third canto sent the Mexican foe into submission, badly dislocating his ankle in the process. The verdict: KO! The Mexican Jorge Cardenas never got up from that bazooka explosion. Score: 3 - 0! Fine… One more and we would be the Champion Team!

It’s now Z’s turn! Coming off a controversial split-decision loss to Fernando Montiel, Z Gorres (27-2-1, 15 KO’s) was never the same again, style-wise. In a complete turn-around, the “Dream” of the past literally became a charging “Tiger” fearlessly dishing out incessant but accurate offensive jab-straight combos that were joys to watch. In my book, with the IBF Junior Bantamweight Intercontinental Title at stake, Botchoy practically swept all seven rounds (70– 63) until the end came in Round 8 when the ring physician stopped the bout. It was a TKO score for the diminutive guy from Nasipit (who was later raised in Mandaue), as Botchoy then sealed the destiny of the tourney. The Philippines won by a wide margin, 4– 0, this time so far shutting out the Mexicans, Erik Ortiz (26-7-1, 17 KOs), the former WBC Junior Flyweight Champion, included.

WE (THE PHILIPPINES) ARE NOW THE CHAMPION! The emotions were high! The crowd in the Arco Arena roared. The entire archipelago soared! I could hear the screams of my neighbors, synchronizing with mine. In a normally quiet neighborhood, shouting at the top of one’s voice is taboo. This time however, it’s excused.

In a swift transition, Gerry Penalosa (52-6-2, 35 KO’s) became the center stage on screen. Although Gerry took the first round, I was fearful of the match-up. The champion, Jhonny Gonzales (34-6, 29 KO’s) and 10 years younger, had too much height and reach. And he is no push-over! It can be remembered that Jhonny twice floored Israel Vasquez (who just TKO’d Rafael Marquez last week) and was leading in the early stages of their own championship encounter when Vasquez turned the tide in a classic fight.

Against Gerry, Jhonny looked good – even better than Ponce de Leon’s last fight with Gerry. With the champion executing dutifully & beautifully a game plan of maintaining distance with cycles of stinging combinations kept him away from Gerry’s stalkings. Gerry in the next rounds found Gonzales difficult to penetrate. The scary moments had come…

After six rounds my score card showed 59-55, in favor of Gonzales. Alarmed, I could only think that being a wily veteran was Gerry's only advantage. It would be hard task for Gerry who had peaked somewhere in the ‘90s to win this one. Noticing more commercials than the Gorres’ stretch, it came to my senses that the bout must have been an abbreviated one. Would it turn-out Gerry being KO’ed? The thought frightened me. Sorry, I told myself to stop scoring the bout. At the instance, I suddenly felt unbearable hunger. I found myself in the kitchen looking for food.

But then in a shocking moment, the 35-year-old veteran Gerry Penalosa badly behind on points suddenly unleashed a perfectly timed rib-cracking bomb to the liver that sent the champion to the the floor grimacing in pain. As the count of ten elapsed, verdict: KNOCK-OUT! Hey guys, we had a new world champion! And Gerry is a World Champion again! I could then feel that the cheering and celebrating in all over the 7000 islands of the Philippines could have caused Philvocs panic when the Richter Scale must had been activated!

Score: 5-0, as the Philippines’ sweep continues at the Arco Arena in Sacramento !

THE MAIN EVENT

Just as fickle as everybody else, the ‘standard’ changed. The ‘desired condition’ amended. At this point in time, the 4–2 objective was scrapped. I suddenly felt: GO 6 -0 SWEEP! WHY NOT? WE HAVE FAITH IN BOOM BOOM!

The main event saw Mexico salvaging some face when WBO super bantamweight champion Daniel Ponce De Leon (32-1, 29 KO’s) crushed our undefeated Rey "Boom Boom" Bautista in the very first round. After coming off a lackluster decision win over Penalosa, De Leon was all business redeeming himself to the Filipinos as he came out throwing bombs from the start. A combination that was punctuated by a right hand to the chin sent Bautista down. Another flurry of big punches easily sent Bautista to the canvass for the second time as the referee stopped the fight preventing any more damage.

THE AFTERMATH

All of a sudden I forgot my ecstasy as I agonized and bled for the young man. The menacing "Raramuri Warrior" was too much test to the kid. Knowing that Rey came from Candijay, Bohol, he could have been my relative. I apologize for my fickleness. A Five-One performance is already beyond expectations. I should have not asked for more.

The rest is now history. Boom Boom will bounce back. I’m quite sure of that. Wait until his full-grown manhood. And remember, he is a Filipino!

Doods A. Amora, PEE
(August 12, 2007)

THE POWER PLANT OF THE INDUSTRIAL PLANT

THE POWER PLANT OF AN INDUSTRIAL PLANT

An industrial plant like a brewery, cement plant, sugar milling plant or a wood-based industrial complex may in some instances elect to put up a self-generating plant to support its power requirements. In the country, these power plants are either diesel or steam power plants. The steam power plants are commonly fuelled by coal, or a combination of bunker oil & wood wastes or a combination of oil & sugar cane refuse called bagasse.

There could be four reasons for the concept, i.e.:

1) there might be no existing power supplier in the vicinity where the industrial plant is to be erected,

2) the local electric cooperative in the area may not be capable to supply the needed power,

3) process steam may be intensive where co-generation with power could be most economically attractive,

4) the cost of self-generation may be very much cheaper than utility’s PPA-laden power rates.

While it is true that power lines of National Transmission Corporation (TransCO) are now criss-crossing the countryside, tapping to a distant 230 KV line may not be cost-effective for a medium size plant of say 10 or 20 MVA. A 69 KV TransCO sub-transmission line may be deemed best but may not be available in the area when the plant was conceptualized. On top of this, a number of Independent Power Producers (IPP’s) are recently courting many industrial plants with Build Own Operate (BOO) or Build Operate Transfer (BOT) schemes - somehow offering rates which are lower than that of the utilities. The idea is to install medium size generating plant (distributed generation) close to the industrial plant to supply the power requirements of the manufacturing plant. If the IPP’s can offer lower power rates but still can produce profits, then self-generation may be attractive.

DESIGN REQUIREMENTS

The appropriate size of the power plant can only be answered as a result of a thorough study of the circumstances surrounding the conditions of the system. For instance, if the power plant in concept is only for emergency supply in the events of power outages by the utility, then, 80% of maximum demand capacity in two (2) or three (3) generating units may be the right size for the system condition in an ATS configuration. In small systems where power interruptions can be tolerated, one or two generating units serving the loads may be sufficient, again with an Automatic Transfer System or ATS.

For medium size systems to act as “Island Generation”, stringent requirements have to be met by the power plant in concept. The determination of the size of the power plant and the number of units may pass through a careful study of the behavior of the plant served as reflected by its load profile and load duration curve. For instance, an electrical engineer who fully understands the behavior & peculiarities of a brewery or cement plant load should be there during the conceptualization of such a project.

For large island generation systems, the more tough requirements are needed in the process of selecting of the sizes and number of generating units. Theory of Probability on forced outages of generating sets is to be employed and inputted into the computations. It’s only then that the number & sizes of generating units can be established.

