Wide-area voltage stability assessment using loading margin sensitivity for increasing linear load levels and wind power penetration

Increase in integration of fluctuating and unpredictable renewable energy to the power grid, raise the complexity of real-time assessment of voltage stability. A precise measurement-dependent real-time wide area loading-margin-sensitivity study is a novel solution to this problem. This is a challenging task for a wind farm integrated WAMS-based large power system with GPS-aided PMU technology. The study here shows the computation of a real-time sensitivity index while increasing static load levels linearly. The index will be utilized for identifying the weakest buses for load shedding and provides situational awareness to the grid operator for load voltage control to avoid any power outages. Moreover, it assists in determining the fittest bus for load adjustment during scheduled maintenance and the auxiliary bus for instant load increment decisions based on demand. This study also investigates the effects of increasing DFIG-based wind energy penetration to determine the best wind-power penetration level. The proposed analysis was found to be accurate for voltage assessment on the WSCC three-machine nine-bus network and the New England sixteen-machine sixty-eight bus large power networks. An experimental study, to validate the results, is performed using a three-phase industrial category load on the SEL-based hardware test-bed using actual PMU recordings.