Operation steps of drop-out fuse

In rural power grids, 10kV distribution line branch lines and distribution transformers with rated capacity less than 200kVA are allowed to operate with load according to the following requirements:

(1) The drop-out fuse is operated by two persons (one person for supervision and one person for operation), but it is necessary to wear insulating gloves that have passed the test, wear insulating boots, goggles, and use qualified insulating rods that match the voltage level Operation, operation is prohibited under thunder and lightning or heavy rain.

(2) In the opening operation, the usual rule is to pull off the central phase first, then pull the side phase of the leeward wind, and finally pull the side phase of the top wind. This is because the distribution transformer is changed from three-phase operation to two-phase operation, and the arc spark that occurs when the center phase is broken is the smallest, which will not cause a short circuit between phases. The second is to pull off the leeward side phase. Since the center phase has been opened, the distance between the leeward side phase and the top wind side phase has doubled. Even if an overvoltage occurs, the possibility of a short circuit between the phases is very small. When the top wind edge phase is finally broken, there is only capacitive current to the ground, and the electric spark that occurs is already very slight.

(3) When closing, the operating sequence is reversed when opening the brake. First close the top wind side phase, then close the leeward side phase, and finally close the center phase.

(4) The operation of the fuse tube is a frequent item. Failure to pay attention to it will cause contact burns and poor touch, overheating of the contacts, annealing of the tension springs, and promotion of poor contact touch, forming a vicious circle. Therefore, you must use moderate force when pulling and joining the fusion tube. After closing, carefully check that the duckbill tongue can tightly clasp the tongue for more than two-thirds of the length of the tongue. You can hook the upper duckbill with the pull lever and press it down several times. Try to pull again quietly to see if it's all right. Failure to be in place or not securely closed when closing, lack of static contact pressure on the fuse, it is easy to cause contact burns or the fuse tube will fall by itself.

Disconnect: Use the tip of the operating rod to push it to the falling spring plate (on the upper contact of the fuse), and the fuse tube will fall off. Closing: Insert the upper hook of the fuse pipe with the horizontal hook of the handle bar and push it upwards (to be satisfied, and to make a reverse hook pull to verify whether the contacts are tightly closed), the fuse pipe will be closed.