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
Summary of Contents for RELION RER670
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