Winding magnetic flux leakage and electrodynamic force calculation method based on transformer segmented model

Abstract

The invention discloses a winding magnetic flux leakage and electrodynamic force calculation method based on transformer segmented models. The method comprises following steps: carrying out finite element magnetic field modeling and solution to a power transformer, calculating the leakage magnetic fields of the transformer by a vector magnetic potential edge finite element method, and calculating and analyzing the electrodynamic force borne by a winding through simulating internal magnetic field distribution of the transformer. According to the method of the invention, the influence of the operation state of the voltage adjusting winding on the leakage magnetic field distribution is considered fully; the leakage magnetic fields under three different operation conditions are respectively calculated and analyzed; the operation conditions comprise maximum shunting, rated shunting and minimum shunting; therefore, the condition that magnetic fields and stresses of the transformer winding change according to different connection methods of the voltage adjusting winding is simulated more accurately; the distribution rules of the leakage magnetic fields and the electrodynamic force are obtained; a basis is provided for judging the structure stability of the transformer winding; and the method is scientific, reasonable, real and effective and has high practical value.

Description

technical field [0001] The invention is a winding flux leakage and electromotive force calculation method based on a transformer section model, which is applied to the stability analysis of the winding structure when the power transformer is short-circuited. Background technique [0002] The power transformer is one of the most critical equipment in the power system. The operation status of its winding not only affects its own safety, but also affects the stability and reliability of the entire power system. In the statistical data of on-site transformer faults, faults caused by short circuits account for a high proportion. When a short-circuit fault occurs in the transformer, a short-circuit current much larger than the normal current value will flow through the winding wire, so a large magnetic field will be generated in the transformer. Under the action of short-circuit current and short-circuit magnetic field, the wire will be subjected to a very huge electromotive forc...

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Problems solved by technology

If the short-circuit resistance design of the transformer is not reasonable enough, the structure of the winding may be deformed under the action of short-circuit electromotive force, and even lead to the collapse of the winding

The structural change of the winding may cause the insulation of the wire to be damaged, thereby reducing the insulation performance of the transformer

At present, the general distribution of the magnetic field and electromotive force inside the transformer can be obtained through the method of test measurement, which provides criteria for theoretical research; but at the same time, it is also limited by many practical conditions, and it is difficult to carry out related short-circuit tests and electromotive force measurements. Carrying out the simulation calculation of the magnetic field and electromotive force inside the transformer has important research value and practical significance

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