Insulation fault location: The concept
How does an insulation fault location system work?
An insulation fault location system comprises an insulation fault test device and an insulation fault evaluator connected to one or more measuring current transformers. The ISOMETER® of the
iso685 series features a built-in insulation fault test device.
Functional sequence
- Start insulation fault location by activating the insulation fault test device ISOMETER®.
- The insulation fault test device briefly connects the live conductors to earth.
- Electronic current limiting, this connection and the insulation fault create a closed circuit, in which a test current IT idetermined by the system voltage flows. The test current is limited to a maximum value.
- The test current pulse flows from the insulation fault test device via the live conductors, the insulation fault Rf and the earth wire (PE conductor) and back to the insulation fault test device.
- The test current signal is detected by all measuring current transformers on the circuit and evaluated by EDS insulation fault evaluators.
- The fault location can be identified using the assignment between measuring current transformers and circuit.
