Determination of neutral trip settings for distribution capacitor banks

The introduction of neutral current detection systems makes the early determination of progressive capacitor unit failure feasible. This is considered to be a valuable supplement to using group fuses as part of a comprehensive distribution capacitor protection system. The author reviews distribution capacitor failures and how the neutral current tripping scheme can be applied. A rational method for the development of neutral current trip settings is presented. It is concluded that neutral trip devices offer an improved method of preventing capacitor case rupture. Settings should be established to accommodate temporary distribution system conditions which could otherwise cause unnecessary operations