Dry type transformer user manual instruciton#U ka sebelisa transformer ea mofuta o omileng joang?

Dry type transformer user manual instruciton#U ka sebelisa transformer ea mofuta o omileng joang?-SPL- power transformer, distribution transformer, oil immersed transformer, dry type transformer, cast coil transformer, ground mounted transformer, resin insulated transformer, oil cooled transformer, substation transformer, switchgear

Dry type transformer user manual instruciton#U ka sebelisa transformer ea mofuta o omileng joang?-SPL- power transformer, distribution transformer, oil immersed transformer, dry type transformer, cast coil transformer, ground mounted transformer, resin insulated transformer, oil cooled transformer, substation transformer, switchgear

Dry type transformer user manual instruciton#U ka sebelisa transformer ea mofuta o omileng joang?-SPL- power transformer, distribution transformer, oil immersed transformer, dry type transformer, cast coil transformer, ground mounted transformer, resin insulated transformer, oil cooled transformer, substation transformer, switchgear

TEBELLO PELE

Re leboha ka ho khetha transformer ea mofuta o omileng e hlahisoang ke k’hamphani ea rona.

U khethile sehlahisoa sa transformer sa mofuta o omileng se nang le lerata le tlase, tahlehelo e tlase, matla a mangata a boima, matla a phahameng a mochini le ts’ebetso e tšepahalang ea motlakase.

E le ho u nolofalletsa ho sebelisa sehlahisoa sena ka katleho le ka botšepehi, ka kopo kenya, hlahloba le ho boloka sehlahisoa ho ea ka litaba tsa Buka ena.

CATALOG

Tlhatlhobo ea sehlahisoa

Maemo a sebetsang

Mehaho e kholo ea theknoloji

Tlhaloso ea Model

Tlhaloso ea tsamaiso ea lihlahisoa

Ho phuthela lihlahisoa le lipalangoang

Tlhahlobo le kamohelo

Tlhahlobo ea pono pele e kenya

Tlhahlobo ea tlhahlobo pele e qala ts’ebetso

Ts’ebetso ea marang-rang

Maintenance

Litaba tsa polokeho

1. Kakaretso ea sehlahisoa

Li-transformer tsa mofuta o omileng oa SCB li na le melemo ea polokeho, ts’epahalo, ho boloka matla le tlhokomelo e bonolo. Ha ho nahanoa ka polokeho ea moruo le ts’ebeliso ea tikoloho, letoto lena la li-transformer le na le menyetla e mengata ea ts’ebeliso. Moqapi oa sehlahisoa o tsoetse pele, ts’ebetso e thata, ‘me teko e nepahetse. Maqhubu a matla a phahameng a nka li-conductors tsa boleng bo holimo, le lisebelisoa tse ntle tse sireletsang tse entsoeng ka vacuum casting le ho phekola. Maqhubu a matla a tlase a entsoe ka thepa ea boleng bo holimo ea foil, ‘me mokokotlo oa tšepe o entsoe ka lakane ea tšepe ea boleng bo holimo e kentsoeng ka mocheso o batang, e entsoeng ka theknoloji e ntle haholo. Ka hona, sehlahisoa se na le matla a phahameng a mochine le matla a motlakase, ‘me se na le ts’ebetso e ntle haholo ea ho senya mocheso, sehlahisoa se na le ts’ebetso e nyenyane e fokolang, e ts’eptjoang haholo, bophelo bo bolelele ba ts’ebetso, ha ho na mongobo, ho thibela lelakabe, ho phatloha, ha ho na tšilafalo, tahlehelo e tlaase. , Boima bo bobebe, taolo ea mocheso e itekanetseng e boloka sebaka sa ho kenya, litšenyehelo tsa tlhokomelo, le motlakase. E ka kenella ka har’a setsi sa meroalo ‘me e loketse kaho ea litoropo, meaho e phahameng, litsi tsa khoebo, libaka tsa bolulo, litsi tsa boithabiso le lipapali, lipetlele, meaho ea bahahlauli, boema-fofane, boema-kepe, liteishene tsa terene, litsela tse tsamaeang ka tlas’a lefatše, kotopo ea litsela tse kholo litsing tsa ts’ireletso ea moea. , likhoebo tsa petrochemical, likhoebo tsa electro-chemical, indasteri ea lijo, tlhoekiso ea likhoerekhoere, lipolanete tsa oli tsa offshore, merafo le libaka tse ling.

