sargent lundy u i/c/9l

... Cale. For Evaluation of 460V Diesel Generator Cak. No. 8982·13-19-4

Cooling Water Pump Mini~um Starting Voltage

x !safety-Related II IHon-Saf ety-Related

Rev • 0 loate i/c/9L of 37

1

1 SARGENT & LUNDY ~ l..:. =:=:=:=::::11 ENGINEERS u • Client Commonwealth Edison Company Prepared b

Project Dresden 2 & 3 Reviewed

Proj. Ho. 8982-13 Equip. Ho. Approved

~ REVISION SUMMARY

Revision O, First Issue, Pages 1 Through 37

, I 9203090291 920303 1 ' \ 1, - ! ~-DR ·A~~:~~~~-~~B~7 ~! ., __ ),__....!..-_:...._ _________________ __,

•

/scl:1561 :9

ATTACHMENT A.

EVALUATION OF UNIT 3 DIESEL GENERATOR COOLING WATER PUMP MINIMUM STARTING VOLTAGE

· CALCULATION 8982-13-19-4

. ~ .

" ' ' - --, ·1 ·~ j

; . . , . ~ • 'I ' .

. ·.:.

~ ~ .-!

... ·/ \ ;' \ •• ·,. ••• • •r ) • I

-. -·i

Cale~ For Evaluation of 460V Dies.:1 G~n~rator Cak. ?'\o. 8982-13-19-4

' : SARGENT & LUNDY ; ' . ' ; ; Cooling Water Pump Minimum Starting Voltage Rev . 0 jDate

x !safety-Related II !Non-Safety-Related Page 2 of 37 : ' • ENGINEERS LJ

Client Commonweal th Ed.ison Company

Project Dresden 2 & 3

Proj. No. 8982-13 Equip. No.

II. METHOD OF REVIEW

QA CALCULATION REVIEW CHECKLIST TYPE OF CALCULATION

Prepared by Date

Reviewed by Date

Approved by Date

LS2(Hand-Prepared Design Calculation Only

D Computer-Aided Design Calculation Only

D Both hand-Prepared and Computer Aided Design Calculation

FOR HAND-PREPARED DESIGN CALC <check the appropriate items)

~Detailed review of the original

0

calculation.

Review by an alternate, simplified or approximate method of calculation.

Review of a representative sample of repetitive calculations.

0 Review of the calculation against a similar calculation previously performed.

FOR COMPUTER-AIDED DESIGN CALC <check the appropriate items)

0 A review to determine if the engineering design and analysis computer program(s) used have been validated and documented and that the calculation, regardless of the program used,contains all the necessary documentation for reconstruction at a later date. (MUST BE PERFORMED)

0 A review to verify that the computer program is suitable to the problem being analyzed. (MUST BE PERFORMED)

0 A review to determine if the input data as specified for program execution is consistent with the design input, correctly defines the problem for the computer program algorithm and is sufficiently accurate to produce results within any numerical limitation of the program. (MUST BE PERFORMED)

0 A review to verify that the results obtained from the program are correct and within stated assumptions and limitations of the program and are consistent with the input. (MUST BE PERFORMED)

0 Validation documentation for temporary changes to listed programs or developmental programs or unique single application programs shall be reviewed to assure that methods used adequately validate the program for the intended application. (WHERE APPLICABLE)

REVIEWER: __ S_ry~-.c..:..W __ ~_~ _______ DATE:_' /_G_/_9_2 __

••

Cale. For Evaluation of 460V Diesel Gen.erator talc. No. 8982-13-19-4

Cooling Water P~ Minilll.lll Starting Voltage

x !safety-Related II INon-Saf ety-Related

Rev. 0 I Date

Page 3

1

1 SARGENT & LUNDY ~ L. =========ii ENGINEERS u

Client Commonwealth Edison Company Prepared by Date

Project Dresden 2 & 3 Reviewed by Date

Proj. No. 8982-13 Equip. No. Approved by Date

PURPOSE

The purpose of this calculation is to 'determine the minimum starting voltage requirement for the 460 volt diesel generator cooling water pump (DGCWP) motor .

of 37

'-" -· Cale. For Evaluation of 460V Diesel Generator talc. No. 8982-13-19-4

Cooling Water P~ Minimun Starting Voltage

x lsafety--Related II !Non-Safety-Related

Rev. 0 I Date

Page 4 of 37 I i SARGENT & LUNDY ~

~-----~' ENGINEERS u



Proj. No. 8982-13 Equip. No. Approved by Date r· .. ··········.·.··.··.··· . .. ·················.·.·.·.·········.·.·.·.···

•. IV. TABLE OF CONTENTS

Section Contents Page No.

I. REVISION SUMMARY . . . . . . . 1

II. METHOD OF REVIEW . . . . . 2

III. PURPOSE . . 3

IV. TABLE OF CONTENTS 4

v. REFERENCES 5

VI. ASSUMPTIONS . . . . 7

VII. METHODOLOGY 8

VIII. CALCULATION . . . . . . 9

x. CONCLUSION . . . . 36

ATTACHMENTS . . . . . . . . . . 37

~~ ...

,. ·-

'·I

•

•

Cale. For Evaluation of 460V Diesel Generator talc. lo. 8982-13-19-4

1

1 SARGENT & LUNDY i ii ~-___ __,1 ENGINEERS LJ

Cooling Water PlJ!ll HinifllJTl Starting Voltage

x lsafety-Related II INon-Saf ety-Related

Rev • 0 I Date

Page 5




L_ REFERENCES

1. Text Book entitled " The Performance anci Design of Alternating Current Machines", second edition, by M. G. Say

- This reference provides the equations used to develop the torque versus speed curves.

2. Louis-Allis Curve No. 18296, dated November 6, 1975. - This references provides the typical torque versus speed

curve for a centrifugal pump. (Attachment A).

3. Instruction Manual for Crane Chempump Model GPS-75L-46H-3T for Dresden Units 2 & 3

- This reference provides general data about the DGCWP and the motor. Specifically, on page 5 it lists overcurrent protection requirements for the motor for locked rotor conditions. (Attachment B)

4. Sargent & Lundy Standard ESC-307, section 11 "Accelerating time and losses"

- This reference provides the method and formulas used to calculate the motor acceleration time

5. GE publication GEH-4821 "Thermal overload relays" - This reference provides the Time-Current characteristics

for GE overload relays. (Attachment C)

6. Paper by R. c. Moore entitled "An Analytical Look at Squirrel Cage Induction Motor Startup", Power Engineering, November, 1964

- This paper recommends. that for conservatism the motor~ accelerating torque be at least 0.25 per unit. (Attachment D)

7. General Electric Curve GES6103C dated April, 1972 for the F225 line type TFJ 200 ampere thermal magnetic circuit breaker protecting the DGCWP motor (Attachment E)"

of 37

•

•

> Cale. For Evaluation of 460V Diesel Generator talc. No. 8982-13-19-4

SARGENT & LUNDY ENGINEERS

Cooling Water PIJTp Minina.rn Starting Voltage

x !safety-Related II . !Non-Safety-Related

Client Commonwealth Edison Company Prepared by

Project Dresden 2 & 3 Reviewed by

Proj. No. 8982-13 Equip. No. Approved by

V. REFERENCES (continued):

Rev. 0 I Date

Page 6

Date

Date

Date

8. Memorandum of telephone conversation between Mr. M. Lesnet of Commonwealth Edison Co. and w. G. Bloethe of S&L (December 31, 1991) This reference provides the data on the DGCWP motor overload heater and the circuit breaker (Attachment F)

9. Test data for the DGCWP motor voltage, current, power, power factor, reactive power, apparent impedance, ·and X/R ratio versus time

- These data are used to derive the torque vs. speed characteristic for the DGCWP motor (Attachment G)

10. Book by A. E. Fitzgerald, c. Kingsley, jr., and A. Kusko entitled Electric Machinery, ·third edition dated 1971

- Some of the equations used in the derivation of the motor model were taken from this book •

of 37

•

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Cale. For Evaluation of 460V Diesel Generator Cale. No. 8982-13-19-4

Cooling Water P~ Minilllill Starting Voltage

x !safety-Related II !Non-Safety-Related

Rev. 0 I Date

Page 7

SARGENT & LUNDY LJ ENGINEERS




VI. ASSUMPTIONS

A. Assumption Requiring Verification:

1. The accuracy of the fault recorder and its associated software and the accuracy of the measurements made is adequate for determining the characteristics of the DGCWP motor. The required accuracy is considered to be 5%.

