Gamma/ transformer triangle winding circumfluence algorithm method and device

Abstract

The invention discloses a calculation method and a device of Y / triangle transformer triangle winding medium circulation and belongs to the main equipment relay protection technical field in electric power system; the method comprises the steps that winding resistance and leakage inductance of two sides of the Y / triangle transformer are obtained; zero sequence voltage of the Y side thereof is obtained or the three-phase winding voltage of the Y side thereof is measured; three-phase winding voltage equations of the Y side and the triangle side thereof are formulated according to the winding resistance, the leakage inductance, the three-phase winding current and the three-phase winding inductive potential of the Y side and the triangle side thereof; all the equations are calculated according to the relation of all parameters; circulating current is obtained by eliminating all unattainable parameters except winding medium circulating current of the triangle side. The device comprises an obtaining module, a voltage calculating module and a circulating current calculating module. When the transformer triangle side winding doesn't use a current transformer, the invention can calculate out the circulating current of winding of the triangle side, calculate out equivalent instantaneous inductances of all phases of the transformer and further judge magnetizing inrush current of the transformer.

Description

technical field [0001] The invention relates to the technical field of relay protection for main equipment in a power system, in particular to a calculation method and device for circulating current in a delta winding of a Y / Δ transformer. Background technique [0002] Power transformers in the form of Y / Δ wiring are widely used in power systems. Since one side of the primary and secondary windings is connected to Δ, it can ensure that the phase potential is close to a sine wave and avoid distortion of the phase potential waveform. However, there is a phase difference between the line currents on both sides of the Y / Δ transformer. In order to make the differential current in the normal operation of the transformer differential protection zero, it is necessary to convert the current on one side of the transformer to the other side to eliminate the phase difference between them. For the existing Y→Δ current compensation method and Δ→Y current compensation method, due to the in...

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Problems solved by technology

The excitation inrush current criterion based on the equivalent instantaneous inductance needs to obtain the winding currents on each side of the transformer. For power transformers with a voltage level of 500kV and above, a three-phase transformer form composed of a single-phase transformer is usually used, and the Δ side winding (that is, the delta winding) Winding current transformers can be configured to measure the winding current; however, for power transformers with a voltage level of 220kV and below, see Figure 1, usually in the form of three-phase three-column, winding current transformers cannot be configured in the Δ side winding, so that it cannot be measured Δ side winding current, including i a i b i c and the circulation i in it p , thus limiting the application of the inrush current criterion based on the equivalent instantaneous inductance

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