Asymptotic numerical method for continuation power flow

In this paper, we use the asymptotic numerical method (ANM) to solve continuation power flow (CPF) problems. ANM can be considered as a higher-order predictor without any corrections. The method has been applied with great success to the areas of fluids, elasticity and structural mechanics. Compared to the general predictor-corrector continuation methods used in power systems. ANM has the following advantages. Firstly, the computation time is smaller. With ANM, the nonlinear problems to be solved are transformed into a recursive sequence of linear systems with the same coefficient matrix, and only one sparse Jacobian matrix factorization is required at each continuation step. Secondly, the computational procedure is automatic. A simple criterion proposed by B. Cochelin et al. can be used to determine the step-length, which makes the continuation easy, and no special step-length control strategy is required. Thirdly, as the solution branch has been expressed into a closed analytical form, the Q-limit points on P-V curves due to reactive power limits violations and other breaking points with the control devices actions can be precisely located with ANM easily. Numerical examples in several power systems were presented to validate the method. (C) 2012 Elsevier Ltd. All rights reserved.