因應全球暖化、環境汙染及天災等因素，再生能源日益普及，尤其是太陽光伏發電系統被廣為應用，但高滲透率的太陽光伏發電系統勢必會對配電系統電壓造成衝擊，進而限制太陽光伏發電系統饋入系統量。安裝智慧變流器與使用適當電壓控制策略，能有效的抑制過電壓問題及減少線路損失，減少電壓衝擊並提高太陽光伏饋入系統量。
為了能有效利用太陽光伏系統之變流器，本論文提出最佳化太陽光伏系統之變流器裝置容量規劃，考量其投資成本並搭配虛功交易機制，建議合適的變流器之裝置容量，同時提出一配電系統兩階段電壓控制策略，用於具高太陽光伏滲透率的系統，使系統電壓能維持在法定的規範內並線路損失達到最小，進而減少太陽光伏系統的饋入削減量，提高太陽光伏系統的利用率，提升整體的經濟效益。本文所提的兩階段電壓控制策略，主要透過有載切換開關變壓器、電容器以及太陽光伏系統之變流器虛功控制達到電壓控制之目的，並限制一天內有載切換開關變壓器及電容器的使用次數。
本論文為驗證電壓控制策略及最佳化裝置容量策略的可行性，使用實際的負載資料及太陽光伏發電量分析其效益，並進一步與文獻現有方法比較。由數值模擬結果可知，所提之方法相比於文獻現有方法更能有效地在減少有載切換開關變壓及電容器的使用下達到電壓控制之目的，提高太陽能光伏系統的饋入量，減少之線路損失亦更為顯著。此外，透過最佳化變流器裝置容量策略，更能再進一步提高太陽光伏系統的饋入量。

Because of global warming, environmental pollution, and natural disasters, renewable energy is commonly used nowadays, particularly a photovoltaic (PV) system. However, the high penetration of a PV system considerably affects the voltage of the distribution system and restricts the feed-in power of PV systems. Therefore, a suitable voltage control strategy is required to mitigate the overvoltage problem, minimize power loss, and increase the feed-in power of PV systems.
The thesis proposes an optimization strategy to determine the optimal capacity of the PV inverter, considering the investment cost of the PV inverter and reactive power transaction. For specified PV inverter capacities, this thesis proposes a two-stage voltage control strategy for the distribution system in a high PV penetration system to regulate the system voltage within an acceptable range, minimize power loss, and minimize the active power curtailment of PV systems. The proposed voltage control strategy is achieved using a transformer on-load tap changer (OLTC) and capacitor bank, and through the reactive power control of a PV inverter. The operation numbers of the OLTC and capacitor bank are limited to one day because of the effects on their lifetime.
To verify the feasibility of the proposed optimization capacity of the PV inverter and voltage control strategy, the real load and PV generation data are used in this thesis and the control strategy is compared with the reference methods. The simulation results show that the proposed voltage control strategy can mitigate the overvoltage problem and increase the feed-in power of the PV system more effectively. The power loss and operation numbers of the OLTC and capacitor bank are also reduced considerably. The proposed optimal inverter capacity strategy can further minimize the active power curtailment of PV systems effectively.

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