ML19320B077
| ML19320B077 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/01/1980 |
| From: | Crouse R TOLEDO EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| 625, NUDOCS 8007090254 | |
| Download: ML19320B077 (5) | |
Text
.
O VERIFICATION TEST
'OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTA'GES FOR DUANE ARNOLD ENERGY CENTER IONA ELECTRIC LIGHT AND POWER COMPANY JOB 11186-232 Prepared By Bechtel Associates Professional Corporation June 1980 800707og pgL 1
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TABLE s.' CONTENTS Page 1.0 TASK OBJECTIVE 1
2.0 LIGIIT LOAD ON STARTUP TRANSFORMER 1
3.0 LIGHT LOAD ON STANDBY TRANSFORMER 2
4.0 LOCA ON STANDBY TRANSFORMER 3
5.0 LOCA ON STARTUP TRANSFORMER 5
6.0 CONCLUSION
5 ATTACHMENTS Tables 1, 2,
3, and 4 P3 ant Single-Line Diagram, Drawing 7884-E-1, Rev 6 W
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t 6
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1.0 TASK OBJECTIVE This report provides a description of the methods used and the results of a verification test of the utation electric distri-bution system voltages for the Duane Arnold Energy Center (DAEC).
The test was performed to verify analyses of the adequacy of the offsite and onsite distribution system of DAEC.
The analysis and test were performed in accordance with the NRC letter to all power reactor licensees dated August 8, 1979.
The test was conducted at the DAEC on April 13, 1980, during the refueling outage.
2.0 LIG!!T LOAD ON STARTUP TRANSFORMER The procedure for this test involved the following:
2.1 Verify that the startup transformer is supplying all required plant auxiliary loads for this case.
2.2 Verify that the actual test light load does not exceed the T
estimated light load.
2.3 Record the steady-state voltages and currents for all safety-re'Ited buses.
A summar. of the test results and analysis is provided in Table 1 as described below.
Column i indicates the actual measured values taken at the DAEC on April 13, 1980.
Column 1 indicates calculated values determined through a load flow co puter simulation of the DAEC auxiliary power system.
The measurea input data such as switchyard voltage, running load, and starting load were entered into the computer program.
The resulting voltages at the dif ferent buses were calculated and are lis ted.
Column 3 indicates the percent variance of calculated voltage values from measured values.
The calculated results are within + 1.2% of the measured values, which indicates a very good correlation.
As such, the test results verify the auxiliary system model for light load conditions supplied by the startup transformer.
n
i Column 4 indicates calculated values which represent an extrapolation to the maximum system voltage for light load.
Maximum voltage at the switchyard (105%) results in a high value of 110.8% (460 V base) on 480 V load center 1B3, which is judged to be acceptable.
Note that the total safety-related auxiliary system load measured was 1.928 MVA versus 2.735 MVA which had been previously estimated in the analysis.
This was expected because the plant was in a ref ueling outage condition when these measurements were taken.
It is anticipated that this measured condition is by far the lightest load that will be experienced.
During normal operation, it is expected that the total loading will be somewhat greater, and con-sequently the voltages will be somewhat lower.
In summary, the test results verified that the system, when connected to the startup transformer, performs satisf actorily under light load for maximum switchyard voltage.
3.0 LIGHT LOAD ON STANDBY TRANSFORMER The procedure for this test involved the following :
3.1 Verify that the standby transformer is s applying all required plant auxiliary loads for this case.
3.2 Verify that the actual test light load does not exceed the es tinated light load.
3.3 Record the steady-state voltages and currents for all safety-related buses.
A summary of the test results and analysis is provided in Table 2 as described below.
The measured results and corresponding calculated values of this table follow the same sequence and rationale as described for Table 1.
Again, the calculated values for the duplicate cases exhibit good correlation with the measured values (+ 2.5%).
This in turn verifies the computer auxiliary system model for light load conditions supplied by the standby transformer.
Extrapolation to the maximum system voltage for light load is indi-cated in Column 4.
Maximum voltage at the switchyard (105%) results in a high value of 110.1% (460 V base) on 480 V load center 184, which is judged to be acceptable.
As discussed for Table 1, this measured condition is by far the lightest load expected.
l l
2 l
In summary, the test results verified that the system, when connected to the standby transformer, performs satisfactorily under light load for maximum switchyard voltage.
4.0 LOCA ON STANDBY TRANSFORMER i
The procedure for this test involved the following:
4.1 Verify that the standby transformer is supplying all required plant auxiliary loads and is available for starting all required safety-related loads on LOCA.
4.2 Align all core spray and RHR pumps for full-flow test operation.
4.3 Connect LOCA test switch to simulate accident conditions.
4.4 Start recorders.
4.5 Turn LOCA test switch to the test position.
4.6 Verify that all LOCA loads started.
,- 7 4.7 Res tore station to normal conditions.
