本文選題：Powerformer　切入點(diǎn)：定子單相接地保護(hù)　出處：《長沙理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：Powerformer是ABB公司研制的一種新型同步發(fā)電機(jī),理論機(jī)端輸出電壓高達(dá)400kV,可省去升壓變壓器直接與電網(wǎng)并聯(lián),具有運(yùn)行效率高、運(yùn)行壽命長、環(huán)境效益好等優(yōu)點(diǎn),應(yīng)用前景廣闊。定子繞組單相接地故障是發(fā)生概率最高的發(fā)電機(jī)內(nèi)部故障之一,是匝間故障及更嚴(yán)重的內(nèi)部故障的先兆,加之Powerformer機(jī)組的運(yùn)行特點(diǎn),定子繞組單相接地故障及故障Powerformer的準(zhǔn)確檢測關(guān)乎Powerformer機(jī)組及電網(wǎng)的安全穩(wěn)定運(yùn)行。然而,現(xiàn)階段國內(nèi)外對選擇性Powerformer定子單相接地保護(hù)研究相對較少,且現(xiàn)有保護(hù)方案存在靈敏性不高與可靠性不強(qiáng)等不足。因此,本文對選擇性Powerformer定子單相接地保護(hù)展開了研究。本文主要包括五部分內(nèi)容。第一部分首先概述了Powerformer的發(fā)展歷程并對發(fā)電機(jī)中性點(diǎn)接地方式進(jìn)行了探討；隨后概述了傳統(tǒng)發(fā)電機(jī)定子單相接地保護(hù)的國內(nèi)外研究現(xiàn)狀,并指出了現(xiàn)有保護(hù)方案的不足；最后概述了選擇性Powerformer定子單相接地保護(hù)的國內(nèi)外研究現(xiàn)狀。第二部分首先介紹了Powerformer的設(shè)計(jì)特點(diǎn)與運(yùn)行特點(diǎn)；隨后詳細(xì)介紹了Powerformer的內(nèi)部故障模型。第三部分首先分析了并列運(yùn)行Powerformer機(jī)組內(nèi)部發(fā)生定子單相接地故障或外部系統(tǒng)發(fā)生單相接地故障時(shí)Powerformer機(jī)組的零序電流等效網(wǎng)絡(luò),提出了Powerformer機(jī)端零序電流與泄漏電流的提取方案；隨后,根據(jù)Powerformer內(nèi)部故障仿真模型對機(jī)端零序電流與泄漏電流提取方案進(jìn)行了仿真驗(yàn)證,仿真結(jié)果體現(xiàn)了理論分析的正確性與提取方案的有效性。第四部分基于信息融合思想提出了基于系統(tǒng)聚類的選擇性Powerformer定子單相接地保護(hù)方案,該保護(hù)方案融合了四種故障信息,首先將訓(xùn)練樣本投射到四維空間,在四維空間中應(yīng)用系統(tǒng)聚類方法將訓(xùn)練樣本分為故障類與非故障類,并求出故障聚類中心與非故障聚類中心；隨后,通過比較待測樣本在多維空間中到兩個(gè)聚類中心的距離判別待測樣本的類別,進(jìn)而判別Powerformer的運(yùn)行狀態(tài)；最后,仿真驗(yàn)證了保護(hù)方案的有效性。第五部分提出了基于判別分析的選擇性Powerforme r定子單相接地保護(hù)方案,保護(hù)方案首先提取四種判別因子,對訓(xùn)練樣本進(jìn)行學(xué)習(xí),構(gòu)造判別模型；隨后,將待測樣本代入判別模型,根據(jù)判別準(zhǔn)則判定待測樣本的類別,判定Powerformer的運(yùn)行狀態(tài)；最后,仿真驗(yàn)證了保護(hù)方案的有效性,并通過與其余保護(hù)方案的對比體現(xiàn)了該保護(hù)方案的優(yōu)越性。仿真結(jié)果表明,論文提出的基于系統(tǒng)聚類與基于判別分析的保護(hù)方案均能有效完成選擇性Powerformer定子單相接地保護(hù),并且不受系統(tǒng)運(yùn)行方式的影響,體現(xiàn)了本文所提出的保護(hù)方案的有效性；不同保護(hù)方案保護(hù)性能的對比體現(xiàn)了本文提出的保護(hù)方案具有更高的可靠性與靈敏性。
[Abstract]:Powerformer is a new type of synchronous generator developed by ABB Company. The output voltage of the theoretical machine is up to 400kV, which can save the direct parallel connection between the booster transformer and the power network. It has the advantages of high operation efficiency, long service life and good environmental benefit. The single-phase grounding fault of stator winding is one of the most probable internal faults of generator, which is the precursor of inter-turn fault and more serious internal fault, as well as the operation characteristics of Powerformer unit. The accurate detection of stator winding single-phase grounding fault and fault Powerformer is related to the safe and stable operation of Powerformer unit and power grid. However, at present, there is relatively little research on selective Powerformer stator single-phase grounding protection at home and abroad. And the existing protection schemes have some shortcomings, such as low sensitivity and low reliability. In this paper, the selective Powerformer stator single-phase grounding protection is studied. This paper mainly includes five parts. In the first part, the development of Powerformer is summarized and the neutral grounding mode of generator is discussed. Secondly, the research status of single-phase earthing protection of generator stator is summarized, and the