B. Assumptions Not Requiring Verification: - None

of 37

Cale. For Evaluation of 460V Diesel Generator talc. No. 8982-13-19-4

Rev. 0 Cooling Water P""P Minill'lill Starting Voltage

x lsafety-Related II !Hon-Safety-Related

I Date

Page 8 of

11 SARGENT & LUNDY 1 I • . • ENGINEERS LJ

•



Proj .• Ho. 8982-13 Equip. Ho. Approved by Date .. ,., ... , ........ ,.,.,.,.,., .... , .. , .. _.,.,., .. , .. ,;'" . ... , .... ··.·

:~ · METHODOLOGY

A. Using the DGCWP motor test data from Reference 12, a motor torque versus speed curve at 100% voltage will be developed as shown in section VIII.A

B. The DGCWP load torque versus speed curve from Reference 2 for the condition with the discharge valve open will be drawn on the same plot with the motor speed versus torque curve at 100% voltage established in Step A. ..

c. Using the motor and load characteristics determined above, and also considering the average starting voltage present during the test (Reference 9), the combined moment of inertia (Wk2 ) of the motor and the pump may be determined by calculating the speed versus time· of the starting motor with an assumed moment of inertia. The moment of inertia is then adjusted until the starting time of the calculation matches the starting time of the test.

D. Considering the fact that the motor torque is proportional to the voltage squared, a minimum voltage that will still provide a 25% margin between the motor and load torque curves will be calculated. (Reference 6)

E. The motor starting time will be calculated for the minimum voltage established in Step c above {Reference 4)

F. The motor starting time at the minimum voltage will be compared to the characteristics of the DGCWP motor protective devices to ensure that there are no spurious trips and that the motor is thermally protected .

37

Cale. For Evaluation of 460V Diesel Generator talc. No •• 8982-13-19-4

SARGENT & LUNDY I Cooling Water Plll'p Minillllll Starting Voltage Rev. 0 I Date ENGINEERS

x !safety-Related II !Non-Safety-Related Page 9 of 37



Proj. No. 8982-13 Equip. No. Approved by Date .·.·,·,·.-.·.···········-·.·.·.···.

11 ·

.·.·.·,·.·.·,··

!!VIII. CALCULATION

A. MOTOR TORQUE VS SPEED CURVE

;:, .. ·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.

In this part of the calculation we will develop the motor and load :\ torque versus speed curve at 100% ·voltage based on the available. ,. test data. The curves developed will be used for the subsequent ii analysis to establish the minimum voltage require~ent for the DG~ motor. 1

The above mentioned curve is developed in two stages. In the first. stage, an initial estimate of the locked rotor, full load, and the i maximum torque is obtained by using a simplified model in which th~ magnetizing branch of the equivalent circuit of an induction motor l is ignored during locked rotor cond~tions. Also, assumptions are i made that the ratio of the magnetizing reactance to the stator ; leakage reactance is 10 and that the ratio of the stator leakage reactance to the stator resistance is greater than 10. Therefore, , the Thevenin voltage across the magnetizing reactance is 90% of th~ motor terminal voltage during the operation of the motor at low !!

slips. In the second stage, the full load, breakdown, and maximum! torques calculated in the previous stage and the full load current ; and power factor, and locked rotor current and power factor :j obtained from the test are us~d to calculate a more detailed model j of the motor. In the second stage the assumptions made in the first stage are removed as the motor parameters obtained during th~ first stage are modified to better match the test data. ''

The equations used for the above mentioned procedure in the first stage are:

Under locked rotor (starting) conditions,

= vstaxting I X Pfstaxting

. starting

and,

vs tax ting 1 = . x sin(cos- ( pfstaxting )) Is tax ting

.·.·.· .·.·.-............... ·.·.·.-..... ·.·.·.·.·.•.•.·.·.·.·.··········"'·"······-·.·.·.·.·.·.•.l~

.;

• ~~


Client Commonwealth

Project Dresden 2 &

Proj. No. 8982-13


Cooling Water PlJ'l'4) Minil!LCll Starting Voltage Rev • 0 I Date


Edison Company Prepared by Date

3 Reviewed by Date

Equip. No. Approved by Date

I.VIII. CALCULATION (continued}

A. MOTOR TORQUE VS SPEED CURVE

Under low slip conditions,

where

~~-·.·.·.·.·.·.·.·.·.·.•,·.· ......... ·.·.·.·.·.·,·.·.·.·.· ..

smax

Tmax 33000 x v~

::,

pmax Nmax • 0. 746] + [3·I.2 . R1 l 5252 max 1000

Ns is the synchronous speed in rpm Nmax is the speed in rpm at which the maximum torque occurs (breakdown torque) :: vc is the Thevenin voltage across the magnetizing

reactance Imax is the current in amperes at which the maximum

occurs r 1 is the stator resistance r 2 is the rotor resistance x1 is the stator leakage reactance x2 is the rotor leakage reactance R1 is the Thevenin resistance x1 is the Thevenin reactance

torque I ::

,·,·.·.·.·······""·'·"""'·'"•'•'•'•'•'•'•'•'•'•'•'• ... •'•'""•"············-·.·.•.·.·.·.·.·.·.·.·.·.·.·.·.·.·.Jj

., ,.

•


Cooling Water P'""" Mini111.111 Starting Voltage

x lsafety-Related II !Non-Safety-Related

Rev. 0 joate

Page 11

I

I SARGENT & LUNDY I ! ENGINEERS J



Proj. No. 8982-13 Equip. No. Approved by Date .. · ..... . .. ..... ·.· .. ·.· ....... ·. ..·.· ... · ....................... · ... · ... · ... · ...

The test conditions in the first measurement interval (locked rotor conditions) were:

v := 236.4 i := 506.8 pf := .2627

Estimate the slip at maximum torque

smax := .157 sync_speed := 1800

of 37

Since the torque is proportional to the power drawn by the mo~or at small slips, the maximum torque occurs when the power drawn by the motor is greatest. At that time, the test gave the following conditions:

v max := 247 i max := 379.8

Make an initial estimate pf the size of the motor and the rotor resistance .

hp := 100 rl := .07 (initial estimate)

Calculate the input impedance of the motor and find rl+r2 = rl r2 and xl+x2 = xl x2

v z : = - rl r2 := z·pf

i

2 xl x2 := - rl r2

Using the estimated slip at maximum torque, calculate rl from the formula or slip at maximum torque. The formula for the slip at maximum torque can be rearranged to give r2, and the test value for rl_r2 can be incorporated by adding rl to give rl + r2 and subtracting rl r2 and ~etting this function equal to 0:

r2 := 0

Then:

rl + r2 - rl_r2 := rl + smax·jr12

+ xl_x22

·- rl_r2 0

Solving for rl and r2 using the built in MathCAD root function,

•

•

<,J


SARGENT& LUNDY ENGINEERS

Cooling Water Punp MiniRLm Starting Voltage

x !safety-Related II . !Non-Safety-Related




r 1

r 1 = 0.05147 rl := r 1 r2 := rl r2 - rl

Rev. 0 IDate

Page 12 of 37

Date

Date

Date

Now verify the estimate of smax by comparing the motor power per phase .ns the test data

max_speed := (1 - smax) ·sync_speed v c := J;°.v_max·0.9

2 33000·v c -T max := -

4 ·,,.-.sync_ speed· 7 46 · [rl xl_x22l + J rl

2 +

T max = 574.70879

hp_max . - T max_speed

max· -5252

p_max := hp_max·0.746 + [ 2 rl l 3·i_max ·1000

p_max = 48.71467

3

The maximum power drawn by the motor in the test was 48.72 kW per phase. .E yalue calculated by the model is in agreement with the test data.

The final parameters of the model as determined in the first step are the following:

r1 = 0.05147 r2 = 0.07106 xl x2 = 0.45007

Now calculate the torque speed characteristic of the motor based on the results of the first step of modeling the motor .

