![background image](http://html1.mh-extra.com/html/abb/relion-670-series/relion-670-series_applications-manual_3052129473.webp)
Section 9
Voltage protection
9.1
Two step undervoltage protection UV2PTUV
IP14544-1 v3
9.1.1
Identification
M16876-1 v6
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Two step undervoltage protection
UV2PTUV
3U<
SYMBOL-R-2U-GREATER-THAN
V2 EN-US
27
9.1.2
Application
M13790-3 v7
Two-step undervoltage protection function (UV2PTUV) is applicable in all situations, where
reliable detection of low phase voltages is necessary. It is used also as a supervision and fault
detection function for other protection functions, to increase the security of a complete
protection system.
UV2PTUV is applied to power system elements, such as generators, transformers, motors and
power lines in order to detect low voltage conditions. Low voltage conditions are caused by
abnormal operation or fault in the power system. UV2PTUV is used in combination with
overcurrent protections, either as restraint or in logic "and gates" of the trip signals issued by
the two functions. Other applications are the detection of "no voltage" condition, for example,
before the energization of a HV line or for automatic breaker trip in case of a blackout.
UV2PTUV is also used to initiate voltage correction measures, like insertion of shunt capacitor
banks to compensate for reactive load and thereby increasing the voltage. The function has a
high measuring accuracy and setting hysteresis to allow applications to control reactive load.
UV2PTUV is used to disconnect apparatuses, like electric motors, which will be damaged when
subject to service under low voltage conditions. UV2PTUV deals with low voltage conditions at
power system frequency, which can be caused by the following reasons:
1.
Malfunctioning of a voltage regulator or wrong settings under manual control
(symmetrical voltage decrease).
2.
Overload (symmetrical voltage decrease).
3.
Short circuits, often as phase-to-earth faults (unsymmetrical voltage decrease).
UV2PTUV prevents sensitive equipment from running under conditions that could cause their
overheating 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.
9.1.3
Setting guidelines
M13851-3 v8
All the voltage conditions in the system where UV2PTUV performs its functions should be
considered. The same also applies to the associated equipment, its voltage and time
characteristic.
1MRK 505 343-UEN B
Section 9
Voltage protection
467
Application manual
Summary of Contents for Relion 670 series
Page 1: ...RELION 670 SERIES Line differential protection RED670 Version 2 1 IEC Application manual...
Page 2: ......
Page 40: ...34...
Page 64: ...58...
Page 150: ...144...
Page 406: ...400...
Page 472: ...466...
Page 494: ...488...
Page 512: ...506...
Page 524: ...518...
Page 604: ...598...
Page 686: ...680...
Page 718: ...712...
Page 722: ...716...
Page 758: ...752...
Page 759: ...753...