Hitachi Relion 670 Series Applications Manual page 192

Section 9
Voltage protection
9.2.1 Function revision history
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revision
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9.2.2 Identification
Function description
Overvoltage protection, two steps
9.2.3 Application
Two step overvoltage protection O2RWPTOV is applicable in situations where reliable detection of
high voltage is necessary. O2RWPTOV is used for supervision and detection of abnormal conditions,
which in combination with other protection functions, to increase the security of a complete protection
system.
High overvoltage conditions are caused by abnormal situations in the power system. O2RWPTOV is
applied to transformers and power lines in order to detect high voltage conditions. O2RWPTOV is
used in combination with low current signals to identify a transmission line open in the remote end.
O2RWPTOV is used to disconnect apparatuses 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. Earth-faults in high impedance earthed systems causes, beside the high voltage in the neutral,
high voltages in the non-faulted phase, (unsymmetrical voltage increase).
O2RWPTOV 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.
186
Product History
revision
2.2.1 -
2.2.1 -
2.2.2 -
2.2.3 -
2.2.3 -
2.2.4 -
2.2.4 -
2.2.5 -
2.2.6 -
2.2.6 Programmable inverse curve for operating characteristic is added.
IEC 61850
identification
O2RWPTOV
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GUID-904CD613-823B-420B-B368-F6D2E1288097 v2
IEC 60617 identification ANSI/IEEE C37.2
device number
59
2(2U>)
IEC15000214 V1 EN-US
Railway application RER670
1MRK506375-UEN Rev. N
M17002-1 v8
M13799-3 v9
Application manual