Method for measuring and calculating transformer pi model saturation excitation curve

Abstract

The invention discloses a method for measuring and calculating a transformer pi model saturation excitation curve, which comprises the steps of: using two independent voltage sources which are simultaneously arranged on one side of a transformer as excitation, wherein the two voltage sources are a direct current voltage source and an alternating current voltage source; when the transformer works in an unsaturated area, obtaining a psi-i characteristic curve of flux and current by adopting trapezoidal integral on voltage, wherein the distribution of a core loss resistance and a magnetization curve during unsaturation is accomplished by equally sharing the loss and a magnetization current, so as to describe the characteristics of excitation inductances L<m1>, L<m2> in the unsaturated area; calculating saturation inductances L<m1_s> and L<m2_s> of excitation branches so as to obtain excitation curve data of the whole saturation section; and converting the L<m1_s> and the L<m2_s> into a flux linkage psi, and distributing a saturation current to two excitation branches of an improved pi model. Through adoption of the method, a saturated excitation curve measurement experiment conditionis easy to achieve, and at the same time, the description of a measurement result and a transformer behavior can be accurate.

Description

technical field [0001] The invention belongs to the technical field of transformer excitation characteristic measurement, in particular to a method for measuring and calculating the saturation excitation curve of a transformer π model. Background technique [0002] Ferromagnetic materials represented by silicon steel sheets are commonly used materials for transformer cores. The magnetic flux density B and magnetic field strength H of such materials are nonlinearly related. On the excitation curve of the iron core, key information such as the parameter values ​​of the transformer in the rated operating state and the excitation characteristics of the iron core can be obtained, which provides great help for further research on the transformer. At present, the most common measurement method is to use the standard open circuit test to obtain the excitation curve when the iron core is not saturated. When the transformer enters a deep saturation state, the AC power required for the...

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Problems solved by technology

[0005] In general, to obtain the saturated inductance values ​​of the primary and secondary sides of the transformer, it needs to be measured separately on both sides, and the operation steps are complicated.

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