GE MiCOM P40 User Manual

2.3 APPLICATION NOTES
2.3.1 UNDERVOLTAGE SETTING GUIDELINES
In most applications, undervoltage protection is not required to operate during system earth fault conditions. If this
is the case you should select phase-to-phase voltage measurement, as this quantity is less affected by single-
phase voltage dips due to earth faults.
The voltage threshold setting for the undervoltage protection should be set at some value below the voltage
excursions that may be expected under normal system operating conditions. This threshold is dependent on the
system in question but typical healthy system voltage excursions may be in the order of 10% of nominal value.
The same applies to the time setting. The required time delay is dependent on the time for which the system is able
to withstand a reduced voltage.
If motor loads are connected, then a typical time setting may be in the order of 0.5 seconds.
Chapter 14 - Voltage Protection Functions P446SV
390 P446SV-TM-EN-1

GE MiCOM P40 Specifications

General

Brand	GE
Model	MiCOM P40
Category	Relays
Language	English