بەکارهێنانی بڕگەی خالی ١٠ کیلووۆڵت
Taybetmendiyên Isolation ya Vacuum
Vacuum taybetmendiyên isolationê çimaşên derbas dike. Di breakerê vacuum de, gaz zafelan derbas e, û molekullên gazê li ser dawerên mezopî yên derbas ên gotin, ku bi vê deman hejmar ên berbiyêna yek biniyê ya din jê re girîng in. Bunaqeyek, ionization li ser berbiyêna nisandin ne yekê ya sereke ye ku breakdowan di rûnda vacuum gapê de were biguherîne. Tu heta, particullên metalî yên ji electrodeyan ve tiştina têkanîya elektrikê ya bêdarbistin re wergerîn, wan yekên serekan in ku guherandina isolationê were biguherînin.
Strenghta isolation ê di rûnda vacuum gap de tu li ser mezinahiya gapê û pêvajoya electric fieldê were pir sedexandin, lê tu heta bi malperêtina materialê ya electrode û rewşa surfaceyê wekheviyê were pir sedexandin. Jema li dema ku vacuum gap zafelan be (di navcheya 2 - 3 millimetre), taybetmendiyên isolation ê wekhevî yên li ser atmosfera air ê ya bavir û SF6 gas ê be. Ev yekî ye ku ji bo ku gapa contact di breakerê vacuum de zafelan be.
Berhevkariya materialan electrodean bi voltageya breakdown ê li ser malperêtina mechanical strength (tensile strength) û melting point ê ya materiala metalî re were hatine nîşan kirin. Ji kerema tensile strength û melting point ê yekê, strenghta isolation ê ya electrode di vacuum de girîng e.
Pencereyan werdigirtin ku li gorî levela vacuum ê voltageya breakdown ê ya gas gapê girîng be. Lêm, ji 10⁻⁴ Torr ve ser, ew gatiye destniha. Ji bo ku taybetmendiyên isolation ê ya vacuum arc-extinguishing chamber ê were mirin, levela vacuum ê nayê li 10⁻⁴ Torr ve herî zafelan be.
Formasyon û Extinction ya Arcs di Vacuum de
Arcs vacuum ji fenomenên discharge ya gas arkê yên ku ewle studi kirin nayên pir sedemandin. Ionization ya gas ne yekê ya sereke ye ku biguherîne formasyona arc. Tu heta, discharge ya vacuum arc di vapor metallic ê yên ji electrodeyan contactan ve wergerîn da form û wara dikin. Tu heta, taybetmendiyên arc li ser mezinahiya currenta interrupting ê were guhertin. Giştî, wan ji bo low-current vacuum arcs û high-current vacuum arcs were cihkirin.
Low-current Vacuum Arc: Ji dema ku contacts di vacuum de were xweşandin, spots cathode yên bi current û energy ê yekê yên tevahî were xweşandin. Dega spots cathode an, amount ê yekê yên tevahî ya vapor metallic were evaporation kirin, ku density ê yekê yên atom û charged particles ê metalî yên girîng e, û arc di environtmenta wê de were burning. Tu heta, vapor metallic û charged particles û arc column were diffusion kirin, û electrodes new particles were evaporation kirin bi tenê bikar bînin. Ji dema ku current zero were guherîn, energya arc were kêm kirin, temperatureya electrode were kêm kirin, effecta evaporation were kêm kirin, densitya particle û arc column were kêm kirin, û finally, spots cathode were guherîn ji dema ku current zero were guherîn, ku extinction ya arc were diguherînin. Yekî ji dema, ji dema ku effecta evaporation nayê bikar bînin li ser rateya diffusion ê ya arc column, arc were extinction kirin bixweber, ku chopping ya current were diguherînin.
