Kusankha ndi Kuteteza Kakonzedwe Koyenera ka 110kV Transformer Neutral Point Grounding Methods

Chiyambi

Mu makina amphamvu amphamvu kwambiri, njira yokhazikitsira pansi ya transformer yopanda ma point ndi chinthu chofunikira kwambiri chomwe chimakhudza chitetezo cha makina, kudalirika, komanso kukhazikika. Pa makina amphamvu a 110kV, kusankha njira yokhazikitsira pansi ya neutral kumakhudza mwachindunji kuchuluka kwa kutchinjiriza kwa zida, chitetezo cha overvoltage, kasinthidwe ka chitetezo cha relay, ndi kudalirika kwa magetsi. Ku China, makina a 110kV nthawi zambiri amagwiritsa ntchito njira yogwiritsira ntchito nthaka yogwira ntchito pang'ono, komwe malo ena osalowererapo a transformer amakhala pansi mwachindunji pomwe ena amakhalabe opanda pansi, cholinga chake ndi kuchepetsa mafunde afupiafupi a gawo limodzi pomwe kupewa zoopsa za overvoltage.

Nkhaniyi ikufotokoza makhalidwe, ubwino, ndi zofooka za njira zosiyanasiyana zokhazikitsira pansi za transformer ya 110kV, ikufotokoza njira zabwino kwambiri zotetezera, ndikuwonetsa zomwe zikuchitika mtsogolo.

Njira 1 Zofunika Kwambiri Zokhazikitsira Pansi pa Malo Osalowerera Pakati pa Ma Transformers a 110kV

1.1 Kukhazikika Molunjika

Kukhazikitsa pansi mwachindunjiikutanthauza kulumikizana mwachindunji kwa mfundo yopanda mbali ya transformer ndi dziko lapansi. Njirayi imakonza bwino mphamvu ya mfundo yopanda mbali, kuonetsetsa kuti panthawi ya vuto la nthaka la gawo limodzi, kukwera kwa mphamvu ya gawo lopanda cholakwika sikupitirira nthawi 1.4 kuposa mphamvu ya gawo. Izi zimathandiza kuchepetsa zofunikira pakuteteza zida ndikuchepetsa ndalama.

Komabe, vuto lalikulu ndi vuto lalikulu kwambiri la gawo limodzi(mpaka ma ampere zikwi zingapo), zomwe zingakhudze kusokoneza mphamvu ya circuit breaker ndi kukhazikika kwa dongosolo. Chifukwa chake, kukhazikika mwachindunji nthawi zambiri kumagwiritsidwa ntchito mu makina a 110kV ndi ma voltage apamwamba komwe kuchotsa zolakwika mwachangu ndikofunikira.

1.2 Ungrounded Neutral

Mu dongosolo lopanda nthaka, mfundo yopanda mphamvu ya transformer imatetezedwa ndi nthaka. Pamene vuto la nthaka la gawo limodzi lachitika, mphamvu yamagetsi imakhala yaying'ono kwambiri (makamaka mphamvu yamagetsi ya dongosolo), zomwe zimathandiza kuti makinawo apitirize kugwira ntchito kwa kanthawi kochepa (nthawi zambiri mpaka maola awiri). Izi zimawonjezera kwambiri kudalirika kwa magetsi.

Komabe, m'makina osazunguliridwa ndi nthaka, zolakwika za nthaka za gawo limodzi zimatha kupangitsa kuti magetsi a gawo lopanda vuto akwere kufika pamlingo wa magetsi olowera. Ngati chotenthetseracho chili chofooka, izi zitha kubweretsa kuwonongeka, ndikukulirakulira kukhala vuto la gawo mpaka gawo. Kuphatikiza apo, kuyika kwa arc grounding nthawi zina kumatha kupanga ma arc overvoltage, kufika pa mphamvu ya phase voltage yokwana 3–3.5, zomwe zingawopseze kutetezedwa kwa transformer.

1.3 Kukhazikika pansi pogwiritsa ntchito njira yaying'ono yolepheretsa kugwedezeka

Kuti pakhale ubwino ndi kuipa kwa njira zomangira nthaka mwachindunji komanso zopanda nthaka, njira yokhazikitsira nthaka ya impedancenthawi zambiri amagwiritsidwa ntchito. Izi zikuphatikizapo kupondereza nthaka pogwiritsa ntchito mphamvu yochepa kapena mphamvu yochepa.