Power Plant Engineering Design is an art that includes selecting and placing the necessary generating equipment so that a maximum of return will result from optimum capital investments & maintenance costs over the working life of the plant (Life Cycle Cost). Most industries that self-generate usually make use of bunker oil-fed diesel engines or steam generators. Power may then be co-generated with steam where bulk of the power produced may be configured to become “free” or “by-product” by using a combination of straight condensing with topping or back-pressure turbines.

Normally in Steam Power Plants, a few diesel-driven generators are also used in combination with steam turbine-driven mainstays for purposes of starts-up or alternate power supply in times where the boilers are in maintenance during weekends.

In any case, the selection of sizes and number of generating units in a well-designed “island power generating plant” for a medium sized industry should consider the following factors:

 Safety - this means safety in design and good workmanship in the execution or installation of the system components. A good design and workmanship will result to safety of personnel and property.

 Economics - this means resulting to the best choice of arrangement that would deliver the most cost effective first cost (P/kw), and operational costs (P/kw-hr) as well. Economics however does not mean not to include the necessary spinning and ready reserve units required in an island generation power plant.

 Maintainability - this means that the power plant can still meet load requirements even if part of the plant is under maintenance. In real life scenario, it always a fact for diesel power plants that one of the generating units is under maintenance at any given time. If ever one unit is under maintenance and the power plant can not serve plant requirements, then that plant is ‘not maintainable’. This is one area that the engineering manager and the finance manager are always in quarrel i.e., in interpreting costs.

 Reliability of Service - The reliability of the power system is measured by its ability to serve all power demands made by its customers without failure over long periods of time. For instance, a common criterion is to install sufficient capacity to prevent interrupting power to customers oftener than one day in a 5-year period on a long time average basis. The second criterion is the appropriate size of the generating units that must be placed in the power plant to satisfy the base units and reserve requirements. This is so because the loss of a large unit will render the power plant incapacitated of this large capacity.

Reliability means capital investments. New Reliability requirements are now expressed in terms of “Reliability Nines” (four to six nines) and they don’t come cheap. The demand for more reserves would increase the cost of power. Inadequate reserve causes great inconvenience and economic loss to the business, both to the power plant and the customer plant. It is thus for the engineer to assess the balance of these two extremes.

 Availability - “Operating Availability” is the statistical measure showing how physically ready the generating unit or plant is, in producing power whether needed by the system or not. It is a measure of overall unit or plant dependability. Availability Performance further shows the effects of forced outages and the unexpected glitches in operation & maintenance. If the power plant in concept has to operate like a utility company or an “island generation” where all the power requirements have to be supplied by the power plant, then the stringent requirements described above have to be met. This means that loss of power is not tolerated, i.e., to protect spoilage of the product that may prove to be too expensive.

PRINCIPLES IN POWER PLANT DIMENSIONING

The design engineer must consider the loads as seen by the power plant in terms of Load Profiles & Load Duration Curves. Having established them, the engineer is now in the position to design the shape of the power plant in concept.

But let us be reminded however, that the power plant has its own complexities where such complexities must be satisfied, to wit;

 What made power plant operation complex is the inherent variability of the loads and the power plant must be ready and serve the load in any eventuality.

 The production, delivery & sale of electricity all happen at the same time. The product of the power plant, which is “power”, is not completed until the instant it is needed and used, at the quantity exactly equal to the demand at that instant.

 There is no simple way to “warehouse” an extra supply of “Kilowatts” or Kilowatt-Hours” against some future period of extraordinary demand, yet it is certain that such a period will occur.

The above simply means that there must be power at any time the customer needs, and this power must be sufficient with spinning reserves. It means further that the power plant supply must always be significantly greater than the demand at the instant and at any instance, for that matter.

There are no hard and fast rules governing the sizing of the power plant. According to the Standard Handbook for Electrical Engineers, 13th Edition, “a design of a generating plant derived from probability calculations is still subjective. It is still the “han-ay sa pinsada” of the engineer that counts.

The electrical engineer of the industrial plant therefore has to consider all the important factors of a reliable power plant that would be best suited to his requirements”. However, experiences and practices of North American and Japanese power engineers can help shed light to this thought process. CESEEPS Power Book 2 (Medium Voltage Systems & Applications in Industries) could be a great help.

Doods A. Amora (July 2007)

MODERN MAINTENANCE MANAGEMENT PRACTICES

MODERN MAINTENANCE MANAGEMENT PRACTICES

by DOODS A. AMORA, PEE

BACKGROUNDER

What has Maintenance got to do with the global competitiveness of the electrical practitioner? This question cropped up because even in the modern times, maintenance is not understood universally…

For instance, in Germany, Sir John Peter Koss in the Beverage World International February 1999 Issue said, “THE FUNCTION OF MAINTENANCE STILL MEANS DIFFERENT THINGS TO DIFFERENT PEOPLE”. The issues & major problems as he continued are the following:

1) Inadequate Definition & Documentation of the Maintenance System,
2) Improper Organizational Structure,
3) Incompetent & Insufficient Personnel,
4) Insufficient Funding for Required Work,
5) Inconsistent Management Comprehension & Attitude.

At the other side of the globe, in America, Sir Jean-Pierre Wolff, a NETA member (interNational Electrical Testing Association), & Vice President of Electro-Test, Inc., Pleasanton, California in one of his EC&M articles said: “Common Maintenance problems can be summarized as follows:

a) Insufficient Proactive Maintenance,
b) Frequent Problem Repetition,
c) Erroneous Maintenance Work,
d) Unnecessary and Conservative PM,
e) Poorly Defined Rationale for PM Action,
f) Maintenance Program Lacks Traceability and Visibility,
g) Blind Acceptance of OEM Inputs, and,
h) PM Variability Between Like or Similar Units”

In the Philippines? Oh, sure, we have all the above!


INTRODUCTION

The challenge to survive the hard times of the new millennium has not spared the area of maintenance. It can be recalled that the decade of the 90's saw the manufacturing business sector in serious search for radical changes to catch up with the demands of world-class competition aggravated by the effects of the region's economic meltdown. With the dim economic recovery scenario, maintenance engineering is no longer an innocent bystander in the dead corner of plant environment but now seen as an active participant in dampening the effects of the national debacle.

Management experts say that the ingredients of today’s competitiveness are: quality, efficiency & productivity. To help attain this goal, several old inefficient plants in the 90's were replaced with high technology lines giving way to modern techniques and processes in manufacturing. On top of this, organizations were restructured to meet new synergistic requirements. Several companies in the country sought for ISO certification - showing to the world that these companies are at par with world class standards. The mood in the 1990’s therefore was modernization to meet global competition. But modernization is in fact going back to basics, again to: quality, efficiency and productivity.

