Kev Ntsuas Tsawg Heev (VLF) yog ib qho kev ntsuas -raws li kev ntsuas kev ncaj ncees ntawm nruab nrab- thiab siab -voltage (MV/HV) fais fab cable rwb thaiv tsev. Nws siv tsawg- zaus AC voltage- feem ntau yog 0.1 Hz- mus rau ib de-energized cable rau lub sij hawm uas tau teev tseg, ces ntsuam xyuas seb lub rwb thaiv tsev tiv thaiv qhov kev ntxhov siab los yog ua tsis tau raws li kev tswj xyuas.
Lub hom phiaj tsis yog tsuas yog "siv high voltage." Nws yog txhawm rau txheeb xyuas qhov kev npaj ua haujlwm, nthuav tawm qhov tsis zoo zais zais ua ntej lawv ua tsis tiav hauv kev pabcuam, thiab ua li ntawd nrog cov khoom siv nqa tau yooj yim uas tus qauv 50/60 Hz AC qhov chaw tsis tuaj yeem ua rau xa mus rau ntev cable.
Lub hom phiaj tseem ceeb: txheeb xyuas cov kab hluav taws xob thaiv kev ncaj ncees
VLF tiv thaiv kev ntsuas ntsuas lub cable saum toj ib txwm ua haujlwm voltage rau lub sijhawm teem-feem ntau 30 lossis 60 feeb ib IEEE 400.2, nyob ntawm chav kawm voltage thiab waveform.
Yog hais tias lub cable tuav → tus neeg teb xov tooj tau txais kev ntseeg siab, lub kaw lus yuav tsum tsis txhob poob rau hauv kev pabcuam
Yog tias muaj teeb meem loj tshwm sim → nws tawg thaum lub sij hawm teem tseg, cia kev kho lossis hloov ua ntej qhov tsis tau npaj tseg
Qhov no tsom iav Hoobkas commissioning logic: xyuas cov khoom puas ua ntej lub zog, tsis yog tom qab tus neeg siv khoom tawm.
Vim li cas VLF tshwm sim: peb qhov teeb meem nrog cov txheej txheem qub
Teeb meem 1: 50 / 60 Hz AC tiv thaiv kev sim yog qhov ua tsis tau zoo hauv thaj chaw
Fais fab cables yog heev capacitive. Them ntev MV cable ntawm kab zaus yuav tsum muaj lub zog reactive loj heev - cov khoom kuaj ua loj, hnyav, thiab kim. VLF ntawm 0.01-0.1 Hz ua rau txo qis kev xav tau ntawm lub zog, ua qhov kev sim ua haujlwm tau yooj yim thiab siv tau yam tsis muaj kev cuam tshuam AC cov yam ntxwv kev ntxhov siab.
Teeb meem 2: DC hipot tsis haum rau niaj hnub polymer cables
Keeb kwm, DC siab -kev sim (hipot) tau tshwm sim hauv thaj teb. Kev tshawb fawb thiab kev ua haujlwm hauv cheeb tsam qhia txog kev txwv rau XLPE, EPR, thiab lwm yam rwb thaiv tsev polymer:
DC tsim qhov sib txawv hluav taws xob sib txawv dua li AC ua haujlwm
Kev kuaj DC tej zaum yuav tsis muaj txiaj ntsig rau kev kuaj xyuas qee yam tsis xws luag hauv cov kab hluav taws xob niaj hnub
DC kev ntxhov siab ntawm cov laus polymer rwb thaiv tsev tuaj yeem ua kom txo qis kev pab cuam lub neej
VLF khaws cov cim AC voltage, tsim cov kev faib tawm los ze zog rau kev ua haujlwm ntawm cable ib txwm-vim li cas IEEE thiab kev siv hluav taws xob xyaum nyiam VLF tshaj DC rau XLPE / EPR systems.
Teeb meem 3: zais qhov tsis xws luag yuav tsum ua tsis tiav ntawm koj lub sijhawm, tsis yog daim phiaj
Lub hom phiaj tseem ceeb tshaj plaws ntawm kev xeem VLF yog qhov tsis xws luag -tsim tsis ua hauj lwm thaum kuaj es tsis yog hauv kev pabcuam. Kev puas tsuaj loj ntawm cov rwb thaiv tsev tsis muaj zog- kev teeb tsa yuam kev ntawm cov pob qij txha, kev sib kis, kev tsim dej, tsim cov ntoo hluav taws xob- tuaj yeem dhau qhov kev tshuaj xyuas qhov muag tseem ua tsis tau raws li qhov siab ntawm AC.