A counter will be set up, a series of slips and the corresponding .speeds will be calculated, and then the torque at each speed will be calculated

Cale. For Evaluation of 460V Diesel Generator talc. tlo. 8982-13-19·4

11 I SARGENT & LUNDY i i . ~----, ENGINEERS LJ

Cooling Water PLl!1' Minilll6ll Starting Voltage

x jsafety-Related II !Non-Safety-Related

Rev • 0 I Date

Page 13 of 37

Client Commonwealth Edison Company Prepared by· Date


Proj. No. 8982-13 Equip. No. Approved by Date ......... ·. ......................... · . ...................................... . ...... ·.·.· ....... · . . .... ·

i : = 1 .. 100

i s : = -- Speed : :=:

[1 - si] ·sync_speed v c := 460 .• 9

i 100 i -

2 v c ·33000·r2 -

T(s) :=

• [[rl

2

xl_x22] 2·rr·sync_speed·746·s· + :2] +

700 ~----

/ \

/ \. I/ \ /

)7 \ / \

/

/

T [s J ./ [._,/ \ vv \ ~

L--- --- \ L.--- ----- \

\ \

. 0

0 Speed 1800 i

Torque versus Speed Characteristic (First Stage Estimate}


1 SARGENT & LUNDY 1u1

ENGINEERS

Cooling Water Pl.Jill MinirTLm Starting Voltage


Rev. 0 I Date

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Client Commonwealth Edison Company Prepared by · Date



r··· In order to verify the model, the results of the model are compared to the test results. From Section VIII.D.; the motor will reach 900 rpm at about 0.56 second. Since the first point corresponds to locked rotor conditions, and the test covers 0.048 second intervals, the 900 rpm point corresponds to the 12th measurement. The measured values for this point are~

Current- 471.2 Amps Apparent power- 112.7 kVA Power factor- 0.3865

v c := 0.91·460·0.9

2 v c ·33000·r2

T(s) : = ~~~~~~~~-\

2-n·sync_speed·746·s·[[rl + :2f + xl_x/]

s 1 := 900

xl x2 sync_speed - s z 11 := rl '+ j ·2 sl 1 :=

3 sync speed

Xl· x2 r2 xl x2 z m := j ·2000 z 2 : = + j

3 sl 1 3

1

z 1

Ji_lJ = 444.00574 '~·v_c·i_ll v c

i 1 : =

3000

! .. cos(arg(i 1)) = 0.39491

These results show good agreement with the t~st data.

Results:

z m·z 2 := z 11 +

z m + z 2

= 96.57611

The locked rotor, maximum, and full load torque obtained from this model are 218, 664, and 243 ft-lb respectively.

.•,•,•,•,•,',•.•,•.•,•.·.·.·.•.•.·.·.·.·,·.·.·.·.·.·,'.•.·.•.·.·.·.·.·.·.·.·.•.·.·.·.• ..... J1

Cale. For Evaluation of 460V Giesel Generator talc. No. 8982-13-19-4

SARGENT & LUNDY 11

ENGINEERS LJ

Client Commonwealth

Project Dresden 2 &

Proj. No. 8982-13

Cooling ~ater PUl1'·Mini111.JT1 Starting Voltage


Edison Company Prepared by

3 Reviewed by

Equip. No. Approved by ~~-· . . . . . . . . . . . . . . . . . . . . . .. ·.· ·.· . ·.·.· •.·.· ·.· ·.· ·.·.· . ·.· . . ......................................................... •'• ...................... •,•,• . ·.·.· .... .

iivIII. CALCULATION <continued)

A~ MOTOR TORQUE VS SPEED CURVE

Rev. 0 I Date

Page 15 of 37

Date

Date

Date

The equations used to develop the motor speed vs torque characteristic using detailed modeling for the motor as described for the second stage of the above mentioned procedure are,

where

NS - N slip =

N is the speed in rpm Xrn is the magnetizing reactance

Ls 1.P = . 1 · I v I ( ) Zeq(slip)

pf(slip) = cos(arg[Zeq(slip)])

I 2(slip)

'!{slip) = [ 33000 ] · 3 . v2 . ______ s_l-'ip"'"·-----2nN ·746 c [ ]2 ·

s Rl + I2(Sll.ip) +(X1 +x2(slip))2 s 1.p .

Ii

In this more detailed model for the motor, r 2 and x 2 are functions . I· of slip instead of being constants as they were in the first stage;

·:

!1 ................................................ '''''''''• ,. ,'.','''

J


1

1 SARGENT & LUNDY 1 I

'--· ____ _,, ENGINEERS u Cooling ~ater Pl.ll1' Mininun Starting Voltage

lsafety-Related II !Non-Safety-Related x



Proj. No. 8982-13 Equip. No.

Induction Motor Parameters The input parameters are:

= Rated Voltage of the Motor = Rated Current of the Motor = Stator resistance = Stator leakage reactance = Rotor resistance at zero slip = Rotor leakage reactance at zero slip = Magnetizing resistance = Magnetizing reactance = Synchronous speed of the Motor = Rating of the Motor

Rev.

Page

v IFLC rl xl r20 x20 rm xm Sy_s VA CR ex sl Ws

= Cage Factors for the Motor Rotor Resistance = Cage Factors for the Motor Rotor Reactance = Slip values at which CRs, and CXs are defined = Angular velocity of synchronous speed in rad/a

0 I Date

16 of

Date

Date

37

460 v := -- Sy _s : = 1800· IFLC := 129 VA := 3·V·IFLC 2 "11'" ~

The base quantities are:

VA v ZBASE := -

IFLC KVA := --

1000 ZBASE = 2.05877

The initial estimated and adjusted values are:

rl := 0.0648563 r20 := 0.0679943 rm := 2068.43

xl := 0.256125 x20 := 0.222717 xm := 2.35402

-We. : =

60

-KVA = 102.77989

•

•

·i!

j


Cale. For Evaluation of 460V Diesel Generator

Cooling Water P~ Minilllml Starting Voltage

x jsafety-Related II INon-sa.fety-Related



talc. lo. 8982-13-19-4

Rev. a I Date

Page 17 of 37

Date

Date

Proj. No. 8982-13 Equip. No. t:.A:!p~p::.:r:.:o:..v:.;e::.d=-::b.:!.y===~======··~·•·-~·-····~•~;::: .. ~;:::.~:;: .. ~:::: ... ~ ...... ~ ..... :::.: ...... ;::; ...... ;::; ...... ::::: ...... ::::: ...... =. ...... . . · .. · ·.·.··:·:· . .:·:····:···: ......... ·.·.·.· .. ·.·•· ..... · .. ·.· .. ; .•... · ···.···.·.·.·.··.············•·.·:. :-:·····:·./·:·:·:·:·«·.:·:·.·:···.·:··········:·:·>:-:

The rotor resistance and the rotor leakage reactance are a function of slip,!: The :: this variation represented as a piecewise linear function of slip.

multiplier of the rotor resistance and rotor reactance is CR and ex respectively. The entire curve is represented by five points, at five different slips. The rest of the values are interpolated, such that connectipg line between two successive points is a straight line. ·

CR := l

CR := 3

CR : = 5

sl := l

The .per

rlpu :=

rmpu :=

1. a

1. a

1. a

a.a sl 2

ex := l

ex := 3

ex :=· 5

:= 0.1

1. a

a.97

.95

sl 3

CR 2

CR 4

sl 0

:= 0.4

:= La

: = 1.0

:= -1

sl 4

:= 0.7

ex :=

ex

2

:= 4

sl 5

1. a

0.94

:= 1. 0

unit values of the motor parameters are calculated as,

rl

ZBASE

rm

ZBASE

where

xl xlpu :=

ZBASE

xm xmpu :=

ZBASE

r2a r20pu :=

ZBASE

rlpu = 0.0315 r20pu = 0.03303 rmpu = 1004.6929

rlpu = per unit stator resistance xlpu = per unit stator leakage reactance r20pu = per unit rotor resistance at zero

x20 x20pu :=

ZBASE

xlpu = 0.12441 x20pu = 0.10818

xmpu = 1.14341

slip x20pu = per unit rotor leakage reactance at zero slip rmpu xmpu

= per unit magnetizing resistance per unit magnetizing reactance

~L ... ·.·.·.·.·.·.·.·.·.·.-..... ·.·.·.·.·.· ... ·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.·.· .................... ·.·.·.·.·.·.·.·.·.-................... ·.·.·.·.

•

•

•



Cooling Water P~ Minin..in Starting Voltage

x Safety-Related Hon-Safety-Related



Rev. 0 I Date

Page 18 of 37

Date

Date

Proj. Ho. 8982-13 Equip. Ho. i;A~p~p;r~o~v~e;.d7.7.b~y~~~::::::7'.~'.7.7'.:::::7.:::::::::::7'.~~D~a7t7e::::::::::::~~~;::;::'.\ }:~7:::'.~7.i~7.::::: ... _.7.7 .... ~~77:::::::::::~~~777. .. ~ .......... ".7'.'.'. ..•.. ::7~:::7'.~.~.-.:::::::'..c-.. ••••••······;· ..... .

