Two Step Residual Overvoltage Protection Rov2Ptov (59N); Identification; Application; Setting Guidelines - ABB Relion 670 Series Applications Manual

Section 8
Voltage protection
8.3 Two step residual overvoltage protection ROV2PTOV
(59N)
8.3.1

Identification

Function description
Two step residual overvoltage
protection
8.3.2

Application

Two step residual overvoltage protection ROV2PTOV (59N) is primarily used in high impedance
grounded distribution networks, mainly as a backup for the primary ground fault protection of the
feeders and the transformer. To increase the security for different ground fault related functions,
the residual overvoltage signal can be used as a release signal. The residual voltage can be
measured either at the transformer neutral or from a voltage transformer open delta connection.
The residual voltage can also be calculated internally, based on measurement of the three-phase
voltages.
In high impedance grounded systems the residual voltage will increase in case of any fault
connected to ground. Depending on the type of fault and fault resistance the residual voltage will
reach different values. The highest residual voltage, equal to three times the phase-to-ground
voltage, is achieved for a single phase-to-ground 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 (59N) is often used as a backup protection or as a
release signal for the feeder ground fault protection.
8.3.3

Setting guidelines

All the voltage conditions in the system where ROV2PTOV (59N) performs its functions should be
considered. The same also applies to the associated equipment, its voltage and time
characteristic.
There is a very wide application area where general single input or residual overvoltage functions
are used. All voltage related settings are made as a percentage of a settable base voltage, which
can be set to the primary nominal voltage (phase-phase) level of the power system or the high
voltage equipment under consideration.
The time delay for ROV2PTOV (59N) is seldom critical, since residual voltage is related to ground
faults in a high impedance grounded system, and enough time must normally be given for the
primary protection to clear the fault. In some more specific situations, where the single
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.
208
IEC 61850 IEC 60617
identification identification
ROV2PTOV
3U0
TRV V1 EN-US
1MRK 511 358-UUS A
ANSI/IEEE C37.2
device number
59N
Application manual
IP14546-1 v4
SEMOD54295-2 v5
M13809-3 v7
M13853-3 v7