Cov kev tiv thaiv kab mob kev tiv thaiv (SPDs) yuav tsum raug kuaj xyuas hauv cov impulse tawm tsiv tsuam nrog cov qauv ntawm 8 / 20 ms thiab 10 / 350 ms. Txawm li cas los xij, nrog kev txhim kho SPD khoom, kev ua tau zoo thiab muaj peev xwm ua tau ntawm SPDs nyob rau hauv kev ntsuas kev sim no yuav tsum tau tshawb xyuas ntxiv. Txhawm rau soj ntsuam thiab sib piv nrog lub peev xwm ntawm SPDs hauv 8 / 20 ms thiab 10 / 350 ms impulse currents, cov kev sim raug coj los ntawm peb hom kev hloov hlau-oxide (MOV) uas siv rau chav I SPDs. Cov kev tshwm sim qhia tau hais tias cov MOVs nrog qhov siab tshaj qhov tsis muaj zog muaj kev ruaj siab muaj peev xwm ua tau raws li 8 / 20ms impulse tam sim no, thaum lub sij hawm xaus 10 / 350ms impulse tam sim no yog txawv. Nyob rau hauv 10 / 350 ms tam sim no, qhov tsis ua rau MOV muaj feem xyuam rau lub zog nqus ntawm ib lub tsev ntim hauv ib qho kev ua haujlwm. Crack yog lub ntsiab kev puas tsuaj hauv 10 / 350ms tam sim no, uas tuaj yeem piav raws li ib sab ntawm MOV yas encapsulation thiab daim ntawv electrode tev tawm. Ablation ntawm ZnO khoom, tshwm sim los ntawm flashover ntawm daim ntawv electrode thiab ZnO nto, tshwm nyob ze ntawm MOV electrode.

1. Taw qhia

Kev tiv thaiv kev tiv thaiv (SPDs) txuas nrog cov tshuab hluav taws xob tsawg, kev sib txuas lus thiab cov tes hauj lwm yuav tsum raug kuaj xyuas raws li cov cai ntawm IEC thiab IEEE cov qauv [1-5]. Xaiv qhov chaw thiab qhov teeb pom kev zoo tam sim no nws yuav raug kev txom nyem, xws li SPDs yuav tsum tau kuaj sim hauv impulse tawm tsiv tsuam nrog cov qauv ntawm 8 / 20 ms thiab 10 / 350 ms [4-6]. Qhov kev hloov waveform ntawm 8 / 20 ms feem ntau yog siv los simulate lub teeb pom kev zoo [6-8]. Cov lus hais tawm hauv lub cev (Hauv) thiab qhov siab tshaj tawm ntawm qhov tam sim no (Imax) ntawm SPDs yog txhais ob lub ntsiab lus nrog 8 / 20 ms impulse [4-5]. Ntxiv mus, 8 / 20 ms tam sim no yog siv rau SPD residual voltage thiab kev kuaj xyuas kev ua haujlwm [4]. 10 / 350ms impulse tam sim no feem ntau yog siv los simulate qhov ncaj qha hluav taws xob rov qab stroke tam sim no [7-10]. Qhov kev ua tau zoo no ua tau raws li cov kev tsis sib haum xeeb rau tam sim no rau chav I SPD, uas yog tshwj xeeb tshaj yog siv rau kev xeem ntawv ntxiv rau chav I SPDs [4]. Lub sijhawm xeem [4-5], tus naj npawb ntawm cov impulse currents yuav tsum tau thov rau SPDs. Piv txwv, kaum tsib 8 / 20 ms currents thiab tsib 10 / 350 ms impulse currents yuav tsum tau ua haujlwm rau kev xeem ua haujlwm rau chav kawm I SPDs [4]. Txawm li cas los xij, nrog kev txhim kho SPD khoom, kev ua tau zoo thiab muaj peev xwm ua tau ntawm SPDs nyob rau hauv kev ntsuas kev sim no yuav tsum tau tshawb xyuas ntxiv. Cov kev tshawb fawb yav dhau los feem ntau feeb ntawm MOV cov kev kawm nyob hauv ntau 8 / 20 ms impulse tam sim no [11-14], thaum qhov kev ua tau zoo dua hauv 10 / 350 ms impulse tam sim no tsis tau soj ntsuam xyuas kom huv si. Tsis tas li ntawd, cov chav kawm I SPDs, tau teeb tsa nyob rau hauv cov ntsiab lus ntawm kev raug mob hauv vaj tse thiab cov khoom tis npe, muaj ntau tus cwj pwm txawv ua rau [15-16]. Yog li, qhov kev ua tau zoo thiab muaj peev xwm ua tau ntawm chav kawm I SPDs hauv 8 / 20 ms thiab 10 / 350 ms impulse currents tsim nyog yuav raug tshawb xyuas. Daim ntawv no yog tshuaj ntsuam xyuas qhov muaj peev xwm ua tau ntawm cov chav kawm I SPDs hauv 8 / 20 ms thiab 10 / 350 ms impulse currents. Peb hom mob MOV siv rau cov chav kawm I SPDs tau txais los rau kev ntsuam xyuas. Qhov siab tshaj tam sim no thiab cov naj npawb ntawm cov impulses yog hloov rau ob peb sim kawm. Kev sib piv yog coj los ntawm kev muaj peev xwm ntawm kev muaj peev xwm ntawm MOV nyob rau hauv ob hom impulse currents. Cov hom mob MOV tsis ua hauj lwm uas ua tsis tau tom qab cov kev kuaj kuj tau tshawb xyuas.

