GE 750 Instruction Manual page 362

PROTECTION SCHEMES
Note
NOTE
7 - 34
 Slowly increase the angle of the Phase A current in the lagging
direction.
At an angle lagging Van by 270° ±2°, any output relays programmed for
this condition should operate if the function is set to "Control". If the
function is set to "Alarm", check that the Alarm and Message LEDs are
flashing, the Neutral Directional Reverse alarm message is displayed,
and any output relays programmed for this condition are operated.
 Continue to increase the lagging angle through 0°, until the block
message disappears at an angle lagging V
 Turn the current off.
 If desired, repeat the above Steps for Phases B and C using I
faulted phase voltage V
To test forward tripping with current polarization, use the test connections specified and
procedure specified below:
FIGURE 7–5: Neutral Directional Test Connection for Polarizing Current
The following description presents angles with reference to the polarizing current.
 Set a current of 0.2 of nominal and inject into the ground current input
(Terminals G10 and H10).
 Set a 3I
(this is the trip direction) and inject into the relay via the phase current
inputs.
and I with faulted phase voltage V
bn c
current to 0.2 of nominal and in-phase with the ground current
0
750 FEEDER MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 7: COMMISSIONING
by 90° ±2°.
an
with
b
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