Maimaitar Daular da Karamin Iwaki na DC
Karamin Maimaita na Tashar Karamin DC Da Turanci: Fungamanta, Abubuwan Dangantaka, da Bincike
Karamin maimaita na tashar karamin DC (High - Voltage Direct Current) shine kayan aiki mai mahimmanci wanda ake yin don koyar hanyar zama na karamin DC a cikin tashar karamin kasa. Idan yadda gajimta ya faru a cikin sassan, yanayin kayan aiki na karamin maimaita sun zama, wanda ya kafa masu zama a cikin tashar. Amma, koyar zama a cikin sassan karamin DC shi ne abu mai zurfi daga ma'aikata da ke nuna a cikin sassan karamin AC (Alternating Current). Wannan ya faru saboda hanyar karamin DC ya yi a matsayin yaduwa kawai, ba tare da kyau a bari har zuwa balon hanyar karamin zero, wanda suka fi yawa a cikin karamin maimaita na karamin AC.
Fungamantar daidai na karamin maimaita na tashar karamin DC shine koyar hanyar zama na tashar karamin DC a cikin tashar kasa. Amma, karamin maimaita na karamin AC suka iya koyar hanyar zama a lokacin da hanyar karamin ya koma zuwa balon hanyar karamin zero a cikin tsarin karamin AC. A wannan lokacin da hanyar karamin ya koma zuwa balon, hanyar karamin da ya danganta da koyar zama ya koma zuwa zero, wanda ya ba yanayin kayan aiki na karamin maimaita lafiya ga yin koyar zama da ya danganta da hanyar karamin natural recovery voltage.
A cikin karamin maimaita na tashar karamin DC, abin da ke faru su ne mai zurfi. Saboda hanyar karamin DC ba ta da balon hanyar karamin zero, koyar hanyar zama bayan samun amfani a kan jikinsu zai iya haɗa da haɗuwar hanyar karamin transient recovery voltage mai yawa. Ba tare da koyar hanyar zama da ba da amfani, akwai sakamako cewa za a yi restrikes, wanda zai iya haifar da yanayin kayan aiki na karamin maimaita. Idan ake yi karamin maimaita na tashar karamin DC, inginiyoyin suka da shawarar kogin uku:
Samun Balon Hanyar Karamin Zero Mai Tsabta: Wannan ita ce muhimmiyar don koyar hanyar zama saboda hali na biyu da ke faru a cikin hanyar karamin DC ya ba su da balon hanyar karamin zero.
Rufin Restrikes: Idan an koyar hanyar zama, an buƙatar takalma a kan rufin ci gaba, wanda zai iya haifar da kayan aiki na karamin maimaita da kuma koyar zama a cikin sassan.
Koyar Enerji da aka Samun a Cikin Kayan Aikinsu: Enerjin da aka samun a cikin kayan aikinsu ya danganta da koyar zama a cikin hanyar karamin DC don hana haɗuwar hukumomi.
Don hana hali na biyu da ke faru a cikin hanyar karamin DC, karamin maimaita na tashar karamin DC suka amfani da siffar samun balon hanyar karamin zero mai tsabta don koyar hanyar zama. Wata hali na amfani shine amfani da L - C (inductor - capacitor) circuit na biyu. Idan an yi amfani a kan wannan circuit, zai haɗa da hanyar karamin arc na ci gaba. Waɗannan ci gaban su ne mai yawa, wanda zai haɗa da balon hanyar karamin zero mai tsabta. An koyar hanyar zama na karamin maimaita a kan waɗannan balon hanyar karamin zero mai tsabta. Don hakan da ya fi yawa, hanyar karamin crest na ci gaban ya danganta da hanyar karamin DC da ya danganta da koyar zama.
Wata babban amfani na amfani shine amfani da series resonant circuit wanda ya samu inductor (L) da capacitor (C) a kan yanayin kayan aiki na karamin maimaita na karamin DC na biyu a kan auxiliary contact (S1). Kuma resistor (R) an samu a kan contact (S2). A lokacin da ake yi aiki a cikin sassan, yanayin kayan aiki na biyu (M) da contact (S2) suna da damma. Capacitor (C) an samu a kan line voltage through high - resistance (R). Amma, contact (S1) na da damma, da line voltage across it. Wannan setup ya ba asisin da za su iya koyar hanyar zama na tashar karamin DC a lokacin da gajimta ya faru, tare da samun balon hanyar karamin zero mai tsabta da kuma ginin hanyar karamin associated electrical processes.
Idan ake koyar hanyar zama na main circuit current Id, mekanismen ya faru sequence of actions. Kafin ake yi, ya koyar contact S2 kuma ya koyar contact S1. Wannan configuration ya haɗa da discharge of capacitor C through inductance L, main contact M, and auxiliary contact S1. Wannan ya haɗa da oscillatory current, wanda ake nuna a figure below. Waɗannan oscillatory current sun haɗa da balon hanyar karamin zero mai tsabta, wanda su ne muhimmiyar don koyar zama na karamin maimaita. Yanayin kayan aiki na biyu (M) na karamin maimaita an koyar precise at one of these artificial current zero points. Idan an koyar hanyar zama na main contact M, contact S1 an koyar, kuma contact S2 an koyar, resetting the system for potential future operations and ensuring the integrity of the HVDC circuit - breaking process.
Alternative Method for Interrupting Main Direct Current
Wata hali na amfani don koyar hanyar zama na main direct current a cikin tashar karamin DC (High - Voltage Direct Current) shine amfani da capacitor, wanda ya haɗa da hanyar karamin da karamin maimaita su da shawarar koyar zama. Wannan hali an nuna a figure below, and it starts with a capacitor C that is initially in an uncharged state.
Idan main contact M na karamin maimaita ya faru zuwa opening, event crucial ya faru: main circuit current, wanda ya faru a cikin main contact M, ya faru zuwa flow into the capacitor C. Wannan redirection ya haɗa da hanyar karamin load da main contacts M su da shawarar koyar zama during the interruption process. Wannan reduction in current magnitude eases the burden on the circuit breaker, making the interruption process more manageable and less likely to cause damage or failure.
In addition to the capacitor's role in diverting the current, a nonlinear resistor R is also an essential component of this system. The nonlinear resistor R plays a vital part in absorbing the energy associated with the current flow without causing a substantial increase in the voltage across the main contact M. By efficiently dissipating the energy, the nonlinear resistor helps to maintain the integrity of the circuit breaker and the overall electrical system, ensuring that the voltage levels remain within acceptable limits during the current interruption process. This coordinated operation of the capacitor C and the nonlinear resistor R provides an effective and reliable method for interrupting the main direct current in an HVDC system.
The rate of rising of the recovery voltage across M is expressed as
In DC circuit breakers that rely on oscillating currents to interrupt the flow, the challenge of preventing restrikes is particularly formidable. This is due to the extremely short duration in which the current is interrupted or "chopped." When the current is rapidly interrupted in such a short time frame, it generates a steep and sudden surge in the restriking voltage across the breaker terminals. This high - magnitude, rapidly rising voltage poses a significant threat to the circuit breaker's integrity. To ensure reliable operation, the circuit breaker must be engineered with sufficient dielectric strength and voltage - withstanding capabilities to endure this intense restriking voltage without succumbing to restrikes, which could lead to damage, electrical arcing, and system failures.