The multipliers for rotor resistance and reactance are specified at five discrete slip values only, and for all the other slip values the multipliers are calculated by linear interpolation. This interpolation is done using the linterp subroutine available in MathCAD.

cr(s) := linterp(sl,CR,s) cx(s) := linterp(sl,CX,s)

r2(s)

Zth :=

where cr(s) = rotor multiplier as a function of slip CX(S) = rotor leakage reactance as a function Of slip

:= r20·cr(s) x2(s) := x20·cx(s)

where r2(s) = rotor resistance as a function of slip x2(s) = rotor leakage reactance as a function of slip

For convenience in displaying the results, place slip, CR, and ~x· .1

one matrix using the MathCAD augment function,

Param := augment(augment(sl,CR),CX)

Calculate Thevenin quantities

1

rl + j ·xl

1

1 + - +

rm

1

j ·xm

Zm := 1

1 1 - + rm j ·xm

Rth := Re(Zth) Xth := Im(Zth) Zl := rl + ( j ·xl)

Vth : = V · [ Zm l Zl + Zm

where Zth Rth Xth Zl Zm Vth

Vl := jVthj

= Thevenin impedance for the motor equivalent circuit = Thevenin resistance = Thevenin reactance = Stator impedance = Magnetizing impedance (parallel combination of rm & :ml = Thevenin voltage

ii

:.


Cooling Water P~ Hini111.111 Starting Voltage

x jsafety-Related II !Hon-Safety-Related

Rev. 0 1Date

Page 19

1 SARGENT & LUNDY u! •

ENGINEERS



Proj. Ho. 8982-13 Equip. Ho. Approved by Date

Z2(s) := + ( j Zeq(s) := Zl + [

Zm · Z2 ( s) l

Zm + Z2(s)

v I(s) := pf(s) := cos(arg(Zeq(s)))

Zeq(s)

= rotor impedance as a function of slip

of

where Z2(s) I ( s) Zeq(s) pf(s)

= current drawn by the motor as a function of slip total input impedance of the motor

T(s) :=

Torque(speed)

power factor of the current drawn by the motor

r2(s)

2 s 3 · Vl · -------------------

r2: s)]

·. -- T [1 [Ssyp-eesdl l

2 2

+ (Xth + x2(s))

Current(speed)

P _ f (speed) , a p+ [::::d]] where T(s) = Torque developed by the motor

37

Torque(speed) = !;~~~e developed by the motor as a function ,f

Current(speed) = Current drawn by motor as a function of speeq P_f(speed) = Powerfactor of the current drawn by the moto~

as a function of speed

:: ... ·.•.·.·.·.·.·.·.·.·.·.

Cale. For Evaluation of 460V Diesel Generator calc. No. 8982-13-19-4

I j

SARGENT & LUNDY 11 ENGINEERS LJ

Rev. O I Date Cooling Water P1.111p Minirm.m Starting Voltage

X lsafety-Related II INon-~afety-Related Page 20 of 37



Proj. No. 8982-13 Equip. No. Approved by .. ·.

m data := READPRN(data) Read available data for torque,current -

m data -

sp := m

mt := m

i :=

power factor

0 569.4 0.2619 218 = 1522 408.7 0.52 664

1750 129 0.76 243

<0> <1> data cu : = m data - -

<3> sp data alp := 1 - ---

Sy_s

0,1 .. (rows(m_data)'- 1)

as a

mp_f

function of speed

<2> := m data

Date

Date

Date

and

The tabulation below compares the calculated torque, current, and powerf .er values against the available data, as function of speed.

Speed Slip Measured Calculated Measured Calculated Torque Torque Current Current

sp alp mt Torque r sp i l cu Current r sp i l i i i i

0 1 218 216.18059 569.4 567.523 1522 0.154 664 659.68747 408.7 396.708 1750 0.028 243 254.9296 129 142.308

Measured Calculated Powrf actor Powerf actor mp_ f P_f rspJ

i 0.2619 0.26086

o .. 52 0.6-3061 0.76 0.61025

Set up a counter to calculate motor quatities at various slips and plot 1em along with the test data at the same speeds

i := 1,2 .. 100 Speed := sy_s· [1 - s i] s. := O.Ol·i i i

k := 0,1 .. (rows(m_data) - 1)

Cale. For Evaluation of 460V Diesel Generator C8lc. No. 8982-13-19-4

I SARGENT & LUNDY I i ENGINEERS u Cooling Water P~ Hini11a.111 Starting Voltage

x jsafety-Related II INon--Safety-Related

Rev. 0 I Date

Page 21 of 37



Proj. No. 8982-13 Equip. No. Approved by Date . -. : . : . : . . . : ... : . . . . . . . . .. ; . . . . . . :- . . . . : . . ' . : . -. -. . . . . . ... .; . . . . . . .•. .; . : . ; .... ; ... ············•·•···•·•··"·.· .. :.· ....... ··.·.··.·.·.·.··.·.·;···.·.·.··········;· ··;···;·:·:·;· . ............. ·.·•·•············•·.·•·•·•·•·•·•·•·•·•·•·•·-.

'

700

~ v ~~

v v v \ J.....------ v v ........ v \ ',, v

../ v

../"

T [ s i], mt k v v v \ \ i.-----v ~ 1---- \ L...--""' L--- '\ ~ L--L--

~

\ 0

0 Speed ,sp 1800 i k

This curve compares the calculated Torque developed by motor at different speeds against the available torque data.

Cale. For Evaluation of·460V Diesel Generator talc. Mo. 8982-13-19-4

SARGENT ~i LUNDY i ! Cooling Water P~ Minilll..l11 Starting Voltage

x !safety-Related II INon-Saf ety-Related ENGINEERS U

Client Commonwealth Edison Company

Project Dresden 2 & 3

Proj. No. -8982-13

600 -r--

t---i--r--- r---

0 0

Prepared by

Reviewed by

I'---

-----r--- r---

Speed ,sp i k

r---

r---

r----.. ......

~ r---~ r---

Rev. 0 I Date

Page 22

Date

Date

Date

~ ""'

\[\ \ \

1800

This curve compares the calculated current and the available data as a function of speed

of 37


Cooling Water Pl.illl Minilll.lll Starting Voltage


Rev • 0 I Date

Page 23 of 37 1

1 SARGENT 2i LUNDY i i . '-------, ENGINEERS LJ



Proj. No. 8982-13 Equip. No. Approved by Date ... ,.· .. · ...... · ...... · ··.·.····'·'·····,···.,.·.· ..... · .. , .......... · ........... , ....... ..

0.8

,,,,,---(

v I \ y / / -v ~ L---v

pf [s J ,mp_f k ~ ~

l--- --- --~ ---- l---_i---:-l---

~ ------

0 0 Speed ,sp 1800

i k

This curve compares the calculated powerfactor again~t the available data for the powerfactor.

RESULTS :

The parameters for the induction motor model are,

Slip CR ex Stator Resistance = rl = 0.06486 -1 0 0 Stator Leakage Reactance = xl = 0.25613 0 l 1 Magnetizing Resistance = rm ::; 2068.43 0.1 1 1 Magnetizing React·ance = xm = 2.35402 Par am = 0.4 1 0.97 Rotor Resistance at zero slip = r20 = 0.06799 0.7 1 0.94 Rotor Leakage Reactance at l l 0.95

zero slip = x20 = 0.22272


Cooling Water P~ Minilll.lll Starting Voltage

x lsafety-Related II · !Non-Safety-Related

Rev. 0 I Date

Page 24 of 37

I SARGENT~\ LUNDY i i ENGINEERS tJ




· 1

~~···· ·.·:·:·:.:···:··· ·:·:··· ... :- ·:·:··· . . . .. '•'• ....... ·.;.·.·. ·.· . .

:VIII. CALCULATION (continued)

,. B. LOAD TORQUE VS SPEED CURVE

From the test results of Reference 9, the steady state real power drawn by the motor is 19.9 kw per phase (59.7 kw). For the motor model developed in Section VIII.A., 19.9 kW per phase input power !'

is consumed when the motor develops 220 ft-lb of torque at a speed ii of 1760 rpm. Therefore, the steady state load torque is equal to · the motor torque of 220 ft-lb.

1 ........... '·········


Cooling Water P~ MinillK.lll Starting Voltage I SARGEN'T & LUNDY I i ENGINEERS l_i


Client Commonwe al th Edison Company Prepared by


13 Equip. No. Approved by .... , ... ,.,.,.,. ....... , .. , ....... , ............. · ......... , ..... · .... , ... ,.,.,. ··.····· .., ... ,., ...

The per phase input power to the motor is,

v := 274.3

m .J Vl : = jvthl +

Vt h ' = V · [ z l z

v I(s) := pf(s) := cos(arg(Zeq(s)))

Zeq(

T(s) := [.737 Ws

kW ( s ) : = V · I (

S)

l

s).

