ABB RELION RET670, Applications Manual

Page: 619 / 1016

Section 10 Voltage protection
10.1 Two step undervoltage protection UV2PTUV (27)
IP14544-1 v3
10.1.1 Identification
M16876-1 v7
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
10.1.2 Application
M13790-3 v8
Two-step undervoltage protection function (UV2PTUV ,27) is applied to power system
elements, such as generators, transformers, motors and power lines in order to detect
low voltage conditions. It is used as a supervision and fault detection function for other
protection functions as well, to increase the security of a complete protection system.
Low voltage conditions are caused by abnormal operation or faults in the power
system, such as:
• Malfunctioning of a voltage regulator or wrong settings under manual control
(symmetrical voltage decrease)
• Overload (symmetrical voltage decrease)
• Short circuits, often as phase-to-ground faults (unsymmetrical voltage decrease)
UV2PTUV (27) is used in combination with overcurrent protections, either as restraint
or in logic "and gates" of the trip signals issued by the two functions. It can also be
used to:
• Detect no voltage conditions, for example, before the energization of a HV line or
for automatic breaker trip in case of a blackout
• Initiate voltage correction measures, like insertion of shunt capacitor banks to
compensate for reactive load and thereby increasing the voltage
• Disconnect apparatuses, like electric motors, which will be damaged when subject
to service under low voltage conditions.
1MRK 504 163-UUS A
Section 10
Voltage protection
Transformer protection RET670 2.2 ANSI 613
Application manual