Ukusuka ekuhlukaniseni kuya kumodi yezintambo, incazelo ebanzi kakhulu ye-grounding transformer

Amagridi kagesi angu-6kV, 10kV kanye nama-35kV ohlelweni lwamandla ngokuvamile asebenzisa imodi yokusebenza engathathi hlangothi. Uhlangothi lwe-low-voltage ye-transformer eyinhloko kugridi yamandla ngokuvamile luxhunywa ngendlela engunxantathu, futhi alikho iphuzu eliphakathi nendawo elingase libekwe phansi. Uma iphutha lesigaba esisodwa sokwenza phansi lenzeka ohlelweni olungenasisekelo, unxantathu we-voltage yomugqa uhlala ulingana. Isistimu yamandla ingaqhubeka nokuhlinzeka amandla kubasebenzisi amahora angu-1 kuya kwangu-2, futhi i-capacitive current incane kakhulu (ingaphansi kuka-10A), engeke ibangele i-arc yesikhashana. Amanye amaphutha okumisa isikhashana anganyamalala ngokuzenzakalelayo, okusebenza kahle kakhulu ekuthuthukiseni ukuthembeka kokuphakelwa kukagesi kanye nokunciphisa izingozi zokunqamuka kukagesi. Kodwa-ke, ngokunwetshwa okuqhubekayo kwegridi yamandla asemadolobheni kanye nokwanda okuqhubekayo kwezintambo eziphumayo zekhebula, i-capacitive current yesistimu eya phansi ikhula kakhulu, kanye ne-capacitive current egeleza endaweni yephutha ngemva kokumiswa kwesigaba esisodwa kukhulu (kungaphezu kwalokho. 10A).

I-arc akulula ukuyicisha, kulula ukujabulisa i-ferromagnetic resonance overvoltage futhi ikhiqize i-arc light grounding overvoltage ngezikhathi ezithile, engase ibangele umonakalo wokuhlukanisa, ihambe umugqa futhi yandise ingozi.

Ngokuqondile:

Ukushabalala kwezikhawu kanye nokubusa kwe-arc ephansi yesigaba esisodwa kuzokhiqiza i-arc grounding over-voltage ene-amplitude efika ku-4U (U inani eliphakeme kakhulu lamandla kagesi wesigaba esivamile) noma ubude besikhathi esiphakeme futhi eside, okuzodala umonakalo omkhulu ekufakweni kwemishini kagesi. futhi kubangele ukuwohloka ekushiseni okubuthakathaka; Dala ukulahlekelwa okukhulu.

I-air dissociation ebangelwa i-arc eqhubekayo ibhubhisa ukufakwa komoya ozungezile futhi ijwayele isigaba ukuya esigabeni esifushane.

I-Ferromagnetic resonance over-voltage ingase ishise kalula i-voltage transformer futhi ibangele ukulimala kwesibambisi, okungase kubangele nokuba isibambisi siqhume. Le miphumela izobeka engcupheni kakhulu ukufakwa kwemishini yegridi kagesi futhi ibeke engozini ukusebenza okuphephile kwegridi kagesi.

Ukuze kuncishiswe i-capacitive current phansi uma kwenzeka iphutha lesigaba esisodwa sokumisa phansi, kuyadingeka ukufaka ikhoyili yokucindezela i-arc nezinye izisetshenziswa zesinxephezelo endaweni engathathi hlangothi ye-transformer. Ngakho-ke, kuyadingeka ukusungula mathupha indawo engathathi hlangothi ukuze ikhoyili yokucindezela i-arc ixhunywe endaweni engathathi hlangothi ukuze kuncishiswe isisekelo sokuphulwa kwesekethe esifushane futhi kuthuthukiswe ukuthembeka kokuphakelwa kwamandla kwesistimu.

