Hauv kev ntsuas hluav taws xob thiab kev saib xyuas, cov ntsuas hluav taws xob uas xav tau cov khoom siv hluav taws xob sab nraud (CTs) yog ubiquitous; lawv yog peb "qhov muag" kom paub qhov tseeb ntawm cov dej ntws loj. Txawm li cas los xij, muab zais rau hauv cov txheej txheem sophisticated no yog ib txoj cai hlau uas yuav tsum tau ua raws txhua lub sijhawm: ob sab ntawm lub transformer tam sim no yuav tsum tsis txhob ua haujlwm nrog qhib Circuit Court. Kab lus no yuav piav qhia txog cov hauv paus ntsiab lus thiab kev phom sij cuam tshuam.
Lub hauv paus ntsiab lus ntawm Kev Ua Haujlwm ntawm Tam Sim No Transformers
Tam sim no transformer (CT) yog ib hom tshwj xeeb ntawm transformer uas ua haujlwm raws li lub hauv paus ntsiab lus ntawm electromagnetic induction. Nws cov qauv tsim qauv tseem ceeb yog "txo tam sim no" thiab "kev cais tawm."
Qauv
Nws feem ntau muaj cov tub ntxhais hlau kaw, thawj winding nrog ib tug kuj me me ntawm lem (txuas nyob rau hauv series nyob rau hauv lub ntsiab Circuit Court), thiab ib tug thib ob winding nrog ib tug kuj loj tus naj npawb ntawm lem (txuas mus rau lub ntsuas hluav taws xob).
Ideal Xeev
Nyob rau hauv ib txwm kaw Circuit Court, CT ua haujlwm nyob rau hauv kwv yees li "luv-circuit" lub xeev. Raws li Ampere txoj cai Circuit Court thiab txoj cai ntawm electromagnetic induction, thawj tam sim no I1 yuav tsim ib qho alternating magnetic flux Φ nyob rau hauv cov tub ntxhais hlau, uas nyob rau hauv lem induces ib tug tam sim no I2 nyob rau theem nrab. Kev sib raug zoo ntawm ob leeg yog:
I1 × N1=I2 × N2 + Im × N1
Qhov twg N1 thiab N2 yog tus naj npawb ntawm lem nyob rau hauv thawj thiab theem nrab windings, thiab kuv yog lub excitation tam sim no. Vim qhov loj excitation impedance nyob rau hauv tus tsim, Im yog heev me me, yog li nyob rau hauv ib tug zoo tagnrho lub xeev, nws yuav ua tau yooj yim mus rau:
I₁ × N₁ ≈ I₂ × N₂ or I₁/I₂ ≈ N₂/N₁=Kₙ
Ntawm no, Kn yog qhov ntsuas hloov pauv, piv txwv li, 1000/5A. Lub sijhawm no, qhov tam sim no loj ntawm thawj sab yog raug hloov pauv hloov pauv mus rau qhov tam sim no me me nyob rau sab thib ob (feem ntau yog tus qauv tus nqi ntawm 5A lossis 1A) rau kev ntsuas kev nyab xeeb los ntawm cov cuab yeej. Ib txhij, lub peev xwm ntawm CT's theem nrab Circuit Court yog tsawg heev (feem ntau tsuas yog ob peb volts), nyob rau hauv ib qho kev nyab xeeb.
Lub hauv paus ntsiab lus tsom xam ntawm Secondary Circuit Open Circuit
Thaum lub voj voog thib ob qhib vim yog vim li cas xws li cov khoom siv xoob xoob, cov xov hlau tawg, lossis kev sib tsoo thaum lub sijhawm kuaj, nws lub xeev kev ua haujlwm tau hloov pauv tsis zoo.
| Kev ua haujlwm | Ib txwm kaw | Secondary Qhib Circuit |
|---|---|---|
| Secondary Tam sim no I2 | Muaj, proportional rau I1 | I2=0 |
| Core Sib Nqus Flux Φ | Ua tau zoo suppressed los ntawm demagnetizing flux generated los ntawm I2, tswj nyob rau theem qis | Loses suppression, sai saturates rau ib tug tsis tshua muaj nqi |
| Secondary voltage U2 | Tsawg heev (ntau volts) | Induces high voltage ntawm ntau txhiab mus rau kaum tawm txhiab volts |
| Lub cev Essence | Kev sib txuas muaj zog, sib sib zog nqus tawm tswv yim: I2 tawm tsam qhov kev hloov ntawm Φ | Kev txiav txim siab -tawm, lub zog tsub zuj zuj: Tag nrho cov thawj ampere- tig I1N1 yog siv rau excitation |
Cov txheej txheem tseem ceeb ntawm lub cev yog raws li nram no:
Disappearance ntawm Demagnetizing tawm tswv yim
Thaum lub sijhawm ua haujlwm ib txwm muaj, qhov sib nqus flux tsim los ntawm theem nrab tam sim no I2 yog ib txwm nyob rau hauv qhov kev coj rov qab mus rau qhov uas tsim los ntawm thawj tam sim no I1, tsim kom muaj zog "demagnetizing" nyhuv uas txwv cov sib nqus flux hauv cov tub ntxhais mus rau theem qis. Tom qab qhib Circuit Court, kuv 2=0, thiab cov nyhuv demagnetizing tam sim ntawd rov qab mus rau xoom.
