Method and device for insulation monitoring and insulation fault location for unearthed power supply networks

A device for insulation monitoring and insulation fault location for unearthed power supply networks without testing current generator, comprising

• an insulation monitoring device (61) at a central point of the supply network, wherein the insulation monitoring device (61) is designed to generate a permanent measuring voltage between the mains conductor (60) and earth (80) and to feed in a measuring current,
• characterised in that the device further comprises
• at least one current transformer (64) arranged in each mains outgoing circuit (79) centrally at the infeed of the power supply network (63) between the insulation monitoring device (61) and the first mains outgoing circuit (79), which is designed for the temporal recording of the course of the fed-in measuring current of the insulation monitoring device (61) and the proportional measuring currents of the insulation monitoring device (61) at the mains outgoing circuits (79) when the transformer (81) is switched on or off,
• at least one evaluation device for evaluating the measuring currents detected, wherein
• the measuring current of the insulation monitoring of the overall network can also be used for insulation fault location in the individual circuits of the network, and
• the measuring current of each current transformer (64) and the measuring voltage of the insulation monitoring device (61) can be used to determine and analyse the ohmic insulation resistance (69) and the capacitive reactance (65) of each mains outgoing circuit (79) over time.