Polynomial Approximation of Transient Stability Region Boundary in Parameter Space Based on Collocation Method

Polynomial approximation based on collocation method is an emerging technique to establish the relationship between changeable parameters and interested transient trajectory in a given parameter space. If transient stability region boundary (TSRB) exists in the parameter space, the approximation may have low accuracy due to the high sensitivity of the real trajectory with respect to parameters on TSRB. Utilizing the approximated trajectory and the high sensitivity characteristic, this letter proposes a complementary method to obtain TSRB by calculating the local maxima of a sensitivity-based index. The effectiveness of the method is verified in IEEE 39-bus test system.