1. After opening, establish a reliable insulation gap, and separate the equipment or lines that need to be overhauled from the power supply with an obvious disconnection point to ensure the safety of overhaul personnel and equipment .
2. Change lines according to operational needs.
3. It can be used to divide and combine small currents in the circuit, such as the charging current of bushings, busbars, connectors, short cables, the capacitance current of the switching voltage equalizing capacitor, the circulating current when the double busbar is switched, and the excitation current of the voltage transformer Wait.
4. According to the specific conditions of different structure types, it can be used to divide and combine the no-load excitation current of a certain capacity transformer.
Isolating switches are mainly used in low-voltage terminal power distribution systems such as houses and buildings in low-voltage equipment. Main function: disconnect and connect lines without load.
1. Used to isolate the power supply, disconnect the high-voltage maintenance equipment from the live equipment, so that there is a clearly visible disconnection point between them.
2. The isolating switch cooperates with the circuit breaker to perform switching operations according to the needs of the system operation mode to change the system operation wiring mode.
3. Used to connect or disconnect small current circuits.
Generally, a set of isolating switches are installed on the front and rear of the circuit breaker. The purpose is to isolate the circuit breaker from the power supply to form an obvious disconnection point; because the original circuit breaker uses an oil circuit breaker, the oil circuit breaker needs frequent maintenance. Therefore, there must be obvious disconnect points on the two sides to facilitate maintenance; in general, the outlet cabinet is powered down from the upper bus through the switch cabinet, and a set of isolation switches is required in front of the circuit breaker to isolate the power supply, but sometimes, There is also the possibility of incoming calls behind the circuit breaker, such as through other loops, capacitors and other devices, so a set of isolating switches is also needed behind the circuit breaker.
The isolation switch is mainly used to reliably isolate the parts that need to be powered off and the live parts in the high-voltage power distribution device to ensure the safety of maintenance work. The contacts of the isolating switch are all exposed to the air and have an obvious disconnection point. The isolating switch has no arc extinguishing device, so it cannot be used to cut off load current or short-circuit current. Otherwise, under the action of high voltage, the disconnection point will produce a strong arc , And it is difficult to extinguish it by itself, and may even cause arcing (relative or phase-to-phase short circuit), burn equipment, and endanger personal safety. This is a serious accident called "pull disconnecting switch with load". The isolation switch 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 running circuit from one bus to another. At the same time, it can also be used to operate some small current circuits.
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