Lêgerîna Serbesteyên Daxuyana Sifreyê û Şeşavên Vebijarka SF6

Stasionên kêmî de, xavterên çewtiyayên bêhêr vêkargirand, ji wan re SF₆ circuit breakers bi tevahiyên herî zor hene. Ev xavteran gasê SF₆ di navbera xasîn de bikar hinin. Berbas dixwazê arc energy, gasa SF₆ compressed dibikin da ku hêza bêtir bike, wêra tiştina currenti ya rated û fault current biguhezîne, li ser rastên kêmî û pîçeyên elektrîkî piştgiriya bike. Sistem bi sistemê operasyonî têkefî hatî, ku dikarin circuit breaker ên bi opening û closing operasyonan kontrol bikin, û funksyonî yên guhertîne.

SF₆ circuit breakers pir her îmkanî yên normal operasyonê yê stasionên kêmî ne. Ji bo dema SF₆ circuit breaker malafillî ye, bi serekeca sisteman yê stasionên kêmî rêbêtir in. Ew nîşan dide ku pêşketina û parastina SF₆ circuit breakers girîng e. Di vê amûran de, lêgerîna analîz û rêbazên treatmena fault ên SF₆ circuit breakers girîngî praktîkî hene.

1 Analîz bi Faultên Common ên SF₆ Circuit Breaker
1.1 Bistîna Gas Pressure SF₆

Di operasyonê real ên SF₆ circuit breakers de, bistîna pressure SF₆ gas dibe. Ji bo dema ev fault dibe, valueya pressure SF₆ pressure gauge jêrîn bese valueya rated pressure. Di remote control de, sistema management background alarm bidin ku management personnel bihin da ku pressure SF₆ gas jêrîn bese.

Ev şit ewa şeş ra çêdibîne, temperatureya ambient yê leh ên SF₆ circuit breaker li, an gas leakage di SF₆ system de, an reading gauge pressureê paqek ne, ku bihinê failure SF₆ density relay, ku bihinê bistîna pressure SF₆ gas û dibe SF₆ circuit breaker malafillî.

1.2 Failure SF₆ Circuit Breaker Close an Open

Di operasyonê SF₆ circuit breaker de, pas bi commandan opening û closing di manual operation de, SF₆ circuit breaker bihêre, ku dibe failure SF₆ circuit breaker close an open.

Sedema problemê fault ên bi serekeca sê aspektan. Yekem, spring energy-storage system malafillî ye û nekin energy û power bihêre ji bo opening û closing operations SF₆ circuit breaker. Duyem, control circuit blocked ye, ku bihinê open circuit û hindering transmission commandan. Sehêm, mechanical linkage failure ye. Jeger commandan bihêre, bi sedema failure an damage mechanical components, commandan bihêre nekin biguhezîne.

1.3 False Opening Fault SF₆ Circuit Breaker

False opening fault yekan common faults SF₆ circuit breakers ne. Bi serekeca SF₆ circuit breaker automatic opening bihêre pa command, SF₆ circuit breaker out of control bese û normal operasyon stasionê kêmî rêbêtir in.

Sedema problemê fault ên bi serekeca human misoperation an accidental touch. Dewamê false opening bi external mechanical vibration bihêre. Electrical faults dibe automatic opening SF₆ circuit breaker, bi serekeca incorrect protection actions an setting values. Di two-point grounding DC system de, pas connection positive an negative power supplies, signal relay protection transmitted an received, bihinê incorrect actions. Dewamê, mechanical faults li ser failure closing bracket support an displacement positioning screw bihêre false opening fault SF₆ circuit breaker.

1.4 False Closing Fault SF₆ Circuit Breaker

False closing fault yekan common faults SF₆ circuit breakers ne. Bi serekeca SF₆ circuit breaker automatic closing bihêre pa command, SF₆ circuit breaker out of control bese û normal operasyon stasionê kêmî rêbêtir in.

Sedema problemê fault ên bi serekeca contacts positive an negative di DC circuit de connected ne bihêre grounded simultaneously, closing control circuit form kir, closing fault bihêre; resistance coil closing contactor small, reducing starting voltage, causing momentary pulse DC system, closing fault forming; an damage opening latch support bihêre false closing fault SF₆ circuit breaker.

