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1、單相接地故障論文：基于FFT的配電網(wǎng)單相接地故障定位研究與實現(xiàn)【中文摘要】我國配電網(wǎng)大多采用的是中性點非有效接地方式,即小電流接地系統(tǒng)。配電網(wǎng)結(jié)構(gòu)復(fù)雜,發(fā)生的故障大多數(shù)都是單相接地故障。因此,配電網(wǎng)單相接地故障能否快速準(zhǔn)確定位,對保障電力線路正常輸配電,保證整個電力系統(tǒng)安全、穩(wěn)定、經(jīng)濟(jì)運行有著十分深遠(yuǎn)的意義。近年來,低頻交流信號注入法在配電網(wǎng)單相接地故障定位中得到了有效而且較廣泛的應(yīng)用。由于導(dǎo)線分布電容的影響,低頻交流信號注入法采用60Hz注入信號代替“S”信號注入法的220Hz注入信號。低頻交流信號法采用二分法沿線路查找故障,探測器顯示當(dāng)前位置的實時電流波形
2、,由于戶外環(huán)境等因素,實時波形有時候難以判斷當(dāng)前位置的電流是分布電容電流還是故障電流。本文對探測器進(jìn)行系統(tǒng)設(shè)計,硬件部分包括濾波放大電路,控制部分和顯示部分,用Protel繪制電路板,主要芯片選擇8051f310和UAF42來完成;軟件部分設(shè)計包括單片機(jī)模數(shù)轉(zhuǎn)換部分,定時計數(shù)部分,中斷及頻譜分析部分,用KeilC來完成程序的編譯工作。本文用FFT算法對探測到的電流信號進(jìn)行頻譜分析,比對工頻信號和注入信號含量,通過顯示兩信號的能量分布來判斷當(dāng)前位置是否是故障點?！居⑽恼縏hedistributionnetworksmostlyadoptneuterpoint
3、not-validgroundinginChina,whichiscalledthesmallcurrentgroundingsystem.Thefaultindistributionnetworksmostlyissingle-phasegroundingfaultbecauseofitscomplexstructure.Thefastandaccuratelocationthatthesinglegroundingfault,notonlytotherepairwireandpromisedependablepowersupply,andcirculate
4、tothesafestabilityandeconomythatpromisesthewholeelectricpowersystemtoallhaveaveryimportantfunction.ThelowfrequencyACsignalinjectionmethodapplieseffectivelyandwidespreadindistributionnetworksinglephase-to-groundingfaultlocation.Traditional“S”injectionmethodwith220Hzinjectedfrequencyi
5、saffectedbythewiresdistributedcapacitance,solowfrequencymethodadopts60Hzinsteadof220Hz.Thelowfrequencymethodusesdichotomyalongtheroutetodetectthefault,anditsdetectordisplaysthereal-timecurrentwaveformofthecurrentposition.Duetotheoutdoorenvironmentfactors,it’sdifficulttojudgetheprese
6、ntcurrentdistributedcapacitancecurrentorthefaultcurrentthroughthereal-timewaveform.Thesignaldetectorisdesignedsystematicallyinthepaper.Thehardwarepartincludesfilterandamplificationcircuit,controlsectionanddisplaysection,usingProteltodrawboardswithsinglechip8051f310andthefilterUAF42.
7、ThesoftwarepartincludesthedesignofmicrocontrollerA/Dpart,timingcounterpart,disruptionsandspectrumanalysis,withKeilCtocompletepartprogramcompileswork.AFFTalgorithmisusedtoanalyzethedetectedcurrentsignal’sspectruminthepaper.Aftercomparedtheenergycontentwiththepowersignalandtheinjected
8、signal,thefaultpoin
