Rotor Ground Fault Protection By Injection - ABB REG316 4 Series Operating Instructions Manual

REG 316*4 1MRB520049-Uen / Rev. F
3.5.25. Rotor ground fault protection by injection (Rotor-EFP)
A. Application
For the detection of ground faults on the rotor windings of gen-
erators. Because of its low sensitivity to spurious signals, this
scheme can be used for all kinds of excitation systems.
B. Features
· detection of ground faults on rotor windings
· injection voltage applied via resistors and coupling capacitors
to both poles of the rotor
· computes the resistance of the ground fault
· monitors the amplitude and frequency of the injection signal
· monitors the measuring circuit with respect to open-circuit
and correct connection of the grounding resistor.
C. Inputs and outputs
I. C.t./v.t. inputs:
· voltage (2 inputs)
II. Binary inputs:
· blocking
· coupling capacitor adjustment
· REr adjustment
III. Binary outputs:
· alarm stage pick-up
· alarm
· trip stage pick-up
· trip
· coupling capacitor adjustment active
· REr adjustment active
· injection open-circuit internally
· injection open-circuit externally
· external blocking
IV. Measurements:
· ground fault resistance RFr
· coupling capacitor Ck"
· grounding resistor REr".
ABB Switzerland Ltd
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