Power System - GE 845 Instruction Manual

SYSTEM
NOTE:
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Power System

4–84
Setpoints\System\Power Sensing
Item Name
Invert Power Metering (J)
Invert Power Metering (K)
Pwr Sens
INVERT POWER METERING
Range: Disabled, Enabled
Default: Disabled
When "Enabled" this setpoint inverts (multiplies phase currents by "-1" ) the CT polarity
for the phase currents from CT bank J1, with respect to the phase voltages from the VT
bank J2.
The setpoint for inversion of the power metering will be useful to avoid the physical
inversion of the CT connections on the relay. As the power metering will affect the power
directional elements, the user must determine the correct forward and reverse direction of
the power, before setup.
The selection of CT&VT polartiy for slot "K" is for future products.
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.
PHASE ROTATION
Range: ABC, ACB
Default: ABC
The selection of the PHASE ROTATION setting must match the power system phase
rotation. The phase sequence setting is required to properly calculate sequence
components and power parameters. Note that this setting informs the relay of the
actual system phase sequence, either ABC or ACB. CT and VT inputs on the relay labeled
as a, b, and c, must be connected to system phases A, B, and C for correct operation.
Value
Disabled
Disabled
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
Unit