Physical modernization does not exempt maintenance from modernizing itself. Old & obsolete concepts in maintenance are seen slowly fading out as we enter into the new millennium. For instance, many businesses realize that production alone is not a guarantee to survival. In the 70’s & 80's, the mood of manufacturing business was production, production, and yes, production. Somewhere along the way, we did what North American managers were preaching, "that high production volume (large lot size) is where profitability is”. The Japanese on the other hand, later reinvented the concept that “production can best be done in smaller lot sizes while instituting built-in process-to-process quality control to ensure perfect products at the end of the line”.

Thus the concept of “zero defect” to the product and the concept of “zero breakdown” to process equipment became loud and very visible in the 90’s.

In the scene of plant maintenance, the concept that maintenance is nothing but a service unit has now been changed to the concept that “maintenance is a function of production, and conversely, production is a function of maintenance”.

Whether or not these new concepts are practicable is one question this paper seeks to answer.


HISTORY OF MAINTENANCE

The reason why the previous mind-sets and the need to shift to these new paradigms can be traced back to history…

Once upon a time, work for instance as in farming, was performed all by hand - without any machines or the benefit of technology. Some time later, tools were developed, and it then became very important to keep them intact and sharp otherwise the work can not be carried out efficiently. The demand for maintenance this time started to grow. Many years later, as electricity was invented then hastened by the Industrial Revolution of the West, production equipment started developing. The tools, implements and simple equipment at the beginning were not sophisticated enough such that a lot of people were required to keep production on stream. Production at this point was more or less, a handicraft.

Maintenance activities could not influence productivity so much (although it was important to keep the equipment running) because the quality and quantity of production were to a large extent decided by the skills of men and their capacity to work fast. All through a long period of time, from generation to generation, maintenance had been thought of as a service department - not a condition to production.

Times had changed. The quality and quantity of production now do not depend on man but on machines. With the increasing degree of automation and robotization in most manufacturing plants today, it is now appropriate to recall Mr. John Moubray a British expert on Reliability Centered Maintenance (RCM) when he said, "that product quality & quantity now depends on equipment". At the other side of the globe, Mr. Seiichi Nakajima, a Japanese guru on Total Productive Maintenance (TPM) preached: "that productivity, cost, inventory, safety, health and production output - as well as quality - now all depend on equipment”.

MISCONCEPTIONS ON MAINTENANCE

Some time in the 1990's, a survey was conducted in manufacturing plants in Cebu, to determine the mind-sets of personnel representing the cross-section of maintenance, operation and production workforce. Hereunder were the results with some comments and analysis:

1) "That Maintenance is an Expense, therefore a Necessary Evil"

That profit is the difference between revenue and expense. Minimizing expense is therefore maximizing profitability. This confirms the thoughts of Mr. William Bleuel of Barber Colman, Rockford, Illinois, when he wrote, “Each year, top management reviews the maintenance budget with an eagle’s eye towards making it as small as possible. Where this attitude prevails, maintenance would likely be given low priority. From this viewpoint, plant management usually takes a hard line that maintenance should be minimized”. This is what Mr. Thomas Alund, a Swedish maintenance consultant termed as “Cost Controlled Maintenance” - meaning that movements in a maintenance program are solely dictated by the money available in the budget.

The reason why maintenance is considered a cost-controlled activity is that engineers and technical men found it difficult to measure the investments on maintenance in total economic terms. It is very easy to find the cost of maintenance but difficult to quantify the results. Like an iceberg, where the biggest part is invisible under the water and only a small part visible above the surface. The visible part represents the direct maintenance expense while the invisible part silently denotes the various factors influenced by maintenance.

2) "That Good Maintenance is Repairing Broken Equipment Quickly"

The survey showed that "quick repairs on equipment" is a virtue. Restoring broken equipment back to operation in so short a time shows the mastery of maintenance men over their equipment. In any plant, there is always a guy – a technician, who always outshines his colleagues in troubleshooting equipment or system faults. Such guy, “Tarzan” the ‘trouble-shooter’ usually called out during the night has to come to the plant to make things going.

Tarzan is easily seen as the hero in the business. Because of this heroism, many Tarzans are promoted to supervisory positions but later found themselves in trouble handling managerial functions. Managerial skills are something else - a very different ballgame.

3) "That Production Group is the Adversary of Maintenance"

Observations in the past showed that production group oftentimes made maintenance the scapegoat and shock absorber whenever something in production went wrong. But it was also the same production people who always not grant maintenance sufficient time to maintain the equipment. Lording over during shifts, production people always make life of maintenance miserable.

4) "That Maintenance Men are Second Class Citizens in an Industrial World, Far Behind the Footings of their Counterparts in Production"

The belief was that, production is where revenue comes in. Production is making money while maintenance, the necessary evil. Hence, production groups are the favorites, maintenance the expense.

5) "That Maintenance Starts After the Equipment or Production Lines Have Been Commissioned"

Projects are someone else’s job. It’s not maintenance job anyway. Neither it’s production's job. But then, when the facility is in operation, people in the plant would start saying, “this should have been like this, and like that”.

6) "That It 's Very Difficult to Operate a PM System in a Plant"

“PM are nuisance activities. It only adds up workload to an already overloaded maintenance crew.” “Whether we like it or not, equipment will breakdown sooner or later. What's the fuss?”

These are just a few realities we gathered from the past perceptions on maintenance. These realities were not unique in the Philippines as they were also happening in advanced countries in Europe and the Americas.


MODERN CONCEPTS IN MAINTENANCE MANAGEMENT

As pointed out earlier, the name of the game in manufacturing today is automation & robotization. Why? Simply because in the global business arena, it is a must! John H. Zenger, a known American management expert in his book "Leading Teams" wrote, "In the 1960's, North America stood at the summit of world economic power. In those days, the order of the day for every manufacturing manager can be summarized by a sign that hung over his desk and that is: GOOD. FAST. CHEAP; PICK ANY TWO..!”

It means that:

"If you want quality and you want it fast, it'll cost you big bucks“.

"If you want it fast and cheap, no problem, but it won't be good enough to last through the winter“.

"If you want good quality at a good cheap price, that's fine too, but don't hold your breath for delivery. It'll probably take forever."

Then comes the customer’s cue to nod in wide-eyed agreement: "You always have to trade off one to get the other two“.

Today in the third millennium, a manufacturing company has to give out all the THREE, in order to survive fierce competition. In a customer-driven business environment, automation therefore becomes the answer to the need of efficiency & speed. Robotization where applicable, is the key to achieve large volume and uniform quality throughput especially in industries where human factor is too hazardous.

That in a nutshell, is why so many companies are putting themselves through so many agonizing internal changes, including the parting away of the traditional maintenance management styles. For until a manufacturing plant becomes "good, fast and cheap", it's an easy prey for any competitor that figures out how to deliver on all three.

In the past, responsibilities of maintenance are to concentrate only in making machines and equipment run in service to the production department. Today, maintenance is already included in the ownership of the quality and quantity of the products produced, because after all, it is maintenance’s job to make the process capability of the plant fit to produce such products.

