Two Step Residual Overvoltage Protection Rov2Ptov; Identification; Application; Setting Guidelines - ABB RER670 Applications Manual

1MRK 506 375-UEN A
9.3
9.3.1
9.3.2
9.3.3
Railway application RER670 2.2 IEC
Application manual
Two step residual overvoltage protection
ROV2PTOV

Identification

Function description
Two step residual overvoltage
protection

Application

The residual voltage will increase in case of any single phase earth-fault occurred
in isolated or compensated two-phase railway supply systems. Depending on the
type of fault and fault resistance, the residual voltage will reach different values.
The highest residual voltage, equal to two times the phase-to-earth voltage, is
achieved for a solid single phase-to-earth fault. The residual voltage increases
approximately to the same level in the whole system and does not provide any
guidance in finding the faulted component. Therefore, ROV2PTOV is often used
as a backup protection or as a release signal for the feeder earth-fault protection.

Setting guidelines

All the voltage conditions in the system where ROV2PTOV performs its functions
should be considered. The same also applies to the associated equipment, its
voltage withstand capability and time characteristic.
All voltage-related settings are made as a percentage of a settable base voltage,
which shall be set to the primary nominal voltage (phase-phase) level of the power
system.
The time delay for ROV2PTOV is seldom critical, since residual voltage is related
to earth faults in a high-impedance earthed system, and enough time must normally
be given for the primary protection to clear the fault. In some more specific
situations, where the residual overvoltage protection is used to protect some
specific equipment, the time delay is shorter.
Some applications and related setting guidelines for the residual voltage level are
given below.
Voltage protection
IEC 61850 IEC 60617
identification identification
ROV2PTOV
2(U0>)
IEC15000108 V1 EN-US
Section 9
IP14546-1 v4
SEMOD54295-2 v6
ANSI/IEEE C37.2
device number
59N
M13809-3 v8
M13853-3 v8
201