2. Txheej txheej ntawm kev sim

Peb hom mob MOV siv rau chav kawm I SPDs raug saws me hauv cov kev sim. Rau txhua hom kev tshawb fawb, 12 samples tau tsim los ntawm EPCOS tau txais los ntawm plaub hom kev sim. Cov teeb meem tsis yooj yim yog qhia nyob hauv PAB I, qhov chaw hauv cov puav nom paug tawm ntawm 8 / 20μs impulse, Imax sawv cev rau ntau tshaj tawm tam sim no hauv 8 / 20μs impulse, Iimp sawv cev rau ntau tshaj tawm tam sim no hauv 10 / 350μs impulse, UDC1mA qhov ntsuas MOV ntsuas hauv 1 mA DC tam sim no, Ur sawv cev rau tus MOV residual voltage nyob hauv.

Daim duab xNUMX qhia tias lub impulse tam sim no generator uas yuav raug kho rau 1 / 10 ms thiab 350 / 8 ms tam sim no impulses. Lub Pearson coil yog siv los ntsuas cov impulse currents ntawm cov kev xeem MOVs. Lub divage voltage nrog piv ntawm 20 yog siv los ntsuas qhov seem voltages. Cov oscilloscope ntawm TEK DPO14.52 yog saws los sau cov kev sim cov qauv kev lag luam.

Raws li kev soj ntsuam SPD [4], cov amplitudes txais yuav rau 8 / 20 ms tam sim no muaj 30kA (0.75Imax) thiab 40kA (Imax). Cov amplitudes uas tau siv 10 / 350 ms tam sim no muaj xws li 0.75Iimp thiab Iimp. Kev siv rau kev kuaj xyuas kev ua hauj lwm rau MOVs [4], kaum tsib 8 / 20ms impulses siv rau MOV cov qauv, thiab lub caij nyoog ntawm kev cuam tshuam yog 60 s. Vim li no, qhov kev sib tw ntawm txoj kev sim yog pom nyob hauv daim duab 2.

Cov txheej txheem kev sim yuav piav tau raws li:

(1) Kev ntsuam xyuas thawj zaug: Tus qauv ntawm MOV yog tsi ntsees nrog UDC1mA, Ur, thiab cov duab thaum pib ntawm kev sim.

(2) Thov kev fifteen impulses: Kho lub impulse tam sim no generator los tso rau qhov kev xav tau tam sim no. Kaum tsib impulses nrog interval ntawm 60 s yog siv rau ntawm tus qauv MOV ua successively.

(3) Sau cov ntawv ntsuas ntawm kev ntsuas ntawm cov MOV ntswj thiab cov voltages tom qab txhua daim ntawv thov kev lam.

(4) Pom kev soj ntsuam thiab ntsuas tom qab xeem ntawv. Kuaj qhov chaw ntawm MOV rau puncture los yog flashover. Ntsuas lub UDC1mA thiab tus Yauj tom qab kev ntsuam xyuas. Siv cov duab ntawm cov MOV uas raug puas tsuaj tom qab kuaj. Cov kev xeem dhau ntawm cov kev sim, raws li IEC 61643-11 [4], yuav tsum tau hais tias ob qho tag nrho cov ntaub ntawv hluav taws xob thiab cov ntaub ntawv tam sim no, nrog rau kev kuaj xyuas pom kev, yuav tsum tsis muaj kev qhia txog qhov nqes tes los yog kev sim ntawm cov qauv. Ntxiv mus, IEEE Std. C62.62 [5] tau qhia tias qhov ntsuas ntsuas tom qab ntsuas (MOV residual voltages ntawm In) yuav tsum tsis txhob ntab ntau dua 10% los ntawm qhov kev ntsuas Predest ntsuas Ur. Lub Std. IEC 60099-4 [17] kuj hais tias UDC1mA yuav tsum tsis txhob ntab ntau dua 5% tom qab qhov kev ntsuam xyuas impulse.