Ntawm IEEE 400.2 xeem qib:
Kev rwb thaiv tsev zoo tsis raug puas los ntawm kev sim
Cov teeb meem loj uas twb muaj lawm raug tsav mus rau hauv ib feem ntawm kev tso tawm, kev loj hlob ntawm tsob ntoo, thiab kev tawg thaum kawg hauv qhov ntsuas qhov rais
Tsawg-lub zog tsis ua haujlwm thaum kuaj feem ntau ua rau muaj kev puas tsuaj tsawg dua li tag nrho hauv - kev pabcuam txhaum cai ntawm lub network thauj khoom
Qhov kev xav no tau tshwm sim nyob rau hauv thaum ntxov 1990s raws li XLPE cable tsis ua hauj lwm txuas mus rau dej-ntoo tshwm sim nce- thiab rhiab heev ntawm - qhov chaw kuaj mob tseem tsis tau muaj dav dav.
Dab tsi ua rau VLF kuaj lub hom phiaj?
| Hom tsis raug | Vim li cas thiaj tseem ceeb |
|---|---|
|
Dej tsob ntoo |
Cov dej noo nyob hauv XLPE rwb thaiv tsev-keeb kwm yog qhov loj MV cable tsis ua haujlwm |
|
Hluav taws xob ntoo |
Ib nrab tso tawm channel loj hlob los ntawm dielectric |
|
Joint/termination defects |
Kev ua haujlwm tsis zoo, voids, noo noo ingress ntawm accessories |
|
Kev puas tsuaj |
Sheath nicks, khoov kev nyuaj siab, txawv teb chaws paug |
|
Muaj hnub nyoog rwb thaiv tsev |
Ntev - kev pab cuam degradation mus txog qhov kawg ntawm lub neej |
VLF tiv thaiv kev ntsuas tsis ntsuas txhua qhov ua ntej- qhov taw qhia kev laus- uas yog lub luag haujlwm ntawm kev kuaj mob xws li tan delta thiab ib nrab tso tawm (PD) ntsuas, feem ntau ua nrog tib qhov VLF.
Tej kev siv
| Daim ntawv thov | Lub hom phiaj ntawm kev xeem VLF |
|---|---|
|
Kev ua haujlwm cable tshiab |
Paub meej tias installation zoo ua ntej energization |
|
Kev tu ncua sij hawm |
Tshawb xyuas kev ruaj ntseg ntawm rwb thaiv tsev ntawm cov khoom muaj hnub nyoog |
|
Tshaj tawm - kho qhov tseeb |
validate splice, sib koom, los yog seem hloov |
|
Kev ntsuam xyuas |
Ua ke VLF + tan delta / PD rau kev kwv yees txij nkawm |
Yuav ua li cas qhov kev xeem VLF ua tiav (cov ntsiab lus)
De- zog thiab cais cov kab hluav taws xob nyob rau hauv kev sim
Disconnect thiab ruaj ntseg hauv av nyob ib puag ncig cov cuab yeej
Txuas lub VLF xeem teeb rau cable conductor thiab sheath / av
Siv VLF AC voltage ntawm theem teev los ntawm tus qauv siv tau
Tuav voltage rau lub sijhawm xav tau (piv txwv li, 30 lossis 60 min)
Saib xyuas kev puas tsuaj, qhov txawv txav tam sim no, lossis kuaj pom (yog tias PD / tan delta enabled)
Cov ntaub ntawv pov thawj rau kev ua raws cai thiab cov ntaub ntawv pov thawj
Cov qauv tseem ceeb
| Txuj | Scope |
|---|---|
|
IEEE 400.2 |
VLF tiv taus qhov ntsuas qhov ntsuas hluav taws xob thiab lub sijhawm ntev |
|
IEC 60060-3 |
VLF xeem txoj kev thiab cov khoom yuav tsum tau muaj |
|
TIAB SA 400 |
Cov lus qhia dav dav rau kev sim teb ntawm cov kab hluav taws xob tiv thaiv hluav taws xob |
|
IEC 60502: Ua |
MV cable manufacturing thiab xeem yuav tsum tau |
Yam tsis muaj (vim los ntawm chav kawm voltage):
Zaus: 0.1 Hz (feem ntau)
Test voltage: feem ntau ~ 2–3 × U₀ (piv txwv li, 22 kV VLF ntawm 15 kV chav kawm cable nrog U₀=8.7 kV)
Duration: 30 min lossis 60 min rau IEEE 400.2
Ib txwm ua raws li tus qauv thiab cov chaw tsim khoom cov ntaub ntawv rau cov chav kawm tshwj xeeb cable- qib xeem thiab lub sijhawm tsis hloov pauv ntawm qhov ntsuas hluav taws xob.