| Summary: | 碩士 === 國立成功大學 === 電機工程學系 === 104 === 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.
|
|---|
