Monitoring Relays for insulation monitoring

Insulation monitoring relays are employed for monitoring the insulation resistance between ungrounded single- or three-phase networks and a protective conductor. Ungrounded, i.e. insulated networks (IT networks), are used whenever a high reliability of the power supply has to be ensured, e.g. with emergency lighting systems. Operation can be continued without risks after a first insulation fault (single fault security).
Nevertheless, the fault has to be rectified as soon as possible before a second insulation fault occurs (e.g. in accordance with DIN VDE 0100-410). For this purpose, insulation monitoring relays are employed for permanently measuring the resistance of the line conductors and the neutral conductor against ground and prompt fault signaling upon shortfall of the set insulation resistance.

Advantages at a glance

  • Devices for AC and DC systems

  • All devices with wide supply voltage range

  • Direct connection to networks with line voltages up to 690 V AC and 1000 V DC
    via series module

  • With AC networks: Frequency range15 ... 400 Hz

  • Monitoring for line breakage

  • Monitoring for faulty settings

  • Application safety thanks to integrated system start after start-up

  • Reset and test option (via button on the front or control contact)

  • Rapid response times thanks to new predictive measuring principle