Insulation error detection arrangement for unearthed alternating voltage networks, whereby an internally generated test voltage is applied and differential current measured at each circuit output

摘要

Arrangement for detection of insulation errors in an unearthed electrical alternating voltage network using an internal test voltage that is provided using rectifiers and current limiters. A differential current transducer is used with differential current sensors to detect an insulation error for each network output. The test voltage is switched in a zero crossover of the network voltage and can have positive or negative polarity.