2. Maemo a ho sebetsa

2.1 Bophahamo ba sebaka sa ho kenya ha boa lokela ho feta 1000m, ‘me mocheso o potolohileng ha oa lokela ho feta 40 ° C (ho ka etsoa ka mokhoa o khethehileng haeba tlhokahalo ena e fetisoa).

2.2 Tšebeliso ea tikoloho: mongobo o lekanyelitsoeng 100%, mocheso o potolohileng: +40 ° C ho -5 ° C (-5 ° C e loketse li-transformer tsa ka hare).

2.3 Sehlahisoa sena hangata ke mofuta oa ka tlung. Sebaka sa ho kenya se lokela ho hloeka,

ha e na lintho tse tsoang kantle ho naha, lerole, le khase e senyang, ‘me e na le maemo a matle a moea. Haeba e kenngoa kamoreng e ka tlaase kapa libakeng tse ling tse sa tsoetsoeng hantle, ho lokela ho nahanoa ka bothata ba moea o qobelloang. Tahlehelo ea sehlahisoa sena ka IKW (Ha ho tahlehelo ea mojaro + tahlehelo ea mojaro) ka 3-4 m3 / min ea moea oa moea.

2.4 Ha sehlahisoa se kentsoe, casing hangata e lokela ho ba hole le 800mm

ho tloha leboteng le litšitiso tse ling, ‘me ho lokela ho ba le sebaka sa 300mm

pakeng tsa mekotla e haufi ea transformer.

2.5 Tlas’a maemo a tloaelehileng, transformer e ka behoa ka ho toba sebakeng sa tšebeliso, ‘me e ka kenngoa ts’ebetsong ka mor’a ho kenya le ho hlahlojoa. Bakeng sa maemo a nang le li-anti-vibration le litlhoko tse ling tse khethehileng, motheo oo transformer e kenngoa ho oona o lokela ho kenngoa ka li-bolts, ‘me transformer e lokela ho lokisoa ke bolts le linate.

 

3. Main entsprechen botekgeniki

3.1 Nako e lekantsoeng: 50Hz

3.2 Mokhoa oa ho pholisa: AN (AF) kapa ho latela litlhoko tsa mosebelisi

3.3 Kereiti ea tšireletso ea khetla: IP20 kapa ho latela litlhoko tsa mosebelisi.

3.4 Leibole ea sehlopha sa khokahano: Dyn11 kapa ho latela litlhoko tsa mosebelisi.

3.5 Tatelano ea karolo ea Transformer: e shebane le lehlakore le phahameng la motlakase ho tloha ka ho le letšehali ho ea ho le letona, lehlakoreng le phahameng la motlakase ke ABC, ‘me lehlakore le tlaase ke a(o)bc.

3.6 Sehlopha sa ho kenya moea ka moea: Sehlopha sa F kapa ho latela litlhoko tsa mosebelisi.

3.7 Boemo ba insulation

Maqhubu a matla a ho mamella voltage ea lihlahisoa tsa grade 10kV ke 35kV, ‘me motlakase o mamellang impulse ke 75kV. Maqhubu a matla a mahlahahlaha a lihlahisoa tsa sehlopha sa 20kV ke 50kV, motlakase o mamellang impulse ke 125kV, le maqhubu a matla a ho mamella voltage ea lihlahisoa tsa sehlopha sa 30kV ke 70kV, ‘me motlakase o mamellang matla ke 170kV.

3.8 Tekanyo ea ho nyoloha ha mocheso:

Mocheso oa mocheso oa tsamaiso (C): 155. Ho phahama ho hoholo ha mocheso (k): 100.

 

4. Tlhaloso ea mohlala

Dry type transformer user manual instruciton#U ka sebelisa transformer ea mofuta o omileng joang?-SPL- power transformer, distribution transformer, oil immersed transformer, dry type transformer, cast coil transformer, ground mounted transformer, resin insulated transformer, oil cooled transformer, substation transformer, switchgear

5. Tlhaloso ea tsamaiso ea lihlahisoa

5.1 Pontšo ea mocheso le mokhoa oa ho laola mocheso

Sehlahisoa sena se ka ba le sistimi ea taolo ea mocheso e bonts’ang mocheso ho latela litlhoko tsa mosebelisi, mme mesebetsi ea eona ke:

(1) Lekola mocheso oa coil ha transformer e sebetsa, ‘me u e bontše

Ka boomo.