Again, automation & robotization bring the equipment or machines to the center-stage. When we say equipment, it means maintenance. Maintenance now plays a much bigger role in production. Along with the shift in philosophies in maintenance, new concepts in modern management had been developed in Europe, among them are as follows:

ROLES OF MAINTENANCE IN MODERN MANAGEMENT

1) Achieve Target Production Outputs by Making the Process Equipment & Machineries Available,

2)Maintain Product Quality by Making Manufacturing Equipment Process Capable to Produce Such Product,

3)Implement Maintenance Services Imposed by Production Group,

4)Implement Systems & Routines to Sustain Equipment Effectiveness (e.g., PM),

5)Maintain Availability of Spare Parts & Materials,

6)Participate in the Conception & Implementation of Projects.

The first two roles of maintenance seem to be encroaching into productions group’s domain. But before anything else, a look at the roles of production in modern day management concept becomes necessary.

ROLES OF PRODUCTION IN MODERN MANAGEMENT

1) Achieve Target Production Outputs at Specified Quality Levels Through Process Efficiency (Zero Process Error), While Optimizing Utilization of Resources (man, machine, materials, method and time),

2) Operate, Clean, Align, Lubricate the Machines, Tighten Bolts, & Fix Simple Faults,

3) Monitor the Health Condition of Machineries & Equipment Leading to Imposition of Major Maintenance Schedules and the Eventual Preparation of the Plant for Maintenance,

4) Ensure Availability of Raw Materials and Finished Product Inventories,

5) Participates in the Conception & Implementation of Projects.

The first role of production focuses on process, practices and techniques in manufacturing. But items 2 & 3 can be perceived as maintenance functions. Seiichi Nakajima’s Total Productive Maintenance (TPM) confirmed this concept when machine operators in Japan became the first line of defense in the maintenance of the equipment. The new management concept in maintenance therefore runs like this:

“50% OF MAINTENANCE JOB IS PRODUCTION" &
"50% OF PRODUCTION’S JOB IS MAINTENANCE”

Radical as it may seem, but this can be aptly understood when applied to our own homes. Putting out a fire in our home is not supposed to be our job because it is the job of the city fire department. Extinguishing the fire as quickly as possible by the fire brigade speaks of its efficiency. But no amount of this type of efficiency can justify the job because in the first place, the fire should have not happened at all.

Exactly the same principle works in the plant. Modern Maintenance Management is not to repair broken equipment as quickly as possible because in the first place, it should have not happened at all. In other words, Tarzan must now be extinct because:

“GOOD MAINTENANCE IS NOT DOING THE WRONG WORK EFFICIENTLY”

There must be no fires. How to fight fires by preventing them to happen is from the very beginning the concern & responsibility of the “Taong Bahay”. Taong Bahay yes, are the production people.

But Mr. Nakajima’s TPM philosophy of “we operate, we maintain” does not really mean that full maintenance has to be accomplished by the operating personnel. In real life scenario, a person has to do maintenance of himself and to some degree performs some autonomy.

Personal maintenance activities like: taking a bath everyday, brushing of teeth, making oneself spic & span, eating the right food, daily exercises, etc. are just some maintenance activities that don’t need some neighbors to do it. To some extent, a headache, a stomach ache or muscle pains can be healed by self-medication, but then, if the problem needs an operation of the kidney or an organ transplant, or correction of an infection, definitely professional doctors are required to do it. In the same manner that annual physical/medical examinations can not be done by just anybody else except the doctors and their clinical staff.

Items 2 & 3 of the Roles of Production in Modern Plant Management, showed maintenance activities by the operators are limited to cleaning, lubricating, aligning, bolt tightening and finally, to fixing simple faults - all in the end view of preventing & controlling deterioration. Monitoring the health condition of the machines they tend, scheduling and preparation of the equipment for the eventual maintenance service are in modern management, obligations of the operating department. Teardowns are to be given to the surgeons - the maintenance department.

CONCLUSION

Modernizing maintenance management first needs top management’s re-thinking and realignment of beliefs. Seiichi Nakajima is telling us that if top management is not convinced of the true benefits of maintenance, then Total Productive Maintenance (TPM) can never take off. Modernizing maintenance must start from the top to bottom and includes all personnel in the plant. As a summary, among these beliefs are as follows:

 That Maintenance is Not a Necessary Evil But a Condition to Production,

 That Maintenance is 50% Production Job and Production is 50% Maintenance Job,

 That Maintenance Should be Seen as a Results-Controlled Enterprise”, Not a "Cost-Controlled Service Department in the Corner“,

 That Equipment Breakdown Should Not Happen at All, Because Good Maintenance is Not Repairing Broken Equipment But By Executing Planned Activities,

 That Production Group is Not the Adversary of Maintenance But Partners Sharing the Same Objectives,

 That Preventive Maintenance With Emphasis on Condition Monitoring is What We Need to make Maintenance More Effective,

 Systems Make Things Possible but It’s People Who Make Them Happen,

 That Honest-to-Goodness Maintenance is Needed to Achieve Good, Fast & Cheap products.

After all the modern concepts are understood, the next move is to define how maintenance performance must be measured. Basing on these measurements, attempts must be done to establish past performances. This will become the baseline reference. All future performances will be based on these baselines.

Target dramatic improvement as specific objective. Aim "zero downtime" first, later "zero breakdown".

Thirdly, is to overhaul existing maintenance management system with emphasis on planned maintenance imbedding the principles described herein this paper. This move normally needs changes in internal organizations.

Develop a new system and implement it in manual mode. It is important to feel the success or failure of the new system. This will also open up opportunities for changes and improvements. Implement changes before deciding to embark into computerization.

Next, is to computerize the entire system. Caution: Do not attempt to computerize your system when not ready. The last but not the least, management must look at maintenance as a new source of profit. A company with a good & effective maintenance program has a competitive edge over the others.

Remember:

In the past:
[COST + PROFIT] = [SELLING PRICE]

Today:
[SELLING PRICE] – [COST] = [PROFIT]

DAA/July 2, 2007

MAINTAINING MAINTENANCE

MAINTAINING MAINTENANCE

By Doods A. Amora, PEE

In the past, responsibilities of engineering maintenance had to concentrate only in making machineries & equipment run in service to production or operation departments. Today, maintenance is already included in the ownership of the quality and quantity of the products produced, because after all, it is maintenance’s job to make the process capability of the plant fit to produce such products. The many new concepts in modern maintenance management will then become as the bases in establishing the yardsticks in measuring performances in maintenance.

Quality maintenance is synonymous to quality product. This means that system equipment must be in tip-top condition, efficient, reliable and above all, available to service at any time they are needed. Quality maintenance in some plants is labelled as “Zero Production Downtime”, or in more strict fashion, others named it as “Zero Breakdown”. A “Zero Breakdown” policy can only be attained through a full time, whole-hearted and effective maintenance management, to include the commitment of top management. The key word here is “effective”. How effective the maintenance efforts are, is a question that every management should answer.

There are several ways in making a maintenance program in a plant. We say that a maintenance program is unique to every plant to fit different patterns of complexities in operation and to the different attributes of top level management policy towards maintenance. Some plants used to refer it as “Preventive Maintenance”, while others call it “Reliability Centered Maintenance” or others label it as “Total Productive Maintenance”. Whatever the program is, the objective is common - that is, to bring the plant to shape.

