Identification; Application; Setting Guidelines - Hitachi Relion 670 Series Applications Manual

Section 9
Voltage protection
9.2.1

Identification

Function description
Two step overvoltage protection
9.2.2

Application

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 expectancy. In many cases,
it is a useful function in circuits for local or remote automation processes in the power system.
9.2.3

Setting guidelines

The parameters for Two step overvoltage protection (OV2PTOV ,59) are set via the local HMI or
PCM600.
All the voltage conditions in the system where OV2PTOV (59) performs its functions should be
considered. The same also applies to the associated equipment, its voltage and time characteristic.
There are wide applications where general overvoltage functions are used. All voltage related settings
are made as a percentage of a settable base primary voltage, which is normally set to the nominal
voltage level (phase-to-phase) of the power system or the high voltage equipment under consideration.
156
IEC 61850
identification
OV2PTOV
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IEC 60617 identification ANSI/IEEE C37.2
device number
59
3U>
SYMBOL-C-2U-SMALLER-THAN V2 EN-US
Phasor measurement unit RES670
1MRK511407-UUS Rev. N
M17002-1 v8
M13799-3 v9
M13852-4 v10
Application manual