A sunmary of the test results and analysis is provided in Table 3 as described below.
Colunn 1 indicates the actual measured values taken at the DAEC on April 13, 1980.
The values shown are minimum values which occurred approximately 0.45 second af ter test initiation.
Column ? indicates calculated values determined through the use of the load flow computer simulation of the DAEC auxiliary power system.
Colunn 3 indicates the percent variance of the calculated voltage values from measured values.
Note that the variance for the voltage reading on 480 V load center 183 is +14.5%.
Review of the voltage traces before trip of the LOCA simulation switches indicates that the trace for 480 V load center 1B3 was miscalibrated.
The trace shows a voltage value of 93.7% (460 V base).
The expected value, based on a straight-forward voltage drop calculation using the measured current, is 109.1% (460 V base).
This provides evidence that the subject trace was miscalibrated.
The other variances are within
+ 4.8%, which is deemed to be an acceptable correlation.
3
, Column 4 indicates calculated values which represent an extrapolation to the minimum system voltage for a LOCA on the standby transformer.
Minimum voltage at the switchyard (95%) results in a low value of 82.9%
(46G V base) on 480 V load center 1B4, which is judged to be acceptable based on an acceptance criterium of 82.67% (460 V base)
An acceptance criterium of 87.4% (460 V base) had been generated as part of the analysis that was communicated to the NRC in our previous submittal.
This criterium was based on the requirement of 80% (460 V base) terminal voltage at the terminals of a specific motor-operated valve.
A separate test was conducted for that motor-operated valve, and verified that the valve will stroke with 67.4% (460 V base) terminal voltage.
It may, in fact, stroke at a lower voltage, but the available voltage source (onsite diesel generator) could not be adjusted to a lower voltage value.
This value translated to a value of 74.8% (460 V base) at the 480 V load center buses.
Because this valve is no longer the wors t case, the other various motor-operated valves become the limiting condition with 82.6% (460 V) required at the 480 V load center bus.
This value is based on an 80% (460 V) terminal voltage at the other various motor-operated valves.
Consequen tly, this is judged to be a conservative criteria.
Voltages on 480 V load centers 1B20 and 1B9 fall to lows of '
l.1%
a nd 7 8. 5% (460 V base), respectively.
This is acceptable because no automatic pickup of loads is required on these load centers for a LOCA with of fsite power available.
Continued system opera-tion is required, and therefore dropout of motor control center contactors becomes a concern.
Dropout for the contactors is in the range of 58%; therefore, this voltage is acceptable.
Review of the voltage traces indicated that the voltages reached the minimum at approximately 27 cycles af ter initiation of the LOCA simula tion.
At approximately 161 cycles (approximately 2.7 seconds), the voltages recovered to near nominal values.
The recovered voltage values are as follows:
Voltage (motor voltage base)
Bus
(%)
l 1A3 107 1A4 104 1
1B3 91 1B4 105 189 99 1B20 99 l
l
This recovery time (2.7 seconds) is well below the melting time for motor control center control circuit fuses and the trip time for motor overloads.
This f ast response or recovery of the system is added assurance that adequate voltage will be available a nd that the system will perform as intended under worst-case conditions.
Although small current variations were observed, no measurable quantity of starting loads was noted on 480 V load center buses 1B3 a nd 1B4.
There was no apparent ef fect on the associated bus voltages.
In summary, the test results verified that the system, when con-nected to the standby transformer, performs satisfactorily under LOCA, for minimum grid voltage.
5.0
,LOCA ON STARTUP TRANSFORMER This particular loading situation was not specifically investigated by test.
An analysis was conducted with the same input values for the safety-related buses that were measured for the LOCA on the s tandby trans former.
The calculated values indicate that the sys tem will perform satisfactorily under the given situation.
Additionally, the LOCA on the standby transformer is judged to be the worst case, based on the fact that the standby transformer is a smaller capacity (MVA) transformer than the startup transformer.
This was verified by the calculated values.
6.0 CONCLUSION
In summary, the test and analysis verified that the offsite and onsite electrical distribution system at the DAEC has sufficient capaci ty to perform its intended function as designed.
