分散式電源微電網特性分析.docxVIP

發電機風場併入市電系統的穩定度分析Stability Analysis For Wind Generator Farm Connected to the Utility System 摘要本文討論一個由6MW的風場以及一2MVA的同步發電機組成的分散式電源所形成之微電網，且將該電網併入市電。其中風場分為感應發電機、感應發電機加上STATCOM補償器以及雙饋式感應機三種不同形式，本論文針對三種形式分析，討論三種形式併入電網時之優劣點。本論文在風場中加入風速變化，以及一個三相短路故障，觀察系統之電壓變動情形。本研究使用Mathwork公司所出版的科學運算軟體Matlab/Simulink內的SimPowerSystem模組來實現系統建構與模擬分析的功能。研究結果顯示雙饋式感應機在電壓穩定度以及受擾動後回復正常穩定度的速度，皆優於其他兩者，值得進一步發展並深入探討評估。關鍵字: 風力發電系統、市電併聯、分散式電源ABSTRACTThis article discusses the formation of micro power grid consisting of a 6MW wind farm and a 2MVA distributed synchronous generators, and the connection of power grid and utility. The wind farm is divided into three different forms: induction generator, induction generator with STATCOM compensator and the double-fed induction generator. This paper analyzes the advantages and disadvantages of three forms connected in the grid. The wind speed change and a three-phase short-circuit fault were also added to the wind farm to observe changes in system voltage conditions. In this study, the SimPowerSystem system module of scientific computing software Matlab / Simulink which is published by Mathwork was used to achieve the function of system construction and simulation capabilities. Research results showed that the double-fed induction machine is better than the other two in the voltage stability and response disturbed by the speed back into stability, and is worth further development and assessment. Keywords: Wind power system, Electricity in parallel, Distributed power一、前 言近二、三十年來，世界上風力發電發展的速度相當迅速，對於電力需求的短缺，提供了一個有效的解決方法，但由於風速都隨著氣候或季節的改變而變化，由渦輪機所擷取的能量經由發電機轉換為電能亦隨風速而變動，造成電力瞬間的改變，也對電網電力品質造成衝擊。在不同運轉模式下，風速的變動對於電力的品質也會造成不同的影響。早期風力發電機是使用同步機、永磁機及感應機做為發電機組，由於永磁發電機機隨著轉速的變化，所產生之電壓及頻率亦隨之不同，必須藉由整流-換流(AC-DC-AC)元件將電壓及頻率轉換至與市電一致，如此便可將風場電力併入電網，而整流-換流設備就必須與發電機有相同的容量，如此將增加發電成本；因感應發電機本身所產生之虛功率較其它機組為大，若直接與市電併聯後，當風速瞬間變化過大時，將使併聯之電壓也造成瞬間的變化，而傳統鼠籠式轉子感應發電機運轉時需藉由電容組或靜態虛功補償器(Static VAR Compensator, SVC)以達到有效的控制虛功率，提升電網電力品質。由於近年來電力電子設備發展有重大的突破，例如：靜態同步補償器(static synchronous compensator, STA