SIZING TRANSFORMERS WITH LARGE MOTOR LOADS (PART II)

LESSONS WE NEED TO LEARN

SIZING TRANSFORMERS

WITH LARGE MOTOR LOADS

(PART II)

By Doods A. Amora, PEE
(December, 2006)

(Last of Two Parts)

6.0: VOLTAGE SAGS IN LARGE MOTOR STARTING

The voltage dip at the transformer terminals is proportional to the motor load required in start-up. As discussed earlier, the voltage drop can be expressed as a percentage of the inrush motor load compared to the maximum capability of the transformer.

% Voltage Drop = (Motor Starting kVA) x 100 /(Motor Starting kVA + Short Circuit kVA)

EXAMPLE:

Now, supposing a lone 2,000 hp, 4.16 kV, Code Letter J motor (Starting kVA = 7.6 times its rated hp) is connected to the 7,500 kVA transformer described above, would it not be that the transformer is too large for the motor load? Probably yes, probably not! Let us see why.

A) IF THE MOTOR CONTROLLER IS ACROSS-THE-LINE (FULL-VOLTAGE CONTROLLER):

Starting kVA of 2,000 hp Motor (SkVA = 7.6):
Starting kVA of 2,000 hp motor = 2,000 kVA x 7.6 or 15,200 kVA

Three-Phase Short Circuit Capacity of the Transformer:
3Φ SC kVA of 7,500 kVA Trafo = 7,500 kVA/0.08 or 93,750 kVA

Note: In this case, the 7.5 MVA transformer has a maximum of 93.75 MVA
short circuit capability.

The voltage drop on motor inrush will be:

VD at Trafo Terminals = 15,200/(15,200 + 93,750) = 0.1395 or, 13.95%
VD at Trafo Terminals = 580 v
Trafo Terminal Volts During Motor Start-Up = 3,580 v

The transformer output voltage will drop from 4,160v to 3,580v (4,160 x 0.8605 = 3,580 v) as against a minimum requirement of 3,600v for a 4,000v motor. Thus, we can see that the transformer even at 7.5 MVA is small for a 2,000 hp motor!

Therefore, the transformer must be sized to a short circuit capability equal to or greater than 15,200 kVA times 10, or, 152,000 SC kVA in order to have a voltage drop of 10% or less.

The next higher standard size transformer at 10,000 kVA 8.0% impedance would have a short circuit output capability of 125,000 kVA which is still not sufficient. Or a 12.5 MVA transformer could be the choice!

In this particular application, the ratio of the selected standard size transformer kVA to motor kVA is 12,500 kVA/2,000 kVA = 6.25. Thus the transformer rating is 625% larger than the rating of the motor! Fantastic!

Note that the voltage sag in reality will even be bigger (actual voltage smaller) because the source can never be infinite in fault duty plus in addition, the voltage drop at the distribution cables from the transformer to the motor end. The total voltage sag is the sum of the sag in the secondary unit substation transformer and the secondary circuit. In the case of very large motors of several hundred to a few thousand horsepower, the impedance of the supply system (or the ‘available fault duty’) should be considered.


B) IF THE MOTOR CONTROLLER IS AN AUTOTRANSFORMER REDUCED VOLTAGE STARTER:

Now therefore, here comes the wisdom in using reduced voltage starting scheme and the choice of Code Letter specification of a motor. Normally in practice, large motors need to be equipped with Auto-Transformer RVS controllers while the motor Code Letter specification can be chosen.

Let us now see the effect with a 2,000 hp Code Letter E motor (Starting kVA = 4.8 times rating) is controlled by an Auto-transformer RVS. Establish further that the Auto-transformer RVS shall be at 65% tap.

From the table below, the line current at 65% tap draws 46% of the full voltage starting current.


Table 2: MOTOR STARTING METHODS FOR SQUIRREL CAGE INDUCTION MOTORS:
(Table re-configured for easy reference) in this blog:

 Full Voltage : 100%: Line Starting Current or kVA

 Reduced Voltage (RVS Autotransformer Type):

80% Tap: 68% of Line Starting Current or kVA of 100% of Full Voltage Starting
65% Tap: 46% of Line Starting Current or kVA of 100% of Full Voltage Starting

 Reduced In-Rush:

Wye-Delta: 33% of Line Starting Current or kVA of 100% of Full Voltage Starting

NOTE: In addition to methods listed above, users should consider solid-state soft-start motor controllers and/or adjustable speed drives.


In this example:
Motor Starting kVA = 46% of 2,000 kVA x 4.8 or 4,416 kVA
Motor Starting kVA can therefore be placed at 4,416 kVA.

The voltage drop at transformer terminals on motor inrush will be:

VD at Trafo Terminals = 4,416/(4,416 + 93,750) = 0.045 or, 4.5%
VD at Trafo Terminals = 187.2 v
Trafo Terminal Volts During Motor Start-Up = 3,972.8 v

The transformer output voltage will drop from 4,160v to 3,972.8 (4,160 x 0.955 = 3,972 v) against a minimum requirement of 3,600v for a 4,000v motor.

Thus, we can see that the 7.5 MVA transformer now becomes sufficient for a 2,000 hp motor with a different code letter and with the use of an RVS. Note also that if the auto-transformer RVS is at 80% tap, the voltage drop as seen by the motor would still satisfy the 10% VD requirements.


7.0: MULTIPLE MOTORS IN A TRANSFORMER

What if there are smaller motors plus other loads among a few large ones in a single transformer source?

EXAMPLE:

Assume that in the 7.5 MVA Substation transformer described above, there are 2,150 kVA smaller 460 v motors in the system through a number of transformers downstream the 4,160 v bus of the substation. Other load, load growth included is 750 kVA. Assume also that there are 800 hp 4.16 kV Code Letter E motors directly connected at the 4.16 kv bus. How many 800 hp motors can be energized into the system complying with the 10% voltage sag requirements? Assume that RVS’s for the 800 hp motors are at 65% tap and the motors shall not be started at one time.

If there are several motors on one transformer:

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 current of the largest motor)

Thus:

TRAFO KVA = 7,500 kVA
Max Demand of Small Group Motors = 2,150 kVA

Other Loads Including Load Growth = 750 kVA

kVA of Large Motors = KVA of LM (Unknown)
Additional Trafo kVA for 800 hp Start-Up = Unknown

Solving for the Starting kVA for 800 hp Code Letter E motor
with RVS at 65% tap:

800 hp Starting kVA = (0.46 x 800 x 4.8)
800 hp Starting kVA = 1766 kVA

Solving for the Additional Trafo kVA Needed for 800 hp Start-Up:

Trafo SC kVA Needed for one 800 hp Start-Up to maintain a 10% VD = 1,766 x10
Trafo SC kVA for one 800 hp Start-Up to maintain a 10% VD = 17,660 kVA

Additional Trafo kVA Needed for one 800 hp Start-Up = SC kVA x %IZ of Trafo
Additional Trafo kVA for one 800 hp Start-Up = 17,660 x 0.08 = 1,413 kVA

Solving for the Number of 800 hp Motors
that can be placed into the system:

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

7,500 kVA = 2,150 kVA + 750 kVA + KVALM + 1,413 kVA

KVA Large Motors = 7,500 – 2,150 – 750 - 1,413
KVA Large Motors = 3,187 kVA

Number of 800 hp motors = 3,187/800
Number of 800 hp motors = 3.984, say 4

The transformer selected will be capable of running and starting all motors
provided that only one large motor is started at any one time. Additional capacity will be required for motors starting simultaneously.


8.0: BACK TO THE BOARD PROBLEM

A 250 hp motor driving a pump is served by 3 x 100 kVA 13.8kV- 480v transformer bank. Other data are as follows:

 Transformer Impedance: 3.7% IZ
 Short Circuit Capacity of Source: 200 MVA
 Motor Starting Current: 8 times of FLC
 Length of Cable from Transformer to Motor Controller: 50 ft

Solve for:

a) Size of Cable & Conduit
b) Branch Circuit Breaker & Controller Size if Auto-Transformer type RVS
c) Determine the voltage dip during motor start-up using full voltage starter
d) Determine the voltage dip during motor start-up using Auto-Transformer Reduced Voltage Starter tapped at 65%.

