Exploring DC Power Quality Measurement and Characterization Techniques

TL;DR

This paper introduces new methods and tools for accurately measuring and analyzing power quality in low-voltage DC grids, which are becoming more important with the rise of renewable energy and DC technologies.

Contribution

The paper presents two traceable measurement chains optimized for both lab and field use to assess DC distortions with high accuracy.

Findings

Two complementary measurement chains were developed for assessing DC distortions with low uncertainties.

The methods can measure voltages up to 1000 V, currents up to 30 A, and frequencies up to 150–500 kHz.

The measurement techniques allow reliable conclusions about the dynamic behavior of low-voltage DC grids.

Abstract

Within the modernizing energy infrastructure of today, the integration of renewable energy sources and direct current (DC)-powered technologies calls for the re-examination of traditional alternative current (AC) networks. Low-voltage DC (LVDC) grids offer an attractive way forward in reducing conversion losses and simplifying local power management. However, ensuring reliable operation depends on a thorough understanding of DC distortions—phenomena generated by power converters, source instability, and varying loads. Two complementary traceable measurement chains are presented in this article with the purpose of measuring the steady-state DC component and the amplitude and frequency of the distortions around the DC bus with low uncertainties. One chain is optimized for laboratory environments, with high effectiveness in a controlled setup, and the other one is designed as a flexible and easily transportable solution, ensuring efficient and accurate assessments of DC distortions for field applications. In addition to our hardware solutions fully characterized by the uncertainty budget, we present the measurement method used for assessing DC distortions after evaluating the limitations of conventional AC techniques. Both arrangements are set to measure voltages of up to 1000 V, currents of up to 30 A, and frequency components of up to 150–500 kHz, with an uncertainty varying from 0.01% to less than 1%. This level of accuracy in the measurements will allow us to draw reliable conclusions regarding the dynamic behavior of future LVDC grids.

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