Isolating switch
What is an isolating switch? It is a switching device mainly used for "isolating power supply, switching operation, connecting and cutting off small current circuit", without arc extinguishing function. When the disconnector is in the off position, there are insulation distances and obvious disconnection marks between the contacts that meet the specified requirements; When in the closed position, the switchgear can carry the current under normal circuit conditions and abnormal conditions (such as short circuit) within the specified time. Generally, it is used as a high-voltage disconnector, that is, an disconnector with a rated voltage of more than 1kV. Its working principle and structure are relatively simple. However, due to its large usage and high reliability requirements, it has a great impact on the design, establishment and safe operation of substations and power plants. The main feature of disconnector is that it has no arc extinguishing ability and can only open and close the circuit without load current. The entry introduces the functions, characteristics, types, applications, error prevention improvement, maintenance, common problems, etc. of disconnectors. The function of the disconnector is to reliably isolate the power cut part of the high-voltage distribution device from the live part to ensure the safety of maintenance work. The contacts of the disconnector are all exposed in the air and have obvious breaking points. The disconnector has no arc extinguishing device, so it cannot be used to cut off the load current or short circuit current. Otherwise, under the action of high voltage, the breaking point will produce a strong arc, which is difficult to extinguish itself, and may even cause flashover (phase to ground or phase to phase short circuit), burn equipment, and endanger personal safety, This is a serious accident called "pulling disconnector on load". Disconnectors can also be used to switch some circuits to change the operation mode of the system. For example, in a double bus circuit, an isolating switch can be used to switch the circuit in operation from one bus to another. At the same time, it can also be used to operate some small current circuits.