1.24
SEL-751A Relay Instruction Manual Date Code 20100129
Introduction and Specifications
Specifications
Power Factor (55)
Setting Range: Off, 0.05–0.99
Accuracy: ±5% of full scale
for current ≥ 0.5 • INOM
Frequency (81)
Setting Range: Off, 20.00–70.00 Hz
Accuracy: ±0.01 Hz (V1 >60 V) with voltage
tracking
±0.05 Hz (I1 >0.8 • Inom) with current
tracking
Pickup/Dropout Time: <4 cycles
Rate-of-Change of Frequency (81R)
Setting Range: Off, 0.01–15.00 Hz/s
Accuracy: ±100 mHz/s, ±3.33% of pickup
Synchronism Check (25)
Pickup Range, Secondary
Voltage: 0.00–300.00 V
Pickup Accuracy, Secondary
Voltage:
±1% ±0.5 volts (over the range of
12.5–300 V)
Slip Frequency Pickup
Range: 0.05 Hz–0.50 Hz
Slip Frequency Pickup
Accuracy: ±0.05 Hz
Phase Angle Range: 0–80°
Phase Angle Accuracy: ±4°
Synchronism-Check Undervoltage (27S)
Setting Range: Off, 2.00–300.00 V
Accuracy: ±1% of setting ±0.5 V
(over the range of 12.5-300 V)
Pickup/Dropout Time: <1.5 cycles
Synchronism-Check Overvoltage (59S)
Setting Range: Off, 2.00–300.00 V
Accuracy: ±1% of setting ±0.5 V
(over the range of 12.5-300 V)
Pickup/Dropout Time: <1.5 cycles
Station Battery Voltage Monitor
Operating Range 0–350 Vdc (300 Vdc for UL purposes)
Pickup Range: 20.00–300.00 Vdc
Pickup accuracy: ±2% of setting ±2 Vdc
Timers
Setting Range: Various
Accuracy: ±0.5% of setting ±1/4 cycle
RTD Protection
Setting Range: Off, 1–250°C
Accuracy: ±2° C
RTD Open-Circuit
Detection: >250°C
RTD Short-Circuit
Detection: <–50°C
RTD Types: PT100, NI100, NI120, CU10
RTD Lead Resistance: 25 ohm max. per lead
Lead Length: <10 m to meet IEC 60255-22-1 and
IEC 60255-22-5
Update Rate: <3 s
Noise Immunity on RTD
Inputs: up to 1.4 Vac (peak) at 50 Hz or greater
frequency
Metering
Accuracies are specified at 20° C, nominal frequency, ac currents
within (0.4–20.0) • I
NOM
A secondary, and ac voltages within
50–250 V secondary unless otherwise noted.
Phase Currents: ±2% of reading, ±2°
3-Phase Average Current: ±2% of reading
Current Imbalance (%): ±2% of reading
IG (Residual Current): ±3% of reading, ±2°
IN (Neutral Current): ±2% of reading, ±2°
3I2 Negative-Sequence
Current: ±3% of reading
System Frequency: ±0.01 Hz of reading for frequencies
within 20.00–70.00 Hz (V1 > 60 V)
with voltage tracking
±0.05 Hz of reading for frequencies
within 20.00–70.00 Hz
(I1 > 0.8 • Inom) with current
tracking
Line-to-Line Voltages: ±1% of reading (±2% with the
xx71xx card), ±1° for voltages
within 24–264 V
3-Phase Average Line-to-
Line Voltage: ±1% of reading (±2% with the
xx71xx card) for voltages within 24–
264 V
Line-to-Ground Voltages: ±1% of reading (±2% with the xx71xx
card), ±1° for voltages
within 24–264 V
3-Phase Average Line-to-
Ground Voltages: ±1% of reading (±2% with the xx71xx
card) for voltages within 24–264 V
Voltage Imbalance (%): ±1% of reading (±2% with the xx71xx
card) for voltages within 24–264 V
3V2 Negative-Sequence
Voltage: ±3% of reading for voltages
within 24–264 V
Real 3-Phase Power (kW): ± 5% of reading for 0.10 < pf < 1.00
Reactive 3-Phase
Power (kVAR): ± 5% of reading for 0.00 < pf < 0.90
Apparent 3-Phase
Power (kVA): ± 2% of reading
Power Factor: ±2% of reading
RTD Temperatures: ±2°C
To Next Page
Loading...
