Three-phase power unbalance degree change trend measuring method and system

Abstract

The invention discloses a three-phase power unbalance degree change trend measuring method and system; the method comprises the steps: S1, collecting three-phase power sine electric signals; s2, converting the sine electric signal into a three-phase electric digital signal; s3, storing the digital signal in a data cache module; s4, adding a timestamp to the digital signal; s5, screening out several data with the minimum occurrence probability in the data corresponding to all the digital signals added with the timestamps, and removing the data; s6, storing the data left after elimination in three arrays according to phases, and copying the last data of the eliminated time point to the eliminated time point to generate a time point array; s7, performing vector summation on the three arrays at each time point; s8, calculating a mean value N of a current period by taking the current time point as a cut-off and taking a vector summation value corresponding to all data as a period; s9, calculating the difference value ratio of the average value of the current period data to the average value of the previous period data to obtain the change trend of the three-phase power unbalance degree.

Description

technical field [0001] The invention relates to the technical field of data analysis, in particular to a method and system for measuring the change trend of unbalanced three-phase power. Background technique [0002] In recent years, with the continuous expansion of the grid scale, the access of clean energy such as wind energy and solar energy, and the development of AC-DC parallel operation, my country's power system has shown the characteristics of huge overall scale, diverse operation modes, rapid power flow changes, and complex operation control. In order to ensure the safety and reliability of power distribution equipment in the power grid, online monitoring of substation equipment through hardware and sensor acquisition technology and computer communication data management technology realizes real-time perception and health status assessment of substation equipment operation status, and at the same time detects faulty equipment in a timely manner. Schedule an overhaul...

AI Technical Summary

Problems solved by technology

[0003] The indicator 3I0 to measure the degree of three-phase unbalance is one of the important indicators in power quality monitoring. Under the working condition, there is a phase angle difference at the three-phase point, and there is fluctuation in 3I0. The smaller the fluctuation, the smaller the degree of three-phase unbalance, and the power quality Relatively higher, but when the degree of fluctuation gradually increases or a large mutation occurs, it means that there may be a large capacity asymmetrical load connected or the harmonics in the grid have a harmful impact on the three-phase electric phase, and the three-phase unbalanced fluctuation An increase can also indicate that the power quality is degraded or the collection device is faulty or damaged

The problem now is that there is a lack of a statistical parameter that can be used to measure the magnitude of the 3I0 change trend. To measure the change trend of the three-phase unbalance degree requires human observation, which is not conducive to accurate quantification

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