【摘要】：隨著智能電網(wǎng)技術(shù)的不斷完善,智能變電站的應用也將越來越廣泛,它解決了傳統(tǒng)階梯式后備保護很多問題,比如整定困難,延時長等。在對智能變電站構(gòu)建方案以及相應保護算法的研究上,國內(nèi)學者主要針對集中式保護結(jié)構(gòu)進行了大量的探索,利用智能變電站能夠?qū)崿F(xiàn)全站各種信息共享的優(yōu)勢來對變電站站域式保護進行優(yōu)化。傳統(tǒng)電流相差高頻保護憑借能抵御系統(tǒng)振蕩、在系統(tǒng)非全相運行狀態(tài)下也能正常工作、構(gòu)造精簡、不需要采集電壓等方面的優(yōu)勢,一直作為超高壓輸電線路的主保護。因此,將電流相位比較原理應用于變電站站域保護當中,利用相差保護的優(yōu)勢來進一步提高站域保護的“四性”是有理論和現(xiàn)實意義的。基于這些原因,本文利用分相電流突變量相位和序電流相位比較原理,對站域保護的實現(xiàn)方案進行深入研究。文章首先簡述了智能電網(wǎng)、智能變電站的歷史以及發(fā)展狀況,并對比了各國的進展,發(fā)現(xiàn)各國雖然對智能電網(wǎng)研究的側(cè)重不同,但是對于電網(wǎng)性能的描述以及對其追求目標是相同的,即建設安全、環(huán)保、高效、經(jīng)濟的新型電網(wǎng)。本文介紹了國內(nèi)外學者對站域保護的研究現(xiàn)狀,包括集中式保護、分布式保護以及站域保護算法;總結(jié)了近年來國內(nèi)對變電站智能化技術(shù)的工程應用現(xiàn)狀:對于220kV等級以上變電站,不對其進行過程層改造,而對間隔層以上應用IEC61850標準模式;對于低于220kV電壓等級的情況,則將IEC61850標準模式應用到過程層及以上。其次,本文在分析傳統(tǒng)后備保護的缺陷;介紹現(xiàn)有數(shù)字化變電站的結(jié)構(gòu)特點;研究適用于變電站系統(tǒng)的網(wǎng)絡結(jié)構(gòu)的基礎(chǔ)上,提出了分電壓等級獨立配置保護的變電站站域保護構(gòu)建方案,即保留一套傳統(tǒng)主保護,配置兩套站域主后備保護。同時,采用雙星型網(wǎng)絡設計了針對不同電壓等級的站域保護系統(tǒng)過程層組網(wǎng)方案。本文簡述了傳統(tǒng)相差高頻原理并分析其優(yōu)缺點,具體研究了應用分相DI、序電流相位比較原理在變電站中線路、母線、變壓器的方案和可行性,從而提出了利用電流相位比較原理的站域保護方案。研究了一種新的原理實現(xiàn)方式,即利用捕捉正弦波起始點從而確定斷路器采集到的電流相位關(guān)系的方法來計算相應電流的相位差。提出了站域保護的跳閘策略并針對變電站特殊問題,如拓撲識別、TA飽和、變壓器勵磁涌流、斷路器失靈,提出了此原理的解決方案。最后,文章利用PSCAD/EMTDC建立變電站拓撲結(jié)構(gòu)并對設計方案進行仿真研究,以Visual Studio為程序開發(fā)平臺,編寫C++和Fortran代碼,嵌入PSCAD/EMTDC仿真平臺,與構(gòu)建的電力系統(tǒng)模型一起,構(gòu)成與實際保護運行特性一致的仿真平臺。通過仿真單點故障、斷路器失靈、通訊失靈等狀況來證明此方案的優(yōu)勢。
[Abstract]:With the continuous improvement of smart grid technology, the application of smart substation will be more and more extensive. It solves many problems of traditional step backup protection, such as difficult setting, long delay and so on. In the research of intelligent substation construction scheme and corresponding protection algorithm, domestic scholars mainly focus on the centralized protection structure for a large number of exploration, Intelligent substation can realize the advantages of all kinds of information sharing to optimize substation protection. The traditional current phase difference high frequency protection is the main protection of EHV transmission line because it can resist the system oscillation, work normally under the condition of the non-phase operation, simplify the structure and do not need the acquisition voltage, etc. Therefore, it is of theoretical and practical significance to apply the principle of current phase comparison to substation field protection, and to further improve the "four properties" of station domain protection by using the advantage of phase difference protection. Based on these reasons, this paper makes a deep research on the realization scheme of the station domain protection by using the principle of phase comparison between the phase of phase current abrupt change and the phase of sequence current. This paper first introduces the history and development of smart grid, smart substation, and compares the progress of other countries. However, the description of power grid performance and the pursuit of its goal are the same, that is, to build a new type of power grid with safety, environmental protection, efficiency and economy. This paper introduces the research status of station domain protection, including centralized protection, distributed protection and station domain protection algorithm. This paper summarizes the engineering application status of intelligent substation technology in China in recent years: for substations above 220kV level, the process layer is not modified, but the standard mode of IEC61850 is applied to the substation above the interval layer, and the voltage level is lower than the 220kV voltage level. Then the IEC61850 standard pattern is applied to the process layer and above. Secondly, on the basis of analyzing the defects of the traditional backup protection, introducing the structural characteristics of the existing digital substation, and studying the network structure suitable for the substation system, In this paper, a scheme of substation station protection is proposed, which consists of one set of traditional main protection and two sets of main backup protection. At the same time, a two-star network is used to design a process layer networking scheme for different voltage levels of the station area protection system. This paper briefly introduces the principle of high frequency phase difference and analyzes its merits and demerits. The scheme and feasibility of applying the principle of phase separation DI, sequence current phase comparison in substation lines, busbars and transformers are studied in detail. Thus, a protection scheme based on the principle of current phase comparison is proposed. In this paper, a new realization method is studied, that is, the phase difference of the corresponding current is calculated by using the method of capturing the starting point of sine wave and determining the phase relation of the current collected by the circuit breaker. The trip strategy of substation protection is put forward and the solution of this principle is put forward aiming at the special problems of substation, such as topology identification of TA saturation, transformer excitation inrush current and circuit breaker failure. Finally, the topology structure of substation is established by PSCAD/EMTDC and the design scheme is simulated. The C and Fortran codes are written on the platform of Visual Studio, and the PSCAD/EMTDC simulation platform is embedded into the simulation platform, which is combined with the power system model. The simulation platform which is consistent with the operation characteristics of the actual protection is constructed. The advantages of this scheme are proved by simulation of single point fault, circuit breaker failure, communication failure and so on.
【學位授予單位】：華中科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM63;TM77

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