fuse application

[sneja]

I have been asked to employ a fuse for protection of 11kV overhead line, a ground mounted 11/0.433kV distribution transformer and a low voltage cable. As I know expulsion fuses are commonly in used for overhead line protection. A H.R.C fuse or current limiting fuse is both employed for transformer protection. A H.R.C fuse suits the cable application as well since prevent conductor temperatures that would damage the cable insulation. There is large range of existing designs of fuses for above applications. I need help in choosing the appropriate type of fuse to employ in those cases since I don't have any practical experience in this area. I welcome all of your suggestions supported by the reasons for your choice.

 

[RajT]

A fuse on the prim side rated at say 1.4-1.5 times the prim flc should suffice

 

[electrifire]

I recommend an explusion fuse at the overhead line origin rated about 2x full load current with an aditional current limiting fuse at the transformer location if pad mounted or aditional explusion fuse if transformer is ground mounted power transformer.

Fuse for transformer protection should be sized to handle inrush at .1 sec and blow faster than transformer damage curve time and current or about 1.5x full load.

Suggest you cantact fuse manufacturer for additional help since you are not familiar with this field.