10-40
745 Transformer Management Relay
GE Power Management
10.6 PROTECTION SCHEMES
10 COMMISSIONING
10
SETPOINTS/S4 ELEMENTS/FREQUENCY/FREQUENCY DECAY/MINIMUM OPERATING VOLTAGE
6.
Repeat ramping action and verify that element does not operate.
If the voltage supervision level has been
set to 0.00, the element continues to operate correctly down to approximately 2% or nominal.
7.
Return voltage to nominal value.
8.
If current sensing is enabled, set the current level below the Minimum Operating Current value set under:
SETPOINTS/S4 ELEMENTS/FREQUENCY/FREQUENCY DECAY/MINIMUM OPERATING CURRENT
9.
Repeat ramping action and verify that element does not operate.
10. For timing tests, an approximate operate time is obtained if a timer is triggered at the same time as the
ramping action and the time interval between the trigger point and the relay operation measured. From that
measured time, subtract the time required for the frequency to reach the threshold value.
c) CURRENT INPUT FUNCTION (VOLTAGE INPUT DISABLED)
1.
Using a frequency-ramping programmable voltage/current source connected to terminals H1 and G1 for
the current signal, set the frequency to 60.00 Hz (or 50Hz). Set the current amplitude to rated CT second-
ary. Monitor the appropriate trip and auxiliary relays. Reset all alarms and indications on the relay. The
relay display should remain unchanged with no trip indications.
2.
Program the function generator to simulate a frequency rate-of-change just above Rate 1. The start fre-
quency should be the nominal frequency of the relay. The end frequency must be below the Frequency
Decay Threshold if the relay is to operate. Note that operation occurs if the rate criterion is satisfied and
the frequency is below the threshold.
3.
Initiate ramping action and verify that the element operates once the frequency drops below the threshold.
4.
Check that the TRIP and PICKUP LEDs are on and the following trip message is displayed:
If the target was selected as
Latched
, the trip LED and the message remain on.
5.
Set the current level to a value below the Minimum Operating Current set under:
SETPOINTS/S4 ELEMENTS/FREQUENCY/FREQUENCY DECAY/MINIMUM OPERATING CURRENT:
6.
Repeat ramping action and verify that element does not operate.
If current sensing has been disabled for
this element, operation will continue down to a current level of approximately 2% of nominal.
7.
For timing tests, an approximate operate time is obtained if a timer is triggered at the same time as the
ramping action and the time interval between the trigger point and the relay operation measured. From that
measured time, subtract the time required for the frequency to reach the threshold value. The expected
time must be computed using the rate of change and the effect of the time delay set under:
SETPOINTS/S4 ELEMENTS/FREQUENCY/FREQUENCY DECAY/FREQUENCY DECAY DELAY:
d) FREQUENCY DECAY RATE 2, 3, & 4
Repeat the above procedure for remainder of decay rate elements, making the necessary changes where
appropriate.
yy
LATCHED (OPERATED):
yy
Freq Decay Rate 1
Summary of Contents for 745 TRANSFORMER MANAGEMENT RELAY
Page 30: ...2 8 745 Transformer Management Relay GE Power Management 2 3 SECURITY 2 GETTING STARTED 2 ...
Page 210: ...7 36 745 Transformer Management Relay GE Power Management 7 2 BLOCK DIAGRAMS 7 SCHEME LOGIC 7 ...
Page 322: ...9 12 745 Transformer Management Relay GE Power Management 9 3 USING 745PC 9 745 PC SOFTWARE 9 ...
Page 396: ...A 4 745 Transformer Management Relay GE Power Management A 1 FIGURES AND TABLES APPENDIXA A ...
Page 400: ...C 2 745 Transformer Management Relay GE Power Management C 1 WARRANTY INFORMATION APPENDIXC C ...
Page 406: ...vi 745 Transformer Management Relay GE Power Management ...
Page 407: ...GE Power Management 745 Transformer Management Relay NOTES ...
