Burden ntawm Tam sim no Transformer

Lub impedance ntawm lub thib ob Circuit Court yog qhia nyob rau hauv ohms, lub hwj chim yam lub kaum sab xis yog hu ua lub nra. Tab sis nws yog feem ntau qhia nyob rau hauv cov nqe lus ntawm pom meej hwj chim nyob rau hauv kVA thiab ntsuas theem nrab tam sim no ntawm lub hwj chim yam ntxwv. Qhov kev siv hluav taws xob no tsis yog lub zog hluav taws xob ntawm theem nrab tam sim no ntawm CT.
Rated 'Burdens' ntawm CTs thiab VTs xa mus rau qhov siab tshaj plaws load nyob rau hauv volt-amperes (VA) uas yuav siv tau nyob rau hauv lub thib ob terminals, yam tsis muaj qhov piv thiab theem lub kaum sab xis yuam kev tshaj qhov tso cai txwv. Lub nra yog nyob ntawm tus naj npawb ntawm cov twj paj nruag lossis relays txuas thiab lawv tus kheej lub nra ntawm tus nqi.
CT Terminal Marking:
Terminal marking yuav tsum txheeb xyuas:
a) Thawj thiab theem nrab windings.
b) Cov seem winding, yog tias muaj.
c) Cov txheeb ze polarities ntawm windings thiab winding seem; thiab
d) Qhov nruab nrab tappings, yog tias muaj.
CT Method of Marking:
1. Cov terminals yuav tsum tau cim kom meej thiab indelibly nyob rau hauv lawv nto los yog nyob rau hauv
lawv thaj tsam tam sim ntawd.
2. Lub cim yuav tsum muaj cov ntawv ua raws, lossis ua ntej, yog tias tsim nyog, los ntawm
tus lej. Cov tsiaj ntawv yuav tsum nyob rau hauv block capitals.
3. Tag nrho cov terminals cim P1, S1 thiab C1 yuav tsum muaj tib lub polarity ntawm ib qho twg
tam sim ntawd.
Magnetization nkhaus: -
Lub magnetization nkhaus ntawm CT qhia qhov excitation yam ntxwv nkhaus ntawm ib txwm oriented hluav taws xob hlau. Lub excitation nkhaus yuav muab faib ua plaub lub ntsiab cheeb tsam (i) los ntawm keeb kwm mus rau pob taws taw tes (ii) los ntawm pob taws taw tes mus rau hauv caug (iii) lub hauv caug cheeb tsam (iv) saturation cheeb tsam. Lub hauv caug taw tes yog txhais tau tias qhov twg 10% nce hauv flux ceev ua rau 50% nce hauv ampere-tig.
Kev tiv thaiv tam sim no transformer feem ntau ua haujlwm ntau dhau ntawm kev ua haujlwm ntawm flux ntom ntom ntawm pob taws taw mus rau hauv lub hauv caug cheeb tsam saum toj no, thaum ntsuas tam sim no transformer muaj qhov flux ntom hauv thaj tsam ntawm pob taws taw tes nkaus xwb.
Ua ntej saturation, flux ceev nyob rau hauv cov tub ntxhais yog proportional rau ampere-tig. Thaum ncav cuag saturation, magnetizing inductance yuav tsawg thiab tag nrho cov thawj tam sim no yog siv nyob rau hauv kev txaus siab rau cov tub ntxhais ib leeg, yog li ntawd, qhov thib ob tso zis ntawm CT ploj.
Lub saturation txuas ntxiv mus txog thaum thawj qhov tam sim no raug txo qis dua qib saturation. Ntawm lub zog nyob rau hauv cheeb tsam saturation, CT coj ib qho qhib circuited. Nws yog ib qho nyuaj kom tsis txhob saturation thaum lub sij hawm luv luv. Cov nyhuv ntawm saturation yog txo cov zis, yog li txo qhov ceev ntawm over-tam sim no relays. Nyob rau hauv sib txawv relays, qhov saturation cuam tshuam qhov sib npaug, thiab kev ruaj ntseg ntawm kev tiv thaiv raug cuam tshuam.
Tam sim no transformer saturation nkhaus feem ntau plotted nyob rau hauv theem nrab volts vs. exciting tam sim no ntsuas nyob rau hauv theem nrab. Rau qhov xav tau qhov loj ntawm qhov nruab nrab voltage, qhov degree ntawm saturation tuaj yeem pom los ntawm qhov nkhaus thiab tseem qhia tau los ntawm qhov loj ntawm qhov zoo siab tam sim no los tsim qhov voltage.