THE MAINTENANCE PERFORMANCE AUDIT

It is important to mention that most manufacturing plants in the country today do not have any visible indicators of the effectiveness of their own maintenance programs.

In many instances, maintenance crew used to content themselves in having successfully weathered major breakdowns which may have earlier required a round-the-clock work. With all the adrenaline flowing, we may call it as “Magdamag Type Maintenance”.

But there can never be quality maintenance in this case, because after the euphoria of its “heroism”, comes the tendency to relax and be complacent from the true attributes of maintenance. What happens next is what we call “Pa-Easy Easy Na Lang Maintenance” or “Waiting-for-Trouble” maintenance. In short, our maintenance attitudes seem to follow a biorhythm cycle - ‘sometimes up, sometimes down’. What if the maintenance referred to in this discussion, is that of an airliner? Something therefore has to be done by way of controlling the direction of maintenance towards consistent and sustained effectiveness. This is what this author called, “Maintaining Maintenance”. Have we ever thought of how to maintain maintenance?

Establishment of a maintenance performance standard is very much wanting if we are determined to monitor and eventually improve its performance. One way to do this is to look into the past by conducting a SYSTEM AUDIT on historical performance levels, where the objectives towards improving them are anchored.

As examples of maintenance audits, two common scenarios can be used as pilot areas, to wit:

 A Utilities/Support Plant which services the requirements of the production process, (a parallel configuration plant).

 A Production Plant producing the main product line, (a serial configuration plant).

THE UTILITY/SUPPORT PLANT

It is typical for support plants like steam, water treatment, refrigeration or power generating plants supplying utilities for production processes to have over its maximum duties, substantial sizes and number of reserve equipment necessary for the continuity & reliability of its operation.

Note that because of the installed spare units in a ‘support plant’, system outages leading to production downtime are always averted, as failure of one equipment could not necessarily affect the operation of a production line at the other side of the wall.

Most support plants are in parallel configuration, or in a few instances, a combination of parallel and serial set-up, while production lines are usually arranged in serial configuration. In the absence of any maintenance audit however, individual equipment maintenance status could not be made readily visible to top management and even by the maintenance group themselves, thus explains the complacency towards the ever-readiness of system machineries.

In a System Audit, the most important parameter that higher management should monitor is the “EQUIPMENT READINESS or AVAILABILITY FACTOR” or to a greater view, the “SYSTEM READINESS or SYSTEM AVAILABILITY FACTOR”. Measuring effectiveness of maintenance is to see how consistently ready the system equipment are, or how capable the support systems are in meeting the variable demands of operation or production. In other words, given a system with ample spare units, it would be unthinkable that if in the event of failure of one operating machine, the supposed back-ups could not be available for service for reasons that these equipments are undergoing maintenance or in a more horrible scenario, still waiting for spare parts to come.

THE PRODUCTION PLANT

One must appreciate that the scenario in a production or manufacturing line is quite different from that of a support plant described above. Most production lines are arranged in serial configuration such that a failure of one process equipment brings the entire plant to a halt as in the case of a Bottling Plant. The interruption means production downtime in terms of minutes or hours or in some cases, days. In these events, equipment breakdowns or maintenance failures are highly visible to top management owing to the loss of opportunity notwithstanding the shooting up of operating costs per unit product. A maintenance performance audit and monitoring is likewise necessary for standard setting, performance improvements and control. However, the standard parameters differ from that of a support plant.

SETTING-UP STANDARDS IN MAINTENANCE

With the discoveries following a system audit, it becomes necessary to set up standards of maintenance effectiveness on the basis of system availability or readiness. System Readiness in a way speaks of the capability of the system in a given time frame. It is also from this context that effective planning of maintenance activities and operations planning, as well must be based. Hence, in planning sessions where Maintenance, Operations & Production groups are in attendance, minimum set standards can be formulated based on critical scenarios.

HISTORICAL PERFORMANCE FITTED IN ESTABLISHED STANDARDS

Looking back to the historical performance gathered from the audit and making use of the established standards, charts will give insights on what happened to system availability or readiness within the subject years of the audit. From the charts, it would likely become evident that there are still much need for maintenance to improve particularly in systems which did not meet the minimum standards.

If and when the system readiness standards are attained through the concerted efforts of operations and maintenance groups, a smooth & uninterrupted plant operation can be assured. In effect, there is no substitute to planning in maintenance. But then, to properly plan the program, it is necessary for the operation group to be actively involved ensuring that a fair share of maintenance time and attention be given to each equipment. A Maintenance-Operation Master Plan becomes inevitable.

THE OPERATION–MAINTENANCE MASTER PLAN

With the standard properly established, what comes next is the conceptualization of a plant strategy in a yearly scope with the end view of injecting “just the right maintenance dose” to each major equipment of the plant. This means that the plan must not exceed the maintenance time allocated for each equipment.

Working as a team, Operations & Maintenance Groups shall formulate the master plan. This is to capture the relevance, practicability & attainability of the plan. Moreover, this strategy will make up the complete faith & commitment to the program and the belief of their capabilities to accomplish what they themselves had planned. Again a Master Plan in forms of Charts may be created and are expected to reap the following benefits:

1) Planning out for a realistic maintenance budget for the year,

2) Procurement of indented spare parts can realistically be programmed viz-a-viz the maintenance service schedule,

3) Equitable share of operation of the system equipment will be realized,

4) Implementation of the master plan as one of the specific objectives (SO’s) of the concerned parties can be made as basis in performance appraisals, thereby eliminating subjectivity,

5) Availability of system equipment is ensured at any point in time.

CONCLUSION

Measuring the effectiveness of maintenance had been proven to have tremendous benefits to management. As a management tool, it provides ease in planning, directing, controlling and implementing maintenance strategies towards a well-defined objective. Results of Maintenance Performance Measurement System should be made available to the people in terms of Daily, Weekly, Monthly and Year-to-Date Charts posted on bulletin boards indicating their performance. The system will boost the morale of the individual as well as the teams challenged for improved performance. The will to achieve and to be counted as one, will become a bandwagon.

It might after all not impossible to achieve that elusive “Zero Breakdown” mark.

DAA/June 2007

THE NEW WAVE OF PROFESSIONAL ELECTRICAL ENGINEERS

Backgrounder: Recent developments brought me to edit and republish my article on similar topic which was posted in this blogsite some time last year.

THE NEW WAVE OF PROFESSIONAL ELECTRICAL ENGINEERS

By DOODS AMORA, PEE 1821

We have just been through with the April 2007 PEE Board exams… As we recall, we started this advocacy in Y2003 when I urged every promising REE to take the PEE licensure. Then we started with several hopefuls, but in the end -- only a few survived. ..

Although the candidates logged in their belts some 10, 15 years or more in actual experience of the profession, it took a series of training regimens in two years time to build-up enough confidence for the first five REE’s to venture out of the comfort of their shells and set sail through an open ocean - eventually ending up submitting themselves to the grueling PEE exams.

