Notes on Power System Load Flow Analysis （在电力系统负载流分析）.pdf

Notes on Power System Load Flow Analysis using an Excel Workbook Abstract These notes describe the features of an MS-Excel Workbook which illustrates four methods of power system load flow analysis. Iterative techniques are represented by the Newton-Raphson and Gauss-Seidel methods. The Workbook also includes two search algorithms: genetic algorithms and simulated annealing. 1. Introduction Load flow studies [1,2] are used to ensure that electrical power transfer from generators to consumers through the grid system is stable, reliable and economic. Conventional techniques for solving the load flow problem are iterative, using the Newton-Raphson or the Gauss-Seidel methods. Recently, however, there has been much interest in the application of stochastic search methods, such as Genetic Algorithms [3,4,5], to solving power system problems. The increasing presence of distributed alternative energy sources, often in geographically remote locations, complicates load flow studies and has triggered a resurgence of interest in the topic. The principles of power system load flow studies are taught within elective modules in the later years of undergraduate electrical engineering courses, or as essential components of specialist masters programmes in electrical power engineering. From the educational viewpoint, therefore, the topic is important, yet a complete coverage presents some significant challenges. Pre-requisites include fundamental concepts from a.c. circuit analysis, such as phasor notation, impedance and admittance, power and reactive power, three-phase and per-unit systems, all of which are regarded as ‘difficult’ by many students. The load flow solution techniques bring extra mathematical hurdles, including matrix representation (with com