S2 System Setup; Current Sensing - GE Multilin 350 Series Instruction Manual

CHAPTER 6: SETPOINTS

6.3 S2 System Setup

S2 SYSTEM SETUP

CURRENT SENSING

POWER SYSTEM
▼
BREAKER SETUP
USER CURVE
FLEXCURVE A
FLEXCURVE B
898781.cdr
6.3.1 Current sensing
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
Courtesy of NationalSwitchgear.com
S2 USER CURVE
PATH:
SETPOINTS > S2 SYSTEM SETUP > CURRENT SENSING
PHASE CT PRIMARY
Range: 1 A to 6000 A
Default: 500 A
Enter the primary rating of the three-phase feeder CTs wired to the relay phase CT
terminals (see above). For correct operation, the relay CT tap must match the feeder CT
tap (5 A or 1 A).
As the phase CTs are connected in wye (star), the calculated phasor sum of the three
phase currents (Ia + Ib + Ic = Neutral Current = 3I
overcurrent. In addition, a zero-sequence (core balance) CT which senses current in all of
the circuit primary conductors, or a CT in a neutral grounding conductor may also be
used.
S2 CURRENT SENSING
PHASE CT PRIMARY
▼
[SENS] GROUND CT PRIMARY
S2 POWER SYSTEM
NOMINAL FREQUENCY
▼
SYSTEM ROTATION
S2 BREAKER SETUP
52a CONTACT
▼
52b CONTACT
BKR CONNECTED
S2 FLEXCURVE A
) is used as the input for the neutral
0
S2 SYSTEM SETUP
S2 FLEXCURVE B
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