Apparatus for detecting insulation defects in devices connected into power distribution networks

摘要

An apparatus for detecting an insulation defect in at least one device connected into an electrical power transmission or distribution network and having: leakage current measuring sensors (10) arranged on a ground line (19a, 19b, 19c) of the device; a measurement signal analogue/digital converter (58, 60); and a signal processing unit (14) including a comparison circuit (75) for comparing the measurement signal with a maximum threshold value representative of the maximum value of the leakage current permitted to flow in the ground line (19a, 19b, 19c), to obtain an insulation defect signal. The processing unit (14) includes a discriminator circuit (76) for discriminating, in the insulation defect signal, between a component of a useful signal and a component of a disturbance signal.