Ukukhethwa kunye noKhuseleko loCwangciso Ukuphucula iindlela zokuGxina zeTransformer ye-110kV

Intshayelelo

Kwiinkqubo zamandla ezisebenzisa umbane ophezulu, indlela yokumisa i-transformer neutral point grounding yinto ebalulekileyo echaphazela ukhuseleko lwenkqubo, ukuthembeka, kunye nokuzinza. Kwiinkqubo zamandla ze-110kV, ukukhetha indlela yokumisa i-neutral point grounding kuchaphazela ngokuthe ngqo amanqanaba okukhusela izixhobo, ukhuseleko lwe-overvoltage, uqwalaselo lokhuseleko lwe-relay, kunye nokuthembeka kokunikezelwa kombane. E-China, iinkqubo ze-110kV zihlala zisebenzisa i- indlela yokumisa umhlaba esebenza kancinci, apho amanye amachaphaza angathathi cala e-transformer asekelwe ngqo phantsi ngelixa amanye ehlala engasekelwanga phantsi komhlaba, ejolise ekunciphiseni i-currents ye-short-circuit yesigaba esinye ngelixa kuthintela izoyikiso ze-overvoltage.

Eli nqaku lihlalutya iimpawu, iingenelo, kunye nemida yeendlela ezahlukeneyo zokumisa i-transformer ye-110kV, liphonononga amaqhinga okucwangcisa ukhuseleko olufanelekileyo, kwaye libonisa iindlela zophuhliso zexesha elizayo.

Iindlela ezi-1 eziphambili zokuGxina iNqanaba elingathathi cala kwiiTransformers ze-110kV

1.1 Ukusikwa Kwehlabathi Ngokuthe Tye

Ukubeka isiseko ngqoibhekisa kuqhagamshelo oluthe ngqo lwe-transformer neutral point emhlabeni. Le ndlela ilungisa ngempumelelo i-neutral point potential, iqinisekisa ukuba ngexesha lokusilela komhlaba kwesigaba esinye, ukunyuka kwe-voltage yesigaba esingenasiphako akudluli kwi-1.4 ye-voltage yesigaba. Oku kunceda ukunciphisa iimfuno zokufakelwa kwezixhobo kunye nokunciphisa iindleko.

Nangona kunjalo, ingxaki enkulu kukuba umbane wesiphako somhlaba wesigaba esinye ophezulu kakhulu(ukuya kuthi ga kumawaka aliqela ee-ampere), nto leyo enokuchaphazela i-circuit breaker ephazamisa amandla kunye nokuzinza kwenkqubo. Ke ngoko, ukumisa ngokuthe ngqo kusetyenziswa ngokubanzi kwiinkqubo ze-110kV kunye ne-voltage ephezulu apho kufuneka kususwe iimpazamo ngokukhawuleza.

1.2 Ukungathathi cala okungagungqiyo

Kwi- inkqubo engagungqiyo, indawo engathathi cala yetransformer igqunywe ngumoya emhlabeni. Xa kuvela impazamo yomhlaba yesigaba esinye, i-fault current incinci kakhulu (ngokuyintloko i-capacitive current yenkqubo), ivumela inkqubo ukuba iqhubeke nokusebenza ixesha elifutshane (ngesiqhelo ukuya kuthi ga kwiiyure ezi-2). Oku kuphucula kakhulu ukuthembeka kobonelelo lwamandla.

Nangona kunjalo, kwiinkqubo ezingagungqiyo, iimpazamo zomhlaba zesigaba esinye zinokubangela ukuba i-voltage yesigaba esingenasiphako inyuke iye kwinqanaba le-voltage yomgca. Ukuba i-insulation ibuthathaka, oku kunokukhokelela ekuqhekekeni, kunyuke kube yimpazamo yesigaba ukuya kwisigaba. Ukongeza, ukugungqa kwe-arc okungapheliyo kunokuvelisa ii-arc overvoltages, ifikelela kwi-voltage yesigaba ephindwe kathathu ukuya kweyesithathu, nto leyo ebeka umngcipheko kwi-transformer insulation.

1.3 Ukusila nge-Small Impedance

Ukulinganisela iingenelo kunye nokungalungi kwenkqubo yokumisa umhlaba ngqo kunye neyokungagxunyekwa komhlaba, indlela yokumisa isiseko se-impedanceisetyenziswa rhoqo. Oku kuquka ukugalelwa komhlaba ngokusebenzisa ukuxhathisa okuncinci okanye ukusabela okuncinci.