2 3·Vl

[Rth +

pf(s) . i := 1000

r2(s)

s

. 2

r2 ~ B) l 2 + (Xth + x2 ( s) )

-

i 1 .. 25 s := -- Speed

i 1000

talc. No. 8982-13-19-4

Rev. 0 .IDate

Page 25 of 37

Date

Date

Date ..· . .:-.-:.:.;.;.; .. · ... ;.;• .... · .... ,.· ... :.;.·-:·:·.·.··:···.

:= Sy_s·[l - SJ i

-··

•

•

. Cale. For Evaluation of 460V Diesel Generator


Cooling Water Pl.Jl1) Minirrain Starting Voltage



Project Dresden 2 & 3. Reviewed by

Proj. No. 8982-13 Equip. No. Approved by . ... , .. ,.

Speed kW rs J T rs i l I rs i l i 1798.2 1.64327 10.53783 105.05062 1796.4 2.54015 21.04022 105.19187 1794.6 3.43575 31. 50448 105.47733 1792.8 4.32984 41. 928 105.90498

1791 5.22219 52.30819 106.47221 1789.2 6.11256 62.64251 107.17583 . 1787.4 7. 0007 3 72. 92844 108.01215 1785.6 7.88648 83.16355 108.97703 1783.8 8.76957 93.34543 110.06597

1782 9. 6498. 103.47173 111.27413 1780.2 10.52696 113.54013 112.59646 1778.4 11.40082 123.54839 114. 02772 1776.6 12.27119 133.49432 115.56255 1774.8 13.13786 143.37578 117.19557

1773 .14. 00063 153.19067 118.92136 1771.2 14. ·05931 162.93699 120.73457 1769.4 15.71371 172.61274 122.6299 1767.6 16.56364 182.21604 124.60219 1765.8 17.40892 191.74503 126.6464

1764 18.24938 201.19793 128.75766 1762.2 19.08484 210.573 130.93127 1760.4 19.91514 219.86859 133.1627 1758.6 20.74011 229.0831 135.44764 1756.8 21.55961 238.21499 137.78194

1755 22.37346 247.26278 140.16168

talc. Mo. 8982-13-19-4

Rev. 0 I Date

Page 26 of 37

Date

Date

Date

..

,·_ ....

\ ;


Cale. For Evaluation of 460v Diesel Generator

Cooling ~ater P~ Minifll.111 Starting Voltage

Cale. Mo. 8982-13-19-4

Rev. 0 I Date

X· !safety-Related II !Non-Safety-Related Page 27 of 37


Project Dresden 2 &·3 Reviewed by Date

Proj. No. 8982-13 Equip. No • Approved by Date .. ,.

c. MOTOR AND LOAD TORQUE VERSUS SPEED CURVE

Based on the results from Step A establishing the motor torque versus speed characteristics at 100% voltage, the steady state_ 1ad calculation of the previous section, and the data from Reference 2, we are plotting below the motor and load torque versus speed curves. The motor torque shown is at 100% voltage.

700

/ ~ / \

v \ v / v

/

TOR [sip J l_t [Speed i] / v v

v v i.--

i---l--- v"' /,.....

/ ,..,,, v

_..... i.-- .....

-~ r--_ ------0

0 Speed 1800

i :.

/

.•. Cale. For Evaluation of 460V Diesel Generator Cale. Mo. 8982-13-19-4

·11 SARGENT & LUNDY 1 l . ~-----,, ENGINEERS U

Cooling Water P~ Minirrum Starting Voltage


Rev . 0 I Date

Page 28 of 37



Proj. No. 8982-13 Equip. No. Approved by Date .·.·.· .• ·.·.· ... ·•·.·.· .. ·.· .. · .. ·.:.:···:·>·.·:·.····:·.·:-.-.-:·:·.·.···.

I/VIII.

.•.•.•.•.•.•:••.•.•,•.•'•'•'•,•,•'••.•,• ··•.·.·.··::

CALCULATION (CONTINUED) :

ii

t ...

D. ACCELERATION TIME REQUIRED TO START THE MOTOR

The acceleration time required to start the motor using the starting voltage at the motor terminals will be calculated in the following spreadsheet.

Column No. 1 beginning of speed interval in percent of full load I rpm.

Column ·No. 2 - beginning of speed interval in rpm (Col. No. 1 times full load rpm) I

Column No. 3 end of speed interval in percent of full load rpm Column No. 4 the magnitude of speed interval in rpm Column No. 5 motor torque output in ft-lb at 100% voltage Column No. 6 motor torque output in ft-lb at the motor minimum

starting voltage (Col. No. 6 times the square ratio of the min. staring voltage divided by unity - 100% voltage) :: '

Column No. 7 - load torque in percent of full load torque read from, the load torque vs speed curve developed in section VIII. C of:: this calculation. . ::

Column No. 8 - load torque in ft-lb (Col. No. 8 times the full loa~ torque) I

Column No.9 - net accelerating torque in ft~lb (Col. No •. 7 minus Col. No. 9) . ·

Column No.10 - time to accelerate through speed interval· - this column is calculated using the following formula (REF.V.4)

where

t = (dRPM)x(WK2)

(308)xTN

t = accelerating time in seconds Arpm = change in rpm (-Col. No. 4) TN = net accelerating torque in ft-lb (Col. No. 10) WK2= total inertia in lb-ftA2

.·.·.·.·.·.· ... -... ·.•.•.·.· ... ·.·.•.·.·.·.·.·.·.· .. ·.·.·.·.·.-... ·.-........... ::

SARGENTS LUNDY ENGINEERS

Client Commonwealth

Project Dresden 2 &

Proj. No. 8982-13 . . . . .


Cooling Water P~ Minilll.lll Starting Voltage Rev. 0 I Date


Edison Company Prepared by Date

3 Reviewed by Date

Equip. No. Approved by Date

::VIII. CALCULATION (CONTINUED) :

.:l,I· D. AC::::~T::~ ::M: :::U::::l::i::~:m:H:oM::::lerate through this and I

all previous time intervals

• ::

:.

Determination of the Moment of Inertia

A review of the test data of Reference 9 shows that the vo.ltage during most· of the starting of the DGCWP during the test was 236 volts line to neutral ·or 89% of the motor rated value of 460 volts :: line to line. Since 'the motor torque is proportional to the square) of the voltage, the motor torque can be calculated for this voltag~ from the results of Section VIII.B. The-test data also show that l the motor requires 0.85 second to start. The moment of inertia is i now calculated by using the spreadsheet described in the previous j section to calculate the starting time. The moment of inertia is i then adjusted until the calculated starting time matches the . ::· experimental data. An initial value of 35 lb-ft2 will now be used to calculate the accelerating time.

;: ..................... , ............... ·.·.·.·.·.·.·.··· ............. ·.·.·,·.·.·,·.·.·.·.·.·.·.·.·.·.-..... -... · ... ·.•.•.·.·.·.-......... ·,·.···············-·.·.·.·.·.·.· ..... ·.·.·.·.·.·.·.•.•.· ..... •.•.·.•.•.·.·.·.·.·,· ........ ,·,·.·.·.·:

:•.·

:

:

:

:

:

.1 ;:

:

:

• SARGENT & LUNDY ENGINEERS

Cale. For Evaluation of 460V Diesel Gene

Cooling Water Pl.fl'P Minimum Starting Voltage

x Safety-Related Non-Safety-Related



Proj. No. 8982-13 Equip. No. Approved by ··:··:·:···:·:·:··: ... ; .. .,.,.,.,. .. ;.;.,.

\ OF INITIAL SPEED @ SPEED MOTOR MOTOR \ OF LOAD FULL SPEED THE END OF INTERVAL TORQUE TORQUE LOAD TORQUE LOAD (RPM) INCREMENT (RPM) IN lb-ft IN lb-ft TORQUE IN

SPEED @ 100\ @89\ lb-ft ( 5) ( 7) ( 8)

( 1) (2) ( 3) (4) (6)

0 0.00 87.50 87.5 218.00 172. 68 15.00\ 33.00

5 87.50 175.00 87.5 228.00 180.60 10.00\ 22.00

10 175.00 262.50 87.5 240 .·oo 190.10 6.00\ 13.20 15 262.50 350.00 87.5 252.00 199.61 5.00\ 11.00

20 350.00 437.50 87.5 266.00 210.70 5.50\ 12.10 25 437.50 525.00 87.5 281.00 222.58 7.50\ 16.50

30 525.00 612.50 87.5 299.00 236.84 10.00\ 22.00

35 612.50 700.00 87.5 317.00 251.10 12.50\ 27.50

40 700.00 787.50 87.5 337.00 266.94 16.00\ 35.20

45 787.50 875.00 87.5 359.00 284.36 20.00\ 44.00

50 875.00 962.50 87.5 385.00 304.96 25.00\ 55.00

55 962.50 1050.00 87.5 414.00 327.93 30.50\ 67.10

60 1050.00 1137.50 87.5 447.00 354.07 36.00\ 79.20

65 1137.50 1225.00 87.5 485.00 384.17 42.50\ 93.50

70 1225.00 1312.50 87.5 528.00 418.23 49.50\ 108.90

75 1312.50 1400.00 87.5 574.00 454.67 56.50\ 124.30

80 1400.00 1487.50 87.5 622.00 492.69 65.00\ 143.00

85 1487.50 1575.00 87.5 658.00 521. 20 72.50\ 159.50

90 1575.00 1662.50 87.5 655.00 518.83 82.00\ 180.40

95 1662.50 1750.00 87.5 550.00 435.66 90.00\ 198.00

100 1750.00 100.00\ 220.00

Cale. No. 8982-13-19-4

Rev. o [Date

Page 30 of 37

Date

Date . Date

. .... c:::;:::; .......... ; .. ; . .