Solution:

a) Solving for the Cable Size & Conduit
Motor Full Load Current = 302 A (From NEC Table)
Size of Cable = 1.25 x 302 or 377 A
USE: 500 MCM THW in 4”Φ Conduit

b) Solving for the Branch Circuit Breaker & RVS Controller Size
Branch Circuit Breaker = 2.0 x 302 A or 604 A
USE: 600AT/600AF, 3P, 600V MCCB
USE: Auto-Transformer RVS NEMA Size 5

c) Solving for the Voltage Dip Using Full Voltage Starter:

SC kVA at Transformer Terminal

Let: kVA Base = 300 kVA
V Base = 480 v
I Base = 361 A

X @ 13.8 kV = kVA Base / SC KVA@ 13.8 kV Source
X @ 13.8 kV = 300 / 200,000
X @ 13.8 kV = 0.00150 pu

X T = %IZ/100 x kVA Base /Trafo kVA
X T = 3.7/100 x 300/300
X T = 0.037 pu

X EQ = 0.00150 + 0.037
X EQ = 0.0385 pu

I SC = IBASE / X EQ
I SC = 361 A / 0.0385
I SC = 9,377 A

Three-Phase Short Circuit Capacity of the Transformer:
KVA SC = √3 x 0.48 x 9,377
KVA SC = 7,796 kVA

Motor Starting kVA:

Motor Starting kVA = 250 hp x 8
Motor Starting kVA = 2,000 kVA

The voltage drop on motor inrush at the transformer terminals will be:

VD at Trafo Terminals = 2,000/(2,000 + 7,796) = 0.2042 or, 20.42%
VD at Trafo Terminals = 98 v
Trafo Terminal Volts During Motor Start-Up = 382 v

Voltage Drop at the Cables:

Impedance ZC of 500 MCM THW Cable in Metallic Conduit= 0.00575 Ω per 100 ft (From IEEE Table)

Impedance of C1: 50 ft, from transformer to Motor Controller:
ZC = 0.00575 Ω/100 ft x 50 ft
ZC = 0.002875 Ω

Voltage Drop along the Cable C:
VDC = √3 x (IMOTOR LINE START) x ZC1
VDC = √3 x (302 x 8) x 0.002875
VDC = 12.0 v

Total Voltage Drop at Motor Controller:
98.0 + 12.0 = 110 v

Voltage at Motor Controller Line Side Terminals during Start-Up = 370 v
Voltage Requirements during Start Up = 414 v for 460 v motors

The set-up can not satisfy voltage dip requirements. Not even 3 x 250 kVA (750 kVA). In fact a 3 x 333 kVA (1,000 kVA) set-up at 5.2%IZ can barely satisfy the requirement!

There could be two remedies for the situation. One is to change the motor controller from full voltage to auto-transformer RVS type. The other alternative is to change the Transformer from 300 kVA (3 x 100 kVA) to 1,000 kVA (3 x 333 kVA).

d) Solving for the Voltage Dip Using Auto-Transformer RVS:

If RVS Auto-Transformer Tap to 65%:
Motor Starting kVA = 0.46 x 250 hp x 8
Motor Starting kVA = 920 kVA

The voltage drop on motor inrush at the transformer terminals will be:

VD at Trafo Terminals = 920/(920 + 7,796) = 0.1055 or, 10.55%
VD at Trafo Terminals = 50.64 v
Trafo Terminal Volts During Motor Start-Up = 429.36 v

Voltage Drop along the Cable C1:
VDC1 = √3 x (IMOTOR LINE START) x ZC1
VDC1 = √3 x (302 x 8 x 0.46) x 0.002875
VDC1 = 5.534 v

Total Voltage Drop at Motor Controller:
50.64 + 5.534 = 56.174 v

Voltage at Motor Controller Line Side Terminals during Start-Up = 423.826 v
Voltage Requirements during Start Up = 414 v for 460 v motors

Therefore, the 3 x 100 kVA transformer need not be replaced if its Auto-Transformer RVS is tapped at 65%. Note that if the RVS is tapped at 80%, the transformer needed must be 750 kVA (3 x 250 kVA)!

9.0: THE REAL ENGINEERING ECONOMICS

While first costs are very important to clients & plant owners; correct engineering practice should not be sidestepped in selecting best systems. More often than not, too much cheap engineering is in fact, costly. By making the first cost not objectionable, it does not mean that the engineer shall use cheap, undersized and substandard materials or equipment. Applying correct Value Engineering, the design must fundamentally conform to good engineering practice, codes and standards. This fundamental or minimum requisite must not be compromised under the cloak of costs.

It is important for the Industrial Power Systems Designer to understand that First Cost is not enough in determining the economics of the project. Total Life Cycle Cost of the power system depends on equipment purchase price & quality, construction & installation costs, operating costs including losses, outage costs, repair costs, useful lifetime of the equipment and administrative costs.

In the USA & other advance countries, the insurance companies play lead roles in the safety and soundness in any installations. That’s why they are strongly behind the National Electrical Code and the National Fire Protection Code. In the Philippines, if it’s “faulty electrical wirings”, the insurance companies pay without much fuss, and nobody seems to ask how standards were complied.

But alas, more often than not, what design engineers consider as “best solutions” may not correspond to what owners perceive. In the name of cost, the ‘economical solutions’ that clients want usually end up into sickly systems that are vulnerable to failure or worse, violations to the Code and Correct Engineering Practice for which we engineers are supposed to profess. Note that there is a common misguided thought in electrical engineering design economics. For instance, why use an expensive RVS when Across-the-Line Starter will do? Or why a 1,000 kVA transformer for a 250 hp motor? In this case, we say that firstly, the engineer must know his codes & standards. The standards must first be satisfied before any value engineering can be focused. Sensitive to safety & system operability in the ultimate analysis, it is the engineer's responsibility to find solutions that satisfy both parties.

Doods A. Amora
December, 2006

SIZING TRANSFORMERS WITH LARGE MOTOR LOADS (Part 1)

LESSONS WE NEED TO LEARN

SIZING TRANSFORMERS

WITH LARGE MOTOR LOADS

By Doods A. Amora, PEE
December 1, 2006)

(First of Two Parts)

1.0: INTRODUCTION

The purpose of this article is to help expand the engineer’s basic understanding on ‘short circuit capacity’ – how it affects voltage sags during starts-up of motors of significant sizes.

But why are Short Circuit & Motor Starting Calculations involved in transformer sizing?

One clue is:

"Starting up one thousand-1.0 hp motors is world apart from starting up one-1,000 hp motor"

SIDEBAR 1:

When I took my PEE board exams 22 years ago, there was one problem under the subject “ELECTRICAL DESIGN & CONSTRUCTION” which ran similar as follows:

A 250 hp motor driving a pump is served by 3 x 100 kVA 13.8kV- 480v transformer bank. Other data are as follows:

 Transformer Impedance: 3.7% IZ
 Short Circuit Capacity of Source Utility: 200 MVA
 Motor Starting Current: 8 times of FLC
 Length of Cable from Transformer to Motor Controller: 50 ft

Solve for:

a) Size of Cable & Conduit
b) Branch Circuit Breaker & Controller Size if Auto-Transformer type RVS
c) The voltage dip during motor start-up using full voltage starter
d) The voltage dip during motor start-up using Auto-Transformer Reduced Voltage Starter tapped at 65%.

To be honest, I wasn’t ready to solve the (c) and (d) parts of the problem. To my defense mechanism, I told myself, “the problem was irrelevant. Nandiyan na ‘yan, naka-install na kunyari; bakit kwentahin pa ang voltage dip?“

To make the story short, lumipas ang mahabang panahon… Then here comes now a real situation. What if one is asked to design a set-up for a 500 hp motor driving a pump somewhere? Would a 750 kVA transformer be sufficient? Maybe yes, maybe not! Try solving the problem and one will discover things that are assumed easy but are actually not quite simple!

SIDEBAR 2:

In one brewery I happened to work with, we had two – 450 hp 4 kV motors driving ammonia compressors controlled by Auto-Transformer RVS. Later, three – 700 hp motors were added but interestingly this time with across-the-line starters. The system was directly connected to the Power Plant’s 4,160 v bus through feeders. No problem was imagined because the Power Plant as a standard operating procedure, used to operate with significant spinning reserve capacity at any given time – and there were nine (9) generating units to support the loads.

However, when we started-up for the first time one of the three 700 hp compressors, a huge voltage dip occurred and the neighboring Glass Plant tripped off all its operating air compressors thus shutting down the entire plant. Pandemonium followed as the Power Plant struggled to recover the voltage by shedding off other major loads. Power Plant finally recovered but with all major manufacturing plants served by it at shutdown, including the brewery.

The event’s aftermath saw signs posted on all compressor control panels that reads: “NOTIFY POWER PLANT BEFORE STARTING”. Why? Because Power Plant had to add more generators on stream before any starting can be done. This was to provide the on-line generating capacity large enough to support the starting kVA needed, thus averting objectionable voltage dips. Interestingly, after the start-up the additional generators had to be shutdown. In the end, the full voltage starters were replaced with RVS units. In the succeeding breweries being built thereafter, MV Soft Starters were employed.

Again, there’s more to it than meets the eye. Recalling back my own PEE board exams, now I understand that after all, the problem on voltage dip was not irrelevant but a test of engineering competence why I should be given a license as PEE.