deficiency of the existing protection scheme is pointed out. At last, the research status of selective Powerformer stator single-phase earthing protection is summarized. The second part introduces the design and operation characteristics of Powerformer. Then the internal fault model of Powerformer is introduced in detail. In the third part, the zero-sequence current equivalent network of Powerformer unit is analyzed when the stator single-phase grounding fault occurs in parallel operation Powerformer unit or the single-phase grounding fault occurs in external system. A scheme for extracting zero sequence current and leakage current at the end of Powerformer is proposed, and the scheme of extracting zero sequence current and leakage current at the end of Powerformer is simulated according to the Powerformer internal fault simulation model. The simulation results show the correctness of the theoretical analysis and the validity of the extraction scheme. 4th, based on the idea of information fusion, a selective Powerformer stator single-phase grounding protection scheme based on system clustering is proposed, which integrates four kinds of fault information. Firstly, the training samples are projected into four dimensional space, and the training samples are divided into fault and non-fault classes by using the system clustering method in the four-dimensional space, and the fault clustering centers and non-fault clustering centers are obtained. By comparing the distance between the tested samples and the two clustering centers in multidimensional space, the categories of the samples to be tested are determined, and the running state of the Powerformer is judged. The simulation results show the effectiveness of the protection scheme. In part 5th, a selective Powerforme r stator single-phase grounding protection scheme based on discriminant analysis is proposed. Firstly, four discriminant factors are extracted from the protection scheme, and the training samples are studied and a discriminant model is constructed. Then, the test samples are substituted into the discriminant model, and the classification of the samples to be tested is determined according to the discriminant criterion. Finally, the validity of the protection scheme is verified by simulation. The simulation results show that the proposed protection scheme based on system clustering and discriminant analysis can effectively accomplish the selective Powerformer stator single-phase grounding protection. And it is not affected by the operation mode of the system, which reflects the effectiveness of the protection scheme proposed in this paper, and the comparison of the protection performance of different protection schemes shows that the protection scheme proposed in this paper has higher reliability and sensitivity.
【學(xué)位授予單位】：長沙理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM31

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 邰能靈,侯志儉,尹項(xiàng)根,陳德樹;新型發(fā)電機(jī)100%定子單相接地保護(hù)方案[J];電力系統(tǒng)自動(dòng)化;2002年03期

2 張琦雪;席康慶;陳佳勝;王翔;沈全榮;;大型發(fā)電機(jī)注入式定子接地保護(hù)的現(xiàn)場應(yīng)用及分析[J];電力系統(tǒng)自動(dòng)化;2007年11期

相關(guān)碩士學(xué)位論文 前1條

1 熊婷婷;基于故障信息聚類的配電網(wǎng)接地保護(hù)方法[D];長沙理工大學(xué);2013年

，

本文編號：1642246