Nyob rau hauv ib qho tseem ceeb nruab nrab voltage cables, txhuas hlau armor yog siv kom tsis txhob eddy tam sim no losses thiab xyuas kom meej tias cov cable yuav tiv taus ib tug tej yam kev nro. Vim hais tias nyob rau hauv qhov tseeb ua hauj lwm ntawm cable installation, ob leeg armor thiab shielding yuav tsum tau grounded. Feem ntau cov tshuab hluav taws xob txawv teb chaws suav nrog Class A systems, qhov chaw nruab nrab ntawm qhov ncaj qha hauv av. Nyob rau hauv xws li systems, ib tug loj grounding short-circuit tam sim no yuav tsum tau. Ntawd yog, nyob rau hauv cov kev tshwm sim ntawm ib tug luv luv Circuit Court nyob rau hauv lub cable, lub shielding thiab armor yuav ua tau tam sim no mus rau hauv av los ntawm ib tug kuj loj luv luv Circuit Court tam sim no, yog li tiv thaiv lub cable los ntawm kev puas tsuaj. Yog li ntawd, kev suav ntawm luv luv tam sim no rau txhuas hlau armor yog ib qho tseem ceeb tshaj plaws kev txawj ntse rau engineering thiab technical cov neeg ua haujlwm. Nyob rau hauv tus qauv IEC, tsis muaj cov qauv rau kev xam qhov luv-circuit tam sim no ntawm txhuas hlau armor, tsuas yog tooj liab daim kab xev shielding thiab tooj liab hlau shielding muaj. Txawm li cas los xij, nws tseem tuaj yeem suav thiab muab tau qhov luv luv tam sim no ntawm txhuas hlau armor raws li IEC cov qauv thiab lwm yam khoom siv hauv tsev thiab txawv teb chaws, thiab tau txais cov ntaub ntawv luv luv tam sim no uas tuaj yeem tiv taus kev sim, yog li ua lub luag haujlwm tseem ceeb hauv kev tshawb fawb, tsim, thiab tsim cov txheej txheem ntawm cables.
Txoj kev suav rau qhov ntsuas luv luv tam sim no ntawm txhua qhov tam sim no nqa hauv ib lub cable feem ntau xav tias cov cua sov tau khaws cia hauv cov kua dej hauv lub sijhawm luv luv (xws li adiabatic cua sov). Qhov tseeb, thaum lub caij luv luv, qee qhov cua sov yuav raug xa mus rau cov ntaub ntawv uas nyob ib sab, uas txhais tau hais tias qhov luv-circuit tam sim no tuaj yeem loj dua, uas yog, xav txog qhov tsis muaj adiabatic nyhuv. Txoj kev uas tsis yog adiabatic yog siv tau thoob plaws hauv tag nrho cov txheej txheem ntawm luv luv Circuit Court.
Piv nrog rau txoj kev adiabatic, siv txoj kev uas tsis yog adiabatic rau kev xam tso cai rau ib tug tseem ceeb nce nyob rau hauv luv luv Circuit Court tam sim no rau shielding txheej, tiv thaiv txheej, thiab conductors me dua 10mm2 (tshwj xeeb tshaj yog siv raws li shielding xov hlau).
Kev suav ntawm tsis yog adiabatic luv-circuit tam sim no rau txhuas hlau armor yog raws li nram no:
1, Kev suav ntawm kev kho qhov tseem ceeb xav txog qhov tsis muaj kev cuam tshuam adiabatic
Vim lub fact tias lub sab hauv ntawm lub txhuas hlau armor yog ib tug PVC tiv thaiv txheej, thaum lub sab nrauv yuav tsum tau khi nrog non-woven npuag ua ntej lub PVC txheej sheath yuav extruded, ib ncig ntawm cov xov xwm tsis tsuas yog xav txog cov PVC tiv thaiv. txheej thiab non-woven ntaub. Hauv cov mis, σ 2, σ 3-- cov cua sov tshwj xeeb ntawm qhov nruab nrab nyob ib puag ncig cov txheej txheem txhuas hlau armor (J / Kom3)
Kuj: PVC tiv thaiv txheej nrog σ 2=1.7 × 106J/Kom3
Tsis-woven npuag fiber σ {{0}}.0 × 106J/Kom3
Tsis tas li ntawd: Thermal resistance ntawm ib puag ncig nruab nrab ntawm txhuas hlau armor txheej nrog ρ 2 thiab ρ 3 (Kom / W)
PVC tiv thaiv txheej ρ {{0}}.0Kom/W
Tsis-woven npuag fiber ntau ρ {{0}}.0Kom/W
F - Kev sib cuag tsis tiav yog xav txog kev tiv thaiv thermal imperfect ntawm txhuas hlau armor thiab ib puag ncig cov ntaub ntawv uas tsis yog xim hlau, F=0.5
σ 1- Tshwj xeeb kub ntawm shielding txheej, tiv thaiv txheej los yog armor txheej, J/Kom3 Aluminium hlau σ 1=2.5 × 106J/Kom3
Los ntawm kev hloov tag nrho cov parameter rau hauv kev suav:
ε=1.158 Tsis yog adiabatic coefficient.