2 Treatmen Faults SF₆ Circuit Breaker
2.1 Treatment Method bi Insufficient SF₆ Gas Pressure Fault

Ji bo dema insufficient SF₆ gas pressure fault dibe, maintenance personnel bihêre record pressure gauge value SF₆ circuit breaker regularly û convert standard temperature determine gas pressure SF₆ circuit breaker normal. Ji bo dema pressure continuous drop, diagnosed gas leakage SF₆ circuit breaker.

Pas charging SF₆ circuit breaker rated pressure, observe change pressure gauge. Use SF₆ leak detector check all parts SF₆ circuit breaker, including connecting parts, sealing rubber rings, position pressure gauge joint. According actual situation, soapy water apply suspected leakage parts determine leakage location.

During leakage treatment, carry out repair welding on the leakage parts. Replace the leaking and damaged parts according to the usage of each part. In practice, since the density relay failure can also cause the system to issue a low - pressure alarm, the maintenance personnel can further check the density relay, especially for the indicator light and switch parts, to rule out the situation of switch adhesion or short - circuit, and replace the damaged relay in time to eliminate the fault.

2.2 Treatment Method bi Failure SF₆ Circuit Breaker Close an Open Fault

Bi dema failure SF₆ circuit breaker close an open, fault bi specific cause failure eliminate.

For the failure of the SF₆ circuit breaker to close or open caused by the failure of the spring energy - storage system, the maintenance personnel should check the operation of the auxiliary switch and energy - storage motor of the spring energy - storage system, and replace the components with burnt - out marks on the outer surface in time. If the appearance is normal, remove the motor wires and test whether the resistance of the energy - storage motor and the auxiliary switch can work normally. If the energy storage is normal after closing and the motor keeps running, it is determined that the energy - storage auxiliary switch cannot disconnect the circuit in time due to reasons such as moisture - induced adhesion or contact burnout, thus causing the failure of the SF₆ circuit breaker. The maintenance personnel should manually disconnect the energy - storage power switch to prevent the components from being burnt out due to the long - term operation of the motor, replace the auxiliary switch, check whether the entire equipment is affected by moisture or water seepage, and take timely moisture - proof and seepage - proof measures to prevent the recurrence of the SF₆ circuit breaker failure.

For the failure of the SF₆ circuit breaker to close or open caused by the blockage of the control circuit, the maintenance personnel should first check the working state of the opening and closing coils of the circuit breaker, check whether the control wires are broken, and rule out the looseness or disconnection of the wiring terminals and auxiliary switch nodes. First, the maintenance personnel should check whether the opening and closing coils are overheated or burnt out, and replace the damaged opening and closing coils in time. Second, according to the wiring diagram of the SF₆ circuit breaker, use a multimeter to check the connectivity of the circuit breaker circuit, and timely rule out the situation of broken wires or loose connections to ensure that the locking circuit is normal. Once an abnormality occurs, the fault point can be immediately determined and the fault can be eliminated.

For the failure of the SF₆ circuit breaker to close or open caused by mechanical linkage failure, the maintenance personnel should stop using the SF₆ circuit breaker and report the mechanical failure to the superior leader. Generally, mechanical failures include problems such as mechanism jamming, loose opening latch, and detachment of the transmission connecting rod. The maintenance personnel should disassemble the mechanically faulty components, restore the original mechanical components to their original positions according to the factory instruction manual, replace the damaged mechanical components, clean the dust on the components, add appropriate lubricating oil, and eliminate the mechanism jamming problem to achieve fault elimination.

