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10 COMMISSIONING
f) WINDING #2 AND #3 ELEMENTS
Because the Winding 2 and 3 elements can be set with completely different parameters than the elements for
Winding 1, it is necessary to repeat the full set of tests described above for each winding.
The blocking from logic input, if enabled, can be tested as described in earlier tests for other
elements.
NOTE
This procedure verifies that the Phase Instantaneous overcurrent performance matches the in-service settings.
The settings for these elements are found under:
SETPOINTS/S4 ELEMENTS/PHASE OC/W1 PHASE INST. OC 1, W2..., W3...
The testing occurs at current multiples of at least five times the rated CT secondary value. Do not leave the
current signal on for more than a few seconds!
a) WINDING #1 ELEMENTS
To ensure that only the Phase Instantaneous Overcurrent 1 element operates the trip relays (and any other
output relays) selected by the logic, disable all protection features except Phase Instantaneous Overcurrent 1.
Use the general test setup shown in Figure 10–9: GENERAL TEST SETUP on page 10–21.
Connect the current supply to terminals X = H1 and Y = G1 to test the Winding 1 A-phase element. Monitor the
appropriate output relays as per the relay FlexLogic settings.
b) PICKUP LEVEL
1. With the interval timer disabled, apply the current signal and increase its magnitude until the trip relay (and
all selected auxiliary relays) operate. Compare the measured operating level against the relay setpoints:
SETPOINTS/S4 ELEMENTS/PHASE O/C/W1 PHASE INST OC 1/W1 PHASE INST OC 1 PICKUP
2. Check that TRIP, PICKUP, and PHASE A (B or C) come on when the element operates. Check that the fol-
lowing message is displayed:
SS LATCHED (OPERATED) ∅A
SS W1 Phase Inst OC 1
3. Reduce the current until the element resets. The reset level should be 97% of the operate level. When the
element resets, the TRIP and PHASE indicators should remain on if the TARGET was selected as latched.
Otherwise, only the TRIP indicator should stay on.
4. Reset indicators and clear messages.
c) OPERATING TIME
Using the setup shown in Figure 10–9: GENERAL TEST SETUP on page 10–21 and the Interval Timer
enabled, set the current level to 1.5 times the operating level of the element. Apply current suddenly by closing
the double-pole switch. Record the operate time and compare it to the setpoint value for:
SETPOINTS/S4 ELEMENTS/PHASE O/C/W1 PHASE INST OC 1/W1 PHASE INST OC 1 DELAY
d) PHASE B AND C ELEMENTS
If the A-phase element performed correctly and met specifications, repeat the PICKUP LEVEL portion of the
above test for phases B and C of Winding 1. For the B-phase, X = H2 and Y = G2. For the C-phase, X = H3
and Y = G3. The displayed message should change to indicate the correct phase, winding, and element that
operated.
GE Power Management
10.6.5 PHASE INSTANTANEOUS OVERCURRENT 1
745 Transformer Management Relay
10.6 PROTECTION SCHEMES
10
10-23
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