Low-zero-sequence-resistance slow-harmonic energy-saving transformer

Abstract

The invention discloses a low-zero-sequence-resistance slow-harmonic energy-saving transformer. Primary side windings of the transformer are connected by adopting a triangle, secondary side windings of the transformer are connected by adopting a dual-output curve; each secondary side winding comprises a first group of windings and a second group of windings, wherein the first group of windings comprises a first phase output winding, a second phase output winding and a third phase output winding; and the second group of windings comprises a fourth phase output winding, a fifth phase output winding and a sixth phase output winding. The invention has the advantages of inhibiting distortion of output voltages on the basis of an electromagnetic filtering principle, reducing zero sequence resistance and operation loss of the transformer, ensuring that harmonics are inhibited, eliminating 3 times, 5 times, 7 times, 17 times and 19 times of harmonics, greatly improving influence of secondary side harmonics to a primary side power grid, weakening primary side and secondary side winding coupling fluxes and primary side winding circulation caused by harmonic currents, and reducing operation loss of the transformer.

Description

technical field [0001] The invention relates to a power transformer based on the principle of electromagnetic filtering, in particular to a low zero-sequence impedance slow harmonic energy-saving transformer. Background technique [0002] Due to the development of power electronic technology and their wide application in single-phase loads such as household appliances and other three-phase rectifiers, nonlinear loads have increased substantially. The current distribution transformers generally suppress the zero-sequence current from flowing into the power grid by using Dyn (primary side delta connection, secondary side star connection) connection, but this type of transformer cannot eliminate the influence of 5, 7 and other harmonics on the power grid , while there are many safety, reliability and power quality issues. For example: the zero-sequence current flowing in the primary side delta winding will cause the distortion of the output voltage and increase the coil loss; ...

AI Technical Summary

Problems solved by technology

The current distribution transformers generally use Dyn (delta connection on the primary side, star connection on the secondary side) to suppress the zero-sequence current from flowing into the power grid, but this type of transformer cannot eliminate the influence of other harmonics such as 5 and 7 on the power grid. , there are still many safety, reliability and power quality issues

For example, the zero-sequence current flowing in the primary-side delta winding will cause distortion of the output voltage and increase coil loss; the harmonic load will induce high-frequency harmonic current in the primary-side winding through electromagnetic coupling and flow into the power grid, affecting the safety of the power grid; The eddy current loss caused by high frequency harmonic current will increase the operating loss of the transformer

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