ABB 615 series Technical Manual page 455

1MAC059074-MB A
615 series ANSI
Technical Manual
INTR_EF outputs can be used for monitoring purposes. The operation of the Transient
detector is illustrated in
Several factors affect the magnitude and frequency of fault transients,
such as the fault inception angle on the voltage wave, fault location, fault
resistance and the parameters of the feeders and the supplying
transformers. If the fault is permanent (non-transient) in nature, the initial
fault transient in current and voltage can be measured, whereas the
intermittent fault creates repetitive transients. The practical sensitivity of
transient detection is limited to approximately few hundreds of ohms of
fault resistance. Therefore the application of transient detection is limited
to low ohmic ground faults.
VG
IG
PEAK_IND
GFC
release
Reset timer
INTR_EF
Reset delay time
GUID-A5B0DD30-710A-4E95-82F8-1D2692452239 V2 EN
Figure 215: Example of operation of Transient detector: indication of detected
transient by PEAK_IND output and detection of restriking or intermittent
ground fault by INTR_EF output (setting Peak counter limit = 3)
Figure 215.
Section 4
Protection functions
Reset delay time
449