- 學位論文
使用DFIG與DDSG分別評估澎湖風力發電最大占比
Study on Maximum Wind Power Penetration in Penghu using DFIG and DDSG Wind Turbines Respectively
摘要
目前澎湖電力系統為一獨立系統，主要由尖山電廠柴油機組供應全島負載，然而因於柴油機組供電成本過高，導致台電公司長年虧損，並且逐年負載增加，虧損隨之上升。澎湖地區夏季時風況較差，平均風速約5~9m/s，風機發電量亦相對較低，對尖峰系統之貢獻有限；反之，冬季時風況良好，平均風速常高於12m/s，風機經常滿載發電且容量因數 (Capacity Factor, CF) 高達70%以上，故澎湖冬季離峰時，非常適合投入更多風力發電運轉。當提高風力發電裝置容量，得以減少投入柴油機組運轉數與發電成本，即可降低發電的營運虧損；但相對當風力發電占比提高時，將可能造成系統運轉不穩定，必須評估適當之風力發電占比。 本文使用PSS/E 軟體作為模擬工具，針對2014年澎湖離峰電力系統負載為40.9MW下，就台澎海纜未興建完成前，澎湖地區仍為一獨立系統，系統中加入現有中屯一期、二期風場與湖西風場，風場內風機分別採用雙饋式感應發電機與直驅式同步發電機兩類型風機，考量尖山電廠柴油機組運轉限制與排程、備轉容量與系統低頻限制等，擬訂可行之模擬案例，進行事故模擬與分析，包括柴油機組跳脫、風場切離及三相短路接地事故模擬，探討兩類型風機對於系統電壓與頻率之差異與系統衝擊之影響，並且依據台電公司「再生能源發電系統併聯技術要點」之低電壓持續運轉 (LVRT) 規範來設置保護電驛，比較風機有、無LVRT設備時，觀察系統之暫態穩定度改善程度，進一步評估在不影響系統運轉安全下之澎湖風力發電之最大占比。最後，本文提出建議各風場內風機裝設零電壓持續運轉設備 (ZVRT)，改善系統暫態穩定度，可使澎湖電力系統之最大風力發電占比達39.36%。
並列摘要
Isolated from the Taipower system, the independent Penghu power system relies mainly on the diesel engines of Jianshan Power Plant. Use of diesel engines, however, incurs a steep power generation cost, causing Taipower to suffer long-term deficit that rises every year with the increased load. In Penghu, the wind condition in summer tends to be less favorable as the average wind speed stays around 5~9m/s; the output of wind-powered generators is therefore relatively low, and its contribution to the system during peak seasons fairly limited. On the contrary, with an average wind speed exceeding 12m/s, the winter wind condition is favorable enough to keep wind turbines running at full capacity and sustain a capacity factor higher than 70%. Wind power generation during the off-peak winter season in Penghu may thus be a profitable investment to reduce the generation cost of diesel engines and to curb the Taipower deficit. However, growth in wind power generation may trigger instability in the power system. It is therefore of crucial importance to assess the optimal wind power penetration in the Penghu power system. In the thesis, the power system analysis software PSS/E is used to simulate the 2014 Penghu power system with its off-peak load set at 40.9MW. As the Taiwan- Penghu submarine cable system has yet to be completed, the 2014 Penghu power system remains independent but incorporates the Zhongtun and Huxi wind farms. Two types of wind turbines – DFIG (doubly-fed induction generator) and DDSG (direct-drive synchronous generator) – are taken into consideration, and the operational constrains, scheduling, spinning reserve capacity, frequency restrictions and other related parameters of the diesel generators at Jianshan Power Plant are examined to simulate and analyze potential accidents, such as diesel engine shut down, wind farm cut out, and three-phase short circuit fault. The differences between DFIG and DDSG in their impacts on system voltage and frequency are also studied while the LVRT (low voltage ride through) regulations stipulated in the Technical Rules of Renewable Energy Generation Connected to Taipower Transmission and Distribution System are consulted to set up protection relays and compare the improvement on system transient stability in two scenarios: presence and absence of LVRT capability in wind turbine. The optimal wind power penetration in the Penghu power system is then evaluated. In its conclusion, the thesis proposes to have the wind turbines of Penghu wind farms equipped with zero voltage ride through (ZVRT) capability so as to improve transient stability and maintain its optimal wind power penetration at 39.36%.