A three-phase high-precision harmonic energy meter

Abstract

The invention provides a three-phase high-precision harmonic electric energy meter, which includes a frequency measurement module, a sampling control module, an amplitude and phase calculation module, a harmonic phase compensation module, and a harmonic electric energy accumulation module connected in sequence. The beneficial effects of the present invention are: 1. Adopt the method of combining hardware frequency measurement and software frequency measurement, and eliminate the interference of high-order harmonics to frequency measurement by means of software and hardware filtering measures, and ensure the whole cycle sampling from the source; 2. The M2 sampling control module adopts the PWM+DMA automatic control method, and the sampling process does not require CPU intervention to ensure data processing efficiency and reliability at high sampling rates; 3. The M3 amplitude and phase calculation module adopts prime factor and subgroup algorithms to reduce frequency 4. The M4 harmonic phase compensation module accurately compensates the phase angle of each harmonic power to achieve high-precision harmonic power measurement, thereby achieving high-precision harmonic Wave power accumulation.

Description

technical field [0001] The invention relates to the field of grid electric energy metering, in particular to a three-phase high-precision harmonic electric energy meter. Background technique [0002] The construction of energy Internet and smart grid solves energy problems, reduces carbon emissions, and improves the reliability and automation level of the power grid. At the same time, due to the extensive use of power electronics technology and nonlinear loads, the harmonic pollution of the power grid is becoming more and more serious. . Harmonic pollution not only causes harm to power grid equipment, but also affects the accuracy of electric energy metering and demand measurement, affects the fairness of metering, and brings economic interest disputes. The main reason is that the current billing energy meters basically use the full-wave algorithm. For non-linear load users, they not only output harmonics to the grid, but also pay less electricity bills. When linear users a...

AI Technical Summary

Problems solved by technology

An important premise for DFT calculation is to ensure that the sampling value is sampled at the current frequency at a full cycle and at equal intervals. If the frequency tracking is inaccurate, resulting in non-full cycle sampling, it will cause spectrum leakage and seriously affect the accuracy of harmonic measurement; especially in harmonic In the case of severe distortion, the ordinary zero-crossing detection method can no longer meet the requirements, and the method needs to be further improved;

[0005] 2) Due to the characteristics of the sensor conversion loop and the high-frequency crosstalk between adjacent loops, the phase characteristics of the hardware sampling loop at different frequencies are different

The actual measurement shows that the response delay of the current transformer is different at different frequencies, and there are differences in the phases of different harmonic orders; at the same time, there are also capacitance and inductance effects between the three-phase circuits, forming zero-sequence and negative-sequence components, resulting in Harmonic Phase Calculation Deviated

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