(2) Etsa hore sefene se qale, ‘me u qale sefene ha mocheso oa coil o fihla ho 80 °C (boleng bo sa lekanyetsoang, bo ka fetoloang).

(3) Alamo ea mocheso o feteletseng, ha mocheso oa coil o fihla ho 130 ° C (boleng ba kamehla, bo ka fetoloang), ho fanoa ka pontšo ea alamo.

(4) Leeto la mocheso o feteletseng, ha mocheso o potolohileng mohala o feta

150 °C (boleng ba kamehla, bo ka fetoloa), lets’oao la leeto le hlahisoa.

(5) Ha moeli o behiloeng oa thermometer ea pontšo o fetisitsoe, fan e ka ba

e qalile le ho emisa, phepelo ea motlakase e ka khaoloa, ‘me transformer e ka sireletsoa.

 

 

 

 

5.2 Sistimi ea ho pholisaMokhoa oa ho ipholisa ke ho ipholisa (AN). Nakong ea ho ipholisa, matla a tlhahiso ke 100%, ‘me nako e khutšoanyane ea nako e telele e lumelloa nakong ea ho qobella moea oa ho potoloha ha moea (AF).

5.3 Tekanyo ea tšireletsoHa transformer e se na casing, boemo ba tšireletso ke IP00 bakeng sa tšebeliso ea ka tlung; haeba mosebelisi a e hloka, e ka hlomelloa ka casing, ke hore, IP20 kapa IP30 kapa IP40 (ha boemo ba ts’ireletso ea transformer bo le holimo, transformer e lokela ho nkoa e le ho nyenyefatsa ts’ebetso).

Tlhokomeliso: Sebaka sa IP20 se ka thibela ho kena ha lintho tse tiileng tsa kantle ho naha tse kholo ho feta 12mm le ho fana ka mokoallo oa tšireletso bakeng sa karolo e phelang. Khetla e sireletsang ea IP30 e ka thibela ho kena ha lintho tse tsoang kantle tse kholo ho feta 2.5mm. 1P40 shell e ka thibela lintho tse tsoang linaheng tse ling tse kholo ho feta 1mm ho kena.

 

6. Ho paka le ho tsamaisa lihlahisoa

6.1 Lihlahisoa li arotsoe ka mefuta e ‘meli: mofuta o bulehileng (o se nang sekoahelo se sireletsang) le mofuta o sireletsang (o nang le sekoahelo se sireletsang), tseo hangata li tsamaisoang ka terene, tsela ea metsi le tsela e kholo. Li-switch, li-thermostats, lisebelisoa tsa ho pholisa moea, lisebelisoa tse sireletsang kantle, joalo-joalo li hloka ho pakoa ka thoko) kapa li pakete ka kakaretso bakeng sa lipalangoang. Li-cranes, li-winch kapa mechine e meng ea lipalangoang e tsamaellanang e ka sebelisoa ho phahamisa le ho laolla lihlahisoa.

6.2 Nakong ea ho tsamaisoa ha sehlahisoa, ho tlameha ho be le mehato e thibelang pula ho thibela metsi a pula hore a se ke a koloba.

6.3 Ts’ebetsong ea ho phahamisa le ho tsamaisa lihlahisoa ka mabokose a liphutheloana, lithapo li lokela ho fanyehoa holim’a batho ba robalang likhutlong tse ‘nè tsa tlase ea lebokose la liphutheloana,’ me lihlahisoa tse sa phuthetsoeng li lokela ho phahamisoa ka lisebelisoa tse khethehileng tsa ho phahamisa, tse ka phahamisoang 100mm. -150mm ho tloha fatše pele, ebe ka mokhoa oa ho Phahamisa.

6.4 Nakong ea lipalangoang, ha hoa lokela ho ba le matsoapo a holimo le a tlaase a fetang 15° moleng oa lipalangoang. E le ho etsa bonnete ba hore koloi e ka jara mojaro ka mokhoa o ts’oanang, setsi sa matla a khoheli a sehlahisoa se lokela ho behoa setsing se otlolohileng sa koloi nakong ea ho laela. E le ho thibela

ho falla le ho phethoha ha sehlahisoa nakong ea lipalangoang, tataiso ea sebaka se selelele sa sehlahisoa se lokela ho lumellana le tataiso ea lipalangoang, ‘me sehlahisoa se lokela ho tlamelloa ka thata koloing ea lipalangoang.

