Harmonic Measurement and Correction Method of Capacitive Voltage Transformer Using Transformation Ratio Fitting

Abstract

The invention brings forward a harmonic wave measuring and correcting method for capacitor voltage transformers through transformation ratio fitting. The method includes the steps: establishing a consistent equivalent circuit for capacitor voltage transformers with the same voltage level, conducting fitting according to equivalent circuit component parameters of a preset model, obtaining a transformation ratio amplitude-frequency response curve and a phase frequency response characteristic curve, adjusting the curves through a translation method or the like on the basis of a fitting result for different equivalent circuit component parameters of other models, and finally realizing correction. The wideband characteristics of capacitor voltage transformers are taken as standards for the actual transformation ratio of the capacitor voltage transformers, a measurement result of the capacitor voltage transformers is corrected at the harmonic frequency, and the problem that capacitor voltage transformers cannot be applied to harmonic wave measurement is solved. The harmonic wave measuring and correcting method is simple in calculation, exhibits the real-time performance, and enables the application bandwidth of capacitor voltage transformers to be increased.

Description

technical field [0001] The invention relates to the field of voltage measurement of capacitive voltage transformers, in particular to a method for measuring and correcting harmonics of capacitive voltage transformers using transformation ratio fitting. Background technique [0002] Capacitive voltage transformer (CVT) is widely used in the voltage measurement of the neutral point directly grounded high-voltage system, and it is the most important secondary signal source for the harmonic measurement of the high-voltage level system at present. However, in the national standard GB / T "Power Quality Harmonics of Public Power Grids", it is clearly stipulated that "capacitive voltage transformers cannot be used for harmonic measurement". [0003] Most of the current related research focuses on the principle analysis of the harmonic measurement error of capacitor voltage transformer (CVT). By establishing the harmonic equivalent circuit and giving the calculation method of its cor...

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Problems solved by technology

However, the existing research mainly focuses on the qualitative analysis of the capacitor voltage transformer (CVT), and does not involve the quantitative analysis and calculation method of the source of each error peak point, nor does it give the error characteristics of the capacitor voltage transformer (CVT) correction method

[0004] The current research on the mechanism of CVT measurement error under harmonic conditions is not in-depth, and there are still insufficient quantitative analysis of different factors affecting CVT harmonic measurement error, especially the lack of analysis of CVT harmonic measurement error with different dampers

Correction for CVT harmonic measurement errors is also missing

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