GE 750 Instruction Manual page 357

CHAPTER 7: COMMISSIONING
750 FEEDER MANAGEMENT RELAY – INSTRUCTION MANUAL
 Assert a logic input to provide a "Block Phase Time 2".
The Pickup LED should immediately go out.
 Repeat Steps 1 and 2 for logic inputs "Block Phase O/C", "Block All O/
C" and "Block 1 Trip Relay" as required.
Phase IOC 1
The procedure to test this element is identical for Phase TOC 1, except for the procedures
below. Pickup, indication and operation are subject to the "phases required for operation"
test, but not subject to the "linear reset timing" and "voltage restrained Phase TOC" tests.
The following procedure checks pickup with two phases for operation:
 Inject current into Phase B at 150% of pickup.
 Inject current at a level below the pickup level into Phase A.
 Slowly increase the Phase A current until the Pickup LED comes on and
note the pickup value.
 Slowly reduce the Phase A current until the Pickup LED goes out.
Note the dropout level, which should be 2% of CT less than pickup
when pickup
 Repeat last 4 steps for phase pair B and C and phase pair C and A.
The following procedure checks pickup with three phases for operation:
 Inject current into Phases B and C at 150% of pickup.
 Inject current at a level below the pickup level into Phase A.
 Slowly increase the Phase A current until the Pickup LED comes on and
note the pickup value.
 Slowly reduce the Phase A current until the Pickup LED goes out and
note the dropout level, which should be 2% of CT less than pickup when
pickup
 Repeat last 4 steps for current at 150% in Phases C and A and adjusted
in B.
 Repeat last 4 steps for current at 150% in Phases B and A and adjusted
in C.
The following procedure checks the blocking from logic inputs:
 Inject current into the required number of phases to cause a pickup.
 Assert a logic input to provide a "Block Phase Inst 1".
The Pickup LED should immediately go out.
 Repeat last 2 steps for logic inputs "Block Phase O/C", "Block All O/C"
and "Block 1 Trip Relay" as required.
The following procedure checks Phase IOC 1 timing:
 Connect the Stop Trigger to the interval timer.
 Preset the current source to a minimum of 110% of pickup current, then
turn the current off and reset the timer.
≤
CT or 97 to 98% of pickup when pickup
≤
CT, or 97 to 98% of pickup when pickup > CT.
PROTECTION SCHEMES
>
CT.
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