With the rapid development of power systems, vacuum circuit breakers have been massively produced and utilized. For maintenance personnel, it has become an urgent issue to enhance their understanding of vacuum circuit breakers, strengthen maintenance, and ensure safe operation. Through the analysis of common faults in vacuum circuit breakers and the summary of treatment experience, it can better guide power plants in carrying out the operation, maintenance, and repair of vacuum circuit breakers, ensuring their safe and reliable operation. The following are some common fault analyses and treatment experiences for vacuum circuit breakers.
The vacuum circuit breaker interrupts the current and extinguishes the arc within the vacuum interrupter. Since the vacuum circuit breaker itself does not have a device to qualitatively and quantitatively monitor the characteristics of vacuum degree, the reduction in vacuum is not easily detectable and its danger level far exceeds other explicit faults.
Main reasons
There may be issues with the material or manufacturing process of the waveguide tube inside the vacuum interrupter, leading to leakage points after multiple operations; there might be tiny leakage points in the material or manufacturing process of the vacuum interrupter itself; in split-type vacuum circuit breakers, the large distance of the operating link directly affects characteristics like simultaneity, bouncing, and overtravel, speeding up the reduction of vacuum. Low vacuum will severely affect the current interrupting capacity and lifespan of the vacuum circuit breaker, and at particularly low vacuum levels, it may cause the vacuum circuit breaker to explode.
Solution
During regular maintenance of vacuum circuit breakers, a vacuum tester must be used to qualitatively test the vacuum degree of the interrupter to ensure it has a certain level of vacuum; if the vacuum degree is reduced, the vacuum interrupter must be replaced, and characteristics tests for overtravel, simultaneity, bouncing, etc., should be conducted.
Main reasons: There are faults in the line; improper operation; issues with the operating or closing power supply or faults in the electrical secondary circuit; mechanical faults in the transmission mechanism of the circuit breaker itself or the operating mechanism.
Solution
To address the circuit breaker refusal to close malfunction, one must be adept at distinguishing fault ranges and determine whether the circuit breaker closed on a latent fault in the line causing a trip. This can be judged by indicators such as impact and deflection on the gauge during closing operation due to short-circuit current, sudden dimming of lights, and a sudden drop in voltage meter indications. If a line fault is confirmed, isolate the fault area before re-engaging the circuit breaker. Determine if it's due to improper operation by checking for closing insurance, whether the control switch has reset too quickly or not positioned correctly, and whether the transfer switch is in the correct position. Check if the closing power supply voltage is too high or too low, whether the closing insurance is blown or has bad contact, whether the control switch and auxiliary contacts have bad contact, and if the circuit has broken wires or wrong connections. Check if the operating mechanism is jammed and whether the auxiliary contacts and mechanism adjustments are improper. Generally, it's due to non-compliant gaps in the connecting parts of the operating mechanism, requiring inspection and replacement of new, high-hardness, compliant parts.
Phenomenon
The vacuum circuit breaker cannot break despite a remote control open command.
Main reasons
Break in the opening operation circuit; break in the opening coil; lowered voltage of the operating power supply; short circuit in the opening coil reducing its opening capability; deformation of the opening push rod causing jams during opening, etc. If opening malfunction occurs during an accident, it will lead to the expansion of the accident.
Solution
If operating personnel find that the open/close indicator light is not lit, they should promptly check if there is a break in the open/close circuit; during power-off maintenance, personnel should measure the resistance of the opening coil and check for deformation of the opening push rod; if the opening push rod is made of copper, it should be replaced with a steel one; low-voltage open/close tests must be conducted to ensure the reliable performance of the vacuum circuit breaker.
Phenomenon
Unable to perform opening operation after closing; energy storage motor does not stop running, etc.
Main reasons
Misplacement of the travel switch either too high or too low, and whether the travel switch is damaged. If the closing energy storage is not in place, any line fault will cause the vacuum circuit breaker to refuse to open, leading to an escalation of accidents; if the energy storage motor is damaged, the vacuum circuit breaker cannot perform open/close operations.
Solution
During switching operations, operating personnel should observe the closure energy storage indicator light to judge the closure energy storage status. If the above faults occur, adjust the travel switch position to ensure the motor stops accurately or replace the damaged travel switch. After maintenance, personnel should conduct two local open/close operations to ensure the vacuum circuit breaker is in good condition.
This fault is latent and can only be determined through characteristics measurements using specialized testers.
Main reasons
Poor mechanical performance of the vacuum circuit breaker body, leading to out-of-sync and high bounce values after multiple operations due to mechanical reasons; in split-type circuit breakers, the large operating rod distance causes deviations between phases when transferring opening force to the contacts, leading to out-of-sync and high bounce values. Out-of-sync or high bounce values will severely affect the current interrupting capability and lifespan of the vacuum circuit breaker.
Solution
Given the numerous fault risks in split-type vacuum circuit breakers, integrated vacuum circuit breakers should be used when replacing them; during regular maintenance, specialized testers must be used for related characteristics testing to timely identify problems.
Other faults
After circuit breaker mechanism energy storage, if the energy storage motor does not stop, adjust the travel switch installation position so that the travel switch's normally closed contact opens when the arm is at the highest position.
If the DC resistance of the circuit breaker increases, adjust the contact opening distance and overtravel of the interrupter.
If the closing bounce time of the circuit breaker increases, appropriately increase the initial pressure of the contact spring or replace the contact spring.
If the gap between the crank and pin exceeds 0.3mm, replace the crank and pin; adjust the transmission mechanism, using the small transmission ratio characteristic when the mechanism is in the closed position beyond the dead point of the drive arm; adjust the mechanism towards the dead point to reduce contact closing bounce.
If the CT surface of the breaker's middle box discharges towards the bracket and the breaker's interrupter cannot open, it is usually due to a decrease in vacuum degree causing a drop in insulation inside the interrupter and failing the voltage withstand test.
As a new generation of advanced switching equipment, vacuum circuit breakers are gradually being widely used. However, with their increasing application, the incidence of defects and faults also rises inevitably. Currently, vacuum circuit breaker faults are varied; apart from the common faults analyzed in this article, new issues may still arise during daily usage. To ensure reliable operation of vacuum circuit breakers, operating personnel should increase patrols and reinforce routine maintenance inspection, promptly identifying and reporting problems. Maintenance personnel should strictly execute electrical preventive tests and adhere to procedural requirements to ensure maintenance quality, improve equipment health status, and avoid accidents.
+86-18666115545
Building 3, No. 2007 Mingzhu South Rd, Qianshan, Zhuhai, Guangdong, China
English 
français 
Deutsch 
русский 
português 
العربية 
tiếng việt 
ไทย 
Malay 
हिंदी 
Indonesia 
