Fusing time should be less than the substation outlet switch current protection device setting time

Transformer primary side fuse is used as the secondary side of the transformer itself and the outgoing fault backup protection and substation outlet switch relay operating time match, must be less than exports mcb circuit breaker breaker opening time, requiring fuse while exports fuse breaker does not operate. Transformer capacity at 100kV. A less, of the one side of the fuse may be 2 to 3 times the rated mcb circuit breaker; in 100kV. A distribution transformer and above, according to its primary side fuse 1.5 to 2 times the rated current selection. Route branch line fuse primarily as overload protection, generally based on the maximum load current branch circuit rated current of selected fuse, fuse time should be less than the substation outlet switch current protection Circuit breaker. Drop-out fuse run establishment and maintenance ledger system, the running time is more than five years in drop-out fuse should be replaced batches. Improve the technical quality and electrical maintenance process. When installing or replacing the fuse, to force them moderately, avoiding too loose, too tight. Presence on both ends of fuse tube uneven casting defects, the manufacturer should be "chamfered" processing or for other improvements.