- NET TIME TO CUMULATIVE ACCELERATING ACCELERA'r,E TIME ( s)

.TORQUE THROUGH (lb-ft) SPEED

INTERVAL ( s) ( 11) ( 9) (10)

139.68 0.07 0.07

158.60 0.06 0.13

176.90 0.06 0.19

188.61 0.05 0.24 198.60 0.05 0.29

206.08 0~05 0.34

214.84 0.05 0.39

223.60 0.04 0.43

231. 74 0.04 0.47

240.36 0.04 0.52

249.96 0.04 0.56

260.83 0.04 0.59

274.87 0.04 0.63

290.67 0.03 0.66

309.33 0.03 0.70

330.37 0.03 0.73

349.69 0.03 0.76

361.70 0.03 0.78

338.43 0.03 0.81

237.66 0.04 0.85

0.85

• Cale. For Evaluation of 480 V Diesel Generator talc. No. 8982-13-19-6

Cooling Water P~ Hinilllill Starting Voltage


Rev. 0 I Date

Page 31 of 31

SARGENT & LUNDY 11

ENGINEERS u



Proj. No. 8982-13 Equip. No. Approved by Date ················ .· .. · ............... ·.···.·.·.··.·.······ ············.·.·.····.· ... ··.·.••.·.· ...................... ·.·.· ............. ,•.•,••.••.•,•,•,•,•.•.•,•.•,•,•.•,•.•,•,• .. •.•,••.••.•.•.•,•,•,•.•.•.•.••.• .. ·····

ii

::VIII. CALCULATION (continued)

D. ACCELERATION TIME REQUIRED TO START THE MOTOR

Since the calculated starting time of 0.85 second agrees with the experimentally determined starting time, it may be concluded that ; the combined moment of inertia of the pump and the motor is 35 lb- j ft2 ~ I

b. Determination of the Minimum Allowable Starting Voltage

el

According to Reference 6, a minimum accelerating torque of 25% of the load torque should be provided. Since the load torque is about, 200 lb-ft, a minimum accelerating torque of about 50 lb-ft should t be provided. The motor starting voltage can be progressively lowered, and the accelerating torque in Column 9 of the spreadshee~ compared to this criterion. :: .

The following spreadsheet demonstrates that with a starting voltagJ of ·70% of 460 volts, the minimum accelerating torque is 73.8 lb-ft! during the period when the motor is starting, meeting this ! criterion. (The point on the spreadsheet at 95% speed represents ~ point at which the motor is settling into steady state operation after the period of acceleration is essentially complete.) The accelerating time ~ith 70% starting voltage is 1.65 seconds •

• ::

II

.:... ........... w,•w.w.•.··.w·.w.w.w.·.ww.w.w.w ·.w.

Cale. For Evaluation of 460V Diesel Gene Cale. No. 8982-13-19-4

II SARGENT& LUNDY ~ Cooling Water P~ MininJn Starting Voltage

~----~' ENGINEERS u Rev. O IDate

x Safety-Related Non-Safety-Related Page 32 of 37




r .,., .. , ... , .. _ .. ,.,.

\ OF INITIAL SPEED @ SPEED MOTOR MOTOR \ OF LOAD NET TIME TO CUMULATIVE FULL SPEED THE END OF INTERVAL TORQUE IN TORQUE LOAD TORQUE ACCELERATING ACCELERATE TIME (s)

••

LOAD (RPM) INCREMENT (RPM) lb-ft @ IN lb-ft TORQUE IN lb-ft TORQUE THROUGH SPEED 100\ @ 70\ (lb-ft) SPEED

( 2) ( 3) ( 4) (6) ( 7) INTERVAL (s) ( 11) ( 1) ( s) (8) ( 9) (10)

l 0 0.00 87.SO 87.S 218.00 106.82 lS.00\ 33.00 73.82 0.13 0.13

5 87.SO 17S.OO 87.S 228.00 111. 72 10.00\ 22.00 89.72 0.11 0.25

10 175.00 262.SO 87.5 240.00 117.60 6.00\ 13.20 104.40 0.10 0.34

i 15 262.50 3SO.OO 87.S 252.00 123.48 S.00\ 11.00 112. 48 0.09 0.43

20 3SO.OO 437.SO 87.S 266.00 130.34 S.SO\ 12.10 118. 24 0.08 0.51

2S 437.SO S2S.OO 87.S 281.00 137.69 7.SO\ 16.SO 121.19 0.08 0.60

30 S2S.OO 612~so 87.S 299.00 146.Sl 10.00\ 22.00 124.Sl 0.08 0.68

35 612.50 700.00 87.S 317.00 lSS.33 12.SO\ 27.SO 127.83 0.08 0.75

40 700.00 787.SO 87.S 337.00 16S.13 16.00\ 3S.20 129.93 0.08 0.83

4S 787.SO 87S.OO 87.S 3S9.00 17S.91 20.00\ 44.00 131. 91 0.08 0.90

so 87S.OO 962.SO 87.S 385.00 188.6S 2S.OO\ ss.oo 133.6S 0.07 0.98

5S 962.SO 1050.00 87.S 414.00 202.86 30.SO\ 67.10 "13S.76 0.07 1.05

60 lOS0.00 1137. so 87.S 447.00 219.03 36.00\ 79.20 139.83 0.07 1.12

65 1137.50 122S.OO 87.S 48S.OO 237.6S 42.SO\ 93.SO 144.lS 0.07 1.19

70 122S.OO 1312.SO 87.S S28.00 2S8.72 49.SO\ 108.90 149.82 0.07 1.26

7S 1312.SO 1400.00 87.S S74.00 281. 26 S6.SO\ 124.30 1S6.96 0.06 1.32

80 1400.00 1487.SO 87.S 622.00 304.78 6S.OO\ 143.00 161.78 0.06 1.38

85 1487.50 1575.00 87.5 658.00 322.42 72.50\ 159.SO 162.92 .0.06 1.44

90 1575.00 1662.50 87.5 655.00 320.95 82.00\ 180.40 140.55 0.07 1. 52

95 1662.50 1750.00' 87.5 550.00 269.50 90.00\ 198.00. 71.50 0.14 1.65

100 1750.00 100.00\ 220.00

1 ... -... ·.·.·.·.·.·.·.·.·.·.·••

l.6S

•

••

•

SARGENT& LUNDY \I ENGINEERS U


Cooling Water P~ Minillllll Starting Voltage




Proj. No. 8982-13 Equip. No. Approved·by

talc. No. 8982-13-19-4

Rev. 0 I Date

Page 33 of 37

Date

Date

Date

llvIII. CALCULATION .. c continued) :

i!E. MOTOR THERMAL PROTECTION AND PROTECTIVE DEVICES TIME TO TRIP ;.

h. Thermal Protection of the Motor

I!

f ............ ·.·.·.·.·.·.·.·.········"""•'•

Reference 3 states that the motor is protected during starting by ·ii an overload heater. The characteristics of a typical Dresden overload relay are shown in Reference 5. By definition, the :: characteristic shown in Reference 5 is less than the actual .thermal. capability of the motor. Therefore, if the motor starting duty does not exceed the maximum tripping time of the overload relay, the motor thermal capability is not being exceeded.