2.0: SUBSTATION TRANSFORMERS VS. LOADS

Generators and transformers react to large motor starting as manifested in voltage dips. Let us first discuss transformers.

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.

3.0: SYSTEM BEHAVIOR IN EVENTS OF FAULTS

Short circuit capacity calculation is used in many applications, some of which are the following:

a) selecting the interrupting capacity ratings of circuit breakers and fuses,
b) specifying the short-time withstand of switchgears,
c) determining if a line reactor is required,
d) and a host of many others.

But unknown to many, Short Circuit Calculations together with
Motor Starting Calculations are also used in Sizing Transformers.

Short Circuit condition brings down the voltage very dramatically. The amount of voltage during a full three phase fault at the terminals of the transformer is determined by the %IZ of the transformer, i.e., if the transformer is connected to an infinite source of short circuit currents.

Take for instance a 7,500 kVA, 8.0% IZ, 69-4.16 kV transformer. The 8.0% impedance rating would mean that full load currents of 1,041 amps will flow in the secondary if the secondary is short circuited and the primary voltage is raised from zero volts to a point at which 8.0% of 4,160 volts, or 332.8 volts, appears at the secondary terminals. Therefore, the impedance (Z) of the transformer secondary may now be calculated:

Z = V / I = 332.8 volts/1,041 amps = 0.3197 ohms

The exercise described above is what is known in textbooks as the “Short Circuit Test” which is actually performed in laboratories or electrical shops (drying up transformers). What if the short circuit at the secondary is real – meaning, the short circuit happened at full 4160v at the inception of the fault? If the transformer is connected directly to a source capable of supplying the transformer with an unlimited short circuit kVA capacity, the short circuit amperage capacity which the transformer can deliver from its secondary is:

4,160 volts /0.3197 = 13,012.5 amps

Another method of calculating short circuit capacity for the above transformer is:

SC Capacity = Trafo FLC/%IZ
= 1,041 A / 0.08
= 13,012.5 amps,

or terms of kVA:

SC Capacity = 7,500 kVA/0.08 = 93,750 kVA

Such three-phase fault will bring down the voltage at the secondary terminals from 4,160v to approaching zero, while at the same time delivering 93.75 MVA of short circuit power to the point of fault. This condition however must of course be short-lived because some sort of protection upstream must operate to interrupt the circuit quickly, otherwise the transformer will fail. Transformer damage (known as the transformer short-time withstand) is dependent on the amount of fault current and the impedance of the transformer. Usually this transformer short-time withstand could only last for a few seconds.

4.0: SYSTEM BEHAVIOR DURING LARGE MOTOR START-UP

Why is motor starting related to short circuit condition? Partly similar to short circuit condition, motors have a high initial inrush current when energized and draw heavy load at a low power factor (0.30 lagging for 100 hp & about 0.16 for 1,000 hp motor) for a very short time. This sudden increase in the current flowing to the load causes a momentary increase in the voltage drop at the supply transformer terminals, the voltage drop along the distribution system, and a corresponding reduction in the voltage at the utilization equipment.

The magnitude of transient current involved in motor starting is however very much lower than the short circuit condition. But in effect, switching “on” to energize a large motor can be likened to a “soft short circuit”. Like short circuits, the effect of starting large motors results to voltage dips. The voltage drop at the transformer secondary terminals is proportional to motor starting kVA over the short-circuit capacity of the transformer. When motor starting kVA is drawn from a system, the voltage drop in percent of the initial voltage is approximately equal to the Motor Starting kVA divided by the Sum of this kVA and the Short Circuit kVA.

% Voltage Drop = (Motor Starting kVA) x 100 /(Motor Starting kVA + Short Circuit kVA)

5.0: MOTOR STARTING KVA

Thus, we need to know the starting kVA of the subject motor. In general, IEEE Red Book says, “the starting current or starting kVA of a standard motor draws several times its full-load running ratings. Without any specific information on a subject motor, a motor is always assumed to require about 1 kVA for each motor horsepower in normal operation, so the starting current of the average motor will be about 5 kVA for each motor horsepower. When the motor rating in horsepower approaches 5% of the secondary unit substation transformer capacity in kilovolt-amperes, the motor starting apparent power approaches 25% of the transformer capacity which, with a transformer impedance voltage of 6.07%, will result in a noticeable voltage sag on the order of 1%. This sudden increase in the current drawn from the power system may result in excessive drop in voltage unless it is considered in the design of the system. The motor-starting load in kilovolt-amperes, imposed on the power supply system, and the available motor torque are greatly affected by the method of starting used”.

The specific starting values for ac motors over hp are indicated in terms of Code Letters on the nameplates of North American-made motors. NEMA Code Letters indicate the motor starting characteristics as presented in the following table.

TABLE 1: NEMA CODE LETTER DESIGNATIONS (STARTING KVA’s)

CODE LETTER KVA per HP

A: 3.15
B: 3.16 – 3.55
C: 3.56 – 4.0
D: 4.1 – 4.5
E: 4.6 – 5.0
F: 5.1 – 5.6
G: 5.7 – 6.3
H: 6.4 – 7.1
J: 7.2 – 8.0
K: 8.1 – 9.0
L: 9.1 - 10.0
M: 10.1 - 11.2
N: 11.3 - 12.5
P: 12.6 - 14.0
R: 14.1 - 16.0
S: 16.1 - 18.0
T: 18.1 - 20.0
U: 20.1 - 22.4
V: 22.5 - and up

The above table means that a 200 hp motor with a NEMA Code Letter ‘G’ requires a starting kVA of 1,140 to 1,260 kVA (1,200 kVA on the average) when using Full Voltage (Across-the-Line) motor controller. This starting kVA is also known as “Locked Rotor kVA” or sometimes “Locked Rotor Amperes”.

With the starting kVA of the motor such as described above, we must then determine the voltage dip caused by the motor inrush on start-up. The ensuing voltage during start-up must stay within the allowable operating voltage of the system. If such condition happens, then no oversizing of the transformer is required. But when the voltage dip exceeds the operating requirement of the system, then the transformer must provide extra kVA.

North American motors are rated for 230, 460, 2,300, 4,000, 6,600 or 13,200 volts for use with distribution sub-systems that are rated at 240, 480, 2400, 4,160, 6,900 or 13,800 volts respectively. Note the difference in motor nameplate voltages viz-a-viz the transformer terminal voltages. The apparent lower motor voltages than distribution nominal voltages are deliberately established by manufacturers to deal with the inherent voltage drops in the system such as: internal voltage drop of the transformer as dictated by its voltage regulation capability, voltage drop along the distribution cables and the impedance of the system. This could mean that the 4,160 v at the transformer at no-load condition may only be 3,800 v at the motor terminals when the system is already heavily loaded. In this condition, when a large motor is started-up somewhere in the system, the lower will the voltage be as felt by other loads in the system.

That’s why NEMA standard motors are designed to be capable of operating at plus or minus 10% of nameplate voltage. Therefore, the voltage drop on inrush should not be allowed to drop more than -10% of the rated voltage. This means 208v for 230v or 414v for 460 volt motors. Likewise, 2.07 kV or 3.6 kV for 2.3 or 4.0 kV motors, respectively. It means that a 4 kV motor can still operate satisfactorily at 3,600 v but any disturbance in the system that brings the system voltage lower, the affected motors may trip off as provided for by its protection – or if not, the motor burns.

(To be continued…)

Doods A. Amora
December, 2006

PLANT EFFICIENCY

DOOD’S KEYNOTE ADDRESS:

SCHNEIDER ELECTRIC ROAD SHOW

PRESENTATION 2006

Parklane Hotel, Cebu City
November 9 & 10, 2006

INTRODUCTION

Invoking ‘PLANT EFFICIENCY’ as Schneider Electric’s theme in this Road Show is very much timely in these times of resurging uncertainties in energy costs as variable inputs to production economy. As we speak today, manufacturing plants in the Philippines are unsure of what tomorrow will bring to the state of oil prices even as business itself has again been sailing into another uncharted economic limbo. After all, [COST + PROFIT] = [SELLING PRICE]; that’s business all about.

In physics; Efficiency means, Output/Input. In engineering, Efficiency = Output/(Output + Losses). We had been taught that efficiency is always less than 100%. And that Output is always less than the Input. In order to gain Maximum Efficiency, Output must be at its possible maximum while losses at its possible minimum. Simple, yet how do we interpret that in the Shop Floor? The center-stage therefore in analyzing efficiency is: losses! To the layman on the shop floor, the better word is “waste”.

Interpreting wastages or losses in real-life plant environment could be cumbersome. It takes not only technical & managerial expertise but also business sense in integrating a labyrinthine maze of nitty-gritties into an orchestrated energy management program. It is not switching off lights or air-conditioning systems during lunch breaks that counts but Energy Management extends beyond mediocre imagination.