• Kukaniza Kochepa: Imaletsa mphamvu yamagetsi kufika pa ma ampere mazana angapo, kuchepetsa kukhudzidwa kwa makinawo komanso kuteteza mwachangu. Njirayi imaletsa mphamvu yamagetsi yochulukirapo ndipo ndi yoyenera ma netiweki ogawa magetsi ambiri okhala ndi mafunde akuluakulu.
• Kukhazikika Kwang'ono kwa Reaction: Imatha kuletsa mphamvu yamagetsi ya dongosololi kudzera mu mphamvu yamagetsi yopangira mphamvu, kuchepetsa mwayi woti arc ibwererenso. Njirayi nthawi zambiri imaonedwa ngati njira yokhazikika yolipirira.

Kuyika pansi pogwiritsa ntchito njira yaying'ono yolepheretsa magetsi kumaphatikiza ubwino wa makina olunjika ndi osakhazikika, zomwe zimapangitsa kuti magetsi azichepa kwambiri komanso kuti magetsi azigwira ntchito bwino. Amagwiritsidwa ntchito kwambiri m'makina a 110kV, makamaka omwe ali ndi mafunde amphamvu kapena omwe amafunikira mphamvu yapamwamba.

2 Chitetezo cha 110kV Transformer Neutral Points

2.1 Ziwopsezo za Kupitirira Mphamvu

Mlingo wotetezera kutentha wa 110kV transformer neutral point nthawi zambiri umakhala chotetezedwa pang'ono, yokhala ndi mphamvu yopirira mphamvu yamagetsi gawo limodzi mwa magawo atatu okha a mzere. Izi zimapangitsa kuti malo osalowererapo akhale pachiwopsezo cha kuwonongeka kwa mphamvu yamagetsi. Mitundu yayikulu ya mphamvu yamagetsi yamagetsi ndi iyi:

• Mphamvu Yowonjezera Mphamvu: Chochitika chifukwa cha kusinthana kwa mizere, ma circuits afupi osafanana, kapena kutayika kwadzidzidzi kwa katundu.
• Kuchuluka kwa Mphamvu ya Resonance: Zimayambitsidwa ndi kugwedezeka chifukwa cha kuyanjana pakati pa zinthu zoyambitsa ndi zowongolera panthawi ya ntchito kapena zolakwika za dongosolo.
• Kusintha kwa Overvoltage: Chochitika chifukwa cha kusintha kwa mphamvu ya maginito ndi yamagetsi panthawi yotsegula kapena kutseka ma circuit breakers.
• Mphamvu Yowonjezera ya Mphezi: Zimayambitsidwa ndi mphezi, zomwe zimadziwika ndi kutalika kwakukulu komanso nthawi yochepa.

2.2 Zipangizo Zoteteza Zofala

Pofuna kuteteza mfundo yosalowerera ya transformer, zipangizo zotetezera zotsatirazi zimagwiritsidwa ntchito nthawi zambiri:

• Ogwira Ntchito Zovuta Kwambiri: Izi zimachepetsa kupitirira kwa mphezi ndi kupitirira kwa ma voltage ena osinthira. Komabe, zoletsa kupitirira kwa ma surge nthawi zambiri sizikwanira pamlingo wotsika wa insulation wa 110kV transformer neutral points, zomwe zimapangitsa kusankha kukhala kovuta.
• Mipata Yodzipatula: Izi zimateteza ku ma frequency a mphamvu ndi ma resonance overvoltage. Pamene overvoltage ichitika, gap imasweka, zomwe zimapangitsa kuti neutral point ichepetse kukwera kwa voltage. Vuto lina ndilakuti vuto ndikusintha bwino mtunda wa gap, zomwe zingayambitse kusagwirizana bwino kwa chitetezo.
• Kulumikizana Kofanana kwa Surge Arrester ndi Gap: Iyi ndi njira yotetezera yomwe imagwiritsidwa ntchito kwambiri. Choletsa kugwedezeka chimagwira ntchito yolimbana ndi kugwedezeka kwa mphezi, pomwe mpata umakhudza ma frequency a mphamvu ndi ma resonance overvoltage. Mpatawu umatetezanso choletsa kugwedezeka kwa mphamvu kugwedezeka kwambiri komwe kungayambitse kulephera kwake. Njirayi imapereka ubwino wowonjezera.