■ Ukusetshenziswa kwamanje ekhaya naphesheya

Isiguquli esiyisisekelo e-China sivamise ukusebenzisa izintambo zohlobo luka-Z (noma izintambo ezimazombezombe). Ukuze kongiwe indawo yokutshalwa kwezimali kanye nesiteshi esincane, iwindi lesithathu elijikajikayo livame ukungezwa kusiguquli esiphansi ukuze sithathele indawo isiguquli esisetshenziselwa ukuhlinzeka amandla ngezinto ezisetshenziswa esiteshini. Ngokwezinga likazwelonke le-Reactor, imodi yaphansi yesiguquli esiphansi singahlukaniswa sibe isisekelo esiqondile; Isekelwe nge-reactor, resistance and arc suppression coil. Isisekelo esiqondile asikaze sisetshenziswe e-China, kodwa eminye iminyango yokucwaninga amandla kagesi isiqalile ukuxoxa ngalesi sici. I-grounding transformer emazweni angaphandle ivamise ukusebenzisa noma uxhumano lohlobo lwe-Z, olusetshenziselwa uhlelo olungenasisekelo lwe-10kV futhi luhlanganisa ukuvikelwa okuyisisekelo kwenethiwekhi yokusabalalisa. Uma isistimu inephutha lesisekelo, i-grounding transformer inikeza ukuvinjelwa okuphezulu kokulandelana okuhle kanye nokulandelana okungalungile kwamanje kanye nokumelana okuphansi kokulandelana kwe-zero wamanje, okwenza ukuvikela okuphansi kusebenze ngokuthembekile.

■ I-transformer enezigaba ezintathu

I-transformer enezigaba ezintathu eziyisisekelo Lolu hlobo lwesiguquli lisebenzisa izintambo zohlobo lwe-Z (noma izintambo ezimazombezombe). Umehluko kuma-transformer ajwayelekile ukuthi ikhoyili yesigaba ngasinye ihlukaniswe ngamaqembu amabili futhi inxeba esigxotsheni sikazibuthe salesi sigaba ngokuhlehla. Inzuzo yalokhu kuxhumana ukuthi i-zero flux kazibuthe elandelanayo ingageleza eduze kwesigxobo sikazibuthe, kuyilapho i-zero flux kazibuthe elandelanayo yeziguquli ezijwayelekile igeleza eduze kwesekethe yokuvuza kazibuthe. Ngakho-ke, ukuvinjelwa kokulandelana kukaziro kweziguquli zohlobo lwe-Z kuncane kakhulu (cishe u-10 Ω), kuyilapho okwabaguquli abavamile kukhulu kakhulu. Ngokusho kwemithethonqubo, umthamo we-transformer evamile enekhoyili yokucindezela i-arc ngeke idlule i-20% yomthamo we-transformer. I-transformer yohlobo lwe-Z ingafakwa ikhoyili yokucindezela i-arc enamandla angu-90% ~ 100%. Ngaphezu kwekhoyili yokucindezela i-arc, i-grounding transformer ingabuye ifakwe umthwalo wesibili, ongangena esikhundleni se-station transformer, ngaleyo ndlela yonga izindleko zokutshala izimali.

■ Single isigaba grounding transformer

I-Single phase grounding transformer I-Single phase grounding transformer isetshenziselwa ikakhulukazi i-generator enephuzu elingathathi hlangothi kanye nekhabhinethi yokumelana nephuzu elingathathi hlangothi le-Satons transformer ukunciphisa izindleko kanye nomthamo wekhabhinethi yokumelana.

■ Izici zokusebenza

(1) I-impedance yokulandelana kukaziro ephansi ukuze kuqinisekiswe ukuphuma kwe-zero yamanje yokulandelana;

(2) I-impedance ye-excitation ephezulu yokunciphisa amandla akhona;

(3) Ukulahlekelwa okuphansi okungalayishiwe ukonga ukusetshenziswa kwamandla ukuze kusetshenziswe nsuku zonke.

