澎湖獨立系統風力發電最大占比及系統穩定度分析

Transient Analysis of Penghu’s Power System with Increased Wind Power Penetration

吳滄堯(Tsang-Yao Wu)

指導教授 ： 陳昭榮

國立臺北科技大學/電資學院/電機工程系研究所/碩士(2010年)

摘要

近年來全球皆面臨能源價格上漲及氣候暖化兩大議題，在政府大力推行「節能減碳」政策下，積極發展再生能源，其中主要為開發風力發電。澎湖地區為台灣最適合發展風力發電的地方，惟澎湖為一獨立電力系統，風力發展需考量系統占比限制，另因柴油機組發電成本高，導致電力公司每年皆產生大幅虧損，且隨負載成長，虧損亦隨之擴大。因此，當增加風力發電量，相對可減少柴油機發電，以降低虧損；但相對風力發電占比太高時，將造成系統運轉不穩定。
本文利用PSS/E軟體為分析工具，以澎湖實際系統進行模擬，並考量尖山電廠柴油機組運轉限制條件、熱機備轉容量及系統低頻限制等，擬訂各年機組排程，論文首先檢討目前中屯風力發電對澎湖系統的衝擊，包括潮流、故障電流、暫態檢討及電壓頻率變動之分析，接續評估2011年湖西風場加入系統之影響。最後就台灣至澎湖海底電纜在2015年興建完成前，澎湖區仍維持一獨立系統，考量在不影響系統運轉安全與穩定下，評估澎湖風力最大占比，其對系統之影響及可能之改善方式。
經暫態模擬結果發現，當澎湖系統最大柴油機組或單一風場事故跳脫時，系統頻率及電壓的變動會與事故時失去多少電源有直接關係，但對系統之影響不大，而三相接地故障時，風場併接點之電壓值與故障點距離遠近相關，其中69kV系統發生故障較配電側故障更為嚴重，將造成併接點之電壓低於0.1 pu，使風機全數切離，導致系統頻率過低，配電饋線低頻卸載。最後本文提出建議澎湖各風場之風機皆需裝設零電壓持續運轉設備（ZVRT），改善暫態穩定度，可使澎湖風力發電占比達33.3%，發揮風力發電最大效益。

關鍵字

再生能源 ； 風力發電 ； 最大占比 ； 系統衝擊 ； 暫態穩定度 ； 零電壓持續運轉設備

並列摘要

In the face of the increasingly critical issues of hiking energy price and climate warming, governments around the globe have been working with great vitally to promote “energy saving and carbon reduction” measures and to develop renewable energies. Wind power, as a major source of renewable energy, has accordingly attracted escalating attention in recent years. In Taiwan, Penghu is considered as one of the most suitable places for the development of wind power. However, Penghu hosts a small-scale independent power system; wind power capacity is restricted by system penetration. Moreover, the cost of diesel power generation remains high in Penghu, causing Taipower to suffer substantial deficit every year. The financial loss keeps aggravating as the power load escalates. Increase in wind power capacity can be expected to reduce reliance on diesel power generation and curb the deficit. Increased penetration of wind power, however, may result unstable system operation.
In the thesis, the power system analysis software PSS/E is used to simulate the Penghu power system, taking into account of the operational constraints, spinning reserve capacity, and frequency restrictions of the diesel generators and performing scheduling simulation. The thesis studies the impacts of the Zhongtun and Huxi wind farms on the Penghu power system, analyzing powerflow, short-circuit current, and system transient stability. Installation of the submarine cables between Taiwan and Penghu is scheduled for completion before 2015 while the Penghu area will continue to rely on an independent power system. Based on the prerequisite of maintaining system safety and stability, the thesis proceeds to study the maximum wind power penetration for the Penghu system, examines its impacts on the system, and suggests potential improvement measures.
Results of transient simulation indicate that, when a diesel engine or a single wind farm experiences N-1 contingency, changes in system frequency and voltage have little effect on the system. When three-phase ground faults occur, the wind farm point of common couping (PCC) voltage value appears to be associated with the distance ot the point of failure. Furthermore, failures of the 69kV system emerge to be more serious than the faults on the distribution side and tend to reduce the PCC voltage to below 0.1 pu, cut off all wind farms, and force the distribution feeders into underfrequency load shedding. In its conclusion, the thesis proposes to have the wind turbines of the Penghu wind farms equipped with zero voltage ride-trhough (ZVRT) capability so as to help improve transient stability and to maintain the maximum wind power penetration at 33.3%.

並列關鍵字

Renewable Energy ； Wind Generation ； Penetration ； System Impact ； Transient Stability ； Zero Voltage Ride Through

參考文獻

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