Research On Algorithm To Explore Static Voltage Stability Region Boundary In Power Systems

Intermittent renewable energy and demand response cause the power direction changing all the time,which is a major challenge for static voltage stability assessment in power system using continuation power flow(CPF).Static voltage stability region(SVSR)is a powerful tool to assess the voltage stability in power system with high penetration of renewable energy and demand response.There are two typical methods to build the SVSR: one is CPF and the other is hyperplane approximation.The CPF can explore the highly accurate SVSR boundary but aggravates the computational burden whereas the hyperplane approximation can improve the computational efficiency of exploring SVSR boundary but may obtain an inaccurate approximated boundary.In this papper,from the two aspects of the optimization method and the predictive-correction method,the fast search method for the SVSR boundary is analyzed.The main contents are as follows:(1)A novel optimization model to explore the SVSR boundary is developed in this paper by referring to the topology of the SVSR boundary.An initial SNB point on the SVSR boundary is first explored by tradition optimal power flow(OPF),and then the optimization model is employed to track other SNB points to explore the SVSR boundary using the tracked SNB.The WECC-9 test system,IEEE-118 test system and Union for the Coordination of Transmission of Electricity(UCTE)1354-bus system are employed to evaluate the performance of the proposed optimization model,the results confirm that the proposed optimization model can improve the computational efficiency to explore SVSR boundary with high accuracy.(2)Aiming at the problem that the convergence efficiency is susceptible to the influence of the accuracy of the initial value for large-scale electrical power systems.According to the topology of the SVSR boundary,a general model to explore the SVSR boundary is developed by using the relationship between two adjacent critical points in the boundary.The model only calling CPF one time to get an initial critical point,and then predictor-corrector algorithm is employed to track other critical points to form the SVSR boundary.The WECC-9 test system,IEEE-118 test system,IEEE-300 test system and(UCTE)2383-bus system are further used to evaluate the performance of the proposed method,the results validate that the proposed method can improve the computational efficiency of exploring SVSR boundary with higher accurate compared with CPF.