Behavioral characteristic simulation research for a novel low voltage combined low power instrument transformer
Youpeng Huangfu, Xilai Hu, Peilin Liu, Shuli Yin, Shuhong Wang · Measurement Science and Technology · 2025
Abstract Low power instrument transformers (LPITs) have been massively penetrated in intelligent grids. This solution can be essentially extended to the case of low voltage networks, where the need for lower electrical insulation requirements allows the exploration of very compact and simple solutions. In this paper, a comprehensive behavioral simulation characterization study is performed to exploit a combined voltage and current LPIT architecture. It is essentially based on proven capacitive division and air-core Rogowski coil (RC) approaches for voltage and current measurements, respectively. To accurately compute the stray capacitances involved in the combined LPIT structure, a 3D electrostatic field finite element model is implemented. Furthermore, to evaluate the behaviors of the capacitive divider, specific field–circuit coupled numerical models in time and frequency domains are constructed. As such, the power frequency, distortion, fast transient as well as frequency responses can be characterized. Moreover, to analyze the performance of the shielded RC based current transformer, a simplified lumped circuit model is built. For reference purposes, analytical solutions are provided. Upon these theoretical analyses, a combined LPIT prototype and experimental setups are implemented for validation purposes. Measurement results verify the effectiveness and accuracy of the developed models. The prototype is further tested with basic accuracy requirements, which confirms the validity of the simple LPIT construction yet with high linear characteristics.