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6.4 BACKUP PROTECTION TESTS
6.4 BACKUP PROTECTION TESTS
1.
Protection Settings:
OVERCURRNT
(601)
50 = YES
(602)
50_DIRCNL = NO
(603)
50PICKUP = [_________] amps
50 is calculated with the following equation:
50 = ( I
– I
) or ( I
A
B
where 50 is the difference in phase-to-phase current. The test current, I
through another to simulate a phase-to-phase fault. When an AB fault is applied, the difference
( I
– I
) equals ( I
A
B
op
2.
Connect the relay as shown in Figure 5–1: PHASE-TO-PHASE TEST CONNECTIONS on page 5–6 for a phase AB,
BC, or CA fault.
3.
Set the relay into test mode 43 (Phase Overcurrent). The LUI should display: INST PHS OVRC ON
4.
Set I
= 0.5·50 + 0.05·50 = [________] amps rms and apply to the relay. The A1 contact should close. Lower I
op
0.5·50 – (0.05·50) = [________] amps rms; the A1 contact should open.
5.
Reduce I
to zero.
op
1.
Protection Settings:
OVERCURRNT
(605)
50G = YES
(606)
50G_DIRCNL = NO
(607)
50GPICKUP = [_________] amps,
6
50G is given by:
where I
is the zero-sequence current and I
0
phase, I
and I
are given by
0
1
I
= I
/ 3
0
op
Substituting Equations 6–13 and 6–14 into Equation 6–12 yields
50G = I
– 0.3 I
op
Therefore IPT will pick up when I
2.
Connect the relay as shown in Figure 4–3: PHASE TO GROUND TEST CONNECTIONS on page 4–12.
3.
Set the relay into test mode 44 (Ground Overcurrent). The LUI displays: INST GND OVRC ON
4.
Set I
to (50G / 0.7) + 0.5 = [________] amps rms and apply to the relay. The A1 contact should close. Lower I
op
(50G / 0.7) – 0.5 = [________] amps rms; the A1 contact should open.
5.
Reduce I
to zero.
op
6.
Change the setting of 50G_DIRCNL back to YES to restore directional control, if required.
6-8
– I
) or ( I
– I
)
(eq. 6–11)
B
C
C
A
– (– I
)) = 2 I
. Therefore 50 will pick up when I
op
op
×
×
50G =
I
I
3
–
0.9
0
1
is the positive-sequence current. Since the test current, I
1
(eq. 6–13)
and
I1 = I
/ 3
op
= 0.7 I
(eq. 6–15)
op
op
= 50G / 0.7.
op
ALPS Advanced Line Protection System
6 FUNCTIONAL TESTS (USER SETTINGS)
6.4.1 T9 – PHASE INSTANTANEOUS OVERCURRENT 50
, is connected to one phase and returned
op
= 0.5 x 50
op
6.4.2 T10 – GROUND INSTANTANEOUS OVERCURRENT 50G
(eq. 6–12)
(eq. 6–14)
to
op
, is single-
op
to
op
GE Power Management
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