Monitoring device and method as well as an extended monitoring device and extended method for the insulation monitoring of an ungrounded electrical system with an earthed operated liquid cooling system

摘要

The invention relates to a monitoring device and a method for monitoring an insulation resistance for an ungrounded electrical system, which has an earthed operated liquid cooling system with a coolant flowing in pipelines. The measurement signal is fed into the pipeline system serially via the coolant resistor. The monitoring device is designed to determine the insulation resistance with a current measurement or with a voltage measurement on the pipe sections and can be expanded to monitor a common insulation resistance of several ungrounded electrical subsystems fed by a common transformer.