Figure 201: Operation in “Alarming EF” mode
Operation mode “Intermittent EF” is dedicated for detecting restriking or
intermittent earth faults. A required number of intermittent earth fault transients
set with the
Peak counter limit
setting must be detected for operation. Therefore,
transient faults or permanent faults with only initial fault ignition transient are not
detected in “Intermittent EF” mode. The application of “Intermittent EF” mode is
limited to low ohmic intermittent or restriking earth faults.
In the “Intermittent EF” mode, the operate timer is started when the following
conditions are met.
• Transient is detected by the Transient detector (indicated with PEAK_IND
output)
• Earth fault is detected by the GFC at time of transient
• Fault direction equals
Directional mode
setting
• Estimated stabilized fundamental frequency residual current exceeds the set
Min
operate current
level
Protection functions
1MRS758755 C
402 REC615 & RER615
Technical Manual
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