• Ukumelana Okuncinci Nokumisa Ingca: Inciphisa umbane we-fault ukuya kumakhulu aliqela ee-ampere, inciphisa impembelelo kwinkqubo ngelixa isenza ukuba kusebenze ngokukhawuleza ukhuseleko. Le ndlela ithintela umbane ogqithisileyo ngokufanelekileyo kwaye ifanelekile kwiinethiwekhi zokusasazwa kwe-cable ezisebenzisa i-capacitive currents ezinkulu.
• Umhlaba Ophantsi Wempendulo Encinci: Inganciphisa umbane we-capacitive wenkqubo ngombane we-inductive, inciphise amathuba okubuyela kwe-arc. Le ndlela idla ngokuthathwa njengendlela yokumisa umhlaba ehlawulelweyo.

Ukumisa umhlaba nge-impedance encinci kudibanisa iingenelo zeenkqubo ezithe ngqo nezingashukumiyo, okubonelela ngoxinzelelo lwe-overvoltage kunye nokuthembeka okuphezulu kombane. Isetyenziswa kakhulu kwiinkqubo ze-110kV, ngakumbi ezo zine-capacitive currents ezibalulekileyo okanye ezifuna umgangatho ophezulu wamandla.

Uqwalaselo loKhuseleko olu-2 lwe-110kV Transformer Neutral Points

2.1 Izisongelo zombane ogqithisileyo

Inqanaba lobushushu le-110kV transformer neutral point lidla ngokuba i-semi-insulated, nge-standing voltage rating kuphela isithathu sesiphelo somgca. Oku kwenza indawo engathathi cala ibe sesichengeni sokonakala kwe-overvoltage. Iindidi eziphambili ze-overvoltage ziquka:

• Uxinzelelo olugqithisileyo lwamandla: Okuvela ekutshintsheni umgca, iisekethe ezimfutshane ezingalinganiyo, okanye ukulahleka komthwalo ngequbuliso.
• Umbane ogqithisileyo weResonance: Okubangelwa kukushukuma okubangelwa kukusebenzisana phakathi kwezinto ezibangela ukwenziwa kwezinto kunye nezinto ezibangela ukwenziwa kwezinto ngexesha lokusebenza kwenkqubo okanye iimpazamo.
• Ukutshintsha i-Overvoltage: Okubangelwa kukuguqulwa kwamandla emagnethi kunye ne-electrostatic ngexesha lokuvulwa okanye ukuvalwa kwee-circuit breakers.
• Umbane ogqithisileyo: Ibangelwa kukubethwa ngumbane, okubonakaliswa bubukhulu obuphezulu kunye nobude obufutshane.

2.2 Izixhobo zoKhuselo oluQhelekileyo

Ukukhusela indawo engathathi cala yetransformer, ezi zixhobo zokukhusela zilandelayo zisetyenziswa rhoqo:

• Ababambisi Bokungxama: Ezi zithintela umbane ogqithisileyo kunye nombane ogqithisileyo otshintshayo. Nangona kunjalo, izithinteli zokunyuka kwesantya eziqhelekileyo zihlala zinganeli kwinqanaba eliphantsi lokufakelwa kwe-110kV transformer neutral points, nto leyo eyenza ukukhetha kube nzima.
• Izikhewu zokuZihlukanisa: Ezi zikhusela kwi-frequency yamandla kunye ne-resonance overvoltages. Xa kwenzeka i-overvoltage, i-gap iyaqhekeka, ibeke isiseko se-neutral point ukuze kuthintelwe ukunyuka kwe-voltage. Ingxaki kukuba kunzima ukulungisa ngokuchanekileyo umgama we-gap, nto leyo enokubangela ukungahambelani kakuhle kokhuseleko.
• Uqhagamshelo oluhambelanayo lwe-Surge Arrester kunye ne-Gap: Le yindlela yokukhusela esetyenziswa kakhulu. I-surge arrester iphatha i-lightning overvoltage, ngelixa i-gap ijongana ne-power frequency kunye ne-resonance overvoltages. I-gap ikwakhusela i-surge arrester kwi-power frequency overvoltages enokubangela ukungasebenzi kwayo. Le ndlela inika izibonelelo ezongezelelweyo.

