Accurate Harmonic Voltage Measurement Based on Series Resistive‐Capacitive Divider for Gas‐Insulated Switchgear

ABSTRACT High‐penetration renewable energy and power electronic devices make high‐order harmonic voltages much concerned in modern power systems. Accurate measurement of harmonic voltages facilitates harmonic source localisation, harmonic mitigation and power quality evaluation. A series resistive‐capacitive divider for harmonic voltage measurement of gas‐insulated switchgear was studied. It has a harmonic voltage amplification characteristic, which enables accurate measurement of high‐order, low‐amplitude harmonics. In this manuscript, a design scheme of the series resistive‐capacitive divider was presented and an equivalent circuit was built. Using the finite element method, the partial capacitances in the equivalent circuit were calculated. Then, they were calibrated through the experiment. Finally, based on the calibrated capacitances, the effectiveness of the series resistive‐capacitive divider in improving the harmonic voltage measurement accuracy was experimentally verified. It amplifies harmonic components, thereby fully utilising the resolution of the analogue‐to‐digital converter, increasing the significant figure for the harmonic voltage measurement and enabling the accurate measurement of harmonics.