The main action basis of arc protection is two different factors of fault: arc and current increment. When arc light and current increment are detected at the same time, a tripping command is issued. Arc protection consists of three parts: arc protection main control unit, arc collector and arc sensor.

The main unit of the arc protection device detects the short-circuit current and the action information from the arc sensor, processes and judges the collected data, and sends a tripping command to remove the fault when the tripping time is met. In addition, the main unit provides the location of the arc fault point according to the action information of the arc sensor transmitted by the auxiliary unit.

The arc light collector is the auxiliary unit. When an arc light fault occurs in the system, the arc light collector collects the action information from the electric arc light sensor and transmits it to the main unit. The address number of the arc light sensor is displayed on the main unit, which is conducive to timely and accurate fault location of the switchgear and provides information for maintenance.

The arc sensor, that is, the arc sensor whose probe is dedicated to bus protection, is installed in the bus room of the switchgear. As a light sensing element, it will detect the sudden increase of light intensity in the occurrence of arc fault, and convert the light signal into a current signal to transmit it to the arc collector.

The arc protection device improves the speed of fault handling, can effectively solve the harm caused by short-circuit fault arc, reduce equipment maintenance and casualties, and improve the safety and economic benefits of the power system.