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Method and device for measuring harmonic impedance

A harmonic impedance and measurement method technology, applied in the direction of measuring devices, measuring electrical variables, measuring resistance/reactance/impedance, etc.

Inactive Publication Date: 2011-12-14
国网电力科学研究院武汉能效测评有限公司
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Problems solved by technology

[0011] The object of the present invention is to provide a harmonic impedance measurement method and measurement device. According to the measurement principle and existing problems of the "incremental method", the present invention proposes "Double synchronous incremental method" aims to solve the error problem introduced by the system frequency change, improve the measurement accuracy, and make it meet the engineering requirements

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  • Method and device for measuring harmonic impedance

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Embodiment 1

[0055] The experimental system is shown in the attached Figure 9 . The short-circuit capacity of the 10kV bus 19 is 319MVA; the transformer capacity is 315kVA, and the impedance voltage is 4.2%; the fundamental wave impedance of the 400kV bus 20 is 0.008+j0.023(Ω). The interference source is a six-pulse rectifier 21, and the DC resistance load 22 is two high-power resistors (100kVA / 5Ω / set). Use this system to carry out the actual measurement test to verify the "double synchronous incremental method" and the harmonic impedance measurement device 23 .

[0056] The synchronization signal is taken from the 220V side voltage signal of the lighting distribution transformer of the 110kV substation. In the test, one resistor is first put in, and then the second resistor is put in to generate disturbance, that is, to generate harmonic voltage and current increment, and to extract the harmonic voltage and current signals before and after the disturbance, respectively, according to fo...

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Abstract

The invention relates to a harmonic impedance measurement method and a measurement device. The present invention aims at the main error source existing in the "incremental method" of the harmonic impedance measurement method, that is, the frequency offset and the synchronization problem of the phase angle of two different time signals, and proposes a "double synchronous incremental method", and develops a corresponding Test equipment; one of its synchronization is to synchronize the reference phase with the system cycle to solve the problem of reference phase drift; the second synchronization is to track the change of the system frequency through the hardware phase-locked circuit, and the sampling frequency is generated by the phase-locked circuit. The frequency is synchronized with the system frequency. The harmonic impedance measuring device includes a sampling frequency and system frequency synchronous circuit and a phase and system period synchronous circuit. The "double synchronous incremental method" of the present invention solves the error problem caused by the reference phase and system frequency fluctuations in the "incremental method"; the device principle is simple and easy to implement; the present invention reaches the engineering practical level and solves the problem of electric power production The harmonic impedance measurement problem in .

Description

technical field [0001] The invention relates to a harmonic impedance measurement method and a measurement device, belonging to the fields of power quality control and management, and power quality measurement methods and devices. Background technique [0002] Harmonic impedance is an extremely important parameter in power production. Whether it is designing a power filter or evaluating the level of harmonics generated by interference loads, the system harmonic impedance is the most basic parameter; use harmonic power flow calculation software to analyze the system network It is a common method to obtain harmonic impedance by frequency scanning, but it is difficult to obtain high-frequency parameters of the network; in addition, the three-phase geometric parameters of the system are not completely symmetrical, and parameters such as capacitance between phases and to ground affect the accuracy of calculation results It is very large, which makes the calculation results deviate...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R27/08G01R23/16
Inventor 李澍森肖遥冯宇陈晓燕石延辉左文霞程军照
Owner 国网电力科学研究院武汉能效测评有限公司
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