Study On The Modeling Of Nonlinear Elements In Electromagnetic Transient Programme

Usually, the power network contains a large number of nonlinear elements, nonlinear components of the operation is very complex, very necessary。It is necessary to quickly and accurately grasp the power of real-time operating systems, and analyze and forecast of trends in the operating system. This paper detailed talks the power system electromagnetic transient calculation of the nonlinear elements, and on this basis to deal with any connection topology of the nonlinear elements of the new algorithm, and prove the new algorithm, and simulate the new model. This paper studies as follows:1 This thesis detailed discusses of the nonlinear and Compensation, and compares EMTP and Microtran technology. Microtran piecewise linear method proposed in this paper is the basis of the new algorithm, the benefits of the technology is effective to overcome the paragraph to paragraph transition overshoot, but paragraph and paragraph over the issue of numerical oscillation have to use CDA (Critical Damping Adjustment) technology. This paper is derived in the course of the compensation law, that when the compensation law for a number of nonlinear elements, require a nonlinear elements have a port, that is, compensation law requires non-linear components as the current source, From the port into a node of the current equivalent to another node from the port of the current outflow. This means that the compensation law for nonlinear components of the topology is limited.2 This thesis gives a new algorithm of electromagnetic transient calculation of arbitrary topology for connecting nonlinear elements. Triangle linking of three single-phase true - nonlinear elements in the EMTP can not run, because DaiWeinan equivalent impedance matrix is singular matrix, not inverse matrix. In this paper, the triangle linking of the nonlinear elements of the equivalent model, form a non-linear circuits with components, and then a part of solving linear circuit. And a detailed demonstration of the method is derived using MATLAB verification procedures of the new method. And, using the new algorithm verification process a few examples, the program runs out of the wave and the actual analysis is very similar to that of the wave, once again proved the correctness of the algorithm.3 However, pseudo-nonlinear elements of type codes 96-99 have nothing with the present explanation which is represented by its companion circuit and solved with the linear part. No iteration is used. The nonlinear characteristic of an element can only be represented by a piecewise-linear curve. Newton-Raphson discrete equivalent circuits for nonlinear resistors and linear companion circuits for nonlinear inductors are derived in detail, proved theoretically, and verified by MATLAB software.4 This thesis work presents a methodology for nonlinear elements in EMTP-type programs for the simulation of electromagnetic transient phenomena. The modeling of nonlinear elements is related to the numerical solution of variable-coefficient difference equations. It can be proven that nonlinear element equations are linearzed at each solution time-point, conductance /resistance matrix becomes the Jacobian matrix of the Newton solution. This approach provides a true-nonlinear solution to all nonlinear elements. It eliminates the less precise pseudo-nonlinear devices and all topological restrictions encountered in the compensation method used.