TODAY’S COMPETITIVENESS

In general terms, Management experts say that the ingredients of today’s competitiveness are: quality, efficiency and 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. That is still valid even up to today…

The phrase ‘energy management’ means different things to different people.

Quality Buffs say, “AIM QUALITY” … and Efficiency as well as Productivity follows…

Productivity Enthusiasts say, “FOCUS ON PRODUCTIVITY” … and Efficiency as well as Quality follows…

Efficiency Practitioners declare, “EFFICIENCY IS EVERYTHING” … Productivity & Quality are built-in.

Whatever it is, it is the same banana. Simply because there must be a “War On Waste”. In our lingo, we say, WOW! And WOW has always been beautiful. Let us therefore dwell in WOW!

THE NEED FOR ENERGY MANAGEMENT

To me, there are three reasons why we need Energy Management.

1) Manufacturing Economics: The company, (meaning, your company and everyone else’s) has to survive. Energy Costs have now been an expensive raw material and closing shops would mean unemployment debacle of large proportions.

2) National Good: Energy management is good for the national economy as the balance of payments becomes more favorable and the peso stronger. Energy management makes us less vulnerable to leaps in energy prices, or curtailments due to political unrest or natural disasters elsewhere.

Although the Philippines has oil, forget about it. We need to realize that until the country strikes a new liquid black gold mine, Philippine indigenous oil is forgettable. The Philippines is consuming an average of 338,000 bbl/day, with net oil imports of 312,000 bbl/day (92.3%). This dependence on imported oil makes the Philippine economy vulnerable to sudden spikes in world oil prices. Although exploration underneath the Malampaya gas field revealed an estimated 85 million barrels of oil, this could probably supply the country for a period of nine (9) years at present production level of 25,000 bbl/day (7.7% of the country’s needs). If Malampaya field supplies the country 100% of its oil requirements of 338,000 bbl/day, Philippine oil deposits would only last for (hold your breath) 8 months.

In comparison, the USA consumes 24.5 million barrels of oil per day in 2004. The Malampaya oil deposit of 85 million barrels will last for only for THREE DAYS in the USA.

3) Energy management is kind to our environment as it eases some of the strain on our natural resources and may leave a better world for future generations.


WHAT IS ENERGY MANAGEMENT?

To the energy managers, energy management is: “the judicious and effective use of energy to maximize profits (minimize costs) and enhance competitive positions”.

According to Mr. Barney L. Capehart, PhD, CEM, in his book “Guide to Energy Management”, the primary objective of energy management is to maximize profits or minimize costs. Some desirable sub-objectives of energy management programs include:

1. Improving energy efficiency and reducing energy use, thereby reducing costs,

2. Developing and maintaining effective monitoring, reporting, and management strategies for wise energy usage,

3. Finding new and better ways to increase returns from energy investments through available controls system & automation,

4. Developing interest in and dedication to the energy management program from all employees. Cultivating good communications on energy matters,

5. Reducing the impacts of curtailments, brownouts, or any interruption in energy supplies.

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What therefore is the relevance of Energy Management to this Roadshow? Let me talk first about “Plant Efficiency”…

PLANT EFFICIENCY

Plant Efficiency is related to production throughput. To a Plant Manager, the cue would always be: ‘Cost Vs. Production’. Low Production Cost is good. Similarly, High Production Output is good. Which is which?

The best is when you have the highest production at the lowest cost, because the two measurements must be integrated into a ratio. The lowest ratio of Cost per unit Product is always seen as the penultimate measure. That is one element of the so-called “throughput”!

Production of course is dependent on the capacity of the plant. But even if production wanted to achieve the same output as the capacity, seldom is it possible because of loss factors such as quality rejects, idling, speed adjustments, line adjustments, technical troubles, waiting times, etc., are influencing production throughputs.

In any industrial plant or commercial complex, energy must be seen as a raw material to production. Nevertheless, Energy Management must not be understood as doing without energy but is in fact, making the most out of it. Often misunderstood, energy management is actually a ‘War on Waste’ (WOW). Its basic strategy is to eliminate unnecessary losses while paying for wastages are mortal sins. Energy Management means that monthly power bills are as normal as eating three square meals per day but paying for unnecessary extras is a waste that every business abhors. Yet in most plants, energy management as a discipline is often “said than done”; because it is always not seriously taken into action.

Energy Management therefore must focus on the following:

a) Managing the Load, because mismanaged load could mean millions of pesos,

b) Managing Power Losses, because unmanaged extra losses mean big bucks.

If your plant doesn’t manage the load or is not concerned on losses, then that plant has never understood energy management. All energy conservation pronouncements by management are just plain rhetoric. Many Plant Managers are usually non-cognizant to the fact on how to tap the seemingly non-existent gold mine in his plant’s backyard!

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The objective of today’s Road Show is to reinforce the managers and engineers in the modern tools to achieve the highest efficiency in plant facilities. Surprisingly, the subjects in today’s Road Show jibe with Mr. Capehart’s goals in energy management. Non-scripted, the following areas are featured as today’s highlights, namely:

a) Power Monitoring,
b) Selective Automation,
c) Energy Efficient Devices & Controls.

But let me add two more things,

d) Effective Maintenance, and
e) Efficiency-Driven Workforce.

All of these are part of WOW. Allow me discuss each …

1) POWER MONITORING

Remember the dictum: “You can’t control if you don’t measure”. We need meters to measure. And there are six good reasons why we should meter a plant. A management, who wants to manage energy but doesn’t want to install measuring means, is an oratorical management who is not serious in energy management. Unless energy usage is measured, it is next to impossible to know where to direct efficiency efforts.

A metering system provides that vital ingredient to a successful energy management program. There are six (6) reasons why we should meter the plant.

• CHARGE OUT ENERGY TO INDIVIDUAL DEPARTMENTS

This is the most basic reason to meter. Experience in this country has shown that a 5–10% reduction in consumption can be achieved after meters are installed just by letting the users know that they are monitored. Up to 10% more reduction can occur when the users start to manage the use of their energy. Ultimately, up to a 25% to 30% reduction will be achieved when metering is tied directly to the process through a Programmable Logic Controller (PLC) or Distributed Control System (DCS), in a closed loop automated process control arrangement.

 ACCOUNTABILITY FOR ENERGY USED

Once metered, establish energy budgets for the various departments. Each month the total energy bill is proportioned to each department. This data is used to compare costs against the department's budget and thus develop a variance-peso value.

Trending of energy consumption per unit of production or per service performed is the basis for initial analysis and resulting corrective actions. Accountable for every kw-h consumed, each department shall be made to explain the variances of the use of energy.

Management and creative personnel are always critical components of an energy management program. Tough, specific, and measurable goals need to be developed. Once the goals are established, management should carefully monitor the results, but the energy management staff should be allowed to perform its functions.

Staff and management need to realize that:

1) energy costs, not consumption, are to be controlled

2) energy should be a direct cost—not an overhead item, and

3) all energy consumers need be metered and monitored closely.

• EFFICIENCY OF UTILITY EQUIPMENT & SYSTEMS

The objective of an energy reporting system is to measure energy consumption and compare it either to company goals or to some standard of energy consumption. Ideally, this should be done for each operation or production cost center in the plant, but most facilities simply do not have the required metering devices. Many plants only meter energy usage at one place—where the various sources enter the plant. Most plants are attempting to remedy this, however, by installing additional metering devices when the opportunity arises. Systems that should be metered include steam, compressed air, and chilled & hot water.

There are established world standards in machine or system performance. For instance, how is your refrigeration system performance compared with world standards? In a Bottling Plant for instance, how much kw-hour does your plant consume per case or per liter of product as compared to established world standards? Is your air-conditioning kw-hours per unit area more than industry standards? It is prudent for plant management to benchmark its performance to the established best practices. This way, management will know if you are performing well or not.

• PROVIDE INFORMATION FOR AUDITS OF ENERGY PROJECTS

With funding becoming increasingly difficult to obtain, audits of cost reduction energy management projects have been required more frequently. But energy audits will be blind without meters.

• IDENTIFY PERFORMANCE PROBLEM AREAS & PROVIDE FEEDBACK TO MANAGERS

The collection of energy-consumption data in support of energy management is seen as a viable tool, greatly aiding in the identification of equipment performance problems. As a side issue, performance problems associated with the people operating the equipment are also identified, allowing managers to take any necessary corrective action.

Cost center orientation is important, as are comparison to some standard or base and calculations of variances.

• IDENTIFY POTENTIAL ADDITIONAL ENERGY SAVINGS

According to IEEE publications, “… with the long-term goal of management being one of continual improvement, metering and trending systems provide data on which to base resource allocation decisions. With regard to audits of the electrical power system, metering results can be used to compile an energy profile that will reveal areas where conservation projects are most beneficial. Monitoring and reporting energy consumption allows for close control while minimizing expenses. It also provides historical energy consumption data to aid in projecting future loads and developing standards for the next year. Such data are essential to financial forecasts and operating budgets. Through proper monitoring, recording, and analysis, the use of meters can lead to corrective actions that produce the desired result of reducing energy per unit of production or per service performed”.

