Method for compensating three-phase unbalanced currents on basis of SVG (static var generator)

A technology of balanced current and compensation method, which is applied in the direction of reducing asymmetry of multi-phase network, eliminating/reducing asymmetry of multi-phase network, reducing harmonic/ripple in AC network, etc., which can solve the problem of increasing calculation burden and convergence time, Unfavorable problems such as real-time control, to achieve the effect of improving detection speed and detection accuracy
CN106300399AActive Publication Date: 2017-01-04QINGDAO TOPSCOMM COMM
2 Cites 14 Cited by

Patent Information

Authority / Receiving Office
CN Β· China
Current Assignee / Owner
QINGDAO TOPSCOMM COMM
Publication Date
2017-01-04

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention relates to a method for compensating three-phase unbalanced currents on the basis of an SVG (static var generator). The method includes determining whether load currents needs to be compensated or not via three-phase unbalanced judging links by the aid of load current signals which are used as control input; acquiring frequencies and phases of power grid voltages via adaptive frequency locking and phase locking links when the load currents need to be compensated; filtering harmonic current components in the load currents by the aid of discrete second-order generalized integrators; computing negative-sequence current values required to be converted for various phases if the three-phase unbalanced currents are in balanced states; transmitting the negative-sequence current values to control instruction computation modules in SVB devices; driving IGBT (insulated gate bipolar transistors) to act; generating currents equal to fundamental negative-sequence components in the load currents so that the three-phase unbalanced currents can be in the balanced states. The negative-sequence current values are used as reference current signals. The directions of the currents are opposite to the directions of the fundamental negative-sequence components in the load currents. The method has the advantages that the three-phase unbalanced currents can be dynamically compensated, and accordingly the stability and the reliability of power grids can be improved; low-pass filters can be omitted when negative-sequence currents are extracted, and accordingly the method is low in computational burden and high in response speed and tracking precision.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to a three-phase unbalanced current compensation method, in particular to a method for compensating three-phase unbalanced current by using a SVG of a fully-controlled converter device. Background technique

[0002] The three-phase current unbalance phenomenon means that the magnitude of the three-phase current is asymmetrical, and its causes can be summarized as accidents and normality. The former refers to the failure of one or two phases in the three-phase power system, resulting in three-phase imbalance; the latter refers to the fact that a large number of user loads are single-phase loads, and the power consumption is not simultaneous, and the distribution system is prone to three-phase Phase imbalance, especially for loads such as electrified railways, whose traction load is a high-power load with single-phase movement and frequent amplitude changes. balance.

[0003] In recent years, with the increasing number of unbalanc...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More