APPLICATION OF SF6 LOAD SWITCH IN DISTRIBUTION NETWORK

Application of SF6 Load Switch in Distribution Network

The medium-voltage switches used in general hub substations all use circuit breakers as control and protection devices, and must have automatic reclosing. However, the power supply capacity of each power distribution station in the ring network is generally not large, its rated current is smaller than the rated current of the ring network, and reclosing is not required, so the power supply unit of the ring network power distribution station can adopt simple structure, low price and high performance. A combination of load switch + fuse that can meet the requirements.

The combination of load switch and fuse to replace the traditional circuit breaker has been implemented abroad for half a century. The ratio with the output of circuit breakers is 1:2.5, which is still far behind the developed industrial countries. It also shows that in my country, SF6 load switches have great prospects in the development of medium-voltage distribution networks.

In summary, by comparing the application of SF6 load switches and circuit breakers in small-capacity distribution networks, the following points can be summarized:

The circuit breaker cooperates with the relay protection and has all the

Protection function and operation function.

SF6 load switch has basically the same function as circuit breaker, except that it cannot break short circuit (not required).

The performance of SF6 load switch breaking no-load transformer is better than that of circuit breaker.

SF6 load switch + current limiting fuse can also break short circuit at one time, which is almost the same as circuit breaker.

SF6 load switch + current limiting fuse is no worse than circuit breaker, but the cost is much lower.