As of today, we have covered three (3) batches of eventful successes. To recall, in the September 2005 exams, five out five, then followed by two out of two in September 2006 and lately, three out of three REE’s in April 2007, a total of ten - all took the exams and successfully passed the PEE Licensure! The ten (10) New Wave PEE’s as we call them - 100%, no more, no less…!

THE SCENES BEHIND

The glorious trumpets were deafening - each note reverberating sweet tunes. But behind those exploits were unspoken but open secret tales of dedication, perseverance, even embarrassments…

Looking back at the very first rung of the ladder, we found ourselves groping in the dark how it is to become a PEE the RA7920 way. Then we realized that the molding of an REE to fit as PEE has to be in a ‘total change in personality’ approach; meaning - bearing competencies transcending not only in technical designing, but also from planning to project execution, from basic communications skills to effective lecturing, from system operation to plant management and more importantly, from a coy personality to a confident responsible engineer that a PEE should be.

The First Wave: The first batch of engineers went through frequent storms and icebergs that clogged the way, then we saw ourselves struggling at every challenge everyday, one episode at a time. That’s the only way. The sailing was rough - it wasn’t easy because in the actual face-off, you would not know what punch will hit you. And you have to cover vast areas of possibilities. Yet five out of fifteen original candidates for PEE’s persevered & survived the tough training episodes and thereafter saw land to seek shelter.

As we reminisce, battle-scarred yet we emerged victorious in our own small ways. Engineers Achilles Ponce of Mactan-Cebu International Airport, Ernie Abunda Jr of San Miguel Corporation–Glass Plant, Fred Mercado of UMMSI, Generoso Bayno Jr of APOCEMCO and Cesar Fernandez Jr of Taiheyo Cement Corporation eventually joined the companeros of PEE’s in this part of the country. We tried and succeeded. The proverbial ice was finally broken - that was September 2005… but history did not end there.

The Second Wave: The journey continued… while regaining strength for the next saga of the journey, the staccato of the engines of change kept throbbing on more relentlessly with power & energy. The fire was burning hot as the promising light beckoning from afar. At least, we already had the experience! We should be bolder, this time.

The tigers’ paws on guard in anticipation while the eagle’s watchful eyes probing into the still unclear wilderness. This time, seventeen hopefuls reported for duty, many of them veterans from the previous training. But then as the days went by, the flame of determination dwindled and flippancy caught several of them too fragile to continue. We wondered if this is a natural course of consequence, or ningas cogon..? Probably, yes… But six contenders somehow endured their wits but only two were readily-geared up to face the second battle in September 2006.

The time came. When the dust cleared, another canto had been captured. As the spoils of the second combat settled, two from this forum successfully made it! And two had been added to the list of new PEE’s in this loop, namely: colleagues Engr. Camilo Castro of Mactan-Cebu International Airport and Engr. Giardelo Guilas of General Milling Corporation. The feeling was superbly satisfying.

The Third Wave: Now refueled, our group was then again ready to embark into another uncharted chapter of the next battle. The four survivors of the training…? Only three were determined to face the April of 2007 arena, while one opted to hibernate in his tunnel, at least for the moment.

Tired but not spent. Weakened but not short of second wind. Still potent and sharp, this time wiser, more experienced… more determined.

Casualties so far? Zero…
Injuries? There were some setbacks, but everybody is standing upright…
Morale? Everybody is proud and smiling…

Engineers Jason Joule Troyo of Konsult Construction Corp., Willie Canizares of Cebu Power Exponents & Services Inc. and Franco Obierez of GTB Industrial Network Inc. finally braved the April 2007 heat into fruition and found themselves in the most demanding, most exciting and most exhausting PEE exams so far experienced. Yet their Technical Reports are highly praised and may even end up as model dissertations in the archives of National IIEE library. Needless to say, the only PEE passers in that examination – you guess it right, they are the only ones…!


HOW DO WE ACHIEVE SUCCESS?

The Fear Factor: The ‘Fear Factor’ as Engr. Noel Fernandez had always pointed out, is the biggest adversary. It is in fact the ‘handicap’ exemplified by the butterflies in one’s stomach that drive one player lose his wits during rounds of grueling combat inside a four walled ring, one against three authorities. As Willie Canizares said, “I felt I was well prepared for the oral exams, but it seemed everything in my mind vaporized when I entered the interview room. It was just good chance that I was able to recover sooner”. Therefore, the candidate must develop the necessary confidence to conquer the fear of the unknown. How? Practice, practice and practice…

Mentoring: After every success, the examinees are always quick in expressing their gratitude to their CESEEPS mentors who are at the same time their tormentors in training. Yes, success in a competitive game is usually won by team play and coaches do play big roles. However, success in one’s personal battle as in the board examinations is not won by coaches. It has to be won by the individual himself because he is not competing against others. He is in fact fighting against his own shadow.

Freddie Roach has made a lot of history. But his role is only limited, he can’t do anything once the player is already inside the ring. Once unleashed, it is the player’s diskarte that matters in solving the puzzles while alone. Let me tell you that our motivation as mentors is only to make our colleagues a much better technocrat in the dispensation of his responsibilities as an engineer. The decision to take the PEE Board Exams is by the individual himself.

Preparedness: The big difference however is preparedness and anticipation. As Achilles Ponce’s Technical Report states, “Looking through the future, there must be that so-called anticipation – and anticipation leads to preparedness as an answer to complete the loop. Surprisingly most of the time, preparedness derived from anticipation can only be discovered if we look back to past and historical performances. And past statistics usually become the answer and guide in future plans of actions”.

It is best to prepare and anticipate. But preparedness does not mean that we allow ourselves to lose track of the basics. It is the bedrock foundation of our competence. Once the basics are forgotten, the foundation will be weakened and the structure might crumble. Do not belittle these Code Basics because you will experience later that these basics after all will make someone a PEE. I am therefore inviting you all to focus on these basics.


WHY ‘NEW WAVE OF PEE’s’?

In our own definition, the new wave PEE’s are those who got their PEE status under the domain of RA7920. That makes RA184 PEE’s like me to belong to the old wave. During our time, we took written exams on the subjects: a) Mathematics, b) General Engineering, c) Electrical Engineering, d) Design & Construction and had to submit a Technical Report. The new wave PEE’s under RA 7920 have only to submit a Technical Report, take the Interview and defend his written report. By quick glance, it seems that the PEE licensure under RA7920 is much easier than its predecessor law. However, there is more to it than meets the eyes. Why is it that with the seemingly easier conditions now, there are only few PEE passers today as compared to the past? In reality, passing the PEE today is a huge job – it is to me, 10 times harder than before.


HOW TO BECOME A PEE?

As what I’ve been saying, there are only three ingredients in passing the PEE board exams and that is: work, work & work. As Franco Obierez puts it, “there is no such thing as something for nothing”. This means that nothing can be harvested if nothing had been planted. We need to work for it. And we mean hard work!