2.3 Uqwalaselo loKhuseleko lweRelay

Ukhuseleko lwe-relay kwi-110kV transformer neutral point luquka ikakhulu ezi zinto zilandelayo:

• Ukhuseleko lwangoku lweZero-Sequence: Kwii-transformers ezisekelwe ngqo, ukhuseleko lwangoku olungenalandelelwano lwenzelwe ukususa ngokukhawuleza iimpazamo zomhlaba. Ukhuseleko luhlala lwahlulwe lube ngamacandelo, kunye nokulibaziseka kwexesha elifutshane ukuze kubekho indawo yeziphene kunye nokulibaziseka kwexesha elide ukuze kukhubeke onke amacala e-transformer.
• Ukhuseleko lweVolthi yeZero-Sequence kunye noKhuseleko lwangoku lweGap: Kwii-transformers ezingagungqiyo, ukhuseleko lwe-voltage oluyi-zero-sequence kunye nokhuseleko lwe-gap current luyamiselwa. Xa impazamo yomhlaba ibangela ukuba inkqubo ilahlekelwe yi-ground point yayo, nto leyo ekhokelela ekunyukeni kwe-voltage ye-neutral point, i-gap iyaphuka. Ukhuseleko lwe-Gap current okanye ukhuseleko lwe-voltage oluyi-zero-sequence lusebenza ngokulibaziseka kwexesha (0.3–0.5s) ukuze luphazamise i-transformer macala onke.
• Ulungelelwaniso loKhuseleko lokuGcinaUkuqinisekisa ukukhetha, ukulibaziseka kwexesha lokukhusela ukulandelelana kwe-zero-sequence kufuneka kuhambelane. Umzekelo, ukulibaziseka kwexesha lokukhusela i-backup kwi-transformer kufuneka kube kude kunokukhusela umgca ewuxhasayo.

3 Iingcebiso zokuphucula kunye noHlalutyo lweTyala

3.1 Imida yeendlela zesintu

Ngelixa ukusetyenziswa kwe izithinteli zokuxinana kwamandla ombane ezihambelana nezikhewuixhaphakile, le ndlela ineengxaki ezininzi:

• Ubunzima ekukhetheni i-Surge Arrester: Kunzima ukufumana izithinteli zokuxhuzula ezisemgangathweni ezihlangabezana neemfuno zevolthi ephezulu yokusebenza eqhubekayo kunye nevolthi esezantsi ye-lightning impulse residual voltage kwi-110kV transformer neutral points.
• Imingeni ekuSekweni kweMisantsa: I-voltage yokuqhekeka kwesithuba somoya ixhomekeke ekusasazekeni, nto leyo eyenza kube nzima ukulungelelanisa ngokuchanekileyo ukusebenza kwesithuba "sokulahleka komhlaba" kunye neemeko zempazamo "ezinomhlaba".
• Ubunzima boKhuseleko lweRelay: Ukhuseleko "ekulahlekelweni komhlaba" (njengokugqithisela umbane ngolandelelwano olungenanto kunye nokukhuselwa kombane ongaphezulu komngxuma) lunokungasebenzi kakuhle, nto leyo ebangela ukuba kubekho ezinye iindlela zokuthintela, nto leyo eyonyusa ubunzima kwaye inciphise ukuthembeka.

3.2 Iingenelo zokuGrounda nge-Small Reactance

Uphando kunye nezenzo zibonisa ukuba ukusekela indawo engathathi cala nge-reactance encinciInika iingenelo ezibalulekileyo kuneendlela zemveli zokumisa umhlaba ngokungaphelelanga:

• Iimfuno zeNqanaba lokuGcina eziNciphisiweyo: Emva kokusebenzisa isiseko esincinci se-reactance, inqanaba lobushushu le-transformer neutral point linokwehliswa ukusuka kwi-35kV ukuya kwi-20kV, oku kususa imfuneko yezithinteli zokushushumbisa kunye nezikhewu kwaye kube lula ukucwangciswa kokhuseleko.
• Imo Yokumisa Emanyeneyo: Le ndlela isusa ukwenzeka kwenkqubo engaxhonywanga, ivumela ukulula okanye ukushiywa kokhuseleko oluhambelanayo, ngaloo ndlela kuphucula ukuthembeka.
• Ukugcinwa kweeNzuzo: Igcina iingenelo zokumisa umhlaba ngokungaphelelanga, njengokhuseleko olulula noluthembekileyo lwe-zero-sequence, ngelixa inciphisa i-currents short-circuit currents yesigaba esinye.

