ABB REB670 Series Applications Manual page 213

1MRK 505 370-UEN D
Section 8
8.1 Two step undervoltage protection UV2PTUV
8.1.1 Identification
Function description
Two step undervoltage protection
8.1.2 Setting guidelines
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.
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
normally is set to the primary rated voltage level (phase-to-phase) of the power system or the
high voltage equipment under consideration.
The trip time setting for UV2PTUV is normally not critical, since there must be enough time
available for the main protection to clear short circuits and earth 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.
8.1.2.3 Power supply quality
The setting must be below the lowest occurring "normal" voltage and above the lowest
acceptable voltage, due to regulation, good practice or other agreements.
Busbar protection REB670
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
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