Ground-fault location: The concept

A ground-fault location system comprises a ground-fault test device and a ground-fault evaluator connected to one or more measuring current transformers. The ISOMETER® of the iso685 series features a built-in ground-fault test device.

• Start ground-fault location by activating the ground-fault test device ISOMETER®. 
• The ground-fault test device briefly connects the live conductors to ground.
• Electronic current limiting, this connection and the ground fault create a closed circuit, in which a test current is determined by the system voltage flows. The test current is limited to a maximum value.
• The test current pulse flows from the ground-fault test device via the live conductors, the ground fault Rf and the ground wire (PE conductor) and back to the ground-fault test device.
• The test current signal is detected by all measuring current transformers on the circuit and evaluated by EDS ground-fault evaluators.
• The fault location can be identified using the assignment between measuring current transformers and circuit.

The ground-fault monitoring device with built-in ground-fault test device, the ground-fault evaluator and the associated measuring current transformers are components of the installation. Ground-fault location is started automatically by the ground-fault monitoring device.