Partial discharge detector for electric equipment

摘要

The discharge detector has an aerial (4), for detecting electromagnetic waves propagating in the equipment tested, a processing unit (6), connected by leads (5a,5b) to the aerial, which processes the signals from the aerial. The detector also includes a pre-amplifier (9) having an input connected to the aerial (4) and an output connected to processing unit (6). The aerial provides very HF signals which represent the EM waves and LF signals which represent the voltage in the conductors (2) of the equipment. The preamplifier circuit includes a VHF signal amplifier (11) and an oscillator controlled by voltage (12,24). The output of the oscillator provides a high frequency carrier signal modulated by the low frequency signal. <IMAGE>