The test of Reference 9 showed that the locked rotor current of the. motor was 506.8 amperes at an applied voltage of 236.4 volts line to neutral (409.5 volts line to line). Since the locked rotor current is p~oportional to the applied voltage during starting, Th6. starting current is 626 amperes at the maximum motor voltage of ::

:::::::::6:6::::~:::dm:::ra::::::a:: :::r:::i:~1::a:::::e:~lt:::eJ on this the locked rotor current of the.motor will range from 486% \ of full load current at the maximum motor voltage to 309% of full ; load current at the minimum starting voltage ... The characteristic :: shown in Reference 5 indicates that the overload relay may take 13 to 21 seconds to trip with the maximum locked rotor current applied. Since the motor starts in 1.7 seconds or less, it is obvious that the motor thermal rating will not be exceeded in starting, and that a more detailed analysis is not necessary •

Cale. For Eval~ation of 460V Diesel Generator talc. lo. 8982-13-19-4


Cooling Water P~ Mini!TlJll Starting Voltage



. Project Dresden 2 & 3 Reviewed by


II. CALCULATION (continued):

Rev. 0 I Date

Page 34

Date

Date

Date

E. MOTOR THERMAL PROTECTION AND PROTECTIVE-DEVICES TIME TO TRIP

2. Nuisance Tripping During Starting

of 37

Reference 8 indicates that the motor starter includes a TFJ 200 ampere molded case circuit breaker. The locked rotor current will range from 1.99 to 3.13 times the breaker rating of 200 amperes. At these currents, the thermal element of the molded case breaker will take from 27 to 90 seconds to trip. Since the motor will take at most only 1.65 seconds to start, the molded case breaker will not trip during starting.

The overload heater.will not trip during starting, as was demonstrated in the previous section.

SARGENT & LUNDY I ENGINEERS U


Cooling Water P~ Mini111.111 Starting Voltage

x !safety-Related II ·!Hon-Safety-Related



talc. No. 8982-13-19-4

Rev. 0 I Date

Page 35 of 37

Date

Date

Date Proj. Ho. 8982-13 Equip. Ho. Approved by '~~7.0~~~~~~~~~.-~.···~•-.···~~~-~.·.·.·.··.·.~·····.~-~~ .••.... ··.·.··~~-~·-.·~·-.·~--~~ .... ~-~~~~~~~~~~~--~--~~~~-.•

•

RESULTS

The equivalent circuit and the moment of inertia of the diesel generator cooling water pumps have been determined. From this, it has been determined that the diesel generator cooling water pump will start successfully with 70% of rated voltage, applied.

'

Cale. For Evaluation of 46ov Diesel Generator talc. No. 8982-13-19-4

Cooling Water P~ Minil1lJ11 Starting Voltage

x !safety-Related II . !Hon-Safety-Related

Rev. 0 I Date

Page 36 of 37

I SARGENT ~l LUNDY i i ENGINEERS LJ



Date Proj. Ho. 8982-13 Equip. Ho. Approved by .. ~~,~~~ .... ~ .. ·.~······~ ... ~~~~·~·.·~·~~~~~~ .. ·.·~···.·~~ .. ·.··.··••····.~ .... ~ .. ~~~.~·~···.~·~~~~~~~~~~~~~~~~ ...

CONCLUSION As demonstrated in this calculation, all the DGCWP motors will start with the postulated minimum starting voltage of ·70% without tripping their protective devices or exceeding the motor thermal capabilities.


Cooling Water Pl.lllp Minimun Starting Voltage


Rev. 0 I Date

Page 37 of 37

11 SARGENT & LUNDY ! l ENGINEERS LJ



Proj. No. 8982-13 Equip. No. Approved by Date ................ ·•·••···.··········.·····.· ·•·•····.·.·•·•·•··•····••·· .. ············ .. ·.·.· ........•.... · ... · ... · ......... ·.·. ·················•····· ...••........ · .......••..... ·.·····.················/.··········•••·.-·•··•······· ... ., ..... .

ATTACHMENTS

Attachment A Typical Centrifugal Pump Torque vs Speed Al-A3

Attachment B Crane Chempump GPS-75L-46H-3T Manual Bl-B17

Attachment c G.E. Thermal Overload Relay Manual Cl-C4

Attachment D Paper on Induction Motor Starting Dl-D5

Attachment E G.E. TFJ Molded Case Breaker Curve El-E2

Attachment F DGCWP Starter Data (Telephone Memo) Fl-F2

Attachment G DGCWP Test Data Gl-G33

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ATTACHMENT B

EQUIPMENT EVALUATIONS FOR UNITS2AND3

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"· ·,.. .... --

:: '.~ ; . ' t < - :?

...--· ... . ' _,

At the limiting critical voltage value for the 4160 Volt safety busses on each unit (Unit 2 - 3784 Volts, Unit 3 - 3832 Volts), the following safety related loads would experience a terminal voltage below the vendor recommendations or NEMA criteria: • Unit 2, 2/3, 3 DGCWP's • CCSW Cubicle Cooler A and B Fans for Unit 2 • CCSW, Cubicle Cooler C and D Fans for Unit 3 • 125 and 250 Volt Battery Chargers (both units) • Five (5) 120 Volt Size 2 Starter Contactors on each unit (used for

MOV's) CECo has performed an assessment of this condition to evaluate the performance of each component. A summary of these assessments follows.

Diesel Generator Cooling Water Pump Minimum Starting Voltage The purpose of this assessment is to evaluate the voltage available for starting the Diesel Generator Cooling Water Pumps (DGCWP). The critical voltage calculations used to determine- the- second level· undervoltage relay setpoint have determined that the running case bounds the starting case when field testing data is used as an acceptance criteria for starting the DGCWP's. The starting analysis utilized a minimum terminal voltage for the DGCWP's as shown in the table below. At this point, another load becomes the critical load for the starting case, but the calculated critical voltage on the 4160 Volt safety bus is still bo.unded by the run condition.

DGCWP Unit Division Available Terminal Percent of Voltage Rated Voltage

2 2 II 372.3 80.9% 3 3 II 342.7 74.5%

. 2/3 2 I 370.6 80.6% 2/3 3 I 349.6 76%

The vendor of the DGCWP's, Chempump Division of Crane Company, does not specify a minimum starting voltage requirement. In response to a request by CECo for a minimum star.ting voltage requirement, the vendor responded that the motor was guaranteed to start and run at 90% of the 460 Volt rating (or 414 Volts) and may not start if the Hne voltage dips by more than 15% (85% of rated or 391 Volts). However, the minimum starting voltage recommendation was based on engineering judgment, and no actual testing was performed under degraded voltage conditions (under 90% of rated voltage). The vendor was unable to provide a motor torquespeed characteristic curve applicable to this pump. This specific motor is no longer used by Crane, and they no longer have one available for testing.

Page 1 of 7 ORSON EOSFl\SAOVA2-3.00C 3/3/92

• Crane obtained a standard motor ,for each of Dresden's DGCWP's. The pump vendor modified each motor to allow for use in a submerged location. To accomplish this, the vendor machined the rotor to increase the air gap and installed a liner in the motor. This liner protects the windings from moisture, thus creating a submersible combination pump/motor in a common enclosure. An integral water cooling jacket was also provided with the housing. Machining the rotor and providing a custom enclosure is standard practice for the vendor. The pumps were supplied to CECo in 1973.

CECo performed a test of the Unit 3 DGCWP to obtain the torque -: speed characteristic curve by developing an analytical model of the motor. Torque - speed curves would normally be obtained using a dynamometer. Due to the design of the DGCWP, the motor shaft can not be connected to a dynamometer. Dynamometer testing may also result in mo.tor failure. Therefore, this method of testing was impractical for the Dresden DGCWP.

Alternate analytical methods are available to determine torque - speed. ' ·. characteristics of induction motors. Generally, these methods are not used'.by manufacturers as potentially destructive dynamometer testing Of. redundant motors is more economical than· the engineering effort required to develop the analytical model. For the Dresden DGCWP, developing an analytical model of the motor based on test data was the only possible. alternative. The test measured the three phase currents and voltage values from the initial inrush current until reaching a steady state value, indicatir:ig that the motor had started. Current and potential transformers were.' . installed in the motor circuit to allow the use of a digital fault recorder to ,. obtain the required data. The bGCWP was then started in accordance with ·normal station operating procedures. The testing accurately monitored the motor and pump as it is installed in the plant with the actual mechanical load applied to the pump impeller (cooling water flow to the Unit 3 diesel generator).

An analytical model of the motor was developed and benchmarked against the test data for validity. This type of motor model accurately represents . the motor speed - torque curve, the chan·ging rotor impedance with time and allows assessment of machine capability in response to available voltage. Additionally, the model can be used to predict motor behavior under all conditions, and is independent of starting voltage actually present during the test. The minimum starting voltage required to start and accelerate the motor was then calculated from the motor analytical circuit model. The assumptions, methodology and the torque - speed curve develo~ed are documented in Attachment A.

