Earth-fault transients
In general, earth faults generate transients in currents and voltages. There are several
factors that affect the magnitude and frequency of these transients, such as the fault
moment on the voltage wave, fault location, fault resistance and the parameters of the
feeders and the supplying transformers. In the fault initiation, the voltage of the faulty
phase decreases and the corresponding capacitance is discharged to earth (→
discharge transients). At the same time, the voltages of the healthy phases increase and
the related capacitances are charged (→ charge transient).
If the fault is permanent (non-transient) in nature, only the initial fault transient in
current and voltage can be measured, whereas the intermittent fault creates repetitive
transients.
GUID-CC4ADDEA-EE11-4011-B184-F873473EBA9F V1 EN
Figure 97:
Example of earth-fault transients, including discharge and charge
transient components, when a permanent fault occurs in a 20 kV
network in phase C
4.2.3.6
Signals
Table 205:
INTRPTEF Input signals
Name
Type
Default
Description
Io
SIGNAL
0
Residual current
Uo
SIGNAL
0
Residual voltage
BLOCK
BOOLEAN
0=False
Block signal for activating the blocking mode
Table 206:
INTRPTEF Output signals
Name
Type
Description
OPERATE
BOOLEAN
Operate
START
BOOLEAN
Start
BLK_EF
BOOLEAN
Block signal for EF to indicate opposite direction
peaks
Section 4
1MRS757454 D
Protection functions
210
611 series
Technical Manual
Summary of Contents for Relion 611 Series
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