Protection Elements - GE B90 Instruction Manual

SPECIFICATIONS

2.5.1 Protection elements

The operating times include the activation time of a trip rated form-A output contact unless otherwise indicated. FlexLogic
operands of a given element are 4 ms faster. Take this into account when using FlexLogic to interconnect with other
protection or control elements of the relay, building FlexLogic equations, or interfacing with other intelligent electronic
devices (IEDs) or power system devices via communications or different output contacts. If not specified, the operate times
given here are for a 60 Hz system at nominal system frequency. Operate times for a 50 Hz system are 1.2 times longer.
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BUS DIFFERENTIAL (87B)
Pickup level:
Low slope:
High slope:
Low breakpoint:
High breakpoint:
High set level:
Dropout level:
Level accuracy:
0.1 to 2.0 × CT rating:
>2.0 × CT rating
Operating time:
Number of zones:
Max number of inputs:
CT TROUBLE
Responding to:
Pickup level:
Pickup delay:
Timer accuracy:
Availability:
ISOLATOR MONITORING
Responding to:
Asserting:
Alarm pickup delay:
Timer accuracy:
TIME OVERCURRENT
Pickup level:
Dropout level:
Level accuracy:
0.1 to 2.0 × CT
above 2.0 × CT
Curve shapes:
TD multiplier:
Reset type:
Curve timing accuracy at 1.03 to 20 x pickup:
INSTANTANEOUS OVERCURRENT
Pickup level:
Dropout level:
Level accuracy:
0.1 to 2.0 × CT
above 2.0 × CT
2-16
0.050 to 6.000 pu in steps of 0.001
15 to 100% in steps of 1
50 to 100% in steps of 1
1.00 to 30.00 pu in steps of 0.01
1.00 to 30.00 pu in steps of 0.01
0.10 to 99.99 pu in steps of 0.01
97 to 98% of pickup
±0.5% of reading or ±1% of rated (whichever is greater) for six circuits or less in the zone
±1.5% of reading of the maximum circuit current
one power system cycle (typical)
1 or 6 (option)
8, 16, or 24 (option)
Differential current
0.020 to 2.000 pu in steps of 0.001
1.0 to 60.0 sec. in steps of 0.1
±3% of operate time or ±1/4 cycle (whichever is greater)
one per zone of protection
Both normally-open and normally-closed auxiliary contacts
Isolator Position, Isolator Alarm, Block Switching
0.00 to 120.00 s in steps of 0.05
±3% of operate time or ±1/4 cycle (whichever is greater)
0.020 to 30.000 pu in steps of 0.001
97 to 98% of pickup
0.5% of reading or 1% of nominal (whichever is greater)
1.5% of reading
IEEE Moderately/Very/Extremely Inverse; IEC (and BS) A/B/C and Short Inverse; GE IAC Inverse,
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Short/Very/Extremely Inverse; I t; FlexCurves™ (programmable); Definite Time (0.01 s base
curve)
0.00 to 600.00 in steps of 0.01
Instantaneous or Timed (per IEEE)
±3.5% of operate time or ±1/2 cycle (whichever is greater) from pickup to operate
0.020 to 30.000 pu in steps of 0.001
97 to 98% of pickup
0.5% of reading or 1% of nominal (whichever is greater)
1.5% of reading
B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CHAPTER 2: PRODUCT DESCRIPTION