A Static Voltage Stability Assessment of a Large Grid Based on VSAT

The motive of contingency screening and ranking function is to shortlist a specified number of critical contingencies caused voltage unstable from a large list of credible contingencies. Based on VSAT(voltage stability analysis toolbox), a method of outage screening, considering voltage stability margin, is introduced in this paper, and by analyzing an real large grid data, the essential outage causing center area voltage unstable is selected from the contingency list. Using modal analysis and reactive power reserve analysis in this example, weak point and weak region are discovered. In the modal analysis, though ranking the participation factor, it is easy to find the weak point. In reactive power reserve analysis, by analyzing RPRI(Reactive Power Reserve Index) to find the key point. Simulations of different operation modes in the grid are made to evaluate its static voltage stability.