Voltage Protection; Two Step Undervoltage Protection Uv2Ptuv (27); Identification; Application - Hitachi Relion 670 Series Applications Manual

1MRK511407-UUS Rev. N
Section 9
9.1

Two step undervoltage protection UV2PTUV (27)

9.1.1

Identification

Function description
Two step undervoltage protection
9.1.2

Application

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.
The function has a high measuring accuracy and a settable hysteresis to allow applications to control
reactive load.
In many cases, UV2PTUV (27) is a useful function in circuits for local or remote automation processes in
the power system.
9.1.3

Setting guidelines

All the voltage conditions in the system where UV2PTUV (27) performs its functions should be
considered. The same also applies to the associated equipment, its voltage and time characteristic.
There is a very wide application area where general undervoltage functions are used. All voltage-related
settings are made as a percentage of the global base value VBase, which normally is set to the primary
Phasor measurement unit RES670
Application manual

Voltage protection

IEC 61850
identification
UV2PTUV
© 2017 - 2023 Hitachi Energy. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
27
3U<
V2 EN-US SYMBOL-R-2U-GREATER-THAN
Section 9
Voltage protection
IP14544-1 v3
M16876-1 v8
M13790-3 v8
M13851-3 v9
153