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LIGilT IBAD ON STARTUP TRANSFORMER Percent Variance Maximum System Measured Test Values Duplicate Analysis of Caldalated Voltage Case
(%)
Values (%)
From Measured (%)
Values (%)
161 kV switchyard voltage 104.2 104.2 105 Tap Settings Startup 1.0 1.0 1.0 LC 183
.975
.975
.975 LC IB4
.975
.975
.975 Volt LDRN LDST Volt LDRN LDST Voltage Volt LDRN LDST Safety-related bus data 4 kV buses IA3 107.0
.245 0
108.2.245 0
+1.2 109.0
.245 0
1A4 107.0
.66 0
108.1.66 0
+1.1 108.9
.66 0
480 V LC buses IB3 110.9 445 0
110.0.445 0
-0.9 110.8
.445 0
184 110.9
.482 0
109.8.482 0
-1.1 110.6
.482 0
189 106.5
.052 0
105.6.052 0
-0.9 106.4
.052 0
1820 106.5
.044 0
105.6.044 0
-0.9 106.4
.044 0
Notes:
-- = Not applicable for stated case Volt = Percent voltage at bus on motor voltage base LDRN = Running load at bus in MVA LDST = Starting load at bus in MVA h
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. AI:1.F. 2 LIGHT LF AD ON STANDBY TRANSFORMER Percent Variance Maximum System Measured Test Values Duplicate Analysis of Calculated Voltage Case isi Values (4)
From Mer,iutat (%)
values (%)
' 161 kV switchyard voltage 103.4 103.4 105 Tap Settings Standby 1.0 1.0 1.0 LC 183
.975
.a75
.975 LC 184
.975
.975
.975 i
Volt LDRN LDST Volt LDRN LDST Voltage Volt LDRN LDST Safety-related bus data l
4 kV buses IA3 105.5
.292 0
106.6.292 0
+1.1 108.3
.292 0
1A4 105.5
.694 0
106.6.694 0
+1.1 108.3
.694 0
480 V LC buses IB3 110.4
.475 0
108.2.475 0
-2.2 110.0
.475 0
184 110.4
.439 0
108.3.439 0
-2.1 110.1
.439 0
189 106.5
.037 0
104.2.037 0
-2.3 105.8
.037 0-1820 106.5
.037 0
104.0.037 0
-2.5 105.7.037 0
Notes:
-- = Not applicable for stated case Volt = Percent voltage at bus on motor voltage base LDRN = Running load at bus in MVA LDST = Starting load at bus in MVA 1
4
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4
J 3Hl.i' LOC A NJ STANDflY TRANSFORMER Percent Variance Minimum System Measured Tm t Values D splic ate Analysis of Calculate 1 Voltage Case
(%)
Valoes (A)
From B anurr1 (+)
Values (%)
161 kV switchyard voltage 103.65 103.65 95 Tap Settings Standby 1.0 1.0 1.0 LC 1B3
.975
.975
.975 LC IB4
.975
.975
.975 Volt LDRN LDST Volt LDRH LDST Voltage Volt LDRN LDST Safety-related bus data 4 kV buses IA3 88.4
.463
.904 90.7
.463
.904
+2.3 82.8
.463
.904 1A4 95.5
.478 1.751 90.7
.478 1.751
-4.8 82.8
.478 1.751 480 V LC buses IB3 77.0
.494 0
91.5
.494 0
+14.5*
83.2
.494 0
184 88.7
.557 0
91.3
.557 0
+2.6 82.9
.557 0
IB9 83.5
.258 0
86.5
.258 0
+3.0 78.5
.258 0
IB20 83.5
.557 0
80.1
.557 0
-3.4 71.1
.557 0
Notes:
-- = Not applicable for stated case Volt = Percent voltage at bus on motor voltage base LDRN = Running load at bus in MVA LDST = Starting load at bus in MVA
, Miscalibration in measured value, see text Section 4.0.
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3 01.!? 4 LOCA ON STARTUP TRANSFORM!'R Minimum System Voltage Case Values (%)
161-kV suitchyard voltage 95 Tap Settings Startop 1.0
' II lit 3
.975 LC lis.:
.975 Volt LDRN LDST Safety-rr: lated bus data 4-kV hones lA3 89.2
.463
.904 1A4 86.7
.478 1.751 4bo-V LC buses In:'
89.9
.494 0
184 87.1
.557 0
IB9 84.9
.258 0
1820 79.2
.557 0
1:o: ca r 2,v-rela ted bus data 4-XV 1r..ncs lAl 89.2 11.513 0
1A2 86.7 11.513 0
480-V L' buses In!
