Measured Parameters; Protection Elements - GE 750 Instruction Manual

750/760
Feeder Management Relay

Measured Parameters

Protection Elements

2–8
In the following specifications, accuracies are based on less than 2 × CT and
50 to 130 V inputs. The full-scale is defined as follows: Full Scale = 2 × CT at
3
1 × VT ×
NOTE
Full Scale
The harmonic components of current and voltage are removed from the input
voltage and current parameters, so all relay measurements based on these
quantities respond to the fundamental component only. To minimize errors, the A/D
process utilizes a sampling rate that is automatically adjusted to be 16 samples per
power frequency cycle when a measurable voltage is available. To prevent
overreaching of overcurrent elements, a digital filter removes the transient DC
component of currents.
CURRENT
Phasors: Phase A RMS current
Phase B RMS current
Phase C RMS current
% of load-to-trip accuracy: ±0.5% of full-
scale
VOLTAGE
Phasors: Phase A-N (A-B) voltage
Phase B-N (B-C) voltage
Phase C-N (C-A) voltage
Accuracy: ±0.25% of full scale
FREQUENCY
Measured: A-N (A-B) bus and line voltage
Range: 16 to 65 Hz
Accuracy: ±0.02 Hz
SYMMETRICAL COMPONENTS
Current level accuracy: ±1.5% of full scale
Voltage level accuracy: ±0.75% of full scale
Current and voltage angle accuracy: ±2°
3Φ POWER FACTOR
Range: 0.00 Lag to 1.00 to 0.00 Lead
Accuracy: ±0.02
3Φ REAL POWER
Range: –3000.0 to 3000.0 MW
Accuracy: ±1% of full scale
3Φ REACTIVE POWER
Range: –3000.0 to 3000.0 Mvar
Accuracy: ±1% of full scale
(see note above)
PHASE / NEUTRAL / GROUND /
NEGATIVE SEQUENCE TIME OVER-
CURRENT
Pickup level: 0.05 to 20.00 × CT in steps of
0.01
Dropout level: 97 to 98% of pickup
Curves: ANSI Extremely/Very/
Moderately/Normally Inverse,
Definite Time (0.1 s base
curve), IEC Curve A/B/C and
Short, FlexCurve™ A/B
(programmable curves), IAC
Extreme/Very/Inverse/Short
Curve multiplier: 0 to 100.00 in steps of 0.01
Reset type: Instantaneous/Linear
Level accuracy: per current input
(I is 3 × input error)
2
Timing accuracy: ±3% of trip time or ±40
ms (whichever is greater) at
≥ 1.03 × PU
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3Φ APPARENT POWER
Range:
Accuracy:
WATT-HOURS
Range:
Accuracy:
VAR-HOURS
Range:
Accuracy:
DEMAND RANGE
Phase A/B/C current: 0 to 65535 A
3Φ real power: –3000.0 to 3000.0 MW
3Φ reactive power: –3000.0 to 3000.0 Mvar
3Φ apparent power: –3000.0 to 3000.0 MVA
DEMAND MEASUREMENT
Thermal exponential, 90% response time
Block interval / rolling demand, time interval
Accuracy:
SENSITIVE GROUND TIME OVER-
CURRENT
Pickup level: 0.005 to 1.000 × CT in steps of
Dropout level: 97 to 98% of Pickup
Curves:
Curve multiplier: 0 to 100.00 in steps of 0.01
Reset type:
Level accuracy: per sensitive ground current
Timing accuracy: ±3% of trip time or ±40
Specifications
–3000.0 to 3000.0 MVA
±1% of full scale (see note
above)
×
–2.1 × 108 to 2.1 108 MWh
±2% of full scale (see note
above) per hour
×
–2.1 × 108 to 2.1 108 Mvarh
±2% of full scale (see note
above) per hour
(programmed):
5, 10, 15, 20, 30, or 60 min.
(programmed):
5, 10, 15, 20, 30, or 60 min.
±2% of full scale
(see note above)
0.001
ANSI Extremely/Very/
Moderately/Normally Inverse,
Definite Time (0.1 s base
curve), IEC Curve A/B/C and
Short, FlexCurve™ A/B
(programmable curves), IAC
Extreme/Very/Inverse/Short
Instantaneous/Linear
input
ms (whichever is greater) at
≥ 1.03 × PU
GE Multilin