6.5 Ha u laolla le ho laolla ntle le krene, litlhoko tsa tekheniki tsa polokeho li lokela ho finyelloa, ‘me matla a ho phahamisa a lokela ho hlahlojoa ho bona hore na a lumellana le boima ba lipalangoang ba sehlahisoa.

 

6.6 Bakeng sa lihlahisoa tse nang le trolley e hlokoang ke mosebedisi, trolley e nang le li-roller e kenngoa ka tlaase, eo ka kakaretso e laolloang nakong ea lipalangoang ho netefatsa botsitso ba lipalangoang tsa lihlahisoa. Ka mor’a ho fihla moo u eang, e tla tsosolosoa le ho kenngoa pele e kenngoa. Lihlahisoa tse nang le trolley. Ka ho fetola tataiso ea li-roller shafts lipheletsong tse peli tsa foreimi ka 90 °,

sehlahiswa se ka tsamaiswa ka ho rapama kapa ho theosa.

6.7 Ka mor’a hore sehlahisoa se isoe sebakeng seo u eang ho sona, nako ea ho paka sebakeng sa lipalangoang e lokela ho khutsufatsoa ka hohle kamoo ho ka khonehang (ho qoba ho paka sebakeng se bulehileng). Pele e kenngoa, e lokela ho emisoa sebakeng se koahetsoeng, se omeletseng le se nang le moea o mongata ka hohle kamoo ho ka khonehang. Ka nako e ts’oanang, mehato e lokela ho nkoa ho etsa hore sehlahisoa se be khahlanong le bosholu, se sa keneleng mongobo le se khahlanong le Lerōle, litšila, sekoti, tšenyo le litšila.

 

7. Tlhahlobo le kamohelo

7.1 Ka mor’a ho fumana sehlahisoa, mosebedisi o lokela ho bula lebokose bakeng sa tlhahlobo le kamohelo ka nako, hlahloba hore na lintho tse thathamisitsoeng lethathamong la ho paka li phethiloe, ho hlahloba hore na transformer e senyehile nakong ea lipalangoang, hore na likarolo tsa sehlahisoa li senyehile ‘me li falla, le hore na li-fasteners li hlephile, ho sa tsotellehe hore na li-insulation li senyehile le hore na ho na le matšoao a tšilafalo, joalo-joalo.

7.2 Sheba hore na lintlha tse holim’a lebitso la sehlahisoa li lumellana le tlhaloso ea sehlahisoa, bokhoni, boemo ba motlakase, leibole ea lihlopha tsa khokahanyo, “short-circuit impedance”, joalo-joalo tse boletsoeng ke mosebedisi.

7.3 Ka mor’a hore sehlahisoa se lokolloe ‘me se hlahlojoe, haeba se sa kengoa tšebetsong hang-hang, se lokela ho phutheloa hape ebe se behoa sebakeng se sireletsehileng sa ka tlung (ho thibela bosholu, ho thibela mongobo, ho thibela lerōle, ho thibela ho senya, ho thibela ho thulana) ho hlokomedisa polokelo ya sehlahiswa.

7.4 Ho amoheloa ha transformer ho tla tekenoa lengolong le tsamaisanang le fanang ka thepa hammoho le lefapha la lipalangoang. Lengolo la phano le tla bontsha mathata a fumanweng nakong ya tlhahlobo.

7.5 Haeba lebokose la ho paka le sehlahisoa li fumanoa li senyehile haholo nakong ea tlhahlobo, mafapha a lipalangoang le inshorense a lokela ho tsebisoa hang-hang, ‘me setša se lokela ho bolokoa bakeng sa ho lahla.

 

8. Tlhahlobo ea pono pele e kenya

8.1 Ka mor’a ho bula lebokose, tlosa balebeli (haeba ba le teng) ho hlahloba boemo ba ka ntle, ho ela hloko ka ho khetheha botšepehi ba mochine oa coil le mokokotlo, tekanyo ea khatello ea selikalikoe sa mohala le mokokotlo, le ho tiisa liboutu ka ntle ho khokahanyo.

