I-magnetizing inrush current ivela nini kuma-transformers?

Izimo ze-magnetizing inrush nazo zenzeka ngemvamisa ephezulu kakhulu kuneziyingi ezimfushane, ngakho-ke le nto kufanele ihlolwe.

Cabangela ukuthi kwenzekani uma ekuqaleni unika amandla i-single-phase transformer. I-flux magnetic in the core ilingana ne-integrated voltage excitation.

Uma isifunda sivaliwe lapho i-voltage idlula ku-zero futhi i-flux yokuqala ingu-zero, i-sinusoidal flux izosuswa ngokuphelele kusuka ku-zero. Inani eliphakeme kakhulu le-offset flux eligcwele liphinda kabili inani eliphakeme le-symmetrical sine wave flux. Ngamanye amazwi, ukugeleza okuphezulu kwegagasi eliphelele le-offset kungase kube cishe kabili ukuguquguquka kokuphakama okujwayelekile, okuvame ukwanele ukushayela umgogodla ekugcwaleni.

Kuleli qophelo, okuwukuphela kwento ekhawulela amandla kazibuthe ukuvinjelwa komoya okuphakathi kokusonta, okungama-oda wobukhulu obuncane kune-impedance evamile yamagnetizing.

Ngakho-ke, phakathi nomjikelezo wesigamu sokugcwaliswa kwe-core, i-current field inkulu kakhulu kune-current field current. Phakathi nomjikelezo wesigamu ophikisanayo, umgogodla awusagcwali futhi i-current field cishe ilingana ne-current field current.

Isimo sibi nakakhulu uma kukhona ukugeleza okusele kumgogodla futhi isiqondiso se-residual flux sifana nesiqondiso se-offset ye-sinusoidal flux wave. Njengoba kukhonjisiwe kuMfanekiso 2 ngezansi. Qaphela ukuthi Izibalo 1 kanye no-2 zihlelwe ngezikali ezihlukene zamanje, ngakho inani eliphakeme elifakwe kuMfanekiso 2 empeleni likhulu kakhulu kunenani eliphakeme lamanje elibekwe kuMfanekiso 1.

02 Inani eliphakeme lokunyuka kwenjabulo

Ukuze uthole amandla okuphakama okuphezulu akhawulelwe kuphela ukusabela kwe-air-core, kulula ukubala i-inductance of the winding usebenzisa amayunithi we-cgs:

lapha:

N – inani lamakhoyili aphendukayo

I-Amt – Indawo engaphakathi kobubanzi obumaphakathi bekhoyili, cm2

l - ubude be-axial yekhoyili, cm

L - i-coil inductance, μH

I-flux ekhiqizwa i-inductor φL ilingana ne-residual flux kanye nezikhathi ezingu-2 ezishintshashintshayo ezivamile kukhishwe i-saturation flux, njengoba i-saturation flux isensimbi. Kepha i-φL ihlobene ne-inductance neyamanje:

Ngakho-ke, i-peak inrush current ivezwa ohlelweni lweyunithi ye-cgs kanje:

lapha:

Ipeak in amps futhi

φr - ukugeleza kwensalela

φn - ushintsho olujwayelekile lwe-magnetic flux

φs - i-saturation flux

Ukube bezingekho izinto eziphikisayo kumjikelezo, inani eliphakeme ngalinye elilandelanayo lizoba nenani elifanayo, futhi ukungena kwamanje bekuzoqhubeka unomphela. Kodwa-ke, lapho kukhona ukumelana kumjikelezo, ukwehla kwamandla kagesi kuwo wonke ukumelana kuzoba kukhulu futhi ukuphakama kokugeleza akudingeki kube phezulu njengomjikelezo odlule.

Okubalulekile kokwehla kwamandla kagesi kumelela ukuncipha kwenetha ku-flux kazibuthe edingekayo ukuze kusekelwe i-voltage esetshenzisiwe. Njengoba ukwehla kwamandla kagesi e-i×R kuhlala kuhlangothi olufanayo, umjikelezo ngamunye wehlisa ukugeleza kazibuthe okudingekayo. Lapho inani eliphakeme le-flux kazibuthe liwela ngaphansi kwevelu yokugcwaliswa kwengqikithi, i-inrush current iyanyamalala. Izinga lokubola alilona i-exponential, nakuba lifana ne-exponential decay current.

kubalulekile! Ngama-transformer amakhulu, i-inrush current ingahlala imizuzwana embalwa ngaphambi kokuthi igcine inyamalala.

Ukusabela komugqa kunomphumela wokunciphisa umthamo omkhulu wokungena ngokumane ungeze i-inductance kumongo womoya we-air of the winding. Kunobudlelwano obuqinisekile phakathi kwe-inrush current kanye ne-short-circuit current, njengoba kokubili kuhlobene nokungeniswa kwe-air-core of the winding.

Khumbula ukuthi ama-circuits amafushane avame ukusunduza ukugeleza ngaphandle komgogodla.

Umthetho wesithupha! Ngokuvamile, umthetho wesithupha ukuthi i-peak magnetizing inrush current ingaphezulu kancane kuka-90% we-peak short circuit current. Kodwa-ke, amandla kazibuthe abangelwa i-magnetizing inrush current ngokuvamile mancane kakhulu kune-short-circuit force. Njengoba isigaba ngasinye siqukethe ukujika okukodwa kuphela, akukho ukuhlehla kazibuthe phakathi kwama-winding.

Inkinga yonke yokuhlaziya i-magnetizing inrush currents iba nzima kakhulu lapho kuhileleka ama-transformer ezigaba ezintathu. Lokhu kungenxa yokuthi ama-engeli esigaba sama-voltage e-excitation ahlukene ngo-120°, kukhona ukusebenzisana kwamanje kanye ne-voltage phakathi kwezigaba, futhi izigxobo ezintathu zedivayisi yokushintsha azivaliwe ncamashi ngesikhathi esifanayo.

Kodwa-ke, kuphephile ukusho ukuthi i-peak inrush current ye-transformer yezigaba ezintathu iseduze nezinga lamanje le-short-circuit.

Esinye sezici ezithakazelisayo ze-magnetizing inrush currents ukuthi kunengxenye enkulu ye-harmonics ngoba imisinga ikhanseliwe ngokuphelele. Ngisho nama-harmonics nawo awavamile ukuhlangana nawo kumasekhethi kagesi.

03 Ukugeleza kozwela

Kukhona futhi into eyaziwa ngokuthi "i-sympathetic inrush", lapho i-transformer ebinikwe amandla ngaphambilini ikhombisa ushintsho olusheshayo lwamanje lapho i-transformer eseduze ivula. Ukuqhuma okuzwelayo kubangelwa ukuguqulwa kwe-voltage yomugqa okubangelwa amandla okungena kwe-transformer yesibili.

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