Comparison of Transmission Line Models by Excluding Frequency Dependence in Complex Power System for Error Estimation

Today, commercial simulation packages can have the capability of solving complex power system networks by using various transmission line models. When there is a change in the modeling routine of transmission lines, their accuracy is also changese main aim of this paper is to compare lumped PI and distribute CP transmission line models in terms of accuracy and optimization capability. The IEEE ۵۷ bus time domain power system models are designed by using these transmission line models for analysis in this paper. In these proposed systems the transmission line parameters are described as frequency independent. Therefore, in CP lines the Clark's transformation method does not provide exact decoupling of lines, to achieve exact decoupling of lines and accuracy the lines are continuously transposed in proposed systems. The NR load flow analysis was used for error estimation in balanced and unbalanced networks. The results had reported voltage error at the buses, transmission line error as function of line length and frequency response of line parameters. The frequency study of the line parameters was shown the PI lines system behaves as low pass filter and the CP lines system behaves as high pass filter. In this paper, also studied the optimization of proposed models by using a well-known Ant Lion Optimization (ALO) algorithm to set control variables, such as generator voltages, position of tap changing transformers and shunt capacitor banks. The optimization results of total power loss, voltage deviation and voltage stability index were compared with other algorithms. The results revealed that the ALO has best cothe nvergence characteristics and best elitism phase. Therefore, the CP lines system had shown considerable improvements of optimization results.

کلیدواژه ها:

Clark's transformation ، Complex power system ، Constant frequency parameters ، Distributed CP line ، IEEE ۵۷ test case ، Lumped PI line ، Modeling routine ، NR load flow ، Time-domain model