Functional Description

Overview

The VigiPacT RMH earth-leakage monitoring relay installed on the front of switchboards and panels provides valuable assistance in the maintenance of electrical installations.

Functions

The VigiPacT RMH relay is used together with a VigiPacT RM12T multiplexer and VigiPacT toroid (open or closed) or a rectangular sensor.

• Measures the earth-leakage current detected by the toroids (12 maximum).

• Displays the earth-leakage current.

• Implements two earth-leakage current thresholds, one corresponding to a pre-alarm and an other to an alarm.

• Communicates via the Modbus communication serial line.

Alarm Detection

The alarm threshold I alarm corresponds to an earth-leakage current that is hazardous for the installation.

An alarm is active when the measured earth-leakage current is greater than the set alarm threshold (I alarm) on at least one toroid for a period of time greater than the set alarm delay (t alarm in milliseconds or seconds) for that particular toroid.

• When an alarm is active, the ALARM and PRE-AL LEDs are switched on.

• When only one alarm is detected, the Metering screen of the corresponding toroid is displayed, and the earth-leakage current value blinks.

• When more than one alarm are detected, the Alarm screen is displayed.

Pre-alarm Detection

The pre-alarm threshold I Pre-alarm correspond to an earth-leakage level that must be eliminated before it becomes hazardous for the installation.

A pre-alarm is active when the measured earth-leakage current is greater than the set pre-alarm threshold on at least one channel for a period of time greater than the set pre-alarm trip delay (t pre-alarm in milliseconds or seconds) for that particular toroid.

• When a pre-alarm is active, the PRE-AL LED is switched on.

• When only one pre-alarm is detected, the Metering screen of the corresponding toroid is displayed, and the earth-leakage current value blinks.

• When more than one alarm are detected, the Pre-alarm screen is displayed.