Evaluation Method of Impulse Voltage Scale Factor Based on Energy Spectral Density

• Published in: IEEE transactions on instrumentation and measurement Vol. 73; pp. 1 - 10
• Main Authors: Long, Zhaozhi, Zhou, Feng, Fan, Jiawei, Diao, Yinglong, Li, Wenting, Wang, Zhehao, Hu, Kangmin, Lin, Fuchang
• Format: Journal Article
• Language: English
• Published: IEEE 2024
• Subjects: Current measurement; Energy measurement; Energy spectral density; experimental validation; impulse voltage; Lightning; measuring device; scale factor; Time measurement; Time-frequency analysis; time-frequency transform; traceability; Voltage measurement; weight
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2024.3446622

To ensure the evaluation uniformity of the values of impulse voltage parameters, a method for determining the scale factor of impulse voltage measurement or a generation system based on multifrequency component synthesis in the energy domain is proposed. According to Parseval's theorem, a functional relationship between the impulse scale factor and the ac scale factors is established for the impulse voltage measuring device. The challenge of accurately obtaining the scale factor for the measuring device under aperiodic instantaneous pulse waveforms is transformed into two problems: obtaining the scale factor for the periodic alternating voltage of different frequencies and calculating the weight of each frequency band. At the same time, the systematic errors introduced by approximation and segmentation during the process of converting mathematical models into measurement models are analyzed. Finally, a specific implementation method based on this evaluation method is proposed. An experimental verification of the impulse scale factors was conducted separately for a digital recorder and an impulse voltage divider. The results showed that the proposed method can accurately assess the scale factors of impulse voltage measuring devices, with feasibility and operability in metrological practices. The extended uncertainty of the impulse voltage scale factor obtained through this method is 0.02%. Furthermore, the evaluation method is universal; therefore, theoretically, any impulse voltage that can be represented with a mathematical function can be decomposed and evaluated for scale factors using this method.