Page 2 of 7 DRSDN EDSFl\SADVA2-3.DOC 3/3/92

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Two requirements must be met at the minimum acceptable starting voltage. Adequate torque must be provided at reduced voltage and the. protective devices must not trip on overcurrent before the inrush current drops to the steady state value. The torque - speed curve determined by the testing shows that the motor will successfully start at 70% of rated voltage. The overload relay will not trip during a degraded voltage start, and the maximum current drawn by the motor is below the trip curve of the breaker.

The motor develops adequate breakdown and pull-up torque at 70% of rated voltage to assure successful starting. The critical factor in this application, by the test data, is net aecelerating torque available. A minimum value of 25% of load torque must be provided to accelerate the load in a reasonable time (approximately 50 lb.-ft. in this application). An accelerating torque of 73.8 lb.-ft. is available at 70% voltage, providing a conservative margin in the calculated result. This will accelerate the pump to operating speed in 1.65 seconds.

At locked rotor current, the overload relay will trip in 13 to 21 seconds, assuring that the thermal rating of the motor is not compromised. As the motor will start in less than two seconds, the overload will not trip th.e motor under starting conditions at 70% of rated voltage. The maximum current will be drawn when the motor starts under the highest expec~ed voltage, which causes a locked r:otor current of 626 Amperes at 110% of rated voltage. The 200 Amp TFJ breaker will take 27 seconds to trip at this current.

Therefore, at 70% of rated voltage or greater, the motor has adequate torque to start and no undesired protective trip will occur.

CCSW Cubicle Cooler Fans The Containment Cooling Service Water (CCSW) System provides long· term decay heat removal. This system has a total of four pumps. Only one ~CSW pump is required for the containment cooling safety function. CCSW

.. pumps A and 8 are powered from ESS Division I and pumps C ·and D are Division II. Two of the CCSW pumps, B and C, are located in vaults to provide protection against local flooding. Each of these two pumps have four cooler fans fed by the respective divisional power source as shown in the following table. CCSW Pumps A and D are not in vaults. Consequently, these pumps do not require cooler fans.


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CCSW Pump ESS Division In Vault? CCSW Cubicle Cooler Fans

A Division I No None B Division I Yes A Fan 1, A Fan 2, B Fan 1

and B Fan 2 c Division II Yes C Fan 1, C Fan 2, D Fan 1

and D Fan 2 D Division II No None

The degraded voltage analysis used an acceptance criteria for terminal voltage for the CCSW Cubicle Cooler fans of 414 Volts for running conditions (90% of rated, based on NEMA) and 391 Volts (85% of rated) for starting. The starting value was based on conservative engineering judgment, rather than a vendor value. No information on the minimum starting voltage has been located, either as a stated value from the vendor or a torque - speed curve applicable to these motors. The voltage available

·to the one division of these fans is adequate fo'r starting and running these motors at the new second level undervoltage relay setpoint for each unit (Division II fans - C and D - on Unit 2, Division I fans - A and B - on Unit 3). However, setting the relay to assure starting of the other division cooler fans (A and· B on Unit 2, C and D on Unit 3) woula result in an unacceptably high relay setpoint. Since the cooler fans only support operation of the CCSW Pumps in vaults, the containment cooling function is still available (this function requires only one pump as indicated above).

For the loss of all four CCSW Pumps, and a resultant loss of the containment cooling function, the simultaneous events of flood, LOCA and degraded voltage with off site power• available must occur, plus a single failure of a loss of the division with adequate voltage to start the fans. This event is not considered to be credible, as it is estimated to be on the order Qf 9.9 x 10-12 per year (not considering·· the loss of one division). Therefore, the potential low voltage on the cooler fans of one division is not a concern.

125 and 250 Volt Battery Chargers The nominal rating of the battery chargers is 480 Volts, not 460 Volts as most motors. Therefore, to meet the NEMA criteria of 90% voltage, 432 Volts is required at the charger terminals. Further, the manufacturer of th.e chargers (Power Conversion Products) has a published specification of 130 Volts ± 1 % output voltage from no load to 200 Amperes with an input of 480 Volts + 15, -10% (values are for the 125 Volt charger; the ~50 Volt charger has the same specification except for a nomin~I output voltage of


•

260). To assure 432 Volts to the chargers would require an unacceptable setpoint for the Second Level Undervoltage Relay, as a higher relay setpoint would trip the preferred power ·source when it is still capable of supplying the critical loads. This would challenge the diesel generators unnecessarily. Therefore, the higher relay setpoint is unacceptable, both from an operating perspective and considering overall plant safety.

The worst case battery charger is 125. V Battery ·Charger 3 which has 410.9 Volts at the terminals during steady state LOCA conditions (after all required motors have been started) with Summer aux power system loading. ·All other chargers have greater than 415V available.

The effect on the charger output at 410 .. 9 Volts (85.6% of 480 Volt rating) has been assessed and CECo has concluded that there· would be less than a 6% reduction in output voltage. This would be sufficient to prevent a discharge of the batteries. The charger maximum current output capability is also reduced; however, with off-site power available the load demand on. the DC system would be less than the design basis loading (e.g. fewer breaker and solenoid operations; inverters remain on AC power). Therefore the small reduction in charger output is acceptable. Additionally it should be noted that th~ batteries were sized based on a loss of off site power with no credit from the battery chargers.

120 Volt Starter Contactors

Five safety related 120 Volt starter contactors on ·Dresden Unit 2 do not meet the vendor stipulated minimum voltage requirement of 75 % of the 120 Volt rating at the critical voltage required for running contir)uous duty motors (DGCWP, etc.; the new second level relay setpoint). These contactors control motor operated valves required for LPCI injection. These valves are:

Reactor Recirculation Pump 2A Discharge Valve, 2-202-5A Reactor Recirculation Pump 28 Discharge Valve, 2-202-58 LPCI Injection Valve 2A, 2-150·1-22A LPCI Injection Valve 28, 2-1501-228 LPCI Full Flow Test Valve 2C, 2:.1501-388

There are also five safety related 120 Volt contactors on Dresden Unit 3 which do not meet the above criteria at the critical voltage level. These contactors perform the same functions on Unit 3 as the Unit 2 contactors listed above. These valves are:


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Reactor Recirculation Pump 3A Discharge Valve, 3-202-5A Reactor Recirculation Pump 38 Discharge Valve, 3-202-58 LPCI Injection Valve 3A, 3-1501-22A LPCI Injection Valve 38, 3-1501,.228 LPCI Full Flow Test Valve 3A, 3-1501-38A

• The valve with the lowest available voltage, LPCI Injection Valve 3A (3-1501-228), has 68.47% of rated voltage available at the contactor at the minimum trip point of the new degraded voltage relay. Raising the relay setpoint to meet the conservative vendor voltage requirement for these contactors would result in an unacceptable relay ·set point as discussed above.

The contactors for the valves listed above were replaced during the fa.II · 1991 outages (Unit 2 forced outage, Unit 3 refueling outage) with safetyrelated, environmentally qualified General Ele-ctric (GE) Series 300 contactors. CECo has tested the minimum pickup of a 300 Series contactor. The test data shows that the GE Series 300 contactor minimum pickup is 58% of rated voltage when new. The GE value for pic~up of 75% is to allovv aging over the useful life of the device (40 years) and to provide a margin for conservatism.

The minimum expected voltage on the safety related 4160 Volt busses under worst case loading conditions (small break LOCA with off site power available immediately following a trip from 100% power) is adequate to assure contactor operation through the spring. This is an extreme condition which would only occur at the highest off site power ·system loading condition with two transmission system contingencies and a LOCA on Unit 2. CECo is a summer peaking utility, and the highest off site power system loading condition occurs on the hottest day of the year. Lower loading conditions of both the transmission system arid the station auxiliary power system will provide higher available voltage during Spring, 1992.

Based on; 1) the qualified GE Series contactor design which assures 75% voltage pickup at the end of its 40 year life; 2) the demonstrated 58% of rated pickup voltage of a new Series 300 contactor through testing; 3). the installation of new Series 300 contactors in all of the safety related sJze two starters; and 4) the minimum expected voltages during the Spring 1992 time period, all contactors will properly perform their safety function .


Modifications will be completed by March 31, 1992 to assure that there is adequate voltage for contactor pickup at the new second level relay setpoint.


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ATTACHMENT C

SECOND-LEVEL UNDERVOLTAGE RELAY SElPOINT CALCULATIONS FOR UNITS 2 AND 3

Unit 2: Calculation 8982-13-19-6 Unit .3: Calculation 8982~ 17-19-2

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