Development of the Model for Simulation of Transient Processes in Cables and Power Lines

Abstract

Aims: The paper presents a model of the power line and the equivalent scheme for the simulation of the transient processes. Many constructions of conductive lines are such that mutual parameters (inductance, capacitance) are the same for any pair of phases, and the phase parameters themselves are approximately the same for all three phases. Therefore, the approximation of three-phase conductors with symmetric single-phase conductors is justified. A special way in which the power lines are considered is a method called a sequence model of three-phase line. Methodology: Techniques used in this paper are based on analytic methods and the formation of algorithms. Modeling and simulation are processes that are necessary for testing faults in measuring transformers in relay protection (current/voltage) when they are very remote and electrically connected by cables. The first step in problem-solving was to define the theoretical model for estimation of the impact of variable parameters on the transmission of electric energy. Further step represented in the paper is simulation of transient processes on different lengths of the power lines when modeling lines and cables, one starts from the fact that parameters differ in certain parts, in lengths, i.e. that the parameters are variable in length, which results in change of longitudinal parameters of basic quadripoles in equivalent schemes. Conclusion: The specificity of the model is that the initial conditions matrix is determined depending on the condition at the beginning of the line and load in equivalent scheme and arises from the idle time or short circuit at the output of the quadripoles. The solution for transient state with the application of quadripole in the equivalent scheme is obtained by matrix procedure using equivalent schemes and by simulation method in the MATLAB program.