GE Multilin 750/760 Feeder Management Relay 2-7
2 INTRODUCTION 2.2 SPECIFICATIONS
2
2.2.3 MEASURED PARAMETERS
In the following specifications, accuracies based on less than 2 × CT and 50 to 130 V inputs. The full-scale is
defined as follows: Full Scale = 2 × CT at 1 × VT
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 volt-
age 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 90 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)
3Φ APPARENT POWER
Range: –3000.0 to 3000.0 MVA
Accuracy: ±1% of full scale (see note above)
WATT-HOURS
Range: –2.1 × 108 to 2.1 × 108 MWh
Accuracy: ±2% of full scale (see note above) per hr
VAR-HOURS
Range: –2.1 × 108 to 2.1 × 108 Mvarh
Accuracy: ±2% of full scale (see note above) per hr
DEMAND
Phase A/B/C current range: 0 to 65535 A
3Φ real power range: –3000.0 to 3000.0 MW
3Φ reactive power range:–3000.0 to 3000.0 Mvar
3Φ apparent power range: –3000.0 to 3000.0 MVA
Measurement type:
Thermal Exponential, 90% response time (programmed):
5, 10, 15, 20, 30, or 60 min.
Block Interval / Rolling Demand, time interval (programmed):
5, 10, 15, 20, 30, or 60 min.
Accuracy: ±2% of full scale (see note above)
2.2.4 PROTECTION ELEMENTS
PHASE / NEUTRAL / GROUND / NEG SEQ TOC
Pickup level: 0.05 to 20.00 × CT in steps of 0.01
Dropout level: 97 to 98% of pickup
Curve shapes: ANSI Extremely/Very/Moderately/Nor-
mally Inverse, Definite Time (0.1 s base
curve), IEC Curve A/B/C and Short,
FlexCurveâ„¢ A/B (programmable
curves), IAC Extreme/Very/Inverse/Short
Curve multiplier: 0.00 to 100.00 in steps of 0.01
Reset type: Instantaneous/Linear
Level accuracy: per current input (I
2
is 3 × input error)
Timing accuracy: ±3% of trip time or ±40 ms (whichever is
greater) at ≥ 1.03 × PU
SENSITIVE GROUND TOC
Pickup level: 0.005 to 1.000 × CT in steps of 0.001
Dropout level: 97 to 98% of Pickup
Curve shapes: ANSI Extremely/Very/Moderately/Nor-
mally Inverse, Definite Time (0.1 s base
curve), IEC Curve A/B/C and Short,
FlexCurveâ„¢ A/B (programmable
curves), IAC Extreme/Very/Inverse/Short
Curve multiplier: 0.00 to 100.00 in steps of 0.01
Reset type: Instantaneous/Linear
Level accuracy: per current input (I
2
is 3 × input error)
Timing accuracy: ±3% of trip time or ±40 ms (whichever is
greater) at ≥ 1.03 × PU
VOLTAGE RESTRAINED PHASE TOC
Pickup adjustment: Modifies pickup from 0.10 to 0.90 × VT
nominal in a fixed line relationship
NOTE
3
Courtesy of NationalSwitchgear.com
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