2) SELECTIVE AUTOMATION

Technology advancements could have been kind to the electrical engineering profession. The electrical engineering we knew of 20 or 30 years ago is no longer the same engineering today. With the entry of power & control electronics highlighted with industrial automation, electrical engineering has raised its dignity significantly. With the new wonders in electrical engineering unfolding, in a high-tech brewery scenario for example, the electrical cost component of a project is now elevated from a forgettable 9% of the past to some 15% today. For a P 2.0 billion brewery, it is not surprising to have an electrical budget of some P 300 million.

The acceptance of new technologies in industries today made the increase of the value of electrical engineering. To keep pace with global pursuit to manufacturing quality and efficiency, more plants in the country are upgrading or modernizing their facilities. Small candy factories for instance are now equipped with variable frequency drives. Tableware factories have now graduated from ancient manufacturing techniques to PLC orchestrated automation. The departure from the traditional TW or THW wires in conduits to industrial multi-core cables (not ‘Cord’, please) in cable trays, the shift to soft starters in lieu of the traditional magnetic contactors and the employment of DIN rail mounting molded case circuit breakers from age-old fuses; are just few examples but significant changes in the industrial plant landscape. Common electrical equipment as transformers, generators, power circuit breakers, protection and control devices had undergone series of evolution compared to counterparts in other engineering disciplines.

For the manufacturing plants, there’s no other way to increase production quality & efficiency throughput but to employ instrumentation that makes automation possible. The trend now is to manage production through a centralized control centre where all operational variables can be supervised through computer screens or mimic boards. There is no escape to new technology and electrical engineering is supposed to be the beneficiary.

The name of the game in manufacturing today is therefore 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 old traditional 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.

3) ENERGY EFFICIENT DEVICES & CONTROLS

INSTRUMENTATION & CONTROLS..? Bulk of power consumption in a plant comes from conveyors running without materials conveyed, machines running even if there are no materials being fed, circulating pumps running even if not needed, air-conditioning in full-blast even if no people around, lights on with no one is using the light, and a host of others. Make an audit and you might discover that 25% to 30% of your power bills are consumed unproductively.

In modern plants, instrumentation & electronics control systems employing sensors are now common scenarios to watch over these problems. They came in the form of automated and intelligent buildings or plants. Machines & comfort equipment are shutdown automatically if sensors can not detect any reason why these machines should run. Pumps are slowing down when volume demand dwindles. Conveyors slowing down when full or gain speed when not loaded or shut down at all. Compressors loading and unloading automatically depending on demand and the list is endless.

4) EFFECTIVE MAINTENANCE

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.

Maintenance is a critical part of a facility’s operation. Effectively maintained equipment and processes are necessary to keep the facility functioning at its optimum capability. Unfortunately, maintenance programs are often the first victims of any cost-cutting effort. Generally, proactively preventive or scheduled maintenance is cut back or eliminated. Then the maintenance effort is directed more toward “repair and replacement” than toward keeping the equipment running most efficiently. When this “run-to-failure mode" of maintenance happens, you are in the state of poor maintenance.

Maintenance should now be an integral part of any energy management program. Maintenance keeps equipment from failing, helps keep energy costs within reason, helps prevent excess capital expenditures, responsible to the quality and quantity of the products produced, and is frequently necessary for safety.

Again, automation & robotization bring the equipment or machines to the center-stage. When we say equipment or process machines, it means maintenance because 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 and anywhere else in the globe, among them are as follows:

 In the past, 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”.

 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”.


5) EMPLOYEE PARTICIPATION

Investing capital for “self-intelligence” & automation will pay off handsomely by eliminating big time losses. However, no amount of automation shall relieve the responsibilities of the attendant. There is still that so-called “human interface”. An energy management program can be successful only if it arouses and maintains the participative interest of the employees. Employees who participate and who feel themselves partners in the planning and implementation of the program will be more inclined to share pride in the results.

The use of company newsletters, bulletin boards, or posters for pictorializing energy conservation objectives and accomplishments will help impress employees with the importance of such matters. Employee participation can be increased by communicating examples of energy conservation ideas being implemented, photographs of persons who submitted the ideas and information on the savings realized.

Five critical factors in organizing an effective energy management program are as follows:

a) Top Management Commitment: This is a formally communicated, financially supported dedication to reducing energy consumption while maintaining or improving the functioning of a facility. This commitment shall be active and visibly communicated to all levels of the organization in terms of words and actions by top management.

b) People Commitment: People at all levels of the organization should be involved in the program. Ideas should be encouraged with rewards for significant contributions to the energy management program. People should be shown why their help is needed, and a team approach should evolve. Note that a most successfully planned program can be devastated by a single person trying to subvert the program.

c) Communication Channel: The purpose of this channel is to report to the organization the results of your efforts, to recognize high achievers, and to identify reward recipients. Use the channel to advertise the program and to encourage cooperation.

d) Organizational Changes: This is to give ample authority and commensurate responsibility for the conservation effort and develop an energy management program.

e) Monitor & Control the Program: An organizational plan, using the above criteria, should then be developed for both implementing and monitoring specific energy management programs.

6) CONCLUSION

In the next hours of the day, Schneider Electric will give you details on how to help achieve the objectives of Plant Efficiency.

In the modern times, we electrical engineers must remember that:

In the past,

[COST + PROFIT] = SELLING PRICE

Today,

[SELLING PRICE] – [COST] = PROFIT




DOODS A. AMORA, PEE
November, 2006

POWERING INTERNET HOTELS & MODERN OFFICE BUILDINGS (PART 4)

POWERING INTERNET HOTELS

& MODERN OFFICE BUILDINGS
(Last Part of the Series)

CONCLUSION

IMPLICATIONS TO THE ELECTRIC POWER INDUSTRY

The implications of this story to the electric power industry are obvious:

1) The Need for new generation capacity;
2) The Need for new transmission capacity;
3) The Need for upgrades to distribution systems;
4) The Increased role for distributed generation; and
5) The Possible revisions to existing tariffs to recover upgrades & redundancy costs.

All the above are financially, socially and politically very difficult to achieve. The distribution upgrades and new generation capacity requirements to include redundancy created by the New Economy, raises the question of whether existing tariffs and policies are sufficient to recover the huge investments or funding required.

But why worry? The rapid growth of the Internet data center sector has not affected the Philippines. It’s California’s or USA’s problem.

But then, there has already been IT Parks sprouting all over in the country (Cebu City included) - hyping to the world that these are the future IT hubs in Asia. And the Philippines being renown of its IT professionals would not become exceptions to the quest of other Internet Hotel sites. Should we forego these opportunities? In Cebu’s Ayala Center and IT Park, multi-national IT heavy companies are now populating there with thousands of employment opportunities given to Cebu, other Visayas and Mindanao professionals. And Call Centers now abound the city and high rise office buildings have shown their might in this part of the country. Economy in Cebu has obviously risen as can be seen in modern world-class malls that we have now. Consequently, the Visayan Electric Company registers a dramatic rise in load growth recently way ahead as compared to national average of 7% per year. These are indications of the effects of IT in our social lives in Cebu.

It may not be good to be dreaming but to me, there’s no escape from these opportunities.

IMPLICATIONS TO THE ELECTRICAL ENGINEERS

The other reason why I’m sharing this piece in this conference is that, we electrical engineers must be the first ones to be aware of what’s going on outside the country, electrically. We should know what Internet Hotels are all about and how power systems have to be fitted to IT environments, especially in modern buildings. This will surely help us Filipino engineers in our journey to become world-class technocrats.

In this conference there will be sessions on Power Advocacy. We must realize gentlemen that the Power Advocacy that we shall be talking about are all addressed to the serious brink of power shortfall we are facing today - reminiscent to the black-outs in the 1990’s. This shortfall however is only referring to existing & the feared but foreseen loads, not the future such as described in this paper.

Thank you and good morning…

Doods A. Amora, PEE

POWERING INTERNET HOTELS & MODERN OFFICE BUILDINGS (PART III)

POWERING INTERNET HOTELS & MODERN OFFICE BUILDINGS
(Third of a Series)

II) THE MODERN OFFICE BUILDING

Let us now look at modern office buildings. Although not so power hungry as the Internet Hotels, the new computer age has also brought along the much needed transformation in the power system landscape that the design of office building wants to achieve. Computer loads are special as they require special treatment, too. They also generate harmonics that makes power systems not only dirty but also cause to reflect more loads into the system. As they themselves are vulnerable to system disturbances they help create, they therefore need to be isolated. These special pieces of office equipment even have special plugs thus needing special outlets. But then in the past and even in the present time, these special loads are not getting the attention they deserve from electrical designs.

