Power System - GE 850 Instruction Manual

CHAPTER 5: DEVICE, SYSTEM, INPUT AND OUTPUT SETPOINTS

Power System

850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
LEA SENSOR 1/2/3 MAG CORRECTION
Range: 0.500 to 1.500 in steps of 0.001
Default: 1.000
The 850 uses magnitude and phase correction factors to correct for manufacturing
tolerances in the line-sensing equipment. This setting specifies the correction
magnitude that must be applied for the measurement taken from the VT1/2/3 input.
The magnitude correction factor equals:
Calculated VT1/2/3 Voltage = VT1/2/3 Magnitude x Measured VT1/2/3 Voltage.
LEA SENSOR 1/2/3 ANGLE CORRECTION
Range: -15.0° to 15.0° in steps of 0.01
Default: 0.0°
This setting provides the leading phase shift correction that should be applied to the
phasor calculations to compensate the angle error provided by the VT sensor.
Example:
Measured Secondary Voltage = 2V
LEA Ratio = 2000
LEA Sensor 1/2/3 Mag Correction = 1.050
Calculated Secondary Voltage
= Measured Secondary Voltage x LEA Sensor 1/2/3 Mag Correction
= 2V x 1.050 = 2.1 V secondary
Calculated Primary Voltage
= LEA Ratio x Calculated Secondary Voltage
= 2000 x 2.1 = 4200 V primary
Path:
Setpoints > System > Power System
NOMINAL FREQUENCY
Range: 60 Hz, 50 Hz
Default: 60 Hz
The power system NOMINAL FREQUENCY is used as a default to set the digital sampling
rate if the system frequency cannot be measured from available AC signals. This may
happen if the signals selected for frequency tracking are not present, or a valid
frequency is not detected. Before reverting to the nominal frequency, the frequency
tracking algorithm holds the last valid frequency measurement for a safe period of time
while waiting for the signals to reappear or for the distortions to decay.
COST OF ENERGY
Range: Range: 0.1 to 100.0 c/kWh in step of 0.1 c/kWh
Default: 5.0 c/kWh
This setpoint allows selection of the cost of energy in cents per kilowatthour.
SYSTEM
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