Preventive Control of Transient Voltage Stability Based on Polynomial Approximation of Transient Voltage Stability Index

A preventive control method based on polynomial approximation of transient voltage stability index (TVSI) is proposed to reduce the difficulty of solving preventive control model embedded with differential-algebraic equations (DAEs). Firstly, an implicit function that maps control variables to certain TVSI is introduced. Secondly, a polynomial approximation method based on collocation point is introduced to approximate the implicit function. Thirdly, transient voltage stability constraint is constructed based on the approximation polynomial, thus transforming the preventive control model into a nonlinear programming (NLP) problem, which can be easily solved by interior point method. Feasibility and accuracy of the proposed method are verified in an actual system.