Zaɓin Rotor Earth Fault
Rotor Earth Fault Protection in Generators
Jinkiri na rotor na generator yana ciki da wani karamin jirgin ruwa, ya'ni yana ciki da hankali mai girma daga tsakiyar. Saboda haka, wani karamin kusa da inganci ba za su iya jan hanyar ruwan kasa mai girma a gaba. A baya, wani karamin kusa ne ba zai iya taimakawa wata matsalolin da ya faru a cikin jinkiri. Amma idan an yi nasara, zai iya kadan kan cin kasa na jinkiri, zai iya haifar da matsaloli masu lalacewa da kudin bayyana. Saboda haka, musamman a jinkirin kudin, yana bukatar tsari na jinkiri na rotor earth fault protection don in taimaka cin kasa.
Idan yana faru wani karamin kusa a cikin rotor, ba zai bukata a gaba don in tabbatar da duk system. Ba tare da halin, relay na inganci ke nuna cewa akwai karamin kusa, wanda ke taimaka masu amfani da shi zuwa rike jinkiri don in yi inganci da kudin bayyana. Akwai hanyoyi da aka amfani da su don jinkiri na rotor earth fault protection, kuma wani na muhimmanci suna nufin a nan.
Rotor Earth Fault Protection Using High Resistance
A wannan hanyoyi, ana sanya wani abu na resistance mai girma a cikin cin kasa na rotor. Tushen wannan resistor ke sauri da relay mai inganci. Idan yana faru karamin kusa a cikin circuit na rotor, relay ke nuna farkon inganci. Idan an samu karamin kusa, relay ke fitaccen bayyana a breaker, tare da ya faru prosesi na kudin abin da ya faru.
Amma, wannan system yana da matsalolinsu. Yana iya nuna karamin kusa a duk fadin cin kasa na rotor, amma ba zai iya nuna karamin kusa a tushen rotor. Don in taimaka wannan matsala, ana iya kawo tap na resistor daga tushen zuwa wurin da ke kusa. Tabbacin haka, sensibility na system ke canzawa, tare da ya iya nuna karamin kusa kamar tushen rotor, wanda ke taimaka masu amfani da shi zuwa karfin system na protection.
AC and DC Injection Methods for Rotor Earth Fault Protection
AC Injection Method
Hanyoyi na AC injection don jinkiri na rotor earth fault protection yana nufin sanya alternating current a cikin circuit na cin kasa da ground. Wannan setup yana da relay mai inganci da capacitor mai cikin bayyana. Idan yana faru wani karamin kusa a cikin rotor, yana faru circuit mai biyu wanda ke da alternating current source, relay mai inganci, da karamin kusa. Saboda haka, relay ke nuna cewa akwai karamin kusa ta nuna farkon inganci a cikin circuit.
Amma, wannan hanyoyi yana da matsalolinsu. Wani matsala mai yawa shine leakage current wanda ke tafi daga capacitor. Wannan leakage current ke haifar da balansu na magnetic field, wanda ke taimaka stress masu bearing na magnetic. Kuma alternating current yana ba da matsala muka: relay ba zai iya jawabi ruwan normal wanda ke tafi daga capacitance zuwa ground. Saboda haka, zai bukatar inganci masu ma'ana don in kudin resonance wanda ke faru a cikin capacitance da inductance na relay. Resonance zai iya haifar da hanyoyi mai ban sha'awa, zai iya haifar da false-positives ko false-negatives a cikin nuna karamin kusa, kuma zai iya haifar da relay ko abubuwa da ke cikin system na protection.
DC Injection Method: A Solution to AC Injection System Challenges
Matsalolin da ke cikin hanyoyi na AC injection don jinkiri na rotor earth fault protection zai iya taimaka ta hanyoyi na DC injection. Wannan hanyoyi na yanayi yana nufin simplicity da kuma karkashin leakage current, wadannan shine matsalolin da ke cikin hanyoyi na AC.
A hanyoyi na DC injection, configuration na circuit yana da wayar. Turancin relay mai inganci ke sanya a exciter, saboda hakan turancin ke sanya a terminal negative na DC power source. Terminal positive na DC source ke sauri. Wannan setup yana faru path mai bayyana. Idan yana faru karamin kusa a cikin rotor, yana faru circuit, tare da fault current ke tafi. Relay mai inganci, wanda ke cikin circuit, ke nuna cewa akwai fault current, tare da ya fitaccen bayyana ko protective action. Tabbacin haka, hanyoyi na DC injection yana ba da solution mai karfi da karkashin leakage currents da resonance concerns wadannan shine matsalolin da ke cikin hanyoyi na AC injection.
