Gamma/delta transformer triangle winding circumfluence algorithm method and device

Abstract

The invention discloses a calculation method and device for circulating current in a delta winding of a Y / △ transformer, belonging to the technical field of relay protection for main equipment of a power system. The methods include: obtaining the winding resistance and leakage inductance on both sides of the Y / △ transformer; obtaining the zero-sequence voltage on the Y side or measuring the three-phase winding voltage on the Y side; obtaining the zero-sequence current on the Y side or measuring the three-phase winding current on the Y side ; Use the winding resistance, leakage inductance, three-phase winding current and three-phase winding induction potential on both sides to list the three-phase winding voltage equations on both sides; calculate all equations according to the relationship between each parameter, and eliminate them except △ All unavailable parameters except for the circulating current in the side winding yield the circulating current. The device includes an acquisition module, a voltage calculation module and a circulation calculation module. The invention can calculate the circulating current in the delta side winding when the current transformer is not used in the delta side winding of the transformer, thereby calculating the equivalent instantaneous inductance of each phase of the transformer, and further distinguishing the excitation 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 / △ transformer. Background technique [0002] Power transformers in the form of Y / △ wiring are widely used in power systems. Since one side of the primary and secondary windings is connected into △, 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 / △ 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→△ current compensation method and △→Y current compensation method, due to the ...

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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 consisting of a single-phase transformer is usually used. The △ side winding (ie, the delta winding) The winding current measured by the winding current transformer can be configured; but for power transformers with a voltage level of 220kV and below, see figure 1 , usually in the form of three-phase three-column, the winding current transformer cannot be configured in the △ side winding, so that the current of the △ side winding cannot be measured, 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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