This article was reprinted.

1. accident course
There was an accident of 110 kV substation with 10 kV parallel capacitor explosion fire. At that time, operating personnel at the scene heard the explosion sound capacitors room, immediately cut off power supply capacitors and fire-fighting. Failure capacitors installed in capacitors close to the side of the wall. The accident caused capacitor side of the wall burns, the other side of the two neighbouring capacitors burned, four capacitors by the spray-drying fuse was melting.

2. causes analysis
After the incident we found that the explosion the fire capacitor fuse fuse, melt the end of the ride capacitors shell, shell and tail of the contacts have traces of discharge. Staff running one hour before the accident had been found that the capacitor fuse fuse, melt the end of the line linking capacitors ride on the shell, but found no other abnormalities.

The capacitors by a single star connection, set up a flow, the pressure and lost pressure protection, the protection of a single installation of capacitors for the jet-by-Fuse, the three-phase imbalance protection is not set, a single capacitor fuse Fuse, capacitors switch will not cause tripping.

Under normal circumstances, the capacitor fuse fuse, the fuse line linking the end of the shell is not charged to the capacitor. But a few minutes before the failure, by one of the 10 kV Chuxian who disconnected the line linking the distribution transformer grounding metal bench, a single-phase ground. Single-phase ground when the periodic off intermittently and rekindle the arc, from the neutral point arc on the ground over-voltage may reach five times in voltage. This over-voltage capacitors through the neutral point and the earth, the ground cover capacitors, links the end of the melt line and directly to the capacitor, resulting in its internal components explosions caused by the fire penetrated the whole incident.

3. inspiration after the accident 
(1) Capacitor explosion of fire cause of the accident and not only confined to the bulk capacitor quality factors, the accident is caused by external factors.

(2) Capacitors construction design, selected by spray-fuse-placed device can not be too short length of pipe insulation; installed at the end of the melt line to tighten, so as not to melt fuse fuse after the end of the line linking capacitors take on the case.

(3) The widespread use of double star-shaped wiring, and uneven distribution with the protection. Star-wiring, fuse links after the end of the melt-ride linked to capacitors shell, or single-phase ground after this situation may arise when it will withdraw from running capacitors.