5-
10
DGP Digital Generator Protection System
GE Power Management
5.3 MEASURING UNIT TESTS
5 PERIODIC TESTS
5
5.3.7 T10: TIME OVERCURRENT WITH VOLTAGE RESTRAINT 51V
1.
Record the following Settings:
51V
(1003) PICKUP (Overcurrent Pickup) = ______ A
(1004) TIME FAC (Time Factor
K
) = ______ sec.
2.
Time Overcurrent is calculated with the following equation:
(equation 5–6)
where:
K
= time factor
I
= phase current
V
NOM
= nominal voltage
I
pu
= pickup level for overcurrent
V
= phase to phase voltage
The time factor
K
is Setting 1004: TIME FAC. Phase current
I
is the current applied to any one phase.
Nominal voltage
V
NOM
is Setting 114: NOM VOLT, the pickup level for overcurrent
I
pu
is Setting 1003:
PICKUP, and the phase to phase voltage
V
is the voltage in the corresponding phase. If the value of phase
current is greater than Setting 1003: PICKUP, the test pickup will operate. If the phase current is above
Setting 1003: PICKUP for a time equal to Trip Time, the test trip relay will operate.
3.
Connect relay as shown in Figure 4–8: STANDARD FUNCTIONAL TEST CONNECTIONS on page 4–26.
4.
Set up relay in test mode for the 51V function; 51V ON will be displayed on the MMI.
5.
Using a 60 Hz source set the voltage (rms) inputs to:
VA = 70 V
∠
0
°
VB = 70 V
∠
–120
°
VC = 70 V
∠
–240
°
6.
Set the current input to PICKUP + 0.1 (0.02) =______ A rms and apply to the relay. The test pickup relay
should operate immediately and the test trip relay should operate after the Trip Time has expired.
7.
Lower the current to PICKUP – 0.1 (0.02) =______ A rms and the test pickup and test trip relays should
not operate.
8.
Apply DC voltage across DI6 (BE2—BE1). Using the MMI and the INFORMATION–VALUES command,
verify that EXT VTFF = CLOSE.
9.
Set the current input to PICKUP + 0.1 (0.02) =______ A rms and apply to the relay. Verify that the test
pickup operates but the test trip does not operate.
10. While continuing to input the current, remove the DC from DI6 (BE2—BE1). The test pickup operates
immediately and test trip operates after Trip Time expires.
Trip Time
K
I V
NOM
⋅
(
)
I
pu
V
⋅
(
)
⁄
1
–
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=
Summary of Contents for DGP Series
Page 2: ......
Page 4: ......
Page 192: ...8 18 DGP Digital Generator Protection System GE Power Management 8 5 PASSWORDS 8 INTERFACE 8...
Page 260: ...B 4 DGP Digital Generator Protection System GE Power Management B 1 CHANGE NOTES APPENDIXB B...
Page 262: ...B 6 DGP Digital Generator Protection System GE Power Management B 1 CHANGE NOTES APPENDIXB B...
Page 268: ...D 2 DGP Digital Generator Protection System GE Power Management D 1 DGP WARRANTY APPENDIXD D...
Page 276: ...viii DGP Digital Generator Protection System GE Power Management INDEX INDEX...
Page 277: ...GE Power Management DGP Digital Generator Protection System NOTES...