Traditionally, computers & peripherals are not recognized as loads with “new identity”. They are just considered as part of the general purpose receptacles usually provided by traditional designs. But then, recent experiences show that computers and electronics equipment in offices now eat up more power than the traditional “plug-in” & appliance loads.

Using load densities intended for GPR’s (general purpose receptacles) with the thinking that computer and IT loads are part of it; is ‘highly argueable’ for reasons that the load densities recommended by the Electrical Code for GPR’s were established long before the advent of computers. Moreover, IEEE recommends that these loads shall have dedicated 3-wire single phase circuits, home-running to dedicated 3-phase, 5-wire panelboards, to be fed by the so-called PDU’s (Power Distribution Units) and to be served by dedicated delta-wye isolating transformer with a minimum factor of 173% in sizing system components to address harmonics.

THE OFFICE COMPUTER LOAD DENSITY*

Modern corporate offices today are expected to be replete with office computers and peripherals that would fill up 85% to 90% of the entire office desks of the building. But alas, the most recent PEC or NEC hasn’t established yet load densities for office computers & peripherals.

It has been learned that today, authorities & experts in the USA are still in the process of surveying or making census on usages of computers in offices. But then, even though load densities for computer loads in offices are not yet available in the present Electrical Code, power allocation for office IT equipments has to be inputted in any office building design. Otherwise then, will be the frantic call for additional power centers.

Researches made in the internet resulted in a number of internationally published technical papers that revealed that for corporate office buildings, an average density of 9 to 10 computer units per 1,000 sq. ft. These translate to about one unit per 100 sq ft or, say “one unit per 9.3 sq. m”. The same surveys say that in addition to the computer unit, about 1.3 peripheral units (printers, scanners, multi-function electronic devices, etc) are also seen as typical installations on a 9.0 sq. m office area. (*See Reference Paper: Energy Analysis Department, Environmental Energy Technologies Division, Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley CA 94720, USA).

If a 400 va load density is assigned per 9.0 sq m, a 30 - 40 va load density per sq m is a reasonable assumption. For Call Centers, a load density of some 50 to 60 va per square meter is seen reasonable for operation areas. These are on top of the traditional building loads.

In other words, by general estimation, new Office Buildings must have about 25% to 35% additional loads for computers & electronic devices on top of traditional building load; that is, depending on the behavior of building clientele’s loads. Or a shift in load densities: from 110–120 va/sq m to 140-150 va/sq m. But these are just approximations, there’s no substitute to focused design computations.

POWERING COMPUTERS & GROUNDING METHODS

The last subject that I would like to share is how IT loads are fitted into the power system of the building– and grounding is the number one concern.

Ninety percent (90%) of the problems with ITE (Information Technology Equipments) installations are internal to the facility; only 10% are related to conditions on the utility electric service. Importantly, 75% of the problems arising within a facility are related to grounding - making proper and adequate grounding the single most important factor in reliable ITE system performance. In powering IT environments, the most recommended system configuration is the Three-Phase Five Wire System which could either be TN-S or TT 5-Wire schemes by choice as seen in Figures on screen. And there’s no way that the delta-delta or the wye-delta ungrounded systems are recommended installations.

On the other hand, the increasing population of non-linear loads in buildings such as UPS’s, controlled rectifiers, variable frequency drives (typical for elevators), computers and PLC’s are producing harmonics that distort the sinusoidal waveform of the power system. Ironically, these Information Technology Equipment or ITE’s are the ones that are fragile to these disturbances they themselves help create. But note that the Computer & Business Equipment Manufacturers Association of America (CBEMA) in a paper on power quality states, that 75% of the problems with perceived power quality problems are actually grounding problems. According to Messrs: Warren Lewis and Frederic Hartwell of Electrical Construction & Maintenance magazine in its February 1996 issue, they wrote: “a proper grounding system is the essential foundation for any other refinements that enhance power quality through reduction of harmonics. Without such a foundation, any sophisticated attempts to improve power quality will likely prove to be temporary, perhaps lasting only until the next thunderstorm.” Would the popular TVSS (Transient Voltage Surge Suppressor) work in ungrounded systems?

(To be concluded...)

POWERING INTERNET HOTELS & MODERN OFFICE BUILDINGS

POWERING INTERNET HOTELS & MODERN OFFICE BUILDINGS
(Second of a Series)

INFORMATION TECHNOLOGY IN TODAY’S MODERN LIVES

Information Technology is fast becoming the new utility of the 21st century. They are the engines that are fueling the phenomenal growth of the Internet Economy, now known as the ‘New Economy’. Today’s data centers are highly secure, highly reliable, and highly expensive, often window-less, bullet proof fortresses built to move information with maximum efficiency. Internet has become the international access to an enormous amount of information from the simple telephone line.

While the internet and e-commerce continuously showing dramatic growth, over 350 million people were estimated “on-line” worldwide in 2005, with the numbers expected to grow to 400 million by 2006. Retail e-commerce in the US alone was conservatively estimated to be over $ 100 billion in 2005. And Internet Hotels or Data Centers are important players in the equation.

THE INTERNET HOTELS

A Data Center is a sort of a hotel which houses (by rental, by lease or by ownership) all the functions and services of highly advanced technologies, permanently guaranteeing users (Internet Service Providers, Application Services Providers, Telecommunications, etc.) entire satisfaction in terms of security, dependability and reliability 7 days a week, 24 hours a day. Internet Hotels are homes to all sorts of Internet-related companies, through whose servers, routers and modems flow the bits and bytes of modern e-commerce. Internet Hotels can be small as a three-storey building or as big as medium-rise towers.

Running the gamut from Internet hotels that host computer services for Internet service providers to telecom carrier hubs, co-location centers, server farms, and private enterprise data centers, these world-class facilities are custom-designed with raised floors, sophisticated environmental control systems, seismically braced racks, and redundant power systems to ensure failsafe site performance of 24/7.

THE TASK OF THE NEW GENERATION ELECTRICAL ENGINEERS

What does it mean to the electrical engineers who are here in this conference?

The engineering community now faces the task of selecting the correct power-system topology for data centers & other IT environments. By evaluating popular power-system topologies, there has emerged a shift in paradigm as deviations from the traditional way of systems designing has dramatically changed.

There are two things here that are worthwhile mentioning and I would like to invite your attention again to the following: a) The Internet Hotels or Data Centers; and, b) The Modern Corporate Office Buildings.

There are many things in common to these facilities but one of them is what I would like to highlight: IT. And the IT revolution has affected the very onus of electrical systems designing…and we, electrical engineers must be the first ones to be aware of. For instance…,

HOW MUCH LOAD WILL DATA CENTERS ACTUALLY REQUIRE?

In Europe in 2001 (the start of Internet explosion in Europe), installed power (connected load) for Internet Hotels had been established at 1.5 kVA/sq meter, excluding back up devices, and seemed all set to double within the next ten years. In only four years time (2006), the envisioned doubling of loads has now nearly reached. From this experience, the global power required to supply these buildings is thus appreciated to be very great and its timetable short.

Particularly electric intensive, The ‘Internet Hotels’ in the USA is now considered as a new ‘power consumer sector’ with usage per square foot at least 10 to 15 times more than typical office buildings when fully built-out. High Density Data Centers (HDDC’s) are ‘Class 1 Clean Rooms’ needing systems to remove particulate matter and cooling for the removal of heat. According to Mike Hellmann’s paper entitled, “Smarter Ways to Bring Power to Critical Power Facilities” as published by CyberTech Inc., dated Dec 19, 2002, he says, “depending on the nature of the IT equipment and its packing density, connected loads in these environments can range from 100 watts to a stunning 300 watts per square foot in the USA today”. With an average load density factor of 200 watts per square foot or 2,150 watts per sq meter, that is, in other words; 2.53 kVA per sq meter — that’s a lot of concentrated power imaginable.

HIGH RELIABILITY REQUIREMENTS

As Mr. Hellmann continues, “in this New Economy environment, the appetite for power is rivaled only by an insatiable need for reliability. In a world where minutes of downtime can translate to losses in the millions of dollars; when it comes to delivering power, the guarantee of reliability and capacity is a leading priority. As a result, Internet Hotels are amongst the most power-hungry of today’s critical power environments”.

Internet Hotels have built their businesses based on the assurance of plentiful power capacity and ironclad reliability. Assuring the reliability of the incoming power source means installing multiple sources of incoming power with dual utility feeds, usually from different substations or power utility grids that are interconnected to the facility’s main systems via circuit breakers. Dual unit substations are then used to step down and deliver power to the server cages, racks, cabinets and server farms. Thus, if one power source or high voltage line goes down, the system can switch to the redundant feed in a fraction of a cycle—a matter of milliseconds—without losing any electrical load. Likewise, if a transformer fails, the backup system picks up the load instantaneously, notwithstanding the electronic stationary UPS’s and another additional rotary UPS’s. Thus new reliability lingo’s have given rise to the novel terms as: N+1, N+2, N+3 or N+n which speaks for the degree of redundancy.

