Analysis of the Impact of Shunt Coefficient on Measurement Accuracy in Grounding Impedance Testing

DOI: https://doi.org/10.62517/jes.202502417

Author(s)

Quan Gan

Affiliation(s)

Guoneng Nanjing Electric Power Test & Research Limited, Nanjing, Jiangsu, China

Abstract

This paper systematically reviews the mechanisms and optimization strategies for the impact of the shunt coefficient on measurement accuracy in ground impedance testing. Based on electromagnetic field theory, the interference of shunt current through paths such as lightning arresters and cables on the injected current and voltage potential difference is analyzed, revealing the mechanism that leads to impedance underestimation. In conjunction with the literature, the definition, role, and existing correction methods for the shunt coefficient are discussed, including quantitative evaluation of current compensation and voltage perturbation models. The study further elaborates on a threshold method for establishing the shunt ratio, simplifying engineering measurements by ignoring minor shunts, improving efficiency and accuracy. The review demonstrates that a shunt correction model that comprehensively considers the effects of current and voltage can significantly improve test reliability, providing theoretical guidance and practical basis for the accurate evaluation of power system grounding devices.

Keywords

Ground Impedance; Shunt Coefficient; Measurement Accuracy; Electromagnetic Field Theory; Correction Method

References

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