Isolating switch for high-voltage switch is most often used in an electric, as the name implies, is in the circuit has the isolation function of its working principle and structure is relatively simple, but due to the use of a large amount of work, high reliability requirements, substation, power plant design, build and operation have a great influence. The knife is the main characteristics of no arc extinguishing ability, only when there is no load current situation, closed circuit.

The isolation switch is in position, contact between the requirements of insulation distance and apparent disconnect symbol; in the closing position, can bear normal circuit conditions the current and within the time specified in the abnormal condition (e.g., short circuit currents of the switching device ).

Relative to the knife switch, isolation switch or a certain superiority, single page there is insufficient at present, thus gradually by the automatic air switch lock replaced. Because of the domestic situations of complexity, the complete replacement of the existence of serious difficulties, so the use is still quite extensive, the isolating switch main mainly manifests in two aspects:

1, isolated power supply, ensure safety

Isolation switch is used to ensure work safety inspection device. In need of repair parts and other live parts, with an isolating switch enough visible air insulating spacer. Isolating switch fracture in any state can spark discharge is generated, so its fracture pressure is generally higher than the insulation withstand voltage higher than 10% ~ 15%. When necessary, the isolating switch with a grounding knife switch, for overhaul grounding.

2, switching operation

The isolation switch electrical equipment or line from a group of switching to another set of bus.

Circuit breaker and isolating switch operation between sequence

Ensure the isolation switch " shorting " ( in the equipotential state, isolating switch can also be a separate operation ), this kind of circuit breaker and isolating switch operation between sequence must be strictly adhered to, can not take load broach gate (i.e., isolating switch), otherwise it will cause the misoperation, arcing and lead to serious consequences.

Isolating switch is mainly used for high-voltage distribution device without portion with the charged part reliably isolated, in order to ensure the safe maintenance work. Isolating switch contact all exposed in the air, having obvious cut-off point, isolating switch no arc extinguishing device, so it can't be used to cut off the load current and short circuit current, or under high pressure, strong arc breaking points, and very difficult to extinguish, even can cause arcing ( relative or white short circuit ), burning equipment, endanger the security of the person, this is the so-called " disconnector with load switch " severe accident. Isolating switch can also be used for certain circuit switching operation, so as to change the operation mode of the system. For example: in the double bus circuit, can use isolation switch will run in the circuit from a bus switching to another bus. At the same time, can also be used to operate a number of small current circuit.