 

 

 

 

 

8.2 Ka mor’a ho hlahlojoa, li-fasteners tsohle le likarolo tsa khatello ea li-coil le li-cores tsa tšepe li tlameha ho tiisoa hape ka tatellano, ‘me ha ho na ho lokoloha ho lumelloang.

8.3 Hlophisa likarolo tse qhaqhoang ho ea ka litokisetso tsa maemo a theknoloji ea fektheri le litaelo tse nepahetseng tsa sete e feletseng ea likarolo tse kentsoeng ho ‘mele oa transformer.

8.4 Bakeng sa lerōle le litšila holim’a sehlahisoa, leka ho sebelisa moea o omileng o hatelitsoeng. Maemong a khethehileng, a kang ho hloekisa ka rag, lesela le tlameha ho ba le omeletseng, le hloekile le le se nang lesela.

8.5 Ha nako ea ho boloka nako e telele, ho na le marotholi a metsi kapa condensation e tebileng holim’a transformer, u lokela ho nka phekolo e omeletseng, ‘me coil e ka sebelisoa ka mor’a hore ts’ebetso ea ho kenya letsoho e tšoanelehe.

 

9. Tlhahlobo ea tlhahlobo pele e qala ho sebetsa

9.1 Lekanya khanyetso ea DC ea maqhubu a phahameng le a tlase (hore na data e lumellana le lintlha tse fanoeng setifikeiting sa tlhahlobo ea feme).

9.2 Sheba ho theoa ha motheo oa tšepe (karolo ea motheo e atisa ho fumaneha qetellong ea joko e ka tlaase ea tšepe kapa joko e ka holimo ea tšepe), hlahloba hore na mobu o ka tšeptjoa, hore na ho na le taba ea kantle ho naha, le hore na ho na le mefuta e mengata. – ntlha ya ntlha ya motheo.

9.3 Ho lekanya ho hanyetsa ha Insulation

 

Sehlopha sa motlakase 10kV 20kV 30kV
Khoeli e phahameng ea motlakase ho ea ho coil ea motlakase o tlase 500MΩ 800MΩ 1000MΩ
Khoeli e phahameng ea motlakase ho ea fatše 500MΩ 800MΩ 1000MΩ
Khoeli e tlase ea motlakase (0.4V) ho ea fatše 50MΩ 50MΩ 50MΩ
Bohareng ba mobu 5MΩ 5MΩ 5MΩ

 

9.4 Ha u etsa tlhahlobo ea maqhubu a matla a motlakase, terata ea probe ea taolo ea mocheso e lokela ho ntšoa ka har’a terata ho thibela ho senyeha ha likarolo tse ka hare tsa thermostat, esita le ho senyeha ha khoele ea transformer.

9.5 Lekola hore na sistimi ea ts’ireletso e maemong a matle.

9.6 Boemo ba ho kenya mochine oa transformer bo lokela ho ba bonyane 800mm ho tloha leboteng le lintho tse ling tse amang maemo a ho senya mocheso. Ka mor’a hore transformer e be teng, li-bolts tsa fatše li lokela ho kopanngoa le potoloho e akaretsang ea motheo bakeng sa motheo o ka tšeptjoang.

 

10. Ts’ebetso ea marang-rang

10.1 Ka mor’a hore sesebelisoa sa ts’ireletso e thusang le tsamaiso ea ho shebella li theohe fatše ‘me li tšoanelehe, transformer e lokela ho qala ho sebetsa tlas’a moroalo,’ me ka mor’a hore makhetlo a mararo a ts’oaetso a koaloe, hlahloba le ho lokisa tsamaiso ea tšireletso ea relay.

10.2 Ka mor’a hore sehlahisoa se tlohe fekthering, libaka tsa lipompo tsa lehlakore la khatello e phahameng li hokahanngoa ho ea ka boemo ba boleng bo lekantsoeng. Ho lokisoa ha motlakase hoa hlokahala nakong ea ts’ebetso. Ho ea ka matla a pompo a bontšitsoeng holim’a lebitso la sehlahisoa, mekhahlelo e meraro e lokisoa ka nako e le ‘ngoe ho khokahanyo ea pompo e lumellanang (ha ho se na tsamaiso le taolo ea motlakase),’ me phepelo ea motlakase ea transformer e khaotsoe.