2, Kev suav cov mis rau luv-circuit tam sim no hauv cov txheej txheem adiabatic:
Ntawm lawv, qhov chaw tiv thaiv kev hla ntawm S - cable, noj YJV7212/20kV1 × 500 ua piv txwv, S=60 * 2.5 ^ 2 * 0.7854=295mm2
IAD aluminium hlau armor shields luv-circuit tam sim no
Qhov sib txawv ntawm qhov kub thiab txias coefficient, 228
Qhov kawg luv luv-circuit kub ntawm θ f yog 250 degree
Pib luv luv-circuit kub ntawm θ i, θ i =90 degree
Qhov tshwj xeeb kub muaj peev xwm ntawm tus neeg xyuas pib ntawm σ c 20 degree, 2.5 × 106J / Kom3
Lub resistivity ntawm tus neeg xyuas pib ntawm ρ 2020 degree yog 2.8264x10-8 Ω. m. T yog lub sij hawm luv luv (S) coj li 1 thib ob.
Tom qab ntawd, cov txheej txheem adiabatic tso cai rau qhov luv luv tam sim no (1 thib ob) ntawm 28.87kA
3, xam cov luv luv Circuit Court tam sim no rau Non adiabatic nyhuv
Raws li cov txheej txheem suav saum toj no,
Qhov tso cai luv luv tam sim no (1 thib ob) rau cov txheej txheem uas tsis yog adiabatic yog: =1.158 * 28.87=33.43kA
Los ntawm cov kev suav sau saum toj no, nws tuaj yeem pom tau tias qhov tsis yog adiabatic luv-circuit tam sim no ntawm txhuas hlau armor tau nce ntau dua piv rau adiabatic luv-circuit tam sim no. Tus qauv IEC949 (1988) twb tau xav tias qhov kev suav phem tshaj plaws, uas txhais tau hais tias cov npoo tau raug txiav txim siab hauv kev suav. Tau kawg, cov txiaj ntsig ntawm kev suav ntawm qhov ntsuas luv luv tam sim no yog kev sib tw rau kev nyab xeeb. Cov kev suav sau saum toj no yog qhov tseem ceeb raws li kev suav cov qauv rau kev tiv thaiv tooj liab hlau thaiv hauv IEC949 (1988) tus qauv, tshwj tsis yog tias qhov nruab nrab ntawm ib puag ncig ntawm aluminium hlau armor txawv ntawm cov tooj liab hlau thaiv, thiab cov tsis sib xws ntawm tooj liab hlau nyob hauv thawj cov qauv tau raug hloov nrog cov khoom ntawm txhuas hlau.
Tsis tas li ntawd, raws li kev paub txawv teb chaws, qhov kawg luv luv-circuit kub ntawm cov hlau thaiv txheej tuaj yeem ncav cuag 350 degree. Rau kev nyab xeeb vim li cas, tseem muaj kev xaiv kom ncav cuag 300 degree. Txhawm rau txhim kho qib kev nyab xeeb ntawm Tuam Tshoj txoj kab hluav taws xob, qhov tseeb suav yog raws li 300 degree. Thiab cov hlau thaiv saum toj no yog tag nrho rau tooj liab strips lossis tooj liab xov hlau. Aluminium hlau armor yuav tsum sib txawv los ntawm tooj liab thaiv vim hais tias txhuas muaj zog tiv taus kub siab tshaj tooj liab. Peb xa mus rau qhov kawg luv luv-circuit kub ntawm aluminium conductor nyob rau hauv qhov tseeb xam, xam ntawm 250 degree. Qhov ntsuas luv luv-circuit tam sim no ua kom ntseeg tau tias cov hlau hlau armored yuav tsis muaj teeb meem kev nyab xeeb vim overload thaum lub sij hawm luv luv.
