Conventional vs non-conventional voltage transformer sensors: experimental performance comparison

Purpose This study aims to experimentally evaluate and compare a conventional voltage transformer and two non-conventional voltage transformer sensors to assess accuracy, robustness and suitability for modern power system measurement and digital substation applications. Design/methodology/approach Comprehensive laboratory tests were performed under identical conditions to examine voltage sensor performance in terms of ratio accuracy, linearity, frequency response, burden capability, overvoltage withstand and temperature stability across a wide operating range of voltages, frequencies, loads and ambient temperatures. Findings The conventional voltage transformer demonstrated superior accuracy, burden handling, and thermal stability under nominal conditions but showed limitations under frequency deviation and overvoltage due to core saturation. The non-conventional voltage transformer sensors maintained linear operation over wider voltage and frequency ranges but exhibited higher temperature sensitivity and required calibration to achieve high accuracy. Quantitatively, the conventional VT achieved ratio errors below 0.2% within its rated range, while the NCVT sensors exhibited approximately 0.5%–2% error prior to calibration but maintained linear operation up to 1.9 per-unit voltage without saturation. Originality/value This work presents a direct, side-by-side experimental comparison of conventional and non-conventional voltage transformer sensors using unified test procedures, providing practical insight into sensor-level trade-offs relevant to future digital substation deployment.