  1. Cov muaj peev xwm ua tau raws li 8 / 20 ms impulse tam sim no

Hauv seem no, 8 / 20 ms impulse currents nrog cov amplitudes ntawm 0.75Imax thiab Imax yog siv rau kev kuaj SPD. Cov kev hloov pauv rau qhov kev ntsuas tom qab ntsuas UDC1mA thiab lub Ur txhais tias:

qhov twg, Ucr nruab nrab yog qhov hloov ntawm kev ntsuas qhov tseem ceeb. Uat nruab nrab yog tus nqi ntsuas tom qab xeem ntawv. Ubt nruab nrab yog tus nqi ntsuas ua ntej kev xeem.

3.1 Cov ntsiab lus hauv 8 / 20 ms impulse nrog lub ncov ntawm 0.75Imax

Qhov kev kuaj sim rau peb hom kev mob MOV nyob rau hauv kaum tsib 8 / 20 ms impulse currents nrog ncov ntawm 0.75Imax (30 kA) muaj nyob rau hauv TABLE II. Qhov tshwm sim rau txhua hom MOV yog qhov nruab nrab ntawm peb tib qho kev kuaj.

ROOJ II

Cov ntsiab lus hauv 8 / 20 ms impulse currents nrog 30 kA peak

Nws tuaj yeem pom los ntawm TABLEII tias tom qab kaum tsib 8 / 20 ms impulses tau siv rau ntawm cov Keeb Kwm, qhov hloov ntawm UDC1mA thiab Ur yog me. Tus "Hloov" rau kev tshuaj xyuas pom tau tias tsis muaj kev puas tsuaj rau cov kev ntsuam xyuas MOV. Ntxiv mus, nws tuaj yeem tau pom tias nrog kev nce ntawm qhov MOV limiting voltage, Ucr me dua. Xws li lub Ucr yog qhov tsawg tshaj plaws rau V460 hom MOV. Nws tuaj yeem hais tias peb hom MOV tau tag nrho kaum tsib 8 / 20 ms impulse nrog 30 kA peak.

3.2 Cov ntsiab lus hauv 8 / 20 ms impulse nrog lub siab ntawm Imax

Xav txog cov kev sim ntawm qhov saum toj no, qhov siab ntawm 8 / 20 ms tam sim no nce rau 40 kA (Imax). Tsis tas li ntawd, pes tsawg tus impulses nce mus rau nees nkaum rau V460 hom MOV. Cov qhab-nees xeem tau tshwm sim nyob rau hauv TABLE III. Yuav kom sib piv tau lub zog nqus ntawm peb hom MOV, Ea / V yog siv los sawv cev rau lub zog uas tsis muaj zog rau ib chav tsev ntim rau qhov nruab nrab ntawm kaum tsib lossis nees nkaum impulses. Ntawm no, qhov "nruab nrab" raug txiav txim siab vim tias lub zog nyob hauv MOV yog qhov sib txawv me ntsis hauv txhua qhov kev lam.

COV LUS III

Cov ntsiab lus hauv 8 / 20 ms impulse currents nrog 40 kA peak

Nws muaj peev xwm raug pom los ntawm TABLE III tias thaum lub amplitude zus ntxiv mus rau 40 kA, Ucr rau UDC1mA muab ntau tshaj 5% rau V230 thiab V275, tab sis qhov hloov ntawm MOV residual voltage tseem nyob hauv ntau yam ntawm 10%. Kev kuaj pom kuj tseem qhia tau hais tias tsis muaj kev puas tsuaj rau ntawm kev ntsuam xyuas MOV. ForV230 thiab V275 hom MOVs, lub Ea / V txhais tau hais tias lub zog uas tau muab ntxig rau ib chav tsev ntim nrog qhov nruab nrab ntawm kaum tsib impulses. Lub Ea / V rau V460 nruab nrab yog lub zog uas tau txais los ntawm ib chav tsev ntim nrog nruab nrab ntawm nees nkaum impulses. COV LUS III qhia tau hais tias cov MOVs nrog qhov siab dua qhov muaj zog (V460) muaj Ea / V loj dua lub MOV nrog qhov tsawg limiting voltage (V275 thiab V230). Ntxiv mus, nrog lub impulse tam sim no thov nyob rau hauv V460, lub zog absorbed ib chav tsev ntim (E / V) nce zuj zus, raws li qhia hauv 3.