2.3 Treatment Method bi False Opening Fault SF₆ Circuit Breaker

For the false opening fault caused by human misoperation or accidental touch, the maintenance personnel should first check the signal display of the SF₆ circuit breaker, rule out the switch fault, and restart the SF₆ circuit breaker to supply power. For the false opening fault caused by electrical faults, the maintenance personnel should first check the signal and setting value of the SF₆ circuit breaker, find the fault point, analyze the cause of the fault, and timely eliminate and repair the faulty components. For the components that are affected by moisture due to poor sealing, replace the sealing components and install a heating device for moisture - proof and dehumidification to eliminate the fault problem. For the false opening fault caused by mechanical faults, the maintenance personnel should disassemble the mechanical part, re - correct the position of the positioning screw, replace or repair the closing bracket, eliminate the false opening fault, and thus ensure the normal operation of the SF₆ circuit breaker.

2.4 Treatment Method bi False Closing Fault SF₆ Circuit Breaker

In the treatment of the false closing fault of the SF₆ circuit breaker, the maintenance personnel should clarify the main cause of the false closing fault of the SF₆ circuit breaker and adopt targeted treatment methods to eliminate the fault. The maintenance personnel should regularly check the moisture - proof situation of each component of the SF₆ circuit breaker. If the closing is caused by the simultaneous grounding of the positive and negative contacts in the DC circuit and it is judged that it is caused by the moisture of the secondary circuit, a moisture - proof and dehumidification device can be installed in the moisture - affected parts, and the water - seepage holes can be blocked in time to eliminate the fault. At the same time, the maintenance personnel should check all secondary circuits, replace the defective or damaged components in time, and eliminate the fault. In addition, the maintenance personnel should check the opening latch component, replace the damaged opening latch component, and eliminate the fault.

3 Case Analysis
3.1 Fault Phenomenon

A LW15 - 252 type SF₆ circuit breaker was put into operation as early as 2007. After the circuit breaker tripped, the latch was still in an over - position, and there was an abnormal spacing of about 10mm between the latch and the closing trigger, with abnormal contact. However, after the closing pulse power supply was provided, the coil and the trigger worked normally, but the latch still could not be disengaged for closing. After manually disengaging the latch, the switch still could not close.

3.2 Fault Analysis

Through the analysis of the operation data records of this circuit breaker, it was found that the circuit breaker had interrupted the current 132 times during operation. When the current is interrupted, a large amount of heat is generated, and the high - temperature arc will promote the accumulation of chemical reaction substances. Especially for the interruption of large currents, a catalytic effect is formed, accelerating the chemical reaction of internal substances and increasing a large amount of dust.

Therefore, the initial diagnosis of this circuit breaker fault is that the arc decomposition products caused by current interruption react chemically with the silicone grease in the sealed environment, forming a large amount of substances such as SiF₄ and Si(CH₃)₂F₂. The solidified substances stay in the braking seal rod, hindering the transmission of the braking seal rod, resulting in a jamming phenomenon and causing the closing failure of the SF₆ circuit breaker.

3.3 Fault Elimination

The maintenance personnel disassembled the faulty circuit breaker body. In the external inspection, it was found that the braking seal rod was obviously dirty, and there was a large amount of silicone grease on the sealing ring in the braking seal system, adhering to the surface of the braking seal rod, increasing the friction between the braking seal rod and the sealing ring during the transmission process, resulting in the inability of the braking seal rod to transmit normally and causing jamming. Replacing the components of the braking system could not fundamentally solve the fault problem, which only addressed the symptoms but not the root cause.

In the internal inspection, the switch body was disassembled, and a large amount of gray - white powder was found adhering to the inner wall of the arc - extinguishing chamber porcelain bushing, the braking seal rod, and the insulating pull rod. These powders are mainly solidified substances such as SiF₄ and Si(CH₃)₂F₂ formed under the high - temperature arc. Once accumulated to a certain extent, it may cause insulation breakdown accidents.

4 Conclusion

In summary, during daily management, administrators should be familiar with the common faults of SF₆ circuit breakers and develop practical solutions. Once a fault occurs, the fault point should be promptly identified and the fault eliminated, removing potential hazards, reducing power - outage time, preventing the occurrence of out - of - sequence tripping, and thereby enhancing the safety and stability of power supply in substations.

Therefore, in addition to replacing the components of the braking system, the maintenance personnel also need to replace the sealing components and arc - extinguishing components, clean the dust in the arc - extinguishing chamber. After the fault was eliminated, the circuit breaker was restarted and operated normally.