Research on test methods for conducted differential mode current disturbances

With the widespread adoption of power electronic devices, frequency converters, and power line communication systems, the issue of differential-mode current disturbances in the 2 kHz to 150 kHz frequency band has become increasingly prominent. Such high-frequency interference, coupled into electrical equipment through AC power ports, may cause measurement deviations or even functional anomalies in energy metering devices, posing a serious threat to the metering accuracy and operational reliability of smart grids. To systematically evaluate the immunity performance of electricity meters, the International Electrotechnical Commission (IEC) and various national type evaluation standards explicitly require conducted differential-mode current disturbance tests, stipulating that the test frequencies must cover the entire band in 1% increments. However, this stringent requirement results in over 400 frequency points per test, posing challenges for traditional analysis methods, including inefficiency and difficulty in extracting key characteristics. To address the massive data processing demands of high-frequency differential-mode interference testing, this paper proposes a graphical analysis method based on the time-frequency domain of interference signals, enabling rapid localization of interference-sensitive frequency bands and precise diagnosis of meter vulnerabilities. The research findings not only provide data support for optimizing the interference immunity design of electricity meters but also offer significant reference value for refining high-frequency interference test specifications in international standards. This approach can substantially improve type evaluation efficiency and reduce R&D testing costs for manufacturers.