Muab xam los ntawm lub hwj chim nyob rau hauv hluav taws xob circuits

Tej hluav taws xob kws yus muaj los ntawm ob peb yam yooj yim tsis, cov uas nyob voltage, tam sim no thiab lub hwj chim. Tej zaum cov ntaub ntawv ib lub hwj chim thiab voltage, tam sim no nyob rau hauv cov ntaub ntawv no yog yooj yim nrhiav tau los ntawm kev siv lub zoo-paub Ohm tus qauv (ntawm chav kawm, ib tug xov tooj ntawm zos - e.g., yuav tsum tau paub cos). Rov qab no kuj muaj tseeb: kev paub txog qhov tam sim no thiab voltage, nws tseem tau mus ua lub hwj chim muab xam. Lub ntiaj teb no network muaj ib tug ntau ntawm cov ntaub ntawv uas nyob rau hauv cov kev kawm, tiam sis feem ntau ntawm lawv yog npaj rau cov kws tshwj xeeb.

Cia saib dab tsi yog meant ntawm lub sij hawm "hluav taws xob lub hwj chim", dab tsi yog nws hom thiab yuav ua li cas ua ib lub hwj chim muab xam. Lub cev kev txiav txim zoo ntawm lub hwj chim ntawd hais sai npaum li cas rau nruab (ntaus) hwj chim hloov dua siab tshiab yuav siv sij hawm qhov chaw nyob rau hauv ib los yog lwm daim ntawv uas pab tau ua hauj lwm. Qhov ntawd yog li ntawd, tej yam yooj yim! lub sij hawm "kev ua tau zoo" nws yog heev tau siv lub tib yam rau uas tsis yog-hluav taws xob pab kiag li lawm.

Cov hluav taws xob sib cais saws, raws li uas muaj ib tug active thiab reactive lub hwj chim. Tus thawj yog ncaj qha mus hloov dua siab tshiab rau hauv pab ua hauj lwm, yog li ntawd, nws yog suav tias yog ib tug loj. Cov chav tsev yog W thiab derivatives -. Kilowatt, Megawatt lwm yam nws yog nyob ntawm khoom vaj khoom tsev. Txawm tias qhov no tsis txhais hais tias muaj yog tsis muaj reactive tivthaiv. Nyob rau hauv lem, tus thib ob - ib tug undesirable, txij li thaum qhov kev siv ntawm lub chaw ua hauj lwm tsis koom, thiab siv rau ntau hom losses. Ntsuas "Var" (volt ampere reactive) thiab derivatives - kilovolt-ampere reactive etc. Tus nqi ntawm cov active thiab reactive Cheebtsam tsim ib tug tag nrho cov hwj huam (volt-amperes VA).

Ib tug piv txwv ntawm cov neeg uas ib tug dawb huv resistive load - ib tug hluav taws xob rhaub. Thaum dhau los ntawm nws ib tug hluav taws xob tam sim no yog generated los ntawm tshav kub, thiab nyob rau hauv ncaj qha kev faib ua feem. Ib yam li ntawd, cov uas ua ntawm reactive zog neeg - ib tug classic transformer. Thaum nws ua hauj lwm nyob rau hauv lub windings tsim ib tug sib nqus teb uas nyob rau hauv nws tus kheej yog tsis tsim nyog (siv electromagnetic induction vaj tse). Lub magnetic tseem ceeb yog magnetized, losses tshwm sim. Nyob rau hauv lwm yam lus:

Q = U * Kuv * kev txhaum nkaus,

qhov twg txhaum nkaus - lub sine ntawm lub kaum sab xis ntawm tam sim no thiab voltage. Nws kos npe rau nyob ntawm qhov xwm ntawm loads (capacitive los yog inductive).

hwj chim muab xam pib nrog txiav txim tam sim no hom: qhov los yog nce mus nce los, raws li cov qauv yog tsis universal.

Nyob rau hauv thawj cov ntaub ntawv, ib tug txais ntawm txoj kev classical Ohm txoj kev cai. Fais fab P yog qhov khoom ntawm qhov tam sim no kuv nyob rau voltage U:

P = Kuv * U (W = A * B).

Thaum lub Circuit Court ib lub hwj chim qhov twg los yog coj mus rau hauv tus account cov kev taw qhia ntawm cov EMF: nws yog tsim nyog rau lub xam ntawm lub qhov impedance. Yog li, lub generator los yog lub roj teeb nyob rau hauv uas tam sim no ntws los ntawm "-" rau "+", muab lub zog mus rau lub load Circuit Court, xa ib lub hwj chim. Yog hais tias tam sim no txaus yog opposite rau lub thov tej zaum (roj teeb them), ces lub hwj chim haum emf qhov chaw.

Fais fab xam mis rau ib tug AC (saw ib leeg-theem) nyiaj coefficient - "hwj chim tshaj." Nws nruab nrab yog cov active hwj chim feem ntawm cov piv rau tag nrho cov. Obviously, nyob rau hauv cov ntaub ntawv ntawm TAN cosine yog sib npaug zos rau 1 (meej), vim tsis muaj reactive tivthaiv. Txwv tsis pub, los txo losses nyob rau generator sab ntawm kev siv ntau yam expansion pob qij txha los yog lwm yam kev daws teeb meem.

Yog li:

P = U * Kuv * cos nkaus.

Muab xam los ntawm lub hwj chim nyob rau hauv peb-theem circuits yog ua rau txhua tus theem, thiab lub resulting qhov tseem ceeb yog ces summed. AC khees hwj chim yog xam raws li lub square hauv paus ntawm lub sum ntawm cov plaub fab ntawm active thiab reactive Cheebtsam. Rau generating pab kiag li lawm (substation) yog xav paub ntxiv tseem ceeb kom paub raws nraim tag nrho muaj peev xwm, raws li raug xaiv rau lub hauv paus ntawm no, tag nrho lwm yam khoom raws li cov chains. Nws yog pom tseeb tias nyob rau hauv feem ntau nws yog tsis yooj yim sua kom paub ua ntej qhov xwm ntawm tus load.