TimerSelZ6: This is used to set the zone timer selection mode of zone 6. i.e. Timers
separated
, Timers linked, General start, PhSel start, Internal start and External
start. The default setting is Timers separated.
OpModetPEZ6: This is used to set the Off/On operation of the phase-to-earth timer
of zone 6. The default setting is Off.
tPEZ6: This is used to set the time delay to trip for phase-to-earth faults in zone 6.
It should be set to 0.0 s.
OpModetPPZ6: This is used to set the Off/On operation of the phase-to-phase timer
of zone 6. The default setting is Off.
tPPZ6: This is used to set the time delay to trip for phase-to-earth faults in zone 6.
It should be set to 0.0 s.
Phase selection
GUID-4A34CA75-7922-4FCD-B078-38AEAD9D8DFC v2
tI0: Delay time for the residual overcurrent start. Residual overcurrent start is
delayed by settable time delay tI0. The default setting is 0.2s.
7.2.2.3 High impedance earthing systems
GUID-0D740A9F-64D9-4A0E-80D2-0C71B48E8D35 v2
In isolated/high impedance networks, following types of errors can be anticipated:
• 2-phase short circuit, with or without earth connection
• Single phase-to-earth fault
• cross country double earth faults
For double earth faults, the disconnection by the distance measurement should be
selective.
For single phase earth fault in isolated systems, voltage shifts occur and a small
capacitive current generates. Trip will occur after a time delay. In an isolated
neutral system, the neutral has no intentional connection to earth. The system is
connected to earth through the phase-to-earth capacitances. Single phase-to-earth
faults will shift the system neutral voltage.
Earth fault
IEC15000384-1-en.vsdx
IEC15000384 V1 EN-US
Figure 41: Earth fault in isolated systems
Section 7 1MRK 506 375-UEN A
Impedance protection
124 Railway application RER670 2.2 IEC
Application manual
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