Kasuwanci Kofin Hausa na Turbin Doka

Yana da kyau cewa, tushen farko ko kungiyar tsakiyar stator ta alternator yana haɗa kan ground suka ƙunshi impedance don hanyar ƙareta tasirin current na ground fault. Tasirin current na ground fault mai yawa yana ba da dacewa masu stator core da winding a lokacin ground ko earth fault. Idan zaka zaune impedance na ground ya yi ƙarin, za mu iya ci current na ground fault da ke gama da current na ra'ayi na generator. Idan haka shi ne, ƙwarewa masu phase relays yana ƙara, musamman suna iya saukin trip a lokacin fault. Misali, current da ke gama da current na ra'ayi yana ba da abin da ba suke iya amfani da differential relays don ground fault.
A halin haka, ana amfani da relay mai kyau na ground/earth fault a matsayin babban differential protection of alternator. Wata irin relay arrangement wanda za a yi a stator earth fault protection of alternator yana nufin da ita ce suka samu saboda hanyoyin stator neutral earthing. A halin resistance neutral earthing, tushen neutral ta tsakiyar stator yana haɗa kan ground suka ƙunshi resistor.

A nan, ana haɗa kan current transformer wata suka ƙunshi neutral da earth connection ta alternator. Daga nan, ana haɗa kan protective relay wata suka ƙunshi secondary ta current transformer. Ana iya sanya alternator don power system biyu, ya kamata ake haɗa kan bus bar na substation ko ake haɗa kan substation suka ƙunshi star delta transformer. Idan generator an haɗa kan bus bars na substation, relay ta haɗa kan CT secondary, za ce inverse time relay saboda haka, ana bukatar relay coordination da wasu fault relays na system. Amma idan stator ta alternator an haɗa kan primary ta star Delta transformer, fault yana ƙara a bayan stator winding da transformer primary winding, saboda haka ba bukatar coordination ko discrimination da wasu earth fault relays na system.

Saboda haka, a nan instant armature attracted type relay yana da kyau a haɗa kan CT secondary.

Yana da kyau cewa, 100% na tsakiyar stator ba a iya inganta a resistance neutral earthing system.

Yadda mafi yawan tsakiyar stator zai inganta a cikin earth fault, yana nufin da ita ce saboda ƙari na earthing resistance da setting ta relay. resistance grounding ta tsakiyar stator zai iya a yi tare da amfani da distribution transformer saboda haɗa kan resistor zuwa neutral path ta winding. A nan, primary ta distribution transformer yana haɗa kan earth da tushen neutral ta tsakiyar stator.
Secondary ta transformer yana da load ta suitable resistor, kuma over voltage relay wata ta haɗa kan secondary ta transformer. Mafi yawan current na allowable earth fault yana nuna da tashin transformer da ƙari na loading register R.

Wannan resistance ta haɗa kan secondary, yana nuna a primary ta transformer tare da square ta turns ratio, saboda haka yana ƙunshi resistance zuwa neutral to ground path ta tsakiyar stator.

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