Yog li, nws muaj peev xwm yuav xaus tias V230 thiab V275 yam MOVs tsis tuaj yeem ua tau kaum tsib 8 / 20ms tam sim no impulses nrog ncov ntawm Imax, thaum V460 hom MOV tuaj yeem qhov siab tshaj tawm kev mus txog 20 impulses. Qhov no txhais tau hais tias cov MOV nrog qhov yooj yim dua qhov voltage muaj kev ruaj siab muaj peev xwm ua tau raws li 8 / 20ms impulse tam sim no.

4. Cov khoom siv peev xwm ntawm 10 / 350 ms impulse tam sim no

Hauv seem no, 10 / 350 ms impulse currents nrog cov amplitudes ntawm 0.75Iimp thiab Iimp yog siv rau kev kuaj SPD.

4.1 Cov ntsiab lus hauv 10 / 350 ms impulse nrog lub ncov ntawm 0.75Iimp

Txij li cov Iimp ntawm peb hom kev sib txuam sib txawv, 10 / 350 ms currents nrog amplitude ntawm 4875A yog siv rau V230 thiab V275, thiab impulses nrog amplitude ntawm 4500 A yog siv rau V460. Tom qab siv tsib foob impulse currents, cov kev hloov rau UDC1mAand Ur ntawm txoj kev kuaj MOV muaj nyob rau hauv TABLE IV. Qhov ΣE / V txhais tau hais tias yog E / V ntawm qhov kev thov impulses.

Nws tuaj yeem pom los ntawm LUB LIM IV tias tom qab siv kaum tsib 10 / 350 ms nrog lub ncov ntawm 0.75Iimp, V230 yuav dhau qhov kev sim, thaum hloov ntawm UDC1mA ntawm V275 ntau tshaj 5%. Kev nplua thiab qe menyuam yaus kuj tshwm nyob rau hauv lub hnab yas ntawm V275. Daim duab ntawm V275 nrog me tawg yog tshwm nyob hauv daim duab 4.

Rau hom V460 MOV, tom qab qhov xij 10 / 350 ms impulse nrog lub ncov ntawm 4500A, cov MOV tawg thiab ntsuas qhov ntsuas thiab cov qauv kev hloov tam sim no txawv txav. Rau kev sib piv, ntsuas voltage thiab tam sim no waveforms nyob rau hauv xya thiab qib xNUMX / 10 ms impulse rau V350 yog muaj nyob hauv daim duab 460.

Daim duab 5. Cov ntsuas voltage thiab tam sim no waveforms ntawm V460 nyob rau hauv 10 / 350 ms impulse

Rau V230 thiab V275, ΣE / V yog lub ntsiab lus ntawm E / V rau kaum tsib impulses. Rau V460, ΣE / V yog lub ntsiab lus ntawm E / V rau yim impulses. Nws tuaj yeem tau pom tias txawm tias Ea / V ntawm V460 siab tshaj V230 thiab V275, tag nrho ΣE / Vof V460 yog qhov qis tshaj. Txawm li cas los xij, lub V460 tau ntsib kev puas tsuaj loj heev. Qhov no txhais tau hais tias kom lub ntim ntawm MOV, qhov tsis ua rau MOV tsis nyob rau hauv 10 / 350 ms tam sim no tsis muaj feem xyuam nrog tag nrho cov kua hluav taws xob (Σ E / V), tab sis tej zaum yuav muaj feem xyuam nrog lub zog nqus (absorbed energy) nyob rau hauv tib lub plhom (Ea / V ). Nws muaj peev xwm yuav xaus lus tias nyob rau hauv 10 / 350 ms impulse tam sim no, tus V230 yuav muaj ntau dua impulses dua li cov V460 yam MOVs. Qhov no txhais tau hais tias cov MOV nrog qhov tsis tshua muaj qhov tsis txaus siab muaj peev xwm muaj peev xwm muaj peev xwm ua tau raws li 10 / 350 ms tam sim no, uas tawm tsam qhov xaus hauv 8 / 20 ms impulse tam sim no.

4.2 Cov ntsiab lus hauv 10 / 350 ms impulse nrog lub ncov ntawm Iimp

Thaum lub amplitude ntawm 10 / 350 ms tam sim no yog nce mus rau Iimp, tag nrho cov kev ntsuam xyuas MOV yuav tsis dhau kaum tsib impulses. Cov ntsiab lus hauv 10 / 350 ms impulse currents nrog amplitude ntawm Iimp yog muaj nyob rau hauv lub rooj V, qhov twg "Withstand impulse naj npawb" txhais tau hais tias lub impulse tus nqi uas MOV yuav tiv thaiv ua ntej keej.