High-current Vacuum Arc: Ji dema ku current mezin were breaking, energya vacuum arc were girîng kirin, û anode heta were heating, ku arc column strong constricted were diguherînin. Tu heta, effecta electrodynamic force were pir sedemandin. Ji bo high-current vacuum arcs, distributiona magnetic field ê di navcheya contacts de li ser stability û performance ya arc-extinguishing ê were decisive influence kirin. Ji dema ku current wekheviyê girîng be, ji limiting interrupting current ve ber, interruption failure were diguherînin. Ji dema ku, contacts were heating, û heta were evaporation kirin ji dema ku current zero were guherîn, û dielectric were difficult bikar bînin li ser recovery, ku current interruption nayê bike.
Structure û Working Principle ya Circuit Breakers
Di navbera zw27-12, structure û working principle ya wê were şirok kirin.
Bodya main ê ya circuit breaker conductive circuit, insulation system, seals, û housing e. Wê structure ê ya three-phase common-box e. Conductive circuit incoming û outgoing conductive rods, incoming û outgoing insulation supports, conductive clamps, flexible connections, û vacuum arc-extinguishing chamber e. Mechanism features electric energy storage û electric opening and closing, û heta function ê ya manual operation e. Structure ê yên bi components ê yên closing spring, energy-storage system, over-current trip device, opening and closing coils, manual opening and closing system, auxiliary switch, û energy-storage indicator e.
Circuit breaker vacuum use phenomenon ê ku ji dema ku current di environmenta high-vacuum de zero were guherîn, plasma were diffusion kirin, ku arc were extinction kirin û goala cutting off ya current were bike.
Debugging ya Circuit Breaker
Opening Distance û Over-travel
Measurementa opening distance û over-travel ê ya circuit breaker: Difference ê yên measured x-values di dema ku circuit breaker open û closed be were opening distance ê ya circuit breaker, û difference ê yên measured y-values were over-travel ê ya circuit breaker. Adjustment were achieved bi lengthening û shortening insulating operating rod û connecting rod between mechanism û main shaft.
Adjustment ya Opening and Closing Mechanism
Control Circuit ya Circuit Breakers
Di most 35kV standardized substations ê yên rural power grids de, principle ê ya separating control busbar from closing busbar were adopted. Ji kerema lightning, rain, û strong wind frequent di mountainous areas de, ku lead to multiple trippings û increased number of switch closing operations, closing coils of switches extremely prone to burnout. Here, I suggest making minor improvement to control circuit.
Insert pair of normally-open contacts of circuit breaker's energy-storage travel switch in series between auxiliary normally-closed contacts of circuit breaker û closing coil. In this way, when circuit breaker is not energized (not energy-stored), closing operation cannot be carried out. This prevents closing when circuit breaker is not energized, thus avoiding situation where closing circuit remains on û burns out closing coil.
Meanwhile, during wiring process, it is necessary to ensure that polarities of closing busbar û control busbar at contacts of energy-storage travel switch consistent be. This is to prevent arcing in closing circuit from puncturing travel switch when switch is being energized, which could cause control fuse to blow û control air switch to trip. This point requires special attention in integrated automated substations.
Operation, Maintenance, û Inspection Tests
Circuit breakers vacuum short arcing time, high insulation strength, û relatively long electrical life e. With small contact opening distances û over-travel, û minimal operating energy, they also enjoy long mechanical life. During daily operation, maintenance tasks relatively few. Mainly, it is necessary to check for wear on moving parts of mechanism, ensure that fasteners are not loose, clean dust off insulation surface, û apply some lubricating grease to moving parts.
During preventive tests, DC resistance test results of switch should be compared with historical data. If any issues are identified, timely replacement û rectification required. Power-frequency withstand voltage test for breaker effective method to check for leakage in vacuum interrupter. (For indoor vacuum circuit breakers, color of flash inside vacuum interrupter when load is disconnected can be used to preliminarily assess vacuum level. Dark red color indicates reduced vacuum level, while light blue color indicates good vacuum level.)
During protection setting verification, low-voltage closing test conducted on circuit breaker to verify whether switch operates reliably when busbar is in fault state û voltage drops.
