Ekwakheni ugesi kanye noguquko lobuchwepheshe, abasebenzi bakagesi ngokuvamile abazi ukuthi bangakhetha kanjani ngokwesayensi indawo enqamula izingxenye zezintambo.Ochwepheshe bezogesi abanolwazi bazobala okwamanje ngokusekelwe kumthwalo kagesi futhi bakhethe indawo enqamula ingxenye yekhebula kalula kakhulu;Inyunyana ikhetha i-cross-section yekhebula ngokusekelwe kufomula yabasebenza ngogesi;Ngingasho ukuthi okuhlangenwe nakho kwabo kuyasebenza kodwa hhayi ngokwesayensi.Kunokuthunyelwe okuningi ku-inthanethi, kodwa ngokuvamile akuphelele ngokwanele futhi kunzima ukukuqonda.Namuhla ngizokwabelana nawe ngendlela yesayensi nelula yokukhetha indawo enqamula ikhebula.Zine izindlela zezikhathi ezahlukene.
Khetha ngokuya ngomthamo ovunyelwe wokuphatha wesikhathi eside:
Ukuze kuqinisekiswe ukuphepha nempilo yesevisi yekhebula, izinga lokushisa lekhebula ngemva kokukhanyisa akumele lidlule izinga lokushisa elishiwo elivunyelwe lesikhathi eside elivunyelwe, elingu-70 degrees wezintambo ezigqunywe yi-PVC kanye nama-degree angu-90 e-polyethylene exhunywe ngokuphambana. izintambo ezifakwe ngci.Ngokwalesi simiso , kulula kakhulu ukukhetha ikhebula ngokubheka phezulu kwetafula.
Nikeza izibonelo:
Umthamo we-transformer wefekthri ngu-2500KVa kanti ugesi ungu-10KV.Uma izintambo ezifakwe i-polyethylene ezixhumene ngokuphambana zisetshenziselwa ukuzibeka ebhulohweni, kufanele ibe yini indawo ephambanayo yezintambo?
Isinyathelo 1: Bala inani lamanje elilinganiselwe 2500/10.5/1.732=137A
Isinyathelo sesi-2: Hlola imanuwali yokukhetha ikhebula ukuze uthole,
I-YJV-8.7/10KV-3X25 umthamo wokuthwala ungu-120A
I-YJV-8.7/10KV-3X35 umthamo wokuthwala ungu-140A
Isinyathelo sesi-3: Khetha ikhebula le-YJV-8.7/10KV-3X35 elinamandla okuthwala angaphezu kuka-137A, elingahlangabezana nezidingo ngokombono.Qaphela: Le ndlela ayicabangi izidingo zokuzinza okuguquguqukayo kanye nokuzinza kwe-thermal.
Khetha ngokuya ngokuminyana kwamanje kwezomnotho:
Ukuze uqonde kalula ukuminyana kwamanje kwezomnotho, indawo ephambanayo yekhebula ithinta ukutshalwa kwezimali kolayini nokulahlekelwa kwamandla kagesi.Ukuze ulondoloze utshalomali, kuthenjwa ukuthi indawo ephambana nekhebula incane;ukuze kuncishiswe ukulahleka kwamandla kagesi, kuthenjwa ukuthi indawo enqamula ikhebula inkulu.Ngokusekelwe kulokhu okucatshangelwayo okungenhla, thola okunengqondo Indawo enqamula izingxenye zekhebula ibizwa ngokuthi indawo ye-economic cross-sectional, futhi ukuminyana kwamanje okuhambisanayo kubizwa ngokuthi ukuminyana kwamanje kwezomnotho.
Indlela: Ngokwamahora okusebenza onyaka ezinto zokusebenza, bheka etafuleni ukuze uthole ukuminyana kwamanje kwezomnotho.Iyunithi: A/mm2
Isibonelo: Isilinganiso samanje sezinto zokusebenza ngu-150A, futhi isikhathi sokusebenza sonyaka amahora angu-8,000.Ithini indawo ephambanayo yekhebula eliwumgogodla wethusi?
Ngokusho kwethebula elingenhla C-1, kungabonakala ukuthi amahora angu-8000, ukuminyana komnotho ngu-1.75A/mm2
S=150/1.75=85.7A
Isiphetho: Indawo ephambanayo yekhebula esingayikhetha ngokuya ngemininingwane yekhebula ingu-95mm2
Khetha ngokuya nge-thermal stability coefficient:
Uma sisebenzisa izindlela zokuqala nezesibili ukukhetha indawo ye-cable cross-sectional, uma ikhebula lide kakhulu, kuyoba khona ukwehla kwe-voltage ethile ngesikhathi sokusebenza nokuqalisa.I-voltage ohlangothini lwemishini iphansi kunobubanzi obuthile, okuzokwenza ukuthi okokusebenza kushise.Ngokwezidingo ze-“Manuwali Kagesi”, ukwehla kwamandla kagesi kolayini ongu-400V angeke kube ngaphansi kuka-7%, okungukuthi, 380VX7%=26.6V.Ifomula yokubala ye-voltage drop (ukwehla kwamandla kagesi aphikisayo kuphela kucatshangelwa lapha):
U=I×ρ×L/SS=I×ρ×L/U
Ukwehla kwe-voltage engu-U ngingumthamo wamanje olinganiselwe wezinto zokusebenza ρ conductor resistivity S indawo enqamula izingxenye zekhebula L ubude bekhebula
Isibonelo: Isilinganiso samanje sezinto zokusebenza ezingu-380V ngu-150A, kusetshenziswa ikhebula eliwumgogodla wethusi (ρ of copper = 0.0175Ω.mm2/m), ukwehla kwamandla kagesi kuyadingeka ukuze kube ngaphansi kuka-7% (U=26.6V), ubude bekhebula Amamitha angu-600, ithini indawo yekhebula eliphambanayo S??
Ngokwefomula ethi S=I×ρ×L/U=150×0.0175×600/26.6=59.2mm2
Isiphetho: Indawo ephambanayo yekhebula ikhethwa njengo-70mm2.
Khetha ngokuya nge-thermal stability coefficient:
1. Uma izintambo ze-0.4KV zivikelwe ukushintshwa komoya, izintambo ezijwayelekile zingahlangabezana nezidingo zokuzinza okushisayo futhi asikho isidingo sokuhlola ngokwale ndlela.
2. Ngezintambo ezingaphezu kuka-6KV, ngemva kokukhetha indawo enqamula ikhebula usebenzisa le ndlela engenhla, kufanele uhlole ukuthi iyahlangabezana yini nezidingo zokuzinza kwe-thermal ngokuvumelana nefomula elandelayo.Uma kungenjalo, udinga ukukhetha indawo enkulu ephambanayo.
Ifomula: Smin=Id×√Ti/C
Phakathi kwazo, i-Ti yisikhathi sokuphuka se-circuit breaker, esithathwa njenge-0.25S, C i-cable thermal stability coefficient, ethathwa njenge-80, futhi i-Id iyinani lamanje lesigaba esifushane lesigaba sesithathu sohlelo.
Isibonelo: Indlela yokukhetha indawo ephambanayo yekhebula lapho i-short-circuit current ingu-18KA.
Smin=18000×√0.25/80=112.5mm2
Isiphetho: Uma isistimu ye-short-circuit current ifinyelela ku-18KA, noma ngabe i-current rated of the equipment incane, indawo yekhebula ephambanayo akufanele ibe ngaphansi kuka-120mm2.
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Isikhathi sokuthumela: Sep-13-2023