2.3 Kukhazikitsa Chitetezo cha Relay

Chitetezo cha relay cha 110kV transformer neutral point chimaphatikizapo zinthu izi:

• Chitetezo cha Zero-Sequence Current: Pa ma transformer okhazikika mwachindunji, chitetezo champhamvu cha zero-sequence chimakonzedwa kuti chichotse mwamsanga zolakwika za nthaka. Chitetezochi nthawi zambiri chimagawidwa m'magawo, ndi kuchedwa kwa nthawi yochepa kuti malo a zolakwika apezeke komanso kuchedwa kwa nthawi yayitali kuti zigwetse mbali zonse za transformer.
• Chitetezo cha Voltage cha Zero-Sequence ndi Chitetezo cha Current Gap: Pa ma transformer osazunguliridwa, chitetezo cha magetsi otsatizana ndi zero-sequence ndi chitetezo cha magetsi otsatizana zimayikidwa. Pamene vuto la nthaka lapangitsa kuti dongosololi litaye malo ake apansi, zomwe zimapangitsa kuti magetsi otsatizana ndi neutral point akwere, malo otsatizana amasweka. Chitetezo cha magetsi otsatizana kapena chitetezo cha magetsi otsatizana chimagwira ntchito ndi kuchedwa kwa nthawi (0.3–0.5s) kuti chigwetse transformer mbali zonse.
• Kugwirizana kwa Chitetezo Chosunga Zosungira: Kuti zitsimikizidwe kuti kusankha kukuchitika, kuchedwa kwa nthawi yoteteza ku zero-sequence kuyenera kugwirizanitsidwa. Mwachitsanzo, kuchedwa kwa nthawi yoteteza kumbuyo pa transformer kuyenera kukhala kotalika kuposa kwa chitetezo cha mzere chomwe chimateteza kumbuyo.

Malangizo 3 Okonza ndi Kusanthula Nkhani

3.1 Zoletsa za Njira Zachikhalidwe

Pamene kugwiritsa ntchito zoletsa kukwera kwa mpweya zomwe zili ndi mipataNdi yofala, njira iyi ili ndi zofooka zingapo:

• Kuvuta pa Kusankha Kuletsa Kuchuluka kwa Odwala: N'zovuta kupeza zotchingira ma surge zomwe zimakwaniritsa zofunikira za voltage yogwira ntchito yopitilira komanso voltage yotsika ya mphezi ya 110kV transformer neutral points.
• Mavuto mu Kukhazikitsa Mpata: Mphamvu yamagetsi yogawa mpweya imafalikira, zomwe zimapangitsa kuti zikhale zovuta kugwirizanitsa bwino ntchito ya "kutayika kwa nthaka" komanso "ndi nthaka".
• Kuvuta kwa Chitetezo cha RelayChitetezo ku "kutayika kwa nthaka" (monga zero-sequence overvoltage ndi gap overcurrent protection) chingalephereke, zomwe zimapangitsa kuti pakhale njira zina zoletsera, zomwe zimawonjezera zovuta ndikuchepetsa kudalirika.

3.2 Ubwino wa Kuyika Pansi Pogwiritsa Ntchito Kanthu Kakang'ono

Kafukufuku ndi machitidwe zikusonyeza kuti kukhazikitsa mfundo yopanda mbali kudzera mu reactance yaying'onoimapereka ubwino waukulu poyerekeza ndi njira zachikhalidwe zokhazikitsira nthaka pang'ono:

• Zofunikira Zochepa Zoteteza Kuteteza: Pambuyo pokhazikitsa maziko ang'onoang'ono a reactance, mulingo wa insulation wa transformer neutral point ukhoza kuchepetsedwa kuchoka pa 35kV kufika pa 20kV, zomwe zimapangitsa kuti pasakhale kufunikira kwa ma surge arresters ndi mipata ndikupangitsa kuti chitetezo chikhale chosavuta.
• Njira Yogwirizanitsa YokhazikikaNjira iyi imachotsa kuchitika kwa dongosolo lopanda maziko, zomwe zimapangitsa kuti chitetezo chogwirizana chikhale chosavuta kapena chosayenera, motero zimawonjezera kudalirika.
• Kusunga Ubwino: Imasunga ubwino wa nthaka yochepa, monga chitetezo chosavuta komanso chodalirika cha zero-sequence, pomwe imaletsa mafunde afupiafupi a gawo limodzi.