10.3 Transformer e amohela thermostat ea letoto la BWDK, ‘me karolo ea ho lekanya mocheso e kenngoa karolong e ka holimo ea coil ea low-voltage, e ka khonang ho lemoha le ho bontša mocheso o fapaneng oa ho sebetsa oa li-coil tsa mekhahlelo e meraro. Ha mocheso oa coil o fihla mocheso o behiloeng, thermometer e ka qala fene ka bo eona, ea emisa fan, alamo, leeto, ‘me mocheso o behiloeng o ka fetoloa ke mosebelisi.

 

11. Tlhokomelo

Ka mor’a hore motlakase oa mofuta o omileng o sebetse ka nako e itseng, motlakase o lokela ho khaoloa ‘me ho lokela ho etsoa tlhahlobo le tlhokomelo e latelang.

11.1 Sheba likhoele, lithapo tse koalang, litheminale tsa lipompo le lifastening likarolong tse fapaneng bakeng sa tšenyo, ho senyeha, ho hlephisa, ho fifala ha mmala, mesaletsa ea ho tsoa le ho bola. lekanya.

11.2 Tlosa lerole ho transformer. Likarolo tsohle tse ka angoang ka matsoho li lokela ho hlakoloa ka lesela le omileng le hloekileng, le se nang lint, joalo-joalo, empa ho se ke ha sebelisoa lihloekisi tse sa tsitsang. Bakeng sa likarolo tse thata ho hlakola ka hare ho coil ea mantlha ea tšepe, moea o omileng o hatelitsoeng o lokela ho sebelisoa ho ntša lerōle.

11.3 Transformer e nang le fan e boetse e lokela ho tlosa lerōle le mobu ho fan (e-ba hlokolosi hore u se ke ua senya mahare a fan ka lebaka la tšenyo) ‘me u hlahlobe mafura a fene,’ me u e tlatse kapa u e nkele sebaka ha ho hlokahala.

11.4 Ka mor’a hore tlhahlobo le tlhokomelo li phethoe, pele transformer e kenngoa ts’ebetsong hape, e lokela ho hlahlojoa ka hloko hore na ho na le ntho leha e le efe ea tšepe kapa e seng ea tšepe e tsoang linaheng tse ling e theohileng, e setseng ka har’a coil le tšepe ea tšepe le likarolong tse sireletsang.

 

12. Litaba tsa polokeho

12.1 Matla a matla a molaoli oa mocheso (le fan) a lokela ho fumanoa ka skrine ea ho fetola, eseng ka ho toba ho transformer.

12.2 Pele transformer e kenngoa ts’ebetsong, tsamaiso ea fatše ea kamore ea transformer e tlameha ho hlahlojoa.

12.3 Monyako oa sebaka se kampetsoeng sa transformer o lokela ho koaloa ho

netefatsa polokeho ea tšebeliso ea motlakase.

12.4 Ho lokela ho be le mehato ea ho thibela liphoofolo tse nyane ho kena ka phaposing ea transfoma ho qoba likotsi.

12.5 Basebeletsi ba tlameha ho roala lieta tsa insulating ha ba kena ka kamoreng ea transformer, ela hloko sebaka se sireletsehileng ho tloha karolong e phelang ‘me u se ke ua ama transformer.

12.6 Haeba ho fumanoa hore lerata la transformer le eketseha ka tšohanyetso, u lokela ho ela hloko ho shebella boemo ba moroalo oa transformer le motlakase oa marang-rang a matla, ela hloko phetoho ea mocheso oa transformer, ‘me u ikopanye le basebetsi ba amehang. therisano ka nako.

12.7 Transformer e lokela ho hlahlojoa le ho hlokomeloa kamehla bakeng sa lilemo tse 1-2 ho netefatsa ts’ebetso e tloaelehileng ea transformer.

12.8 Ho kengoa, ho lekoa, ho sebetsa le tlhokomelo ea

transformer e tlameha ho etsoa ke litsebi tse tšoanelehang.

 

Dry type transformer user manual instruciton#U ka sebelisa transformer ea mofuta o omileng joang?-SPL- power transformer, distribution transformer, oil immersed transformer, dry type transformer, cast coil transformer, ground mounted transformer, resin insulated transformer, oil cooled transformer, substation transformer, switchgear