3.3 Uhlalutyo lweSifundo seTyala

Umzekelo lutshintsho lwesitishi esingaphantsi kwesiphelo se-110kV. Uyilo lokuqala lusebenzise i- isixhobo sokumisa umfutho ohambelana nendawo evulekileyoukhuseleko lwenqaku elingathathi cala. Nangona kunjalo, emva kokusebenzisa isiseko esincinci se-reactance, imfuneko yenqanaba lokufakelwa kwe-transformer i-neutral point yancitshiswa, izixhobo zokukhusela zenziwa lula, kwaye ukuthembeka kokusebenza kwaphuculwa. Ubalo lubonise ukuba ukumelana nokumisa umhlaba kunokuwunciphisa umbane wephutha ukuya kumakhulu ambalwa ee-ampere, kwaye ukhuseleko lwe-zero-sequence lunokulungelelaniswa ngokulula.

Elinye ityala libandakanya impazamo kwisitishi esingaphantsi kwe-110kV apho impazamo yomhlaba yesigaba esinye esidlulayo kumgca ongenayo ikhokelele ekuqhekekeni kwesithuba sendawo engathathi cala kunye nokukhubeka kwetransformer. Uhlalutyo lubonise ukuba nangona impazamo yomgca yayiyeyesikhashana, impendulo evela kwinani elikhulu leemoto ezingatshintshiyokwicala lomthwalo linike amandla kwi-arc, nto leyo egcina impazamo. Oku kubonisa ukuba kwii-transformers ezinemithwalo emikhulu yeemoto (imithombo elinganayo), ukhuseleko olupheleleyo lwenqaku elingathathi cala, kuquka ukhuseleko lwe-zero-sequence overcurrent, i-gap current, kunye nokhuseleko lwe-zero-sequence voltage, kubalulekile ngexesha lesigaba soyilo.

4 Isiphelo kunye neNjongo

Ukukhethwa kwendlela yokumisa isiseko se-transformer ye-110kV kunye nolwakhiwo lwayo lokhuseleko ngumsebenzi oneenkalo ezininzi ofuna ukuqwalaselwa kolwakhiwo lwenkqubo, iimpawu zomthwalo, kunye neemfuno zokuthembeka. Nangona indlela yendabuko yokumisa isiseko engaphelelanga kunye nezithinteli zokushushuba kunye nezikhewu ixhaphakile, ijongene nemingeni ekukhetheni isixhobo kunye nokulungelelanisa ulungiselelo. indlela yokumisa isiseko esincinciinika enye indlela ethembisayo, enokunciphisa iimfuno zokukhusela ubushushu, yenza lula ukhuseleko, kwaye iphucule ukuthembeka.

Iindlela zophuhliso lwexesha elizayo ziya kugxila kwezi ndawo zilandelayo:

• Ukusetyenziswa kwezixhobo ezintsha: Ezifana nezikhewu ezidityanisiweyo okanye izikhewu ezinokulawuleka ezisetyenziswa ngaxeshanye nezithinteli zokuxinana, ziphucula ukuthembeka nokuchaneka kokhuseleko.
• Itekhnoloji yoKhuselo lweDijithali: Ukusebenzisa ukhuseleko olusekelwe kwi-microcomputer olune-algorithms eziphambili (umz., ukuchongwa kwe-waveform, uhlalutyo lwe-harmonic) ukuphucula uvakalelo kunye nokuthembeka kokhuseleko lwempazamo yomhlaba.
• Ukumiswa ngokusemthethweni kunye nokuguqulwa: Ukuphuhlisa izixhobo zokukhusela amanqaku ezisemgangathweni nezinemigangatho ukuze kube lula ukuyila nokugcina izinto zisemgangathweni.

Ngamafutshane, ukuphucula indlela yokumisa i-transformer ye-110kV neutral point kunye noqwalaselo lokhuseleko kubalulekile ekuphuculeni ukhuseleko, ukuthembeka, kunye nokusebenza koqoqosho kwenkqubo yamandla. Ngokuhambela phambili kwezobuchwepheshe, kulindeleke ukuba izisombululo ezikrelekrele nezisebenzayo zivele kwaye zisetyenziswe ngokubanzi.