High voltage load switch life tips

A high-voltage load switch is a high-voltage electrical device specifically used to connect and disconnect load current. When equipped with a tripper, it can also automatically trip in overload conditions. However, it only has a simple fire extinguishing device, so it cannot cut off short-circuit current. In most cases, the load switch is connected in series with a high-voltage fuse to cut off short-circuit current with the help of the fuse. It is divided into indoor and outdoor types. For example, the appearance of an indoor compressed air high-voltage load switch is very similar to that of an isolating switch. With an arc extinguishing device, etc.

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

An isolating switch is a switching device without an arc extinguishing device. It is mainly used to disconnect circuits with no load current and isolate power supplies. It has an obvious disconnection point in the open state to ensure the safe maintenance of other electrical equipment. In the closed state, it can reliably pass normal load current and short-circuit fault current. Because it does not have a special arc extinguishing device, it cannot cut off load current and short-circuit current. Therefore, the isolating switch can only be operated when the circuit has been disconnected by the circuit breaker. It is strictly forbidden to operate with load to avoid serious equipment and personal accidents. Only voltage transformers, lightning arresters, no-load transformers with excitation current not exceeding 2A, and no-load lines with current not exceeding 5A can be directly operated with isolating switches.

Load switches are a type of switching device between circuit breakers and isolating switches. They have a simple arc extinguishing device and can cut off rated load current and a certain overload current, but cannot cut off short-circuit current.

How to choose the size of a high-voltage load switch?

The selection of high-voltage load switches is basically the same as that of circuit breakers. They must meet the five conditions of rated voltage, rated current, breaking current, limiting current and thermal stability.