ABB RELION 670 Series Applications Manual page 207

1MRK 505 337-UUS A
Section 8
8.1 Two step undervoltage protection UV2PTUV (27)
8.1.1 Identification
Function description
Two step undervoltage protection
8.1.2 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 settings base voltage
normally is set to the primary rated voltage level (phase-to-phase) of the power system or the high
voltage equipment under consideration.
The setting for UV2PTUV (27) is normally not critical, since there must be enough time available for
the main protection to clear short circuits andground faults.
Some applications and related setting guidelines for the voltage level are described in the
following sections.
8.1.2.1 Equipment protection, such as for motors and generators
The setting must be below the lowest occurring "normal" voltage and above the lowest acceptable
voltage for the equipment.
8.1.2.2 Disconnected equipment detection
The setting must be below the lowest occurring "normal" voltage and above the highest occurring
voltage, caused by inductive or capacitive coupling, when the equipment is disconnected.
Application manual
Voltage protection
IEC 61850
identification
UV2PTUV
IEC 60617 ANSI/IEEE C37.2
identification device number
27
3U<
V2 EN-US SYMBOL-R-2U-GREATER-THAN
Section 8
Voltage protection
IP14544-1 v3
M16876-1 v6
M13851-3 v8
VBase , which
M13851-50 v3
M13851-53 v3
201