Igridi iyinethiwekhi exhumanisa izimboni zokuphehla amandla kagesi nezintambo zikagesi eziphezulu ezithwala ugesi ebangeni elithile ukuya eziteshini ezincane - “ukudlulisa”.Uma indawo okuyiwa kuyo ifinyelelwa, iziteshi ezincane zehlisa i-voltage "yokusabalalisa" emigqeni yamandla kagesi aphakathi nendawo bese iqhubekela kwemigqa yamandla kagesi aphansi.Ekugcineni, i-transformer esigxotsheni socingo iyayehlisa ibe amandla kagesi asendlini angama-120 volts.Bheka umdwebo ongezansi.

Igridi iyonke ingacatshangwa njengeyakhiwe izigaba ezintathu ezinkulu: ukukhiqiza (izitshalo kanye nama-transformer akhuphukayo), ukudluliselwa (olayini nama-transformer asebenza ngaphezu kuka-100,000 volts - 100kv) nokusabalalisa (olayini nama-transformer angaphansi kuka-100kv).Izintambo zokudlulisa zisebenza ngama-voltage aphezulu kakhulu angu-138,000 volts (138kv) kuya ku-765,000 volts (765kv).Izintambo zokudlulisela zingaba zinde kakhulu - emigqeni yombuso ngisho nelayini yezwe.

Olayini abade, kusetshenziswa ama-voltage aphezulu asebenza kahle kakhulu.Isibonelo, uma i-voltage iphindwe kabili, yamanje inqunywa phakathi kwenani elifanayo lamandla adluliswayo.Ukulahlekelwa kokudluliswa kwelayini ngokulingana nesikwele samanje, ngakho-ke umugqa omude "ukulahlekelwa" kunqunywa ngesici sezine uma i-voltage iphindwe kabili.Imigqa "yokusabalalisa" yenziwa indawo kuwo wonke amadolobha nezindawo ezizungezile futhi iphephezelisa ngendlela efana nesihlahla.Lesi sakhiwo esifana nesihlahla sikhulela ngaphandle sisuka esiteshini esincane, kodwa ngokwezinjongo zokuthembeka, ngokuvamile siqukethe okungenani uxhumo oluyisipele olungasetshenzisiwe esiteshini esiseduze.Lokhu kuxhumeka kunganikwa amandla ngokushesha esimweni esiphuthumayo ukuze indawo yesiteshi esincane inikelwe esinye isiteshi esincane.