Pehea e koho ai i ka ʻāpana cross-sectional?

I ka hoʻolālā uila a me ka hoʻololi ʻenehana, ʻaʻole ʻike pinepine nā limahana uila i ke koho ʻepekema i ka ʻāpana cross-sectional o nā kaula.E helu ʻia nā mea uila ʻike i ke au e pili ana i ka ukana uila a koho maʻalahi i ka ʻāpana cross-sectional o ke kaula;Koho ka uniona i ka pauku uwea ma muli o ke kumu o ka mea uila;E ʻōlelo wau he kūpono kā lākou ʻike akā ʻaʻole ʻepekema.Nui nā pou ma ka Pūnaewele, akā ʻaʻole lawa ka paʻakikī a paʻakikī ke hoʻomaopopo.I kēia lā, e haʻi aku wau iā ʻoe i kahi ala ʻepekema a maʻalahi no ke koho ʻana i kahi ʻāpana cross-sectional.ʻEhā mau ala no nā manawa like ʻole.

uwea mana

E koho e like me ka hiki ke lawe i ka wā lōʻihi:

I mea e hōʻoiaʻiʻo ai i ka palekana a me ke ola lawelawe o ke kaula, ʻaʻole pono ka mahana o ke kaula ma hope o ka mana-on ma mua o ka mahana hana i ʻae ʻia no ka wā lōʻihi, ʻo ia ka 70 degere no nā kaula PVC insulated a me 90 degere no ka polyethylene cross-linked. uwea insulated.Wahi a kēia loina, maʻalahi loa ke koho ʻana i ke kaula ma ka nānā ʻana i ka papaʻaina.

Hāʻawi i nā laʻana:

ʻO ka mana transformer o kahi hale hana he 2500KVa a ʻo ka lako mana he 10KV.Inā hoʻohana ʻia nā kaula i hoʻopaʻa ʻia i ka polyethylene i hoʻopaʻa ʻia e hoʻomoe iā lākou i loko o ke alahaka, he aha ka ʻāpana keʻa o nā kaula?

KaʻAnuʻu Hana 1: E helu i ka helu o kēia manawa 2500/10.5/1.732=137A

KaʻAnuʻu Hana 2: E nānā i ka manual koho kelepona e ʻike ai,

ʻO YJV-8.7/10KV-3X25 hiki ke lawe ʻia he 120A

ʻO YJV-8.7/10KV-3X35 hiki ke lawe ʻia he 140A

KaʻAnuʻu Hana 3: E koho YJV-8.7/10KV-3X35 uwea me ka hiki ke lawe nui ma mua o 137A, hiki theoretically hoʻokō i nā koi.'Ōlelo Aʻo: ʻAʻole noʻonoʻo kēia ʻano i nā koi no ke kūpaʻa dynamic a me ke kūpaʻa wela.

 

E koho e like me ka nui o kēia manawa:

No ka hoʻomaopopo wale ʻana i ka nui o ka hoʻokele waiwai o kēia manawa, pili ka ʻāpana cross-sectional o ke kaula i ka hoʻopukapuka laina a me ka nalowale o ka ikehu uila.I mea e mālama ai i ka hoʻopukapuka kālā, ua manaʻo ʻia e ʻoi aku ka liʻiliʻi o ka ʻāpana cross-sectional cable;i mea e hōʻemi ai i ka nalowale o ka ikehu uila, ua manaʻo ʻia e ʻoi aku ka nui o ka ʻāpana cross-sectional.Ma muli o nā manaʻo ma luna aʻe, e hoʻoholo i kahi kūpono Ua kapa ʻia ka ʻāpana cross-sectional o ke kaula ka ʻāpana cross-sectional hoʻokele waiwai, a ua kapa ʻia ka nui o kēia manawa ʻo ka ʻāpana o kēia manawa.

Ke Kaʻina Hana: E like me nā hola hana makahiki o nā mea hana, e nānā i ka papaʻaina no ka loaʻa ʻana o ka nui o kēia manawa.Huina: A/mm2

No ka laʻana: ʻO 150A ka helu o kēia manawa o nā mea hana, a ʻo ka manawa hana makahiki he 8,000 mau hola.He aha ka ʻāpana keʻa o ke kaula keleawe kumu?

