It is understood that the disconnector is the most used electrical appliance in high-voltage switch electrical appliances, as the name implies, it plays an isolation role in the circuit. Its own working principle and structure are relatively simple, but due to the large amount of use, the high requirements for working reliability, the impact on the design, establishment and safe operation of substations and power plants are greater. The main feature of the knife gate is that it has no arc extinguishing ability, and can only divide and close the circuit without load current.
Introduction to disconnectors
Disconnector (disconnector) means that when the position is divided, there is an insulation distance and a clear disconnection mark between the contacts that meet the specified requirements; A switchgear that can carry current under normal loop conditions and current under abnormal conditions (such as short circuit) within a specified period of time. （IEV441-14-05)
What we call disconnector (commonly known as "knife gate"), generally refers to high-voltage disconnector, that is, the rated voltage of 1kv and above the disconnector, usually referred to as the disconnector, is a high-voltage switch electrical appliances used the most electrical appliances, its own working principle and structure is relatively simple, but due to the large amount of use, high requirements for work reliability, the design, establishment and safe operation of substations and power plants have a greater impact. The main feature of the disconnector is that it has no arc extinguishing ability, and can only divide and close the circuit without load current. Disconnectors are used for all levels of voltage, used to change circuit connections or isolate lines or equipment from the power supply, it has no current breaking ability, can only be used with other equipment to disconnect the line before operation. Generally, there is an interlock device to prevent misoperation when the switch is loaded, and sometimes a pin is needed to prevent the switch from being opened under the magnetic force of a large fault.
1. Provide an electrical interval during the maintenance of electrical equipment, and it is a visible disconnection point to ensure the personal safety of maintenance personnel.
2. The disconnector can not be operated with load: it cannot be operated with rated load or large load, and cannot be divided and combined load current and short circuit current, but the arc extinguishing chamber can be operated with small load and no-load lines.
3. General power transmission operation: first close the disconnector switch, then close the circuit breaker or load switch; When the power is off: first disconnect the circuit breaker or load switch, and then disconnect the disconnector.
4. When selected, it is the same as other electrical equipment, and its rated voltage, rated current, dynamic stable current, thermal stability current, etc. must meet the needs of the use occasion.
The function of the disconnector is to disconnect the circuit with no load current. So that the equipment to be repaired and the power supply has obvious disconnection points to ensure the safety of maintenance personnel, the disconnector does not have a special arc extinguishing device can not cut off the load current and short circuit current, so the circuit must be in the circuit breaker disconnection circuit can operate the disconnector.