81.9 1.25 0
1R2 79.4 1.25 0
1n5 79.7 1.5 0
136 77.0 1.5 0
)
187 77.0 2.0 0
108 74.2 2.0 0
NOfl?S :
1 Volt = Percent voltage at bus on motor voltage base LDRN = Running load at bus in MVA LDST = Starting load at bus in MVA
TABLE 1 LIGIT LOAD O*4 STARWP TRANSFORMER Percent Variance Maximum System Measured Test Values Duplicate Analysis of Calculated Voltage Case
(%)
Values (%)
From Measured (%)
Values (%)
161 kV switchyard voltage 104.2 104.2 105 Tap Settings I
Startup 1.0 1.0 1.0 LC 183
.975
.975
.975 LC IB4
.975
.975
.975 Volt LDRN LDST Volt LDRN LDST Voltage Valt LDRN LDST Safety-related bus data 4 kV buses IA3 107.0
.245 0
108.2.245 0
+1.2 109.0
.245 0
1A4 107.0
.66 0
108.1.66 0
+1.1 108.9
.66 0
480 V LC buses 1B3 110.9
.445 0
110.0.445 0
-0.9 110.8 445 0
184 110.9
.482 0
109.8.482 0
-1.1 110.6
.482 0
IB9 106.5
.052 0
105.6.052 0
-0.9 106.4 052 0
1B20 106.5 044 0
105.6.044 0
-0.9 106.4
.044 0
Notes:
-- = Not applicable for stated case Volt = Percent voltage at bus on motor voltage base LDRN = Running load at bus in MVA LDST = Starting load at bus in MVA 1
0 k
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_ = _ _
TADLE 2 LIGHT LOAD ON STANDBY TRANSFORMER Percent Variance Maximum System Measured Test Values Duplicate Analysis of Calculated Voltage Case
(%)
values (%)
From Measured (%)
Values (%)
161 kV switchyard voltage 103.4 103.4 105 Tap Settings Standby 1.0 1.0 1.0 LC IB3
.975
.975
.975 LC IB4
.975
.975
.975 Volt LDRN LDST Volt LDRN LDST Voltage Volt LDRN LDST Safety-related bus data 4 kV buses IA3 105.5
.292 0
106.6.292 0
+1.1 108.3
.292 0
1A4 105.5
.694 0
106.6.694 0
+1.1 108.3
.694 0
480 V LC buses IB3 110.4
.475 0
108.2.475 0
-2.2 110.0.475 0
184 110.4
.439 0
108.3.439 0
-2.1 110.1
.439 0
189 106.5
.037 0
104.2.037 0
-2.3 105.8
.037 0
1820 106.5
.037 0
104.0.037 0
-2.5 105.7.037 0
3 Notes
-- = Not applicable for stated case Volt = Percent voltage at bus on motor voltage base LDRN = Running load at bus in MVA LDST = Starting load at bus in MVA 9
0
E$.'$ :
LOCA ON STAf;DBY TRANSFORMER Percent Variance Minimum System Measured Test Values Duplicate Analysis of Calculated Voltage Case
(%)
Values (%)
From Meanureel (%)
Values (%)
161 kV switchyard voltage 103.65 103.65 95 Tap Settings Standby 1.0 1.0 1.0 LC IB3
.975
.975
.975 LC 184
.975
.975
.975 Volt LDRN LDST Volt LDRN 2 DST Voltage Volt LDRN LDST Safety-related bus data 4 kV buses IA3 88.4
.463
.904 90.7
.463
.904
+2.3 82.8
.463
.904 1A4 95.5
.478 1.751 90.7
.478 1.751
-4.8 82.8
.478 1.751 480 V LC buses 183 77.0
.494 0
91.5
.494 0
+14.5*
83.2
.494 0
IB4 88.7
.557 0
91.3
.557 0
+2.6 82.9
.557 0
189 83.5
.258 0
86.5
.258 0
+3.0 78.5
.258 0
1B20 83.5
.557 0
80.1
.557 0
-3.4 71.1
.557 0
Notes:
-- = Not applicable for stated case Volt = Percent voltage at bus (n motor voltage base LDRN = Running load at bus in PVA LDST = Starting load at bus in MVA
- Miscalibration in measured value, see text Section 4.0.
0
TABI.E 4 LOCA ON STARTUP TRANSFORMER Minimum Sys tem Voltage Case Values (?)
361-kV suitchyard voltage 95 i
Tap Settings Startup 1.0 LC 1B3
.975 LC 1H4
.975 r
sa e! y_--rel a ted bus da ta 4-kV buser 173 89.2
.463
.904 1A4 86.7
.478 1.751 l
480-V LC buses
.~
1B3 89.9
.494 0
1B4 87.1
.557 0
1B9 84.9
.258 0
1D20 79.2
.557 0
t:onsto;gg-related bus data 4-:CJ bunes
)
1A1 89.2 11.513 0
1A2 86.7 11.513 0
l l
480 " LC buses i
181 81.9 1.25 0
182 79.4 1.25 0
1B5 79.7 1.5 0
186 77.0 1.5 0
1B7 77.0 2.0 0
IB P.
74.2 2.0 0
NOTES:
Vo l t = P,rcent voltage at bus on motor voltage base LDRN = Ruining load at bus in MVA LDST = Starting load at bus in MVA t
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