ABB Relion REC670, Applications Manual

Page: 251 / 658

9.2.1 Identification
M17002-1 v8
Function description IEC 61850
identification
IEC 60617 identification ANSI/IEEE C37.2
device number
Two step overvoltage protection OV2PTOV
3U>
SYMBOL-C-2U-SMALLER-THAN V2 EN-US
59
9.2.2 Application
M13799-3 v9
Two step overvoltage protection OV2PTOV (59) is applicable in all situations, where
reliable detection of high voltage is necessary. OV2PTOV (59) is used for supervision
and detection of abnormal conditions, which, in combination with other protection
functions, increase the security of a complete protection system.
High overvoltage conditions are caused by abnormal situations in the power system.
OV2PTOV (59) is applied to power system elements, such as generators, transformers,
motors and power lines in order to detect high voltage conditions. OV2PTOV (59) is
used in combination with low current signals, to identify a transmission line, open in
the remote end. In addition to that, OV2PTOV (59) is also used to initiate voltage
correction measures, like insertion of shunt reactors, to compensate for low load, and
thereby decreasing the voltage. The function has a high measuring accuracy and
hysteresis setting to allow applications to control reactive load.
OV2PTOV (59) is used to disconnect apparatuses, like electric motors, which will be
damaged when subject to service under high voltage conditions. It deals with high
voltage conditions at power system frequency, which can be caused by:
1. Different kinds of faults, where a too high voltage appears in a certain power
system, like metallic connection to a higher voltage level (broken conductor
falling down to a crossing overhead line, transformer flash over fault from the high
voltage winding to the low voltage winding and so on).
2. Malfunctioning of a voltage regulator or wrong settings under manual control
(symmetrical voltage decrease).
3. Low load compared to the reactive power generation (symmetrical voltage
decrease).
4. Ground-faults in high impedance grounded systems causes, beside the high
voltage in the neutral, high voltages in the two non-faulted phases, (unsymmetrical
voltage increase).
OV2PTOV (59) prevents sensitive equipment from running under conditions that could
cause their overheating or stress of insulation material, and, thus, shorten their life time
1MRK 511 401-UUS A
Section 9
Voltage protection
Bay control REC670 2.2 ANSI 245
Application manual