Nws tuaj yeem raug cai ntawm TABLE V tias V230 nrog Ea / V ntawm 122.09 J / cm3 yuav tiv tau yim 10 / 350 ms impulses thaum V460with Ea / V ntawm 161.09 J / cm3 yuav tsuas dhau peb lub impulses, tab sis lub sijhawm tam sim no tau txais V230 (6500 A) yog siab tshaj qhov ntawd rau V460 (6000 A). Qhov kev lees paub qhov tseeb tias cov MOV uas muaj kev txwv tsis pub muaj hluav taws xob yooj yim dua hauv 10 / 350 ms tam sim no. Qhov tshwm sim no tuaj yeem piav qhia raws li: qhov loj zog uas nqa los ntawm 10 / 350 ms tam sim no yuav muab ntxig rau hauv MOVs. Rau MOVs uas muaj kev txwv siab tshaj nyob rau hauv 10 / 350 ms tam sim no, ntau zog yuav tsum tau nyob hauv chav dej ntim ntawm MOV tshaj li uas nyob hauv MOV nrog qhov tsis tshua muaj qhov tsis txaus siab, thiab lub zog ntau dhau yuav ua rau MOV tsis ua. Txawm li cas los xij, txoj kev tsis ua hauj lwm hauv 8 / 20 ms tam sim no xav tau kev tshawb nrhiav ntau dua.

Kev soj ntsuam kev pom tau pom tias tib txoj kev puas tsuaj yog raug pom ntawm peb hom MOV hauv 10 / 350 ms tam sim no. Ib sab ntawm cov yas MAP yas thaiv thiab daim ntawv pov thawj electrode tev tawm. Ablation ntawm ZnO khoom tshwm nyob ze ntawm daim ntawv electrode, uas yog tshwm sim los ntawm flashover ntawm MOV electrode thiab ZnO nto. Daim duab ntawm kev puas tsuaj V230 yog muaj nyob hauv daim duab 6.

5. xaus

SPDs raug tseev kom muaj kev ntsuam xyuas hauv impulse tawm tsiv tsuam nrog cov qauv ntawm 8 / 20 ms thiab 10 / 350 ms. Txhawm rau soj ntsuam thiab sib piv nrog lub peev xwm ntawm SPDs nyob rau hauv 8 / 20 ms thiab 10 / 350 ms impulse currents, muaj ntau yam kev sim yog siv tawm nrog ntau tshaj tawm tam sim no rau 8 / 20 ms (Imax) thiab 10 / 350 ms (Iimp) waveform , as Well as amplitudes ntawm 0.75Imax thiab 0.75Iimp. Peb hom mob MOV siv rau cov chav kawm I SPDs tau txais los rau kev ntsuam xyuas. Qee cov lus xaus yuav raug twv tau.

(1) Cov MOV nrog qhov yooj yim dua qhov muaj peev xwm muaj peev xwm muaj peev xwm ua tau raws li 8 / 20ms impulse tam sim no. Lub V230 thiab V275 hom MOVs tsis tuaj yeem ua tau kaum tsib 8 / 20ms impulses nrog ncov ntawm Imax, thaum VOVNUMX hom MOV yuav kis tau nees nkaum impulses.

(2) Cov MOV nrog qhov txo qhov muaj qhov tsis txaus siab muaj peev xwm muaj peev xwm ua tau zoo raws li 10 / 350 ms tam sim no. Cov hom V230 MOV yuav tiv tau yim 10 / 350 ms impulses nrog ncov ntawm Iimp, thaum V460 yuav tsuas dhau peb lub impulses.

(3) Xav txog lub tsev ntim ntawm MOV nyob rau hauv 10 / 350 ms tam sim no, lub zog nqus hauv ib qho kev sib tw yuav muaj feem rau MOV txoj kev ua haujlwm, tsis yog lub ntsiab lus ntawm absorbed zog nyob rau hauv tag nrho cov ntawv thov impulses.

(4) Qhov kev puas tsuaj yog pom ntawm peb hom MOV nyob rau hauv 10 / 350 ms currents. Ib sab ntawm cov yas MAP yas thaiv thiab daim ntawv pov thawj electrode tev tawm. Ablation ntawm ZnO khoom, tshwm sim los ntawm flashover ntawm daim ntawv ntawm electrode thiab ZnO nto, tshwm nyob ze ntawm MOV electrode.