GE Feeder Management Relay 750 User Manual

GE Multilin 750/760 Feeder Management Relay 8-31
8 COMMISSIONING TESTS 8.4 PROTECTION SCHEMES
8
For the following Frequency Decay test procedures, the injected voltage and currents are always above the
minimum operating levels.
The following procedure checks the Frequency Decay Pickup:
1. Starting with the V
a
frequency at a level well above the FREQ DECAY PICKUP, drop the frequency of V
a
at a speed
greater than the FREQ DECAY RATE setting, to a level still well above the FREQ DECAY PICKUP. The Pickup LED should
remain off.
2. Continue dropping the V
a
frequency at a speed greater than the FREQ DECAY RATE. When the frequency drops below
the
FREQ DECAY PICKUP, the Pickup LED will come on.
The following procedure checks the Frequency Decay Rate:
1. With the V
a
frequency at a level well below the FREQ DECAY PICKUP, drop the frequency of V
a
at a speed less than the
FREQ DECAY RATE setting. The pickup indicator should remain off.
2. With the V
a
frequency at a level well below the FREQ DECAY PICKUP, drop the frequency of V
a
at a speed greater than
the FREQ DECAY RATE setting. The pickup indicator will come on.
The following procedure checks Blocking From Logic Inputs:
1. Decrease the Va frequency at a rate to cause a pickup.
2. Assert a logic input to provide a "Block Frequency Decay". The Pickup LED should immediately go out.
3. Repeat Steps 1 and 2 for logic input “Block 1 Trip Relay” as required.
The following procedure checks the Frequency Decay Timing:
1. Connect the Stop Trigger.
2. Preset the ramp-rate to a minimum of 110% of the pickup and reset the timer.
3. Inject the preset voltage into the V
a
bus voltage input and note the measured delay time. Reset the timer.
4. Repeat Step 3 four more times and obtain an average of the time intervals.
5. Disconnect the Stop Trigger.
8.4.8 BREAKER FAILURE
To test Frequency Decay, use the test connections specified in Figure 8–1: Relay Test Wiring – Wye Connection or Figure
8–2: Relay Test Wiring – Delta Connection on page 8–3. The Indications and Operations are as outlined for Phase TOC 1
on page 8–16. This element has no Trip function.
1. Ensure the wiring to the circuit breaker trip and close circuits is complete.
2. Energize the breaker trip and close circuits and close the breaker.
3. Carefully disconnect a wire to open the trip circuit.
4. Set a test current level 3% above the
BRKR FAILURE CURRENT setpoint and inject current into a phase current input (all
overcurrent protection features are “Disabled”).
5. Assert a Trip logic input, which cannot be performed by the breaker. After a delay the element should generate an out-
put (the delay time can be checked in the Event Recorder). Turn the current off and reset the relay.
6. Reduce the current magnitude to 3% below the BRKR FAILURE CURRENT setpoint and inject current into a phase current
input. Assert a Trip logic input, which cannot be performed by the breaker. The element should not generate an output.
NOTE
Courtesy of NationalSwitchgear.com

GE Feeder Management Relay 750 Specifications

General

Brand	GE
Model	Feeder Management Relay 750
Category	Protection Device
Language	English