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Quick harmonic and reactive current detection method based on instantaneous reactive power theory

A technology of instantaneous reactive power and detection method, applied in reactive power/actual component measurement, current/voltage measurement, measuring device, etc.

Inactive Publication Date: 2015-01-14
STATE GRID CORP OF CHINA +2
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

When harmonic components need to be detected, two low-pass filters are used in this method, resulting in different delays

Method used

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  • Quick harmonic and reactive current detection method based on instantaneous reactive power theory
  • Quick harmonic and reactive current detection method based on instantaneous reactive power theory
  • Quick harmonic and reactive current detection method based on instantaneous reactive power theory

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Embodiment Construction

[0036] The technical solution of the present invention will be specifically described below in conjunction with the accompanying drawings.

[0037] Such as figure 1 and Figure 4 As shown, the present invention provides a fast detection method for harmonics and reactive current based on the theory of instantaneous reactive power, including providing a current disturbance system, which includes a starting unit, an LCL filter, a converter unit and Control and monitoring unit, the input end of the starting unit is connected to the output end of the three-phase grid, the control and monitoring unit includes a current detection control circuit for monitoring harmonics and reactive current in the system, the current detection control circuit The harmonic and reactive current monitoring process is as follows:

[0038] S1: Acquisition of the instantaneous value of the three-phase voltage in the three-phase grid , , and three-phase current instantaneous value , , ;

[00...

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Abstract

The invention relates to a quick harmonic and reactive current detection method based on the instantaneous reactive power theory. The method includes the step that a current disturbance system is provided. The current disturbance system comprises a control and monitoring unit. The harmonic and reactive current monitoring process of a current detection control circuit for monitoring harmonic and reactive currents in the system in the control and monitoring unit includes the steps that firstly, three-phase voltage and current instantaneous values in a three-phase power grid are collected; secondly, by the adoption of alpha-beta transformation, three-phase voltage and currents are changed into an alpha beta orthogonal stationary coordinate system; finally, virtual voltage vectors are added for replacing real voltage vectors participating in operation, instantaneous active and reactive power is calculated, and direct current power components are acquired through filtering of an LPF; fundamental components in detected currents are calculated through reverse transformation; harmonic components can be acquired by subtracting the fundamental components from the detected currents. The method can quickly detect harmonic currents and reactive currents.

Description

technical field [0001] The invention relates to a fast detection method for harmonics and reactive current based on the theory of instantaneous reactive power. Background technique [0002] Traditionally, before the 1970s, power electronic equipment was not widely used, and the harm caused by harmonics was not paid enough attention. With the advent and development of semiconductor devices and the popularization of nonlinear loads such as large silicon controlled rectifiers and inverters, the voltage and current waveforms of the power grid are distorted, and the pollution of harmonics to the power grid is becoming more and more serious. of high attention. In order to ensure safe and reliable operation of power equipment and improve power quality, people began to study effective devices for harmonic control, which requires current disturbance generators to test the performance of harmonic control devices. [0003] Accurately detecting the harmonic current and reactive curren...

Claims

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Application Information

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IPC IPC(8): G01R19/00G01R19/06
Inventor 林焱吴丹岳黄道姗张逸林国庆卢敬伟李发禄
Owner STATE GRID CORP OF CHINA
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