Wahi a ka papa ma luna o C-1, hiki ke ʻike ʻia no nā hola 8000, ʻo 1.75A/mm2 ka nui o ka hoʻokele waiwai.

S=150/1.75=85.7A

Ka hopena: ʻO ka ʻāpana cross-sectional cable hiki iā mākou ke koho e like me nā kikoʻī kelepona ʻo 95mm2

 

E koho e like me ke koena kūpaʻa wela:

Ke hoʻohana mākou i nā ala mua a me ka lua e koho i ka ʻāpana cross-sectional cable, inā lōʻihi loa ke kaula, e loaʻa kahi hāʻule uila i ka wā o ka hana a me ka hoʻomaka.ʻOi aku ka haʻahaʻa o ka volta ma ka ʻaoʻao o ka mea hana ma mua o kahi ākea, kahi e wela ai ka mea hana.E like me nā koi o ka "Electrician's Manual", ʻaʻole hiki ke emi mai ka kulu uila o kahi laina 400V ma lalo o 7%, ʻo ia hoʻi, 380VX7%=26.6V.ʻO ke ʻano helu helu hāʻule ʻana o ka volta (ʻo nā hāʻule kūʻē kūʻē wale nō e noʻonoʻo ʻia ma aneʻi):

U=I×ρ×L/SS=I×ρ×L/U

ʻO ka hāʻule ʻana o ka volta U ʻo I ka manawa i helu ʻia o nā mea hana ρ conductor resistivity S ʻo ia ka ʻāpana cross-sectional uwea L ʻo ka lōʻihi o ke kaula.

Ka Laʻana: ʻO ka helu o kēia manawa o nā mea hana 380V he 150A, me ka hoʻohana ʻana i ke kaula keleawe kumu (ρ o ke keleawe = 0.0175Ω.mm2/m), pono ka hāʻule ʻana o ka volta ma lalo o 7% (U=26.6V), ʻo ka lōʻihi o ke kaula. 600 mika, he aha ka ʻāpana kea S??

E like me ke kumu S=I×ρ×L/U=150×0.0175×600/26.6=59.2mm2

Ka hopena: Ua koho ʻia ka ʻāpana cross-sectional e like me 70mm2.

 

E koho e like me ke koena kūpaʻa wela:

1. Ke pale ʻia nā kaula 0.4KV e nā hoʻololi ea, hiki i nā kaula maʻamau ke hoʻokō i nā koi kūpaʻa wela a ʻaʻohe pono e nānā e like me kēia ʻano.

2. No nā kaula ma luna o 6KV, ma hope o ke koho ʻana i ka ʻāpana cross-sectional uea me ka hoʻohana ʻana i ke ʻano o luna, pono ʻoe e nānā inā hoʻokō ia i nā koi kūpaʻa wela e like me ke ʻano ma lalo.Inā ʻaʻole, pono ʻoe e koho i kahi ʻāpana cross-section nui.

Kumu: Smin=Id×√Ti/C

Ma waena o lākou, ʻo Ti ka manawa haʻihaʻi o ka mea hoʻokele kaapuni, i lawe ʻia e like me 0.25S, ʻo C ka coefficient thermal stability cable, i lawe ʻia e like me 80, a ʻo Id ka waiwai o kēia manawa pōkole pōkole ʻekolu o ka ʻōnaehana.

Laʻana: Pehea e koho ai i ka ʻāpana cross-sectional uwea inā ʻo 18KA ka ʻōnaehana pōkole pōkole.

Smin=18000×√0.25/80=112.5mm2

Ka hopena: Inā hiki i ka 18KA ka ʻōnaehana pōkole o kēia manawa, ʻoiai inā he liʻiliʻi ka helu o kēia manawa o nā mea hana, ʻaʻole pono ka liʻiliʻi o ka ʻāpana cross-sectional ma mua o 120mm2.

 

 

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Ka manawa hoʻouna: Sep-13-2023