Renewable Integrated Transient Voltage Stability Mechanism Analysis using Hopf Bifurcation and Discrete Wavelet Transform

The power system nonlinearity has increased due to large-scale renewable energy integration. Therefore, the new power system suffers for the transient voltage stability challenge. The bifurcation theory has proven to be a powerful method to understand the nonlinear dynamic voltage oscillations and stability issues. From the perspective of bifurcation theory, the renewable energy integrated power system voltage unstable situation belongs to the Hopf Bifurcation type. In this paper, a new mechanical analysis is proposed using the discrete wavelet transform to help translate the dynamic voltage issues from eigenvector plane to time-domain decomposed signals. It connects the voltage support behavior with the DAE equations characteristics by capturing the voltage curve transition time period. This analysis explains the transient voltage behavior directly and convenient for comparison. The modified CEPRI 36 bus system is utilized for demonstration. Based on the aforementioned mechanism analysis, a remedial SVC device is deployed to avoid the severe case into a Hopf bifurcation unstable situation.