CALCULATION OF TRANSIENTS IN TRANSFORMER ON THE BASIS OF MAGNETO ELECTRICAL EQUIVALENT SCHEMES WITH THE USE OF TCHEBYSHEV’S POLYNOMIALS

Abstract

Transient modeling in transformers is presently executed by formation and solution of the state equations for the magneto-electrical equivalent schemes. These processes can be very long, that results in a considerable time of calculation at the modern software use. The aim of the given work is the development of more fast-acting method of calculation of electromagnetic transients in transformers, using solution approximation by polynomials, and also development of comfortable scheme model of method for putting into practice. On the basis of solution approximation of the state equations by the Tchebyshev’s polynomials the method of transients calculation in magneto-electrical equivalent schemes is worked out. Scheme interpretation of the developed method is offered. It is shown that in the special equivalent scheme the Kirchhoff’s laws are fair for the images of currents and magnetic fluxes as vectors, containing the values of coefficients of decomposition of these values by the Tchebyshev’s polynomials. This method allows to replace operations with the instantaneous values of currents by operations with direct currents in offered equivalent scheme. As a result the integrodifferential state equations are submitted by algebraic equations. The calculation with the offered method of transient in a three-phase transformer processor allows to reduce time more than twice as compared to calculations with the help of the well-known methods. The given method is especially comfortable for the transient’s calculation in magneto-electrical circuits, since it allows to use voltage sources controlled by the current derivative as well as easily evaluate the integrals of solution