SVG negative sequence and zero sequence current compensation method based on improved instantaneous symmetrical component method

Abstract

The invention discloses an SVG negative sequence and zero sequence current compensation method based on an improved instantaneous symmetrical component method. An instantaneous value is determined by using the improved symmetrical component method and a trigonometric function decomposition method of the instantaneous value in a phasor time domain; the method comprises the following steps: decomposing the system into a positive, negative and zero three-sequence network to obtain positive, negative and zero three-sequence components without delay, making the SVG to emit reactive current and harmonic current requiring compensation in a power grid by positive sequence current control, and compensating negative sequence and zero sequence components generated by unbalance of three-phase loads by negative sequence and zero sequence current control; and when the volume of the SVG is limited, preferably compensating the negative sequence and zero sequence components to ensure the maximum compensation of the reactive components. By adoption of the SVG negative sequence and zero sequence current compensation method disclosed by the invention, the defects of time delay in the traditional instantaneous symmetrical component method is overcome, the flexibility of the SVG compensation ability is given play, the three-phase symmetry of a common node is preferably ensured, the actual demands of the power distribution system are satisfied, and the psychological expectations of industrial users are also satisfied.

Description

technical field [0001] The invention relates to the technical field of reactive power compensation, in particular to an SVG negative-sequence zero-sequence current compensation method based on an improved instantaneous symmetrical component method. Background technique [0002] With the development of power electronic technology, a large number of nonlinear equipment such as power electronic devices and various new impact loads (such as industrial electric arc furnaces, electric locomotives, rolling mills, etc.) As well as a large number of applications in household appliances, the demand for reactive power has increased significantly, and the harmonic content of the power grid is large. At the same time, problems such as voltage fluctuations, flicker and three-phase imbalance are particularly prominent. Static var generator (SVG) is currently the most advanced reactive power compensation device, which can perform reactive power compensation to the power grid, improve the po...

AI Technical Summary

Problems solved by technology

The compensation degree of SVG is not high in normal working state, which makes the utilization rate of SVG lower if SVG only compensates the reactive power in the grid

In the actual power distribution system, the negative-sequence and zero-sequence components of the load current are usually less than the reactive components, but the negative-sequence and zero-sequence components are more harmful to the system.

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