3.3 Kusanthula Phunziro la Nkhani

Chitsanzo ndi kusintha kwa siteshoni ya terminal ya 110kV. Kapangidwe koyambirira kanagwiritsa ntchito choletsa kukwera kwa mphepo chofanana ndi mpatapofuna kuteteza mfundo zosalowerera. Komabe, atagwiritsa ntchito kukhazikika pang'ono kwa reactance, kufunikira kwa insulation level ya transformer neutral point kunachepetsedwa, zida zotetezera zinachepetsedwa, ndipo kudalirika kwa ntchito kunawongoleredwa. Kuwerengera kunawonetsa kuti kukana kwa nthaka kumatha kuchepetsa mphamvu yamagetsi kufika pa ma ampere mazana angapo, ndipo chitetezo cha zero-sequence chikhoza kugwirizanitsidwa mosavuta.

Nkhani ina inali yokhudza vuto la siteshoni ya 110kV pomwe vuto la nthaka la gawo limodzi lokha pa mzere wolowera linapangitsa kuti pakhale kusweka kwa malo opanda kanthu komanso kugwetsa transformer. Kufufuza kunasonyeza kuti ngakhale vuto la mzere linali la kanthawi kochepa, mayankho ochokera kwa ma mota ambiri osasinthasinthaKumbali ya katundu kunapereka mphamvu ya arc, zomwe zinapangitsa kuti vuto lipitirire. Izi zikusonyeza kuti kwa ma transformer omwe ali ndi magalimoto ambiri (magwero ofanana), chitetezo chokwanira cha mfundo zosalowerera, kuphatikizapo zero-sequence overcurrent, gap current, ndi zero-sequence voltage protection, ndizofunikira panthawi yopangira.

4 Mapeto ndi Chiyembekezo

Kusankha njira yokhazikitsira pansi ya 110kV transformer ndi makonzedwe ake oteteza ndi ntchito yambiri yomwe imafuna kuganizira za kapangidwe ka makina, mawonekedwe a katundu, ndi zofunikira zodalirika. Ngakhale njira yachikhalidwe yokhazikitsira pansi pang'ono pamodzi ndi zoletsa kuthamanga kwa madzi ndi mipata ndizofala, imakumana ndi zovuta pakusankha chipangizo ndi kuyanjana kwa makina. njira yochepetsera mphamvu ya reaction pang'onoimapereka njira ina yabwino, yomwe ingachepetse kufunika kwa kutenthetsa, kuchepetsa chitetezo, komanso kukulitsa kudalirika.

Zochitika zamtsogolo pa chitukuko zidzayang'ana kwambiri madera otsatirawa:

• Kugwiritsa Ntchito Zipangizo Zatsopano: Monga mipata yophatikizika kapena mipata yowongolereka yomwe imagwiritsidwa ntchito limodzi ndi zoletsa kugwedezeka, kukulitsa kudalirika ndi kulondola kwa chitetezo.
• Ukadaulo Woteteza Za digitoKugwiritsa ntchito chitetezo chozikidwa pa kompyuta yaying'ono pogwiritsa ntchito ma algorithms apamwamba (monga kuzindikira mawonekedwe a mafunde, kusanthula kwa harmonic) kuti muwongolere kudalirika ndi kudalirika kwa chitetezo cha zolakwika za nthaka.
• Kukhazikika ndi Kusintha: Kupanga zida zodzitetezera zokhazikika komanso zokhazikika kuti zikhale zosavuta kupanga ndi kukonza.

Mwachidule, kukonza njira yokhazikitsira pansi ya transformer ya 110kV komanso kasinthidwe ka chitetezo ndikofunikira kwambiri pakukweza chitetezo, kudalirika, komanso kayendetsedwe ka chuma ka makina amagetsi. Ndi kupita patsogolo kwaukadaulo, mayankho anzeru komanso ogwira mtima akuyembekezeka kuonekera ndikugwiritsidwa ntchito kwambiri.