Earth-fault transientsIn general, earth faults generate transients in currents and voltages. There are severalfactors that affect the magnitude and frequency of these transients, such as the faultmoment on the voltage wave, fault location, fault resistance and the parameters of thefeeders and the supplying transformers. In the fault initiation, the voltage of the faultyphase decreases and the corresponding capacitance is discharged to earth (→discharge transients). At the same time, the voltages of the healthy phases increase andthe related capacitances are charged (→ charge transient).If the fault is permanent (non-transient) in nature, only the initial fault transient incurrent and voltage can be measured, whereas the intermittent fault creates repetitivetransients.GUID-CC4ADDEA-EE11-4011-B184-F873473EBA9F V1 ENFigure 164: Example of earth-fault transients, including discharge and chargetransient components, when a permanent fault occurs in a 20 kVnetwork in phase C4.2.3.6 SignalsTable 351:INTRPTEF Input signalsName Type Default DescriptionIo SIGNAL 0 Residual currentUo SIGNAL 0 Residual voltageBLOCK BOOLEAN 0=False Block signal for activating the blocking modeTable 352:INTRPTEF Output signalsName Type DescriptionOPERATE BOOLEAN OperateSTART BOOLEAN StartBLK_EF BOOLEAN Block signal for EF to indicate opposite directionpeaksSection 4 1MRS758755 AProtection functions322 REC615 and RER615Technical Manual
