GE 750, Instruction Manual

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GE Power Management 750/760 Feeder Management Relay 17-
53
17 COMMISSIONING 17.9 CONTROL SCHEMES
17
17.9.2 SYNCHROCHECK
1. Make test connections per Figure 17–1: RELAY TEST WIRING – WYE CONNECTION or Figure 17–2:
RELAY TEST WIRING – DELTA CONNECTION on page 17–4 and also connect a variable voltage source
to the line voltage input.
2. Initially set the function setpoint to Control, the Dead Source Permissive setpoint to Off and the Maximum
Voltage Difference setpoint to 100 kV.
3. As there are no input voltages, any selected output relays should now be operated along with the Out Of
Sync control message.
4. Change the function setting to Alarm. The alarm message and LED should be displayed, and any selected
output relays should remain operated.
5. Inject a balanced three-phase voltage at nominal voltage and frequency into the bus voltage input.
6. Turn off the voltage and make parallel connections (observing polarity) from the bus voltage input that cor-
responds with the selection made under subheading
S2 SYSTEM SETUP \ LINE VT SENSING \ VT CONNECTION
to
the line voltage input. Turn the voltage on and check that these voltages show difference measurements of
0 under
A2 METERING \ VOLTAGE \ SYNCHRO DELTA
. (The
∆
V will not be 0 unless the bus and line VTs have
identical ratings. If the difference is not shown as 0, calculate the two equivalent primary voltage values for
the injected voltage; they should be the same.) This checks that the relay has selected the correct bus volt-
age input for the synchrocheck measurements. Turn the voltage off and remove the parallel connections.
7. Inject a single-phase voltage at nominal voltage and frequency into the bus voltage input that corresponds
with the selection made under subheading
S2 SYSTEM SETUP \ LINE VT SENSING \ VT CONNECTION
.
8. Inject voltage and frequency into the line voltage input and adjust this voltage until
∆
V,
∆Φ
and
∆
F as
shown under subheading
A2 METERING \ VOLTAGE \ SYNCHRO DELTA
are all 0. Reduce the line voltage magni-
tude to 0.
9. The “Out of Sync” alarm will be displayed as the line voltage is below the minimum voltage requirement.
Slowly raise this voltage until the “Out of Sync” alarm is no longer displayed. This magnitude should be the
setpoint value.
10. Raise the line voltage input to the nominal value, and lower the bus voltage magnitude to 0. The “Out of
Sync” alarm will be displayed as the bus voltage is below the minimum voltage requirement. Slowly raise
this voltage until the “Out of Sync” alarm is no longer displayed. This magnitude should be the setpoint
value.
11. Enter the required setting of Maximum Voltage Difference. The “Out of Sync” alarm will be displayed as the
voltage difference is above the maximum difference requirement.
12. While monitoring
∆
V on the display, slowly raise the bus voltage until the “Out of Sync” alarm is no longer
displayed. Check that the voltage difference is the selected value.
13. Set the bus voltage magnitude to nominal, and the line voltage to a level above the minimum required volt-
age.
14. The “Out of Sync” alarm will be displayed as the voltage difference is above the maximum difference
requirement.
15. While monitoring
∆
V on the display, slowly raise the line voltage until the “Out of Sync” alarm is no longer
displayed. Check that the voltage difference is the selected value.
16. Set both line and bus voltage magnitude and frequency to nominal. Adjust the line voltage phase position
to lag the bus voltage by 180
°
.
17. The “Out of Sync” alarm will be displayed as the angle difference is above the maximum difference require-
ment.