Rapid Saturation ntawm Magnetic Flux
Thawj ampere- tig I1 thiab N1, tam sim no tsis muaj kev txwv, tau hloov pauv tag nrho rau hauv magnetizing ampere- tig. Txij li thaum lub hauv paus ntoo khaub lig-sectional cheeb tsam yog tsim los rau tsawg sib nqus flux ceev, cov tub ntxhais nkag mus rau hauv ib tug sib sib zog nqus saturation xeev.
Raws li Faraday txoj cai ntawm electromagnetic induction, alternating magnetic flux induces electromotive force hla lub winding. Thaum qhov sib nqus flux nce ntau heev, qhov tsis tshua muaj hluav taws xob siab U2 yuav raug cuam tshuam los ntawm qhov sib nqus winding.
Generation ntawm High Voltage
Nyob rau hauv lub hwj chim zaus tej yam kev mob, rau ib tug thawj tam sim no ntawm ntau pua amperes, lub induced voltage ntawm ib tug qhib- Circuit Court ob sab yuav yooj yim mus txog ob peb txhiab volts, thiab nyob rau hauv heev mob, tshaj 10 kilovolts.
Kev phom sij ntawm Qhib Circuit Court ntawm Secondary Sab ntawm Tam Sim No Transformer
Lub siab voltage thiab nrog phenomena generated los ntawm ib tug qhib Circuit Court nyob rau hauv lub thib ob sab yuav ua rau ib tug series ntawm saw tshua muaj kev phom sij.
Kev phom sij ntawm hluav taws xob poob siab
Lub xub ntiag ntawm ntau txhiab volts ntawm high voltage ntawm lub thib ob terminals ncaj qha ua rau muaj kev pheej hmoo ntawm hluav taws xob poob siab. Kev tu thiab kho cov neeg ua haujlwm uas tau ntsib nrog qhov hluav taws xob no yam tsis muaj kev ceev faj yuav raug hluav taws xob poob siab.
Cov khoom puas tsuaj
Rwb thaiv tsev tawg: Cov hluav taws xob siab yuav ua ntej ua txhaum ntawm inter-tig thiab inter- txheej rwb thaiv tsev ntawm cov cua ntsawj ntshab thib ob, lossis rhuav tshem cov rwb thaiv tsev rau hauv av nyob rau hauv lub voj voog thib ob, ua rau muaj kev puas tsuaj mus tas li rau qhov tam sim no transformer (CT).
Overheating thiab Burnout: Thaum cov tub ntxhais hlau muaj qhov txaus txaus, nws yuav tsim cov eddy tam sim no thiab hysteresis poob, ua rau cov tub ntxhais hlau overheat, uas yuav hlawv tawm lub rwb thaiv tsev winding thiab txawm ua rau hluav taws.
Hluav taws xob Arc thiab tawg: Ib qho qhib Circuit Court taw tes (xws li lub davhlau ya nyob twg xoob) yuav tsim kom muaj hluav taws xob txuas ntxiv nyob rau hauv high voltage. Qhov kub ntawm lub arc yuav hlawv tawm cov cuab yeej, ignite ib puag ncig combustibles, thiab lub siab - gases kub nyob rau hauv lub kaw txee tej zaum yuav txawm ua rau hluav taws xob tawg.
Kev Ua Haujlwm Kev Nyab Xeeb
Kev ntsuas qhov tsis raug thiab tsis ua tiav: Rau CT- hom ntsuas hluav taws xob, xoom input tam sim no yuav ua rau lawv tsis tuaj yeem ntsuas hluav taws xob, ua rau poob hluav taws xob thiab muaj peev xwm daws teeb meem kev lag luam.
Generation of Dangerous High-Voltage Sparks: Qhov no tsis yog qhov hluav taws kub xwb, tab sis qhov ua rau muaj zog electromagnetic pulses tuaj yeem cuam tshuam nrog cov khoom siv hluav taws xob nyob ze.
Xaus
Ib qho qhib hluav taws xob nyob rau sab thib ob ntawm lub tshuab hluav taws xob tam sim no ua rau muaj kev kub ntxhov ntawm cov hluav taws xob hluav taws xob, thaum kawg ua rau muaj kev puas tsuaj rau lub cev uas tshwm sim raws li qhov siab voltage, muaj zog hluav taws xob arcs, thiab overheating. Yog li ntawd, "tiv thaiv qhib circuits" yuav tsum nruj me ntsis ua raws li nyob rau hauv tag nrho cov hauj lwm nrog CT circuits.
Nyob rau tib lub sij hawm, lub thib ob sab ntawm lub tam sim no transformer txuas nrog lub ntsuas hluav taws xob yuav tsum tau grounded. Qhov no, nrog rau "thov txwv tsis pub qhib circuits nyob rau sab thib ob," yog ob lub ntsiab cai ntawm kev ua haujlwm ntawm CT thiab kev saib xyuas. Grounding tso cai rau txhua qhov hluav taws xob hluav taws xob siab kom tawm sai sai rau hauv av los ntawm cov xaim hauv av, tiv thaiv kev nce ntxiv hauv cov peev txheej thib ob uas tuaj yeem ua rau cov khoom siv hluav taws xob lossis hluav taws xob poob siab.