Power grid voltage and current harmonic analysis method and system

A technology of current harmonics and grid voltage, applied in the grid voltage and current harmonic analysis method and its system field, can solve the problems of large dynamic error of spectrum analysis, increase of system cost, loss of lock, etc., and achieves wide application fields and simple system structure , easy-to-achieve effects

Inactive Publication Date: 2020-01-14
JIANGSU UNIV
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Problems solved by technology

This method can fundamentally solve the problem of spectrum leakage, but the PLL structure is more complicated, which increases the system cost
When the input signal frequency changes, the tracking speed of PLL is low, and the dynamic error of spectrum analysis is large. At the same time, due to the limitation of PLL frequency tracking speed and range, when the input signal frequency changes in a large range, it will lose lock and lose automatic tracking. ability

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  • Power grid voltage and current harmonic analysis method and system
  • Power grid voltage and current harmonic analysis method and system
  • Power grid voltage and current harmonic analysis method and system

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Embodiment Construction

[0033] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

[0034] A kind of network voltage and current harmonic analysis system proposed by the present invention, in order to realize the hardware system of the analysis method of the present invention such as figure 2 As shown, the MCU is used as the core of data processing, and STM32F407 is used. Specifically, the MCU has a 12-bit AD converter on-chip; the input signal is sampled by using the MCU on-chip AD converter. The input signal of the AD converter is the measured power grid signal, and the output of the AD converter is connected to the input of the first sampling data buffer; the output of the fir...

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Abstract

The invention discloses a power grid voltage and current harmonic analysis method and system. An AD converter samples an input voltage signal; a secondary virtual sampling unit is used for carrying out secondary sampling on first sampling data in a virtual sampling period s; a spectrum analysis unit analyzes the data by using an FFT algorithm to obtain the spectrum of the voltage signal; a spectrum leakage estimation unit scans and accumulates all spectral lines except the power frequency signals and harmonic waves thereof in the spectrum to obtain total energy leakage d of the spectrum; and avirtual sampling period adjustment unit adjusts the virtual sampling period s according to the spectrum leakage. According to the invention, a simple fixed hardware circuit is utilized to realize self adaption to frequency drift of the power frequency signals, so that the minimum spectrum leakage of an analysis result is ensured.

Description

technical field [0001] The invention belongs to the technical field of grid signal detection and signal analysis, in particular to a grid voltage and current harmonic analysis method and system thereof. Background technique [0002] Harmonic analysis of power grid signals is an important part of power system power supply quality monitoring, and is widely used in various links such as power transmission, transformation and distribution. At present, the basic method for online harmonic analysis of power grid signals is the Fast Fourier Transform (FFT) algorithm. There is a basic limitation in the application of this algorithm, the number of input data must be 2 N . However, the frequency of the grid is not constant. The current grid standard in my country allows a maximum error of 0.5Hz in the grid frequency. Therefore, under a certain sampling period, the sampling data corresponding to 2 N The subsampling time window may not be an integer multiple of the input signal peri...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16
CPCG01R23/16
Inventor 秦云杨梦琪骆英徐晨光
Owner JIANGSU UNIV
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