本文選題：電壓暫降　切入點：改進MRA法　出處：《山東大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著現(xiàn)代電網(wǎng)中敏感負荷所占的比重不斷增大,電能質(zhì)量問題越來越受到人們的關(guān)注。在所有電能質(zhì)量問題的投訴中,電壓暫降所占的比重最大。系統(tǒng)中短路故障的不可預(yù)知性造成了電壓暫降的隨機性,進而對系統(tǒng)中敏感設(shè)備的正常工作狀態(tài)產(chǎn)生影響,造成電力用戶的經(jīng)濟損失。因此針對含有多個電壓等級的實際配電網(wǎng)做到電壓暫降的全面可觀測對于減小電力用戶的經(jīng)濟損失、提升供電質(zhì)量具有重要的現(xiàn)實意義�？紤]到電能質(zhì)量監(jiān)測設(shè)備的成本投入,在保證電壓暫降可觀測的前提下,力求選取的監(jiān)測點最少。在確定電壓暫降監(jiān)測點優(yōu)化配置方案以后,如何有效解決監(jiān)測點電壓暫降檢測數(shù)據(jù)量龐大,難于存儲和傳輸?shù)膯栴},是一個極具應(yīng)用價值的研究方向。本文主要針對以上兩個問題,對電壓暫降監(jiān)測點優(yōu)化配置及暫降數(shù)據(jù)壓縮方法做出了研究。提出基于改進MRA法的電壓暫降監(jiān)測點優(yōu)化配置方法。將系統(tǒng)中的母線按照電壓等級進行分類,根據(jù)監(jiān)測母線與被監(jiān)測線路相對位置關(guān)系確定零序阻抗矩陣,克服了傳統(tǒng)方法構(gòu)建單一零序阻抗矩陣的缺點。根據(jù)變壓器的接線方式以及系統(tǒng)是否有效接地對電壓暫降幅值進行修正。針對已有MRA法采用的仿真算例主要為標(biāo)準(zhǔn)節(jié)點測試系統(tǒng)的問題,本文采用含有4個電壓等級的實際配電網(wǎng)進行仿真分析。通過將本文所提方法與已有MRA法所得結(jié)果進行對比表明,本文所提的方法能夠解決已有MRA法對實際配電網(wǎng)進行優(yōu)化配置時存在監(jiān)測盲區(qū)的問題,有效對含有多個電壓等級的實際配電網(wǎng)進行電壓暫降監(jiān)測點優(yōu)化配置。在優(yōu)化配置的基礎(chǔ)上,相較于傳統(tǒng)凹陷域以敏感負荷為中心,本文采用以故障點為中心的同心松弛凹陷域計算方法計算凹陷域。同心松弛凹陷域計算方法能夠有效地減少供電部門凹陷域計算的工作量,為電壓暫降產(chǎn)生的責(zé)任劃分問題提供解決依據(jù)。針對現(xiàn)階段電壓暫降檢測數(shù)據(jù)量龐大,難于存儲與傳輸?shù)膯栴},本文將壓縮感知理論應(yīng)用于電壓暫降信號的采集與傳輸中。電壓暫降信號的重構(gòu)算法采用正交匹配追蹤算法,通過對不同壓縮采樣比情況下電壓暫降信號恢復(fù)效果進行對比,得出采樣點數(shù)越高,重構(gòu)效果越好的結(jié)論。在以FFT作為稀疏基的條件下,通過選取不同的測量矩陣來對電壓暫降信號進行重構(gòu),經(jīng)過仿真試驗發(fā)現(xiàn),部分哈達瑪矩陣的重構(gòu)效果最好。為進一步探究信號的稀疏度K對電壓暫降信號的重構(gòu)效果的影響,本文通過在正交匹配追蹤算法中設(shè)置不同的稀疏度K,將得到的算法重構(gòu)效果進行對比,得出信號的稀疏度K的選取對重構(gòu)的效果有很大影響的結(jié)論。通過仿真分析,證明了本文所提的基于壓縮感知理論的電壓暫降數(shù)據(jù)壓縮方法的有效性。
[Abstract]:With the increasing proportion of sensitive load in modern power grid, people pay more and more attention to the problem of power quality. The unpredictability of the short-circuit fault in the system causes the randomness of the voltage sag, which in turn affects the normal working state of the sensitive equipment in the system. Therefore, for the actual distribution network with multiple voltage levels, the overall observable voltage sag can reduce the economic loss of the power users. It is of great practical significance to improve the quality of power supply. Considering the cost of power quality monitoring equipment, the voltage sag can be observed on the premise that the voltage sag can be observed. After determining the optimal configuration scheme of voltage sag monitoring point, how to effectively solve the problem of large amount of data of voltage sag detection at monitoring point, which is difficult to store and transmit, This paper focuses on the above two problems. The optimal configuration of voltage sag monitoring points and the method of data compression are studied. A method of optimal configuration of voltage sag monitoring points based on improved MRA method is proposed. The busbar in the system is classified according to the voltage grade. The zero-sequence impedance matrix is determined according to the relative position between the monitoring bus and the monitored line. It overcomes the shortcoming of the traditional method of constructing a single zero-sequence impedance matrix. According to the connection mode of the transformer and whether the system is effectively grounded, the voltage temporary drop value is corrected. The simulation example used in the existing MRA method is mainly used as the standard. The problem of quasi-node test system, In this paper, the actual distribution network with four voltage levels is used for simulation and analysis. By comparing the proposed method with the results obtained by the existing MRA method, it is shown that, The method proposed in this paper can solve the problem of monitoring blind area when MRA method is used to optimize the distribution network. The optimal configuration of voltage sag monitoring points for the actual distribution network with multiple voltage levels is effectively carried out. On the basis of the optimized configuration, the sensitive load is the center of the traditional sag region. In this paper, the calculation method of concentric relaxation sag region, which is centered on fault point, is used to calculate the sag region. The calculation method of concentric relaxation sag domain can effectively reduce the workload of calculation of the sag region in power supply department. In order to solve the problem of responsibility division caused by voltage sag, it is difficult to store and transmit the large amount of data in voltage sag detection at the present stage. In this paper, the theory of compression sensing is applied to the acquisition and transmission of voltage sag signal. The reconstruction algorithm of voltage sag signal adopts orthogonal matching tracing algorithm, and the effect of voltage sag signal recovery under different compression sampling ratio is compared. It is concluded that the higher the sampling number is, the better the reconstruction effect is. Under the condition that FFT is used as the sparse basis, different measurement matrices are selected to reconstruct the voltage sag signal, and the simulation results show that, In order to further investigate the effect of signal sparsity K on the reconstruction effect of voltage sag signal, part of Hadamard matrix is the best. In this paper, by setting different sparse degree K in orthogonal matching tracking algorithm, the reconstruction effect of the algorithm is compared, and it is concluded that the selection of signal sparsity K has great influence on the reconstruction effect. The validity of the voltage sag data compression method proposed in this paper based on compression sensing theory is proved.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM714.2

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