Isolation switch operation essentials - Solutions - Huaqiang Electronic Network

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

SMD aluminum electrolytic capacitor

MOS power IC full range

Photocoupler

When the operator performs the switching operation, it must be carefully checked that the circuit breaker is indeed in the disconnected position. For the three-phase linkage isolating switch, the three-phase landing should be at the same time, the difference should not be greater than 3mm, allowing the opening and closing operation of the isolating switch.
1. If the operation of the isolation switch is closed, the operator should first dial out the interlock pin and then close it. The start should be slow. When the moving contact approaches the static contact, it should be closed quickly to prevent arcing. . If an arc occurs at the beginning of the closing, the disconnector should be closed immediately, and the operator is prohibited from pulling the disconnector back again, because the pullback will cause the arc to expand, causing further damage to the equipment. At the end of the closing, the force should not be too strong to avoid the closing too deep, so that the supporting porcelain bottle is damaged. After the isolating switch is closed, the operating personnel should carefully check whether the closing is good and whether the moving contact completely enters the static contact to prevent the static and dynamic contacts from heating due to poor contact.
(1) For the isolating switch on the rotating shaft, the blade should be placed on the plane of the vertical fixed contact after closing, so as to ensure the pressure at the contact and the necessary contact resistance.
(2) For the swing type isolating switch, for example, the GW5 type isolating switch, the blade should be turned to the horizontal position after closing, and the arm should be straight. If the movable contact cap is to the right, the moving contact arm hammer is over the head.
When the outdoor isolating switch is operated in winter, the freezing and frosting on the contact can be rubbed off by several times of turning on and off, so that the contact of the movable and static contacts can be ensured after the isolating switch is closed. The condition that the isolating switch operates reliably is that when the isolating switch has a transmission, it should be ensured by its correct adjustment; if there is no transmission, it should be ensured by the correct operation of the insulating rod.
All kinds of isolating switches are not allowed to fall off automatically during short circuit. For this reason, when the isolating switch is in the closing position, it should be locked with five anti-locking devices. The duty personnel should carefully check these devices. After each isolation switch is closed, the isolating switch is buckled with a pin, and the five anti-locking devices are locked to prevent the isolation switch from automatically disengaging and causing an accident.
In view of the above analysis, it is summarized as follows: When the isolation switch is manually closed, it must be quickly and decisively. When the isolation switch is fastened to the end, it cannot be used too much to avoid damage to the supporting insulator. When there is an arc or misalignment when it is found in the end, the isolation switch is not allowed to be pulled apart, so as to avoid the load disconnecting switch due to misoperation, and the accident is enlarged.
2. When the isolating switch is opened, the isolation switch should be slow and cautious. When the moving contact leaves the static contact, if an arc occurs, the operator should immediately close the isolation switch and stop the operation. However, when the small load current and the charging current are cut off, an arc is generated when the isolation switch is opened. At this time, the isolation switch should be quickly disconnected to smoothly extinguish the arc. It should be slow at the end of the pull-up. This is to prevent damage to the supporting porcelain bottle and the operating mechanism. Finally, the operator should check whether the chain pin is sold well. After the isolating switch is opened, the operating personnel should carefully check that the isolating switch is indeed in the disconnected position, the disconnected air insulation distance should be qualified, and check that the moving contact has indeed been pulled to the end, and the angle of pulling should be in accordance with the manufacturer's Provisions. For the indoor isolation switch, if the insulation distance of the disconnection is not enough, the insulation partition should be inserted, otherwise the discharge short-circuit accident will occur on the side of the live side and the power-off ground line.
In view of the above analysis, it is summarized as follows: When manually opening the isolating switch, it should be slow and cautious. If the arc occurs when the contact is just separated, the arc should be quickly closed and stopped, and immediately check whether the arc is caused by misoperation. Before operating the isolating switch, the operating personnel should first judge whether the arcing switch will generate an arc. Under the premise of ensuring no error, the operation of arcing should be quick and decisive, and the arc should be extinguished as soon as possible to avoid burnout. Contact.
3. The isolation switch equipped with electromagnetic lockout should strictly abide by the anti-missing device unlocking regulations when operating the lockout failure, carefully check the actual position of the equipment, and obtain the consent of the shift dispatcher before removing the lock. At present, most substation disconnectors are usually equipped with grounding knives for grounding when wiring, circuit breakers, and disconnectors are inspected. A mechanical locking device is installed between the working isolating switch and the grounding knife. When the working isolating switch is turned on, the grounding switch will not be closed; and after the grounding knife is closed, the working isolating switch will not be closed. Such locking devices are currently commonly used in substations to prevent false grounding.
4. The operating switch of the electric operation encounters the operation failure of the electric failure. The running personnel should immediately find out the actual position of all the circuit breakers, the isolating switch and the grounding knife that have the latching relationship with the isolating switch. The disconnector operates the power supply for manual operation.
The above is the operating principle of the isolating switch in the operation process. In order to help the operator to correctly grasp the operation essentials of the manual pull-in isolating switch, the following points are summarized:
After the manual closing is slow, the manual opening is fast. After the slow operation, it is necessary to calm down. Please carefully analyze and find the reason. Do not blindly separate the joints, in case the damaged support is divided or combined, the porcelain bottle is not standing below.