Powerful servers require high quality and reliable electricity, as electronic equipment cannot tolerate interruptions in electricity for more than a couple hundredths of a second. This translates into a need for an electricity supply that is at least available 99.9999% (also known as “six nines”) of the year. The need for highly reliable electricity is even more acute for the services that Internet Data Centers support. E-commerce firms & e-markets will lose millions of dollars and customers if they fail while transactions are occurring. When electricity is unreliable, web-hosting services, along with other high technology and new economy companies, may choose to relocate.

For instance, the ongoing electricity crisis in California has led many new economy companies to rethink their California operations. Web hosting companies, such as Rackspace, are actively marketing their non-California-based locations to gain new business and steal business from California hosting sites. Thus today, reliability requirements have been elevated from six-nines to nine-9’s (99.9999999%) meaning a downtime of only 30 milliseconds per year. That means colossal investments by the utility companies & Data Center owners for the several layers of costly back-ups & redundancy.

In the data center world, promising and delivering power reliability in the “high nines”—doesn’t come cheap. Requiring a continuous source of high-quality uninterrupted power, critical Internet infrastructures must rely on internal power quality protection systems. The caliber of these systems is often a defining factor for users who increasingly feel the ill effects of power-related problems in millions of dollars per incident.

The ‘Reliability Nines’ are new measurements for service dependability, consistency and trustworthiness packaged in official terms as reliability. To compare with other types of services, the following new global standards may give some insights & discoveries for us here in this conference:

1) Homes: Three 9’s (99.9%), 9 hours downtime per year
2) Factories/Manufacturing Plants: Four 9’s (99.99%), 59 minutes per year
3) Hospitals, Airports: Five 9’s (99.999%), 5 minutes per year
4) Banks: Six 9’s (99.9999), 32 seconds per year
5) E-Commerce/On-Line Markets: Nine 9’s, 30 milli-seconds per year

A few years ago, a performance of four-9’s by Power Utility companies, (meaning 59 minutes per year downtime) was acceptable. However, in ‘mission-critical’ operations such as e-commerce & e-markets, a reliability of six-9’s (32 seconds downtime per year) is now required of these utility companies. As trade-off, other systems enhancements for redundancy purposes to reach nine-9’s are understood to be of the data center owner’s concern.

HIGH LOAD FACTOR

Internet data centers have high load factors. The ‘always on-line’ nature of the Internet translates into the need for 24/7 operation for companies and services associated with the Internet, especially with regard to servers and storage facilities at Internet data centers. Research on the load behaviors of data centers suggests an almost flat load curve with a load factor of over 95 percent or close to unity.

(to be continued...)

POWERING INTERNET HOTELS & MODERN OFFICE BUILDINGS

POWERING INTERNET HOTELS
& MODERN OFFICE BUILDINGS

By D. A. AMORA, PEE

(First of a Series)

(A Technical Presentation Delivered during the 7th IIEE Visayas Regional Conference held at Waterfront Hotel, Cebu City on August 17, 2006)

INTRODUCTION

A power distributor company in the USA had just finished the construction of a distribution system on a suburban site planned for 5.0 MW. When the infrastructure became ready for use, piles of application for power connection reached an aggregate demand of 45 MW – a staggering 10 times of what was envisioned! In order to accommodate these load applications, the distribution company needed to install additional transformers. But new transformers were not enough, and new feeders were needed. But the new feeders were not enough; they needed to upgrade their network. In the end, the power company put up three additional substations and is posing to build more for redundancy requirements. This is not an isolated case, as this is happening everywhere and every time today in the modern world. The reason? INTERNET HOTELS….

Somewhere at the other side of the globe, a new office tower has just been inaugurated for business. A few months thereafter, the building management became frantic to install additional substation to satisfy clients’ needs. In the end, it was the clients who financed and installed their own power centers in an already cramped location allocated supposedly for electrical services. And this is not even an Internet Hotel, the tower is just an edifice built for corporate office clientele. The building owner or its representative architects did not recognize that today, there are new electrical footprints that has to be dealt with in designing power systems for buildings. Computers, IT peripherals & office electronic equipments and the harmonics they bring – they are not loads in the past, but now are eating more power than that of the traditional plug-in appliance loads. Again, this is not an isolated case. It’s happening anywhere else in the world.

The two scenarios presented above are not simple as they may seem. As they are happening everywhere in the world, the phenomenal appearance of these loads propagates back through systems and will require system-wide upgrades, not only locally but nationally; and even seen to infect globally…

I would therefore like to invite your attention to this piece entitled: “POWERING INTERNET HOTELS & MODERN OFFICE BUILDINGS”.


I) THE INTERNET HOTEL

THE CRITICAL POWER AVAILABILITY

Unknowingly to us, the recent surge in Internet usage has been accompanied by an equally large demand for high-quality power to feed the evolving infrastructure. I say ‘evolving’ because in the USA, Internet power consumption is now growing by the hundreds of megawatts per week—taxing the already stressed electrical grid. One of the reasons is that these power hungry data centers can require up to 10 to 15 times more energy than commercial office space even as newer and more powerful servers & data storage devices are unveiling almost every year.

As the Internet continues toward its ultimate destiny, its criticality and reliability now take the center stage of new importance. In a few years past, we in the Philippines have been hearing of power quality as the number one issue affecting sensitive electronics & IT equipment reliability. Today in the USA, the most critical concern is no longer power quality but power availability when system requirements of Internet Data Centers are emerging almost exponentially, along with the consequences of power interruptions.

For instance in December of 1999 the Puget Sound Energy (see Seattle Puget Sound Business Journal - October 2000 issue), a medium size utility company outside of Seattle, had no requests for electricity to serve sizeable loads. A few months later, in August 2000, they had been receiving requests for 445 MW from data center applicants. By September, the requests had reached 700 MW. Briefly, requests ballooned to over 1,000 MW. In other words, in an almost instantaneous fashion, additional loads reached more than 1,000 MW out of the blue. Capital investments supporting the new system can just be imagined as super-enormous and its urgency mind-boggling. By proportion, this increase of load alone is about the demand of the entire Visayas Grid of the Philippines and that is only for a Seattle suburban area.

Based on a survey in 2001 with 17 localities in the USA (see Broadband Wireless Business Magazine, May & June 2001 issues), in the next 5 years, there will be between 5,000 and 10,000 MW of new electricity demand from data center requests currently on the board. In the other futures, the Internet economy in the USA as a country -- including wireless, personal access devices and growth in the multimedia and entertainment industries -- continues to grow robustly necessitating between 15 gigawatts and 20 gigawatts of additional capacity. That translates to about 150% to 200% of the present total power demand of the Philippines. And that is only ‘additional’ capacity for I.T. centers alone. What’s going on, then?

(To be continued)

PROJECT MANAGEMENT AS AN ART

PROJECT MANAGEMENT AS AN ART

The IPSD (Industrial Plant Systems Designer) must be well versed in the art of Project Management. Project Management is defined as "directing nature, quantity and timing of temporarily assembled resources, skills and knowledge to reach specified technical & financial objectives within quality, safety, social & environmental constraints”.

In project management, contractors are the players in the other side of the equation. Regardless of the classification of the contractor, a good project management is the key to the accomplishment of the project at the right quality, most effective cost and on target schedules. Of course, the bottom line of a good project management maybe the realization of the hard-earned profit on the part of the contractor while a nice, safe, operational, built-to-standard edifice, plant or facility that the client envisioned is delivered at the target schedule.

However, the lowest bid is not enough. Clients and their engineers must be quick to identify tell-tale signs if the contractors hired are good ones or not. And ‘standards’ must be in the center stage.

The following are some tips indicating a good & reliable designer or contractor.

1) A good technical design prepared to the highest standards and value creation by the client engineer or its designated designer or project managers. This forms part of the Scope of Work that will make the work commonly clear & understood by constructors.

2) A reliable & realistic cost estimate that leads to a contract price commensurate to the money invested, the efforts and risk involved in undertaking the project,

3) A good team of qualified & experienced technical men assigned in the field.

To orchestrate a project by the client engineer requires depth of understanding of the project. The client must present a clear Scope of Work & Work Specifications, in other words, a clear picture of what the client wants. Scopes of Work must be accompanied with technical plans, layout, diagrams & material specifications to be presented during a pre-bidding conference attended by the contractors all convened at the same time. Remember that contractors will base their bids on a common ground. This common denominator will spell fair play amongst bidders. Lapses must be proactively identified (most common cause of project delays) and should there be changes in plans before the final bidding conference must be covered by bid bulletins with all the players copied.