■ Imodi yocingo

Ukuxhumana kwe-YNyn

I-transformer enale modi yokuxhumana ivamise ukusebenzisa umgogodla wensimbi wezigaba ezintathu zekholomu, futhi indawo emaphakathi ohlangothini lwe-voltage ephezulu ingaxhunywa nekhoyili yokucindezela i-arc ukuze ibone ukuphansi. Kodwa-ke, lapho isigaba samanje sokulandelana esisekelwe ku-zero esisekelwe phansi sigeleza ohlangothini olusohlangothini lwevoltage ephezulu, amandla kazibuthe akhiqizwayo ayiziro awakwazi ukulingana amandla kazibuthe esibili, futhi ukugeleza kazibuthe okulandelanayo okuyiziro ohlangothini olufanayo akukwazi ukwakha iluphu ngaphakathi. ikholomu yensimbi emithathu, ukuze inani elikhulu lokulandelana kukazibuthe okulandelanayo likwazi ukudlula kuphela ku-clamp, umzimba kawoyela kanye nethangi likawoyela ukuze kwakheke iluphu evaliwe, ngaleyo ndlela kubangele ukulahlekelwa okwengeziwe ethangini likawoyela kanye ne-clamp, okuholela ekushiseni ngokweqile kwendawo, Ukusetshenziswa kwamandla e-transformer kunomkhawulo. Imithethonqubo yokusebenza efanele yomkhakha wamandla waseShayina yenze izinhlinzeko ezilandelayo mayelana nesimo sokusebenza sekhoyili yokucindezela i-arc point connection ye-YNyn connection transformer:

(1) Amandla ekhoyili yokucindezela i-arc ngeke adlule u-20% wamandla alinganisiwe we-transformer;

(2) Ukwehla kwamandla kagesi wokulandelana kukaziro okukhiqizwa i-zero elandelanayo yamanje egeleza ikhoyili yokucindezela i-arc ku-transformer ngeke kudlule u-10% wevolthi yesigaba esilinganiselwe;

Imodi yokuxhuma ye-YNd uxhumano transformer kanye ne-arc suppression coil XL ibonakala ngokuthi uxhumano lukanxantathu ohlangothini lwesibili lunganikeza indlela evaliwe yokulandelana kwe-zero yamanje, ngakho-ke ukusabela kokulandelana kwe-zero kuncane. Ukwengeza, njengoba amandla kazibuthe wokulandelana kweziro wama-winding ayisisekelo nawesibili kukholamu ngayinye ewumgogodla uyabhalansiswa, ukuvuza kazibuthe okulandelanayo ku-zero nakho kuncane. Kodwa-ke, uma ukujikajika kokuxhuma kwe-YN kungaphandle, ukulandelana kweqanda ukulahlekelwa okwengeziwe okudalwe ethangini likawoyela nezinye izingxenye akukwazi ukugwenywa ngokuphelele. Uma ixhunywe ngekhoyili yokucindezela i-arc, ukusetshenziswa komthamo wayo kusazonqunyelwa. Ucwaningo lokuhlola lwangaphandle lubonisa ukuthi imodi evumelekile yokusebenza ye-YNd exhunywe i-grounding transformer ithi:

(1) Uma umthwalo wesibili ogcwele ujwayelekile, amandla ekhoyili yokucindezela i-arc exhunywe ohlangothini lwe-YN angeke eqe u-50% womthamo olinganiselwe we-transformer;

(2) Uma umthwalo wesibili ungama-50% kuphela womthamo we-transformer ngezikhathi ezijwayelekile, umthamo wekhoyili wokucindezela i-arc ungalingana nomthamo olinganiselwe we-transformer.

Nakuba uhlangothi lwesibili lwalokhu kuxhumana lunganikeza amandla emithwalweni yesifunda noma isiteshi esingaphansi ngokwaso, ukusetshenziswa kwaso kuzonqunyelwa kakhulu ngoba ukuxhumana kukanxantathu kunzima ukunikeza amandla kubasebenzisi bamandla ayingxube nabasebenzisi bokukhanyisa ngesikhathi esifanayo.