Of course, what constitutes hard work are the following:

Know your Engineering. The REE must re-engineer himself worthy in the PEE face-off. An engineer who thinks that ‘oido engineering’ can bring him success, he better think more seriously because he can never pass the PEE that way. Fact is that, the BSEE course plus experience is not enough. You might be an experienced engineer in a Power Plant or a Manufacturing Pant for 20 years but repetitive chores might have brought it down to an actual equivalency of only three years. You need to explore and be conversant of the other spectrums of the profession. Remember, the PEE license gives you the authority to practice the full scope of the profession. Thus the PEE interview anchors on all established principles of electrical engineering and not on “invented” practices without theoretical basis. The PEE candidate can not therefore escape engineering theories, because all good responsible practices came from proven engineering principles.

Know your English. An engineer no matter how good he is in work but who is not good in his English is not a ‘good’ PEE candidate. Writing the Technical Report needs mastery of Technical English. The most difficult part of the PEE journey as admitted by most candidates is the actual writing of the report. It is therefore advised that if you are grooming yourself for the PEE board exams in the near future, you must have right now in your possession books on “Technical Report Writing”. Practicing the recommendations of these books now will help you express yourself technically comes the Technical Report preparation and the actual PEE interview.

Know your Drawings. A working knowledge in A-CAD or Visio software is a heavy advantage. However, what matters most is the mastery on how to construct complete & correct single line system diagrams in internationally accepted symbologies. Internationally accepted symbology doesn’t mean amalgamating ANSI and IEC symbols in one diagram. Most Single Line Diagrams that we saw used to be in this predicament and it only shows that the author doesn’t know his standards. If you intend to use ANSI, it should be ANSI all throughout. If IEC-based, it should be IEC all throughout. On top of these, several System Single Line Diagrams are incomplete thus; a system presented with lacking components can not in reality stand alone and won’t work! A lot of PEE candidates that I know need improvements in this department.

Know How to Answer Questions. Questions by the examiners need to be answered surely and confidently. Answers with pre-qualifying words, “I think…” won’t work, because a follow-up question like, “are you sure?” will send your structure crumbling. Do not lie or guess. If you don’t know the answer, honestly tell the examiners, you don’t have the actual experience. Moreover, do not think that the interview is only a question and answer affair. You may be required to write your calculations on the board. That’s why practice lecturing and repetitively drawing your system on the board will give you the taste of this competence.


NOW BACK TO BASICS

The danger of success is success itself – it’s intoxicating. We therefore need to always look back where we were before. “Ang taong hindi lumingon sa pinang-galingan ay hindi makakarating sa patutunguhan”. Looking back, we need to re-nurture the conviction of the principles we had been applying in the past several years. “If we rest, we rust. We shall never sit on our laurels. Our best is not enough. Our cup must never be full”. Do not mind the pressures imposed on you by the mentors. As I said, pressures in work are realities to live with, because we need it! Open a faucet and water flows from it. Why? Because there is pressure! Be a part of the team. Never be in the sideline, because if you are, you will be left behind.

Work is Force Times Distance: The tons of force exerted are nothing if you covered no distance. Passing the PEE Board is a vast mile covered. That is big work done!

To the new PEE’s, there's one fact in life that I would like you to keep in mind always. Just as life is temporal, life's setbacks are more recurring. The duration of these setbacks are a lot shorter than life itself. So don't allow these setbacks to spoil what otherwise is a life worth living. Your perseverance in turning around some of the extemporaneous setbacks in your interview performance was something not entirely surprising to me. It would have been surprising if it were someone else who did it. But knowing you and what you are capable of doing, you just have to do it because that's the stuff you are made of. Let me tell you this as part of your development and growth: I've known you people to be the kind of characters who eat personal challenges for breakfast, lunch and dinner. The problem as I see it is this: When those challenges disappear, you begin to starve. The biggest challenge therefore for you is how to keep looking at every situation as one that needs challenge. In other words, the challenge to challenge, and don't let mere words get the better of you.

You will therefore do your share in training others. It will be something of a work in a lifetime.

Doods A. Amora, PEE
May 8, 2007

A PROLOGUE TO FAULT CALCULATIONS (Part IV)

A PROLOGUE TO FAULT CALCULATIONS
(Last Part of a Series)

SELECTION OF EQUIPMENT

To recap, short circuits must therefore be quickly removed from the power system and this is the reason why protective devices such as circuit breakers and fuses are being placed there. To accomplish this, the protective devices must have the ability to interrupt the maximum short circuit current without injury; otherwise the injured breaker becomes the fault itself. The maximum value of short circuit current is frequently referred to as the “available short circuit current” or in some other terminology, the “available SC MVA”. The protective devices at any point of the system must be sized such that in any event of fault wherever they might be in the system, the associated upstream device closest to the fault must first interrupt the fault without disturbing others. The value of short circuit current is directly related to the size and capacity of the reference power source and is independent of the load current of the circuit being protected. The larger the capacity of the reference power source (e.g. larger transformer sizes), the greater the short circuit will be, while cable impedances along its path tend to lower them down.

Once the short-circuit levels are determined, the engineer can specify proper interrupting rating requirements, selectively coordinate the system and provide component protection. With personnel safety while minimizing equipment damage in mind, it is essential to use equipment with short circuit ratings greater than the available short circuit current that can occur at the equipment location. The 2005 National Electrical Code states that: “Art. 110.9 Interrupting Rating. Equipment intended to interrupt current at fault levels shall have an interrupting rating sufficient for the nominal circuit voltage and the current that is available at the line terminals of the equipment. Equipment intended to interrupt current at other than fault levels shall have an interrupting rating at nominal circuit voltage sufficient for the current that must be interrupted”.

When these requirements are applied to a circuit breaker, busway or to switchgear bracing, the maximum 3-phase fault current the breaker will be required to interrupt must be calculated. This current is applied as the short-circuit current available at the terminals of the protective device.

Distribution equipment, such as circuit breakers, fuses, busways, switchgears and MCCs have interrupting or withstand ratings defined by the maximum rms values of symmetrical current. In MV systems, as GE Publication GET-3550F say: “a circuit breaker can't interrupt a circuit at the instant of inception of a short circuit. Instead, due to the relay time delay and breaker contact parting time, it will interrupt the current after a period of five to eight cycles, by which time the DC component would have decayed to nearly zero and the fault will be virtually symmetrical.”

“Closing a breaker against an existing fault makes it possible to intercept the peak asymmetrical short-circuit current, which is greater than the rms value of the symmetrical current. Fault analysis must thus calculate and compare symmetrical and asymmetrical current values in order to select a protective device to adequately protect a piece of electrical distribution equipment. For this reason, equipment is also tested at a particular test X/R ratio value typical to a particular electrical apparatus, such as switchgear, switchboards, or circuit breakers, and is designed and rated to withstand and/or close and latch the peak asymmetrical current described above.” It is also for this reason that modern circuit breakers have built-in rms momentary rating equal to 1.6 times the symmetrical current rating for medium voltage circuit breakers and typically 1.25 times for low voltage circuit breakers.