With a confident house estimate, it would be easy for the client engineer to spot or detect which contractor is gambling on the tightrope. In reality, it's very easy to eliminate the highest bids but it's difficult to ignore the lowest bid. His finance managers and auditors, (usually members of the bidding committee), will haunt him. The client engineer might even be suspected of doing monkey business. The finance guys are looking after the lowest numbers while the technical side is for the engineer to worry.

Experience shows that life would be miserable in a project, if it is started with an incorrect budget. However, most electrical budgets are always born without electrical parents. It just comes out as if, by magic. In the end, quality & standards suffer.

DAA

DOODS' SPEECH: 1989 CIT PARANGAL RITES

SPEECH DELIVERED BY ENGR. DOODS A. AMORA ON THE OCCASION OF CIT PARANGAL RITES ’89, HELD AT THE CIT QUADRANGLE, 4:00 PM, MARCH 8, 1989.

(Backgrounder: The Parangal Rites of Cebu Institute of Technology (CIT) is the most solemn & most prestigious commencement ceremonies of the institution. It aims to honor the King or Queen of Engineers for the year - by way of a Julius Caesar-like coronation. The King or Queen of Engineers is one who achieved the highest average grades from first year to fifth year in his/her engineering course, in other words, the best among the best. The Parangal also honors the ‘laude’s’ of the batch and all other honor students graduating for the year. For the record, as a sidebar, Ernie Abunda, the first president of IIEE North Cebu Chapter & PEE of SMC Glass Plant was the King of Engineers for the year 1995.)

“Our beloved President of the Cebu Institute of Technology, Don Rodulfo T. Lizares Sr., Executive Vice President of CIT, Mr. Gregorio L. Escario, Mr. Rodulfo A. Lizares Jr., First Vice President, Dean Achilles Alfafara of the College of Engineering & Architecture, Dean Ariel Jumalon, of the College of Liberal Arts, Atty. Corazon Evangelista Valencia, Dean, College of Commerce, Department Heads, Faculty Members, The Queen of Engineers of CIT batch ’89 and the members of her court, Outstanding Honorees from the College of Commerce and Liberal Arts, parents, graduating students, guests, ladies & gentlemen, good afternoon …..”

“To be a “King or Queen of Engineers” of a leading school of engineering in this country is NOT THE CUP OF TEA of your speaker, and because of that, I have to honestly say, that with contradicting feelings of pride and humility, I accepted your invitation with mental reservation but without purpose of evasion.”

“I take pride to be part & parcel of the CIT PARANGAL ’89 as your guest speaker; in fact, I consider it one of the greatest challenges in my career. To my mind, it is almost an impossible dream to address to a body as august as this – in an occasion highlighting the beautiful tradition of this prestigious academe – the act of recognizing the cream of the crop – the way of extolling the best among the best in terms of today’s PARANGAL rites.”

“This beautiful tradition had started many years back since the early days in the history of technical education in this part of the country and has continued up to the present days. Since then, the impact of being a King or Queen of Engineers had become a by-word -– it has formed into a monumental legacy that lives up the reputation of CIT as producer of quality engineers. This legacy had been attemptedly imitated by many others schools, but the living imprints of what is CIT, cannot just be obliterated, and that, no engineer in his right mind could ever dare not to recognize. IBA ANG MAY TATAK CIT, MAY PANGALAN ITO, PARE KO…!”

“In the midst of that pride and enthusiasm that I feel this afternoon, I am at the same time, humbled in the wake of the presence of the Queen of Engineers, the immediate members of her court and the outstanding honorees from other colleges whom I am to give honor today. As I pointed out earlier, to be one of them is not my cup of tea, and that only reminds me of a story I gathered in one of our recent management trainings which runs like this:

"Not every long ago, there was an open market of brains somewhere in this part of the globe. What was being sold in that markets are solely human brains (utak). In one of the display booths, the brain of the famous Albert Einstein sported a price tag of $1,000. The brains of Thomas Edison & other scientists were tagged at $2,000 a piece. Then, in the Filipino section of the market, the brain of the genius, Dr. Jose Rizal commanded a price of $5,000. Together with Rizal’s brain were a bunch of brains labeled “CIT Queen of Engineers & Her Court-Batch 89”, which were priced at $5,000 each (same as Rizal’s). Every prospective buyer seemed satisfied with the pricing scheme except for one unlabelled brain which carried a price tag of $1,000,000. The curious buyers asked the attendant why the brain was incredibly so expensive when it was not even 'labelled'. The attendant replied that the brain was a special one because it was owned by an engineer of San Miguel Corporation, specifically Mandaue Brewery. The owner of the brain even became a guest speaker in one of CIT’s Parangal, the attendant added. So what then if the brain was an SMC engineer? What made it so special?... the buyers insisted. Then the attendant concluded, this brain is very expensive, because it’s slightly used!"

"There you are… Ladies & Gentlemen… my job this afternoon is therefore not easy. I come here to honor the super stars in this academe when I am not even a moon… But just the same, let me praise the Queen, the members of her court and the honor graduates from the college of Commerce & the College of Liberal Arts, by saying that, you are all polished diamonds outshining over a heap of other gems – the very jewels that our Alma Mater is so proud of. It is indeed my honor too, to be with you in this momentous occasion."

"May I therefore request the audience to give them a big applause of congratulations!"

"But let me ask you this question, who do you think are the happiest and proudest creatures at this peak moment? Is it the school? Is it the honorees themselves? Or is it your boyfriends or girlfriends hiding somewhere amidst the crowd? Let me venture to say, that there can never be any prouder and happier creature today, than the parents of these diamonds we are honoring today. The parents, yes, the unsung heroes, yet the most important ingredient of this testimonial honor. To you, proud parents, we salute to your undying devotion, to your inexhaustible dedication, to your unwaning support and love towards your children. Words can never be sufficient in appropriately describing your sacrifices and heroism."

"To the parents, let us give them our sincerest congratulations!"

"At this point, let me pass on this message to the honorees as well as the graduating students of this institute. Now that you have succeeded in the academe with your mission, goals and objectives, you are now in the position to aspire for greater heights of achievements such as working on your own career paths to mold your own life as professionals as you develop the necessary competence and capability necessary for your journey ahead. You should be ready and willing to demand the best from yourselves as the road to this new dimension of success is narrow and steep upward as you can observe within any corporate working environment. The road is literally littered with people tumbling down, having failed or fallen on their way up. Up the organization ladder, the triangle accommodates only a few at the apex for the best qualified."

"Let us all remember that there is no victory without a struggle and victories should never be subject to contentment, because if they are, your progress stops. You have just passed your first acid test…you’ll have more baptisms of fire later on."

"Everyone must find his route to success. You must possess a certain degree of imagination and vision. You must be able to think ahead – to visualize a plan beyond the immediate present. In other words, look beyond where you are to where you want to be. But you have to work hard to reach it. Again let me say, that you have just made the first mile… and you have much more miles to tackle ahead."

"Let us all remember that as professionals; it is our responsibility to make this world better than what we found it."

"I wish to say that the Parangal is a venue to honor the cream of the crop. But this honor is not only for them, but to all of you, graduating students of this institute, because you are the best among all others. You are a class by itself."

"I would like to close this speech by giving some food for thought. For the engineering graduates, in case you do not know, a few days from now, you will be starting to practice the oldest profession. I know that not all of you would agree with me when I say that the engineering profession is the oldest profession. Proof…? In the book of Genesis, Chapter 1, Verse 3, it says…” When God created the world, He commanded, Let there be light… and there was light.” Does it mean Electrical Engineering? Yes."

"But who runs the boilers & the turbines? Mechanical Engineers? Yes. But who treated & prepared the water? Chemical Engineers? Yes. But who constructed & maintained the buildings? Civil Engineers? Yes. But who provided the statistical efficiency & productivity control charts? Industrial Engineers? Yes. But who maintained the electronics controls & instrumentations? Electronics Engineers? Yes…and the list goes on from computer software to hardware engineers."

"But the list doesn’t end up there, because one would surely ask, who handles the finance? CPA’s & the bankers? Yes. But who handles the education of all of the above? Is it the product of Dean Jumalon’s college? Of course, Yes."

"You see…, everyone has a mission. Even in the academe, from the school itself, to the faculty, down to the last student, we all have roles to play. In CIT, these roles had been played and achieved all these years, from generation to generation without interruption. Do you care to ask why? Because, in CIT, “IBA ANG MAY PINAGSAMAHAN!”

"As I close my piece, may I request everybody to please rise…

At this point, let us congratulate ourselves by giving out our loudest applause….

Thank you very much for your standing ovation…!"


Engr. Dominico A. Amora, PEE
March 8, 1989