Operation method and procedure of drop type fuse with load

In the branch line of 10KV distribution line of rural power grid and distribution transformers with rated capacity less than 200V, they should be operated with load according to the following requirements:

1. The drop type fuse shall be operated by two people (one person supervises and one person operates). During the operation, qualified insulating gloves, insulating boots and protective eyeglasses shall be worn.

2. In the brake operation, usually first pull off the central phase, then pull the leeward side phase, and finally pull off the wind side phase.

This is because the distribution transformer from three-phase operation to two-phase operation, the central phase of the breaking of the arc spark occurred at the minimum, to avoid the formation of interphase short circuit. Since the central phase has been pulled apart, the distance between the two phases is doubled, and the possibility of short circuit is very small when the leeward phase is broken. When the upwind phase is finally broken, only the capacitance current to the ground is generated, and the electric spark is very slight.

3. When closing the switch, the operation sequence is opposite to that when pulling the switch. First close the upwind side phase, then close the leeward side phase, and finally close the center phase.

4. The operation of the molten tube is an important project, a little careless will constitute the contact burns, resulting in bad touch, so that the contact overheating, spring annealing, promote the contact touch is more bad, forming a vicious circle.

Therefore, when pulling and closing the tube, it is necessary to exert moderate force. After closing, it is necessary to carefully check that the tongue of the duck mouth can tightly buckle more than two-thirds of the length of the tongue. The brake rod can be used to hook the duck mouth and press it down a few times, and then gently try to pull it to see whether it is closed. When the switch is not in place or not firmly closed, the lack of static contact pressure on the fuse, etc., is easy to constitute contact burns and the fall of the fuse.

Disconnect: the fuse will fall off by pushing the operating rod towards the upper contact of the fuse.

Closer: hook the upper ring of the fuse tube with the operator rod and push it up. The fuse tube will close.