本論文提出了以雙饋式感應發電機為基礎之兩個聚集等效離岸式風場，分別經由線換向轉換器高壓直流傳輸系統與電壓源轉換器高壓直流傳輸系統連接至兩個電網端，兩高壓直流傳輸系統之輸出交流側經由連接傳輸線做連接，形成多端饋入式混合高壓直流傳輸系統之架構。本論文提出於線換向轉換器高壓直流傳輸系統之整流站加入靜態同步補償器與其設計的比例-積分-微分阻尼控制器，以比較其對系統穩定度之改善特性。
在穩態特性方面，本論文分析了不同風速以及連接傳輸線長度變動對系統特性之影響，在動態模擬方面完成了風速變動之模擬，在暫態部分則完成電網端電壓三相短路故障模擬結果。由模擬結果分析得知，連接傳輸線長度變動會影響系統之穩定度，而系統加入靜態同步補償器與其比例-積分-微分阻尼控制器後，對所研究系統在風速變動及其他干擾下之穩定度可獲得有效的改善。

This thesis presents two equivalent aggregated offshore wind farms (OWFs) based on doubly-fed induction generator (DFIG). They connect to two power grids through a high-voltage direct-current transmission system based on line-commutated converter (LCC-HVDC) and an HVDC system based on voltage-source converter (VSC-HVDC), respectively. Two systems constitute multi-infeed hybrid HVDC transmission systems by connecting a tie-line between the AC-side outputs of the two HVDC systems. Comparative stability improvements of the studied system with and without a static synchronous compensator (STATCOM) joined with the designed proportional-integral-derivative (PID) damping controller are also performed.

Steady-state characteristics of the studied system under different values of wind speed and length of the tie-line are examined. Dynamic and transient simulations of the studied system subject to a wind-speed disturbance and a three-phase fault at the power grid are also carried out. It can be concluded from the simulation results that length of the tie-line can affect the system stability. Moreover, the STATCOM joined with the designed PID damping controller are capable of improving the performance of the studied system under variable wind speeds and other disturbance conditions.

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