YN, uxhumano oluvulekile lwe-d luxhunywe nekhoyili ye-arc-suppression XL, efana nokuxhuma kwe-YNd. Imodi yokuxhuma ye-d evulekile ingaxhunyaniswa ne-resistor noma i-reactor ohlangothini lukanxantathu ovulekile ukuze kulungiswe ukusabela kwe-zero-sequence ye-transformer, futhi uxhumano lwe-resistor lungaphinda lucindezele i-ferromagnetic resonance yenethiwekhi. Uma ikholomu ye-iron core yezigaba ezintathu yamukelwa, inani le-impedance lokulandelana kwe-zero lingakhuphuka kakhulu, futhi kungenzeka ngisho nokushiya ikhoyili yokucindezela i-arc, kodwa isakhiwo siyinkimbinkimbi futhi izindleko ziyanda. Ngaphezu kwalokho, ukusetshenziswa kwesibili kokuxhumeka kukanxantathu ovulekile akukwazi ukuhlangabezana nezidingo zamandla kagesi emithwalweni yesifunda namandla okuzisebenzisa, ngakho le ndlela ayisetshenziswa kabanzi.

I-ZN, i-yn connection transformer ixhunywe ne-arc suppression coil XL, okuyindlela evamile yokuxhumana ye-grounding transformer. Ngenxa yokuthi amandla kazibuthe alandelanayo kumawindi angaphezulu nangaphansi kwesigamu kukholomu yensimbi efanayo yendlela yokuxhuma amazombe angusayizi ofanayo kanye nendawo ephambene, ephikisanayo, ukugeleza kokuvuza okulandelanayo okuziro kuyehliswa kube inani elincane kakhulu. , ukuze inani layo lokusabela kokulandelana kukaziro libe lincane kakhulu, futhi umthamo walo ungalingana nomthamo wekhoyili yokucindezela i-arc exhunyiwe.

I-grounding transformer esetshenziswa kabanzi ekhaya nakwamanye amazwe ixhunywe kakhulu ngale ndlela. Njengoba indlela ye-yn junction yamukelwa ngasohlangothini lwe-voltage ephansi, inganikeza amandla endawo noma amandla okuzisebenzisa wesiteshi esingaphansi ngesikhathi esifanayo. Amandla ohlangothi lwe-voltage ephansi ngokuvamile abe mancane kunalawo ohlangothi lwamandla kagesi aphezulu. Ezimweni eziningi, amandla ohlangothi lwe-voltage ephansi angaphakathi kwebanga lika-80-200kVA.

Nakuba umthamo olinganiselwe wohlangothi lwe-high-voltage ungalingana nomthamo wekhoyili yokucindezela i-arc exhunyiwe, ukuxhumana okumise okwe-Z kuzoba nokuphenduka okuphindwe izikhathi ezingu-1.15 kunokuxhumana okumise okuka-Y, ngakho-ke umthamo wangempela wesiguquli esiphansi kufanele kube izikhathi ezingu-1.15 zomthamo wekhoyili yokucindezela i-arc.

■ Umgomo wokusebenza

Umdwebo wesimiso sokusebenza se-grounding transformer uma kwenzeka iphutha lesigaba esisodwa ohlelweni uboniswa yizintambo ezivamile ze-ZNyn. Uma i-grounding transformer idlula kusayizi othize wokulandelana kukaziro wamanje ngesikhathi sokusebenza, okwamanje okugeleza kumawindi amabili esigaba esisodwa kukholomu yomgogodla wensimbi efanayo ibheke ngendlela ehlukile futhi nosayizi uyalingana, ukuze amandla kazibuthe akhiqizwe I-zero sequence current iphambene ne-offset, ukuze i-impedance yokulandelana kwe-zero nayo ibe mncane kakhulu.

Uma i-grounding transformer ihluleka, indawo engathathi hlangothi ingageleza kumanje wesinxephezelo. Ngenxa ye-impedance encane ye-zero-sequence, lapho i-zero-sequence yamanje idlula, ukwehla kwe-impedance voltage okukhiqizwayo kufanele kube kuncane ngangokunokwenzeka ukuze kuqinisekiswe ukuphepha kohlelo. Ngenxa yokuthi i-grounding transformer inezici ze-impedance ephansi yokulandelana kwe-zero, lapho iphutha lesigaba esisodwa sesisekelo lenzeka esigabeni C, isigaba C se-ground current I sigelezela endaweni engathathi hlangothi emhlabeni, futhi sihlukaniswe izingxenye ezintathu ezilinganayo ukuze zigelezele i-grounding transformer. Njengoba imisinga yezigaba ezintathu egeleza ku-transformer ephansi ilingana, ukufuduka kwephoyinti elingathathi hlangothi N kuhlala kungashintshiwe, futhi i-voltage yomugqa wezigaba ezintathu ihlala i-symmetrical.

