Apparatus for testing the insulation of an electrical conductor passing through an electrode

摘要

Apparatus for testing the insulation on an insulated conductor wherein a high AC test voltage is applied to an electrode through which the insulated conductor is passing is presented and includes a testing station for applying the high AC test voltage potential to an electrode at a desired magnitude and frequency. Current induced in the electrode due to corona effects or arc current pulses due to a defect in the insulation are sensed by a current sensing transformed circuit to develop a insulation condition voltage signal. The insulation condition voltage signal together with a low voltage test signal proportional to the magnitude of the high AC test voltage potential are coupled to a remotely located controlled unit. A negative peak detector receives the low voltage potential to produce a bias voltage at the input to the fault detection circuit. The characteristics of the current sensing transformed circuit are such that current induced in the test electrode due to corona effects are shunted to ground reference voltage potential. Arc current pulses induced in the test electrode cause the insulation condition voltage signal to be produced at sufficient magnitude to exceed the bias voltage at the control unit and cause the fault detection circuit to provide a fault indication signal representation of a flaw or defect in the insulation of the portion of the insulated electrical conductor within the test electrode.