Distributed local discharge on-line monitoring method and device for high voltage cable system

The invention provides a distributed local discharge on-line monitoring method and a distributed local discharge on-line monitoring device for a high voltage cable system. A high-frequency broadband electromagnetic coupling sensor is arranged on each accessory of an entire cable line; the sensors are sleeved on grounding lines or crossed and interconnected lines of the cable accessories for coupling a local discharge signal; a 50Hz current sensor is sleeved on a cable body for coupling a power frequency current signal; a lower computer is used for conditioning a sensor signal, acquiring the sensor signal at a high speed and preprocessing the sensor signal; and a digital signal is transmitted to upper computer monitoring software through an optical fiber transmission network; thus on-line monitoring of distributed local discharge of high voltage cable equipment is realized. The method and the device have the advantage that: the on-line monitoring of the local discharge can be realized by performing distributed synchronous high-speed sampling on three-phase accessories of a high voltage cable according to field requirements.