Kodwa-ke, enqubweni yokukhiqiza, ukujika kanye nobukhulu bejiyomethri bamajika angaphezulu naphansi okujikajika kwe-voltage ephezulu angeke alingane ngokuphelele, okwenza kungenzeki ukuthi amandla kazibuthe akhiqizwe i-zero yokulandelana kwamanje ukuthi asuswe ngokuphambene. isiqondiso, futhi isakhiqiza i-impedance ethile yokulandelana kukaziro, ngokuvamile engaba ngu-6-10 Ω. Uma kuqhathaniswa nokuvinjwa kokulandelana kukaziro kwenkanyezi exhunywe isiguquli esingu-600 Ω, izinzuzo zayo ziyabonakala. Ukwengeza, i-zigzag grounding transformer ingenza futhi ukulahlekelwa kwamanje nokungalayishi kube kuncane ngangokunokwenzeka. Uma kuqhathaniswa ne-transformer yokuxhumana kwenkanyezi ejwayelekile, ingxenye ngayinye yensimbi yesigaba se-zigzag connection transformer yakhiwe ngama-wingings amakholomu amabili ensimbi. Ngokomdwebo wayo we-vector, uma iqhathaniswa ne-transformer yenkanyezi evamile, idinga ukulinyazwa izikhathi ezingu-1.16 ngaphezulu lapho i-voltage ifana. I-amplitude ye-ziro impedance yokulandelana kanye nokuvinjwa kokulandelana okuhle kwenethiwekhi yokusabalalisa yasemadolobheni enesisekelo sesigaba esisodwa ngaphansi kwemodi yokusekela yephoyinti engathathi hlangothi ihluka kakhulu. Lapho imisinga yokulandelana kwezigaba ezintathu ephozithivu nenegethivu igeleza, amandla kazibuthe kukholamu ngayinye ewumgogodla wensimbi we-grounding transformer iyisamba sama-phasors wamandla kazibuthe wamajika amabili ezigaba ezihlukene kukholomu yomgogodla wensimbi. Amandla kazibuthe ezinsikeni ezintathu zomgogodla wensimbi iyiqembu lamanani okulingana ezigaba ezintathu anomehluko wesigaba ongu-120 °. I-flux kazibuthe ekhiqizwayo ingaba iluphu ezinsikeni ezintathu zensimbi. Ukumelana kazibuthe kwesekethe kazibuthe kuncane, i-flux kazibuthe inkulu, futhi amandla atholwe makhulu, abonisa ukulandelana okuhle okuhle kanye ne-impedance yokulandelana okungalungile; Ngakho-ke, i-grounding transformer inezici ze-impedance enkulu yokulandelana okuhle nokubi kanye ne-impedance encane yokulandelana kwe-zero.

■ Imingcele yezobuchwepheshe eyinhloko

Ukuze kuhlangatshezwane nezidingo zokunxeshezelwa kwekhoyili yokucindezelwa kwe-arc kunethiwekhi yokusabalalisa, futhi kuhlangabezane nezidingo zamandla esiteshi esincane nomthwalo wokukhanyisa, i-Z-type connection transformer ikhethiwe, futhi imingcele eyinhloko ye-grounding transformer idinga ukusetha ngokunengqondo.

(1) Umthamo oyinhloko oseceleni wesiguquli esiphansi esinomthamo olinganiselwe kufanele uhambisane nomthamo wekhoyili yokucindezela i-arc. Ngokusho kokucaciswa komthamo wekhoyili ekhona yokucindezela i-arc, kunconywa ukusetha umthamo we-grounding transformer njengezikhathi ezingu-1.05-1.15 zomthamo wekhoyili yokucindezela i-arc. Isibonelo, amandla e-grounding transformer efakwe ikhoyili eyodwa yokucindezela i-arc engu-200kVA ngu-215kVA.

