Aiki na ƙarfin 10kV vacuum circuit breakers
Fasahohin Kwalitoci da Duka
Duka na nufin kwalitoci mai yawa. A cikin fasahar duka, gasar ya zama da mutuwar da ba ta fi yawa, saboda hanyoyin gas suna da kyau, kuma masu gas suka da wata irin lokaci mai yawa, wanda ya ba da adadin gaba-gaban da za a iya faruwa da shi. Saboda haka, fasahar duka ba sa cewa abin da za a iya faruwa da shi, amma masu sararin da za a iya faruwa daga alamar da ke faruwa su ne muhimman abubuwan da ke faruwa.
Kwalitocin da ake samu a cikin fasahar duka babu da rana da girman fasahar ko idan tsohon gasar, amma ana iya tabbatar da shi da muhimmin sarautar material da ake amfani da shi don alamun da kuma halayen jirgin rasu. Idan fasahar duka yana da girman (da take kan 2-3 millimeters), kwalitocinsu yana da muhimmanci da kafin gasar da pressure mai yawa da SF6. Wannan shine mafi karin da fasahar duka yake da kafin gasar da pressure mai yawa da SF6.
Tushen material da ake amfani da shi a fasahar duka yana iya tabbatar da kwalitocin da za a iya faruwa, musamman tsari da shirin material da ake amfani da shi. Idan tsari da shiri suna da muhimmanci, kwalitocin da za a iya faruwa a fasahar duka yana da muhimmanci.
Saiyuka ta bayyana cewa idan level of vacuum yana da muhimmanci, kwalitocin da za a iya faruwa a fasahar duka yana da muhimmanci. Amma idan level of vacuum yana da 10⁻⁴ Torr, kwalitocin da za a iya faruwa yana daidai. Saboda haka, don inganta kwalitocin da za a iya faruwa a fasahar duka, level of vacuum ba zai iya zama 10⁻⁴ Torr ba.
Bayyana da Fasahar Duka
Fasahar duka ba da tasirin fasahar gasar da ake bayyana. Gasar da ake faruwa ba shi ne muhimman abubuwan da ke faruwa, amma fasahar duka yana faruwa daga vapor da ake faruwa daga alamun. Kuma siffofin fasahar suna da muhimmanci da tsari da ake faruwa. Idan ake bayyana, ana iya faɗa fasahar duka da takaitaccen current da fasahar duka da current mai yawa.
Fasahar Duka da Takaitaccen Current: Idan fasahar duka yana faruwa, masu cathode spots da current da energy suka faruwa. Ana faruwa da vapor metal da ake faruwa daga cathode spots, inda density of metal atoms da charged particles yana da muhimmanci, kuma fasahar yana faruwa a cikin wannan environment. Da kuma, vapor metal da charged particles a column of arc suka faruwa outward, kuma alamun suka faruwa da abubuwan da za a iya faruwa don inganta. Idan current yana faruwa zero, energy of the arc yana ci, temperature of the electrode yana ci, effect of evaporation yana ci, density of particles in the arc column yana ci, kuma finally, cathode spots yana zama zero, wanda yake faruwa fasahar.
Fasahar Duka da Current Mai Yawa: Idan fasahar duka yana faruwa, energy of the vacuum arc yana yawa, kuma anode yana da heat mai yawa, wanda yake faruwa column of arc mai yawa. Da kuma, effect of electrodynamic force yana da muhimmanci. Saboda haka, for high -current vacuum arcs, magnetic field distribution between the contacts yana da muhimmanci da stability and arc-extinguishing performance. Idan current yana da yawa, kuma yana da yawa da limiting interrupting current, interruption failure yana faruwa. A wannan lokacin, contacts yana da heat mai yawa, kuma yana da evaporation even after the current yana faruwa zero, kuma dielectric recovery yana da yawa, saboda haka, current interruption yana da yawa.
Siffar da Tattalin Circuit Breakers
Idan ake bayyana zw27-12, a nan ake bayyana siffar da tattalin circuit breaker.
Gwiwar circuit breaker yana da conductive circuit, insulation system, seals, da housing. Yana da three-phase common-box structure. Conductive circuit yana da incoming and outgoing conductive rods, incoming and outgoing insulation supports, conductive clamps, flexible connections, da vacuum arc-extinguishing chamber. Mechanism yana da electric energy storage da electric opening and closing, amma yana da manual operation function. Siffar yana da components like closing spring, energy-storage system, over-current trip device, opening and closing coils, manual opening and closing system, auxiliary switch, da energy-storage indicator.
Circuit breaker yana amfani da phenomenon da a high-vacuum environment, idan current yana faruwa zero, plasma yana faruwa outward, kuma yana faruwa fasahar da cutting off the current.
Debugging of Circuit Breaker
Opening Distance and Over-travel
Measurement of the opening distance and over-travel of a circuit breaker: The difference in the measured x-values when the circuit breaker is in the open and closed states is the opening distance of the circuit breaker, and the difference in the measured y-values is the over-travel of the circuit breaker. The adjustment is achieved by lengthening or shortening the insulating operating rod or the connecting rod between the mechanism and the main shaft.
Adjustment of Opening and Closing Mechanism
Control Circuit of Circuit Breakers
In most 35kV standardized substations in rural power grids, the principle of separating the control busbar from the closing busbar is adopted. Due to frequent lightning, rain, and strong wind in mountainous areas, which lead to multiple trippings and an increased number of switch closing operations, the closing coils of switches are extremely prone to burnout. Here, I suggest making a minor improvement to the control circuit.
Insert a pair of normally-open contacts of the circuit breaker's energy-storage travel switch in series between the auxiliary normally-closed contacts of the circuit breaker and the closing coil. In this way, when the circuit breaker is not energized (not energy-stored), the closing operation cannot be carried out. This prevents closing when the circuit breaker is not energized, thus avoiding the situation where the closing circuit remains on and burns out the closing coil.
Meanwhile, during the wiring process, it is necessary to ensure that the polarities of the closing busbar and the control busbar at the contacts of the energy-storage travel switch are consistent. This is to prevent the arcing in the closing circuit from puncturing the travel switch when the switch is being energized, which could cause the control fuse to blow or the control air switch to trip. This point requires special attention in integrated automated substations.
Operation, Maintenance, and Inspection Tests
Vacuum circuit breakers have a short arcing time, high insulation strength, and a relatively long electrical life. With small contact opening distances and over-travel, and minimal operating energy, they also enjoy a long mechanical life. During daily operation, maintenance tasks are relatively few. Mainly, it is necessary to check for wear on the moving parts of the mechanism, ensure that fasteners are not loose, clean the dust off the insulation surface, and apply some lubricating grease to the moving parts.
During preventive tests, the DC resistance test results of the switch should be compared with historical data. If any issues are identified, timely replacement or rectification is required. The power-frequency withstand voltage test for the breaker is an effective method to check for leakage in the vacuum interrupter. (For indoor vacuum circuit breakers, the color of the flash inside the vacuum interrupter when the load is disconnected can be used to preliminarily assess the vacuum level. A dark red color indicates a reduced vacuum level, while a light blue color indicates a good vacuum level.)
During protection setting verification, a low-voltage closing test is conducted on the circuit breaker to verify whether the switch operates reliably when the busbar is in a fault state and the voltage drops.
