Common faults and troubleshooting techniques of vacuum circuit breakers
The common faults and troubleshooting techniques of vacuum circuit breakers can be summarized as follows:
1、 Decreased vacuum degree
1. Fault phenomenon: The vacuum circuit breaker interrupts the current and extinguishes the arc inside the vacuum bubble, but the vacuum circuit breaker itself does not have a device for qualitative and quantitative monitoring of the vacuum degree characteristics, so the vacuum degree reduction fault is an implicit fault.
2. Reason for malfunction: The main reason includes problems with the material or manufacturing process of the vacuum bubble, which leads to small leakage points in the vacuum bubble itself; Or the distance between the operating links of the split type vacuum circuit breaker is large, which affects the synchronization, bounce, overtravel and other characteristics of the switch, accelerating the speed of vacuum degree reduction.
3. Fault hazard: It will seriously affect the ability of vacuum circuit breakers to break overcurrent, and lead to a sharp decrease in the service life of the circuit breaker. In severe cases, it may cause switch explosions.
4. Handling method: When conducting regular power outage maintenance on circuit breakers, a vacuum tester must be used to qualitatively test the vacuum degree of the vacuum bubble to ensure that the vacuum bubble has a certain degree of vacuum; When the vacuum degree decreases, it is necessary to replace the vacuum bubble and conduct characteristic tests such as stroke, synchronization, and bounce.
2、 Vacuum circuit breaker tripping failure
1. Fault phenomenon: The circuit breaker cannot be remotely opened by remote control; Manual disconnection on site cannot be achieved; The relay protection is activated during the accident, but the circuit breaker cannot be disconnected.
2. Fault causes: including disconnection of the opening operation circuit, disconnection of the opening coil, decrease in the operating power supply voltage, increase in the resistance of the opening coil leading to a decrease in the opening force, deformation of the opening top rod causing jamming or jamming during opening, etc.
3. Fault hazard: If the disconnection failure occurs during an accident, it will cause the accident to escalate and expand the scope of the accident.
4. Handling method: Check if the circuit breaker is disconnected, if the circuit breaker coil is disconnected, and measure the resistance value of the circuit breaker coil to ensure it is qualified; If the switch top rod is deformed, it should be replaced with a steel rod to avoid deformation.
3、 Fault in the closing energy storage circuit of the spring operated mechanism
1. Fault phenomenon: Unable to perform opening operation after closing; The operation of the energy storage motor does not stop, which may even cause overheating and damage to the motor coil.
2. Causes of malfunction: including the installation position of the travel switch being too low or too high, damage to the travel switch, etc.
3. Fault hazard: In the case of insufficient energy storage during closing, if the circuit breaker refuses to open due to an accident on the line, it will cause the accident to escalate; If the energy storage motor is damaged, the vacuum switch cannot be opened or closed.
4. Solution: Adjust the position of the travel switch to achieve accurate power-off of the motor; If the travel switch is damaged, it should be replaced in a timely manner.
In addition, there are faults such as asynchronous opening and closing, large bounce values, etc., which need to be addressed by measuring and adjusting the length of the three-phase insulation rod through a characteristic tester. At the same time, attention and handling are also needed for faults such as electrical wear and tear on the contacts of vacuum arc extinguishing chambers.
In general, common faults in vacuum circuit breakers require regular power outage maintenance and characteristic testing to prevent, detect, and promptly address these faults to ensure the safe and reliable operation of the equipment.