Drop-out fuses and pull-load drop-out fuses are outdoor high-voltage protective appliances. It is installed on the high-voltage side of the distribution transformer or on the branch line of the distribution line, and is used for short-circuit, overload protection, and split and combined load current of transformers and lines. The drop fuse is composed of an insulating support and a fuse tube. The static contact is installed at both ends of the insulating support, and the moving contact is installed at both ends of the fuse tube. The fuse tube consists of the inner arc extinguishing tube and the outer layer. It consists of phenolic paper tube or epoxy glass cloth tube. Pull-load drop-out fuse enhances the elastic auxiliary contact and arc extinguishing cover to divide and combine the load current.
In the normal operation of the drop-out fuse, the fuse tube is tensioned by the fuse to form a closed position. When the system fails, the fuse is quickly blown out when the fault current occurs, and an arc is formed. The arc extinguishing tube is heated by the arc and decomposes a large amount of gas, which causes a high pressure in the hall and a vertical blow along the pipeline. The arc is quickly stretched. And goes out. After the fuse is blown, the lower moving contact loses its tension and turns over twice. The machine is locked, the fuse tube is released, and the fuse tube is dropped, forming an obvious breaking position. When the load needs to be pulled, use the insulation rod to pull the contact. At this time, the active and static contact are still in contact. If you continue to use the insulation rod to pull the contact, the auxiliary contact is also separated, and an arc occurs between the auxiliary contacts. It is stretched in the extinguishing slit, and at the same time, the extinguishing hood generates gas, and when the current crosses zero, the arc is extinguished.
Outdoor high-voltage fuse is suitable for 35kv and below 50Hz power frequency system, for overload and short circuit protection of transmission lines, power transformers, only use the rated load current, mechanical life ≥ 2000 times.
1. Applicable to the upper limit of ambient temperature 40 ℃, lower limit of -30 ℃.
2. The altitude does not exceed 1000m, and the wind speed does not exceed 35m / s.
3. Fuses are not suitable for the following places
3.1 Places with danger of fuel or explosion.
3.2 Places with severe vibration or impact.
3.3 Areas with different electrochemical gas effects and severe air pollution and smog.
The fuse is composed of two parts, the base and the arc extinguishing device. The lower end of the arc extinguishing tube is equipped with a spring bracket that may rotate. The fuse is always under tension to ensure the self-locking of the arc extinguishing tube in the closing position. In the overload or short circuit of the transformer, the fuse is blown, and the fuse is quickly pulled out of the arc extinguishing tube. The arc extinguishing tube is designed to exhaust the contradiction between large and small current on the same fuse.
Rated voltage kv
Rated current A
Breaking current kA
Surge voltage BIL
Power frequency withstand voltage kv
Porcelain (or ceramic insulator )