Structural characteristics of high voltage load switch

A high-voltage load switch is a high-voltage electrical device specially used to switch on and off load current. When equipped with a trip unit, it can also trip automatically under overload conditions. But it only has a simple fire extinguishing device, so it cannot cut off the short-circuit current. In most cases, the load switch is connected in series with the high-voltage fuse, and the short-circuit current is cut off by the fuse. Divided into indoor and outdoor. For example, the shape of the indoor compressed air high-voltage load switch is very similar to that of the isolation switch. With arc extinguishing device, etc.

What is the difference between a high voltage load switch and an isolating switch?

The isolating switch is a switchgear without an arc extinguishing device. It is mainly used to disconnect the circuit with no load current and isolate the power supply. It has an obvious disconnection point in the open state to ensure the safe maintenance of other electrical equipment. It can reliably pass normal load current and short-circuit fault current in the closing state. Because it does not have a special arc extinguishing device, it cannot cut off the load current and short-circuit current. Therefore, the isolation switch can only be operated when the circuit has been disconnected by the circuit breaker, and operation with load is strictly prohibited to avoid serious equipment and personal accidents. Only voltage transformers, arresters, no-load transformers whose excitation current does not exceed 2A, and no-load lines whose current does not exceed 5A can be directly operated with isolating switches.
The load switch is a switching appliance between the circuit breaker and the isolating switch. It has a simple arc extinguishing device, which can cut off the rated load current and a certain overload current, but cannot cut off the short-circuit current.

How to choose the size of high voltage load switch?

The selection of high-voltage load switch is basically the same as that of circuit breaker, and must meet five conditions of rated voltage, rated current, breaking current, limit current and thermal stability.