Calculations seeking for maximum fault duties for purposes of establishing KAIC or MVA ratings of circuit breakers or switchgears must not be misinterpreted as applied to breaker trippings. As explained earlier, the KAIC or MVA rating of a protective device is intended to be over & above the actual fault currents flowing into it such that the same shall not disintegrate or injure itself in the course of interrupting such faults. That’s why in breaker KAIC sizing, it is important to know the maximum possible fault current at any condition because the interrupting ratings of the devices placed in the system must be capable of enduring the tremendous energy associated with faults.

‘Breaker Tripping’ in MV systems on the other hand is applied to ‘Protective Relaying’. Tripping points are settable and can be programmed, in fact, contrary to KAIC capabilities; minimum fault current values are sought in protective relaying. Arming up relays are programmed not at maximum fault currents ‘per se’, but on lesser fault values suited for its operation depending on the Time Current Performance Curve selected and the way the engineer wants them to perform. These settings also include varying degrees of overloads.

Therefore, a high interrupting capacity rated circuit breaker does not mean that it can not trip during low magnitude faults. Nor that it would only trip during high fault current condition. The relay trips the breaker according to how the relay is set. This is true to all power circuit breakers whether medium or low voltage.

For low voltage Molded Case Circuit Breaker applications, the principle of KAIC sizing remains in effect. The only difference is the absence of protective relays in MCCB’s. In MCCB’s, its built-in thermal element takes care of overload conditions as can be selected through its Continuous Current Rating while its magnetic trip element for faults.

DIMENSIONING THE CIRCUIT BREAKER

We have to establish and completely specify the KAIC or MVA ratings of circuit breakers. What then is KAIC all about?

To start with, each circuit breaker has three most important ratings – a continuous current rating, a voltage rating and an interrupting capacity (IC) rating. The IC rating is the maximum amount of current that the device will open safely to relieve a fault condition - without injuring itself. The ‘injury’ means the condition where after interrupting a fault, the breaker ceased to be operable - or worse, the breaker disintegrated because the fault current is too much for the breaker to handle. It must be remembered that breakers are placed in the system to protect the system itself. What if during a fault, it is the protective device that disintegrated? Isn’t it the design engineer’s lapses? Well and good, “the installation is operating for five years and no untoward incident like this happened, if it is my fault, why only now?”, says the engineer. Fine.., because in five years time there was no fault! It’s worthwhile to mention that breakers are not placed in the system for normal conditions; breakers are expected to perform its intended work during abnormal conditions. Abnormal conditions don’t just happen during the first energization event. They happen when the installations are going older where faults are lurking and loads are becoming more demanding.

New generation circuit breakers do not include anymore the “momentary rating” in its nameplates. The “momentary rating” (in answer to the asymmetrical current during the inception of the fault) as expressed in the old generation breakers refers to the greatest current that the device must withstand during the first half-cycle of the fault - where the transient contributions of the synchronous & induction motors in the system along with the DC component (which make the fault current asymmetrical) do occur.

It should not be understood that the momentary rating is already scrapped out. What was done was that the momentary rating is already built-in the KAIC symmetrical rating of the modern day protective device. In the interest of simplicity in the calculation and specification, the recent general procedure in breaker sizing is only to compute for the symmetrical fault current values and specify the KAIC ratings based on those values. New generation breakers do express in their nameplates the symmetrical KAIC or MVA but in reality, the momentary rating is already built-in (normally with the factor of 1.6 times the nameplate KAIC for high & medium voltage and 1.25 for low voltage circuit breakers).
.
Therefore, it is not enough to specify the Continuous Current Rating and Voltage Rating of the breaker but most importantly, the engineer must specify the KAIC ratings of these protective devices. This does not only cover the large breakers but must transcend to all breakers including the smallest branch circuits at the end points of the system.

THE VALUE OF FAULT CALCULATIONS

The output of a fault calculation exercise will bear in the engineer’s frame of mind, the following realities. During fault conditions, i.e., three-phase faults, phase-to-phase faults, single line-to-ground faults whether bolted or arcing faults, the system behaves tremendously different from normal conditions:

1) During fault conditions, the system current behavior is to skyrocket to magnitudes in the KA levels at fraction of a second time condition where sub-transient reactances (not steady state) in the system prevail,

2) That during these conditions the protective devices must work as intended to,

3) That the protective device must not disintegrate or injure itself during these abnormal conditions and it is the responsibility of the engineer in providing such technical expertise in the design of the system in the first place,

4) That too much over-sizing or under-sizing of breaker KAIC ratings because of oversight is not supposed to be acceptable. Too much over-sizing results to tremendously large costs than what is needed while KAIC undersizing might result to disintegration of the breaker,

5) That lengths & sizes cables, sizes & impedances of transformers, fault duties of utility companies influence determination of the KAIC specifications of the breakers,

6) That the design engineer must perform a “Power System Study/Analysis” on the industrial plant he is supposed to be designing, especially in breaker KAIC sizing, protective relay settings and coordination/ discrimination,


MEDIUM VOLTAGE POWER CIRCUIT BREAKERS

Power Circuit Breakers for medium voltage application in the Philippines industries are in the 2.4, 4.16, 6.9, 13.8, 34.5 & 69 KV levels. These circuit breakers are in the forms of: Air, Oil, SF6 Gas or Vacuum types. Air & Oil Circuit Breakers are now obsolete while Vacuum Circuit Breakers are in the trend today – soon to replace the SF6 types which are lately found as non-environmentally friendly.

Vacuum Circuit Breakers at the time of this writing have reached the confidence level at the 25 KV Class while a few manufacturers claimed to have produced vacuum breakers at 36 KV levels. Leading electrical manufacturing countries in the world have been developing vacuum circuit breakers for applications at higher voltage classes with the intention that new generation vacuum breakers will replace the existing SF6 breakers in the immediate future. In the meantime, breakers at 36 KV, 69 KV and above have yet to contend with SF6 types.

LOW VOLTAGE CIRCUIT BREAKERS

The larger low voltage circuit breakers with trip units are known in the USA as "LV Power Circuit Breaker” while in Europe this type is called “Air Circuit Breaker”. LV Power Circuit Breakers are usually used in Power Transformers with low voltage secondaries. Consequently, Molded Case Circuit Breakers downstream the distribution feeders are recommended. Note the KAIC ratings of these circuit breakers on the manufacturers’ standard tables.

The Industrial Plant Systems Designer (IPSD) must know the fault duties of circuit breakers at any point of the system including the low voltage side. These fault duties will be pegged as the minimum KAIC ratings of the circuit breakers which will then be matched with standard ratings of circuit breakers available in the market. The engineer then has to specify the KAIC ratings in terms of standard sizes. The process may look easy in words but because of so many frame sizes & types with corresponding KAIC ratings in a continuous current rating of the breaker, the exercise is confusing than it may suggest. Before performing any fault calculation exercise, it is imperative to look at the ratings of modern-day molded circuit breakers. Note however that other manufacturers especially European–based have different KAIC ratings. It is therefore recommended to consult product journals/catalogs so that specifications will be done accordingly.

(End of Article)