利用電壓穩定度指標與靜態同步補償器控制加以改善電力系統穩定度

Abstract

本文提出了一個控制方法，被動性控制，控制靜態同步補償器補償系統虛功來改善電壓穩定度。並且搭配電壓穩定度指標來判斷電壓崩潰的發生與否。在系統發生緊急事故時能做為緊急用電的儲備電力，例如市電切離的情況下。當發電機達輸出上限時，嘗試讓靜態同步補償器的虛功補償支撐整個系統，使其不至於崩潰。又或者在負載端發生三相短路故障造成的電壓驟降問題時，將靜態同步補償器投入改善電壓與電流在暫態響應時的穩定時間，減少線路傳輸損失降低發電成本。另一方面在系統穩定運轉的情況下，要在何時知道發電已達上限，系統正處於崩潰邊緣，電壓穩定度指標亦提供了一個易於觀察的判斷準則，使得危機得以解除在災難發生之前。

In this thesis, we present a control theory, passivity-based control. Improving the power system stability by using voltage stability index(VSI) and static synchronous compensator (STATCOM). Controlling STATCOM to compensate reactive power and determining the danger of voltage collapse by investigating voltage stability index. When the power system is in case of emergency, it can compensate reactive power to power system as storage power. When the output of generator is up to limit, it can control the STATCOM to support the whole power system for preventing voltage collapse. Even when the three-phase ground fault occurs to a load bus and results in voltage dip, compensation of STATCOM can improve the transient response time of voltage and current. As a result, the cost of line transmission loss can be reduced. On the other hand how can we notice the emergency of voltage collapse when the power system operates in the unstable case. The voltage stability index provides a obvious criterion.