As the hub of power supply system, 6-35kV medium voltage complete set of switch cabinet, due to small size of switch cabinet, insulation damage, product defects and so on, the arc fault in the switch cabinet is caused. This kind of accident is highly hazardous and seriously causes the switch cabinet to be burned. Casualties and long-term power failure of users. Therefore, it is very important for the safe operation of the substation distribution system whether the fault can be quickly removed when the switch cabinet arc fault occurs. On the other hand, the reliability of power supply is more and more required by users. Based on the above reasons, it is necessary to set up special fast bus protection arc protection device for medium voltage switchgear.

For example, in a 110kV Substation in Zhejiang Province, the contact arm on the circuit breaker of 10kV outlet cabinet was short circuited, resulting in the arc light short circuit between phases. The contact arm on the circuit breaker and the metal valve of the switch cabinet melted. The cabinet was burned and scrapped, the adjacent switch cabinet was damaged, and the bus bar was cut off.

Domestic 6 ~ 35kV bus is generally not equipped with special bus protection. The arc protection system can make up for the defect. Its function and function are completely equal and superior to the existing bus differential protection, which can protect the whole bus.

The key technologies of arc protection device mainly include: electronic equipment stability and anti-interference technology; sensor and its signal processing technology; fault current rapid identification technology; fault fast trip signal output and primary equipment fast breaking technology; early warning technology of single-phase arc grounding state at the initial stage of arc fault.