(2) Isamba samanje esigeleza endaweni engathathi hlangothi ye-transformer uma kwenzeka iphutha lesigaba esisodwa sesinxephezelo sephoyinti elingathathi hlangothi lamanje:

Kuphi:

U-U yi-voltage yomugqa wenethiwekhi yokusabalalisa (V); I-Zx iwukuvinjwa kwekhoyili yokucindezela i-arc (Ω);

I-Zd iyisivimbelo esiyinhloko sokulandelana kukaziro sesiguquli esiphansi (Ω/isigaba);

I-Zs i-impedance yesistimu (Ω);

Ubude besikhathi samanje sesinxephezelo sephoyinti elingathathi hlangothi buzofana naleso sekhoyili yokucindezela i-arc, okuzoba amahora angu-2 njengoba kucacisiwe.

(3) Ukuvimbela ukulandelana kukaziro Ukuvinjelwa kokulandelana kukaziro kuyipharamitha ebalulekile yesiguquli esiphansi, esinomthelela obalulekile ekuvikelweni kwe-relay ukuze kubekwe umkhawulo wesigaba esisodwa esiphansi sesekethe emfishane yamanje nokucindezela ukugcwala ngokweqile. Okwezigzag (uhlobo Z) kanye nenkanyezi/i-delta evulekile exhunywe ama-grounding transformer ngaphandle kwamakhoyili esibili, kunokuvimbela okukodwa kuphela, okuyi-zero sequence impedance, ukuze umnyango wokukhiqiza ukwazi ukuhlangabezana nezidingo zomnyango wamandla.

(4) Ukulahlekelwa kuyipharamitha yokusebenza ebalulekile ye-grounding transformer. Ku-transformer ephansi enekhoyili yesibili, ukulahlekelwa kwayo okungenamthwalo kungase kufane nalokho kwe-transformer ephindwe kabili enomthamo ofanayo. Ngokulahlekelwa komthwalo, lapho uhlangothi lwesibili lusebenza ngokugcwele, ukulahlekelwa komthwalo ohlangothini oluyinhloko kungaphansi kwalokho kwe-transformer ephindwe kabili enomthamo ofanayo nohlangothi lwesibili ngenxa yomthwalo wokukhanya ohlangothini oluyinhloko.

(5) Ngokwendinganiso kazwelonke, ukukhuphuka kwezinga lokushisa kwe-grounding transformer kungokulandelayo:

1) Ukwenyuka kwezinga lokushisa ngaphansi kwamandla aqhubekayo alinganisiwe kufanele kuhambisane nezinhlinzeko zendinganiso kazwelonke yama-transformer ohlobo olomile lwama-general power transformers, kodwa ikakhulukazi asebenza kuma-grounding transformer anomthwalo ovamile ohlangothini lwesibili;

2) Lapho ubude besikhathi somthwalo wesikhathi esifushane bungaphansi kwama-10s (ikakhulukazi lapho indawo engathathi hlangothi ixhunywe ukumelana), ukukhuphuka kwezinga lokushisa kuzohambisana nezinhlinzeko zesiguquli samandla esijwayelekile sikazwelonke kumkhawulo wokukhuphuka kwezinga lokushisa ngaphansi kwesekethe emfushane. izimo;

3) Ukukhuphuka kwezinga lokushisa kwe-grounding transformer kanye nekhoyili yokucindezela i-arc lapho kusebenza ndawonye kuzohambisana nezinhlinzeko zokukhuphuka kwezinga lokushisa kwekhoyili yokucindezela i-arc: izinga lokushisa elimazombezombe eligeleza ngokuqhubekayo kumanje elilinganiselwe ngu-80K, elisebenza kakhulu inkanyezi/i-delta evulekile yokuxhuma i-grounding transformer; Ohlelweni lokusonga olunesikhathi sokugeleza esiphezulu samanje esilinganiselwe esicaciswe njengo-2h, izinga lokushisa elishiwo ngu-100K.

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