The circumstance of neutral-point displacement voltage due to imbalance of three-phase voltage in 66 kV resonant grounding system is more and more remarkble

which affects the safe operation of the equipment and increases the line loss. For calculating the capacitance parameters of the single and double-loop overhead line on the same tower with asymmetric arrangement

the potential coefficient matrix and capacitance matrix are introduced to represent the parameters of the line itself and the coupling relationship between the lines so to keep the calculation result more close to the practical parameters. The generating mechanism of neutral-point displacement voltage of voltage resonance circuit consisting of equivalent inductance and capacitance under action of asymmetrical voltage is analyzed in detail. The detailed equivalent model based on Matlab/Simulink platform is set up in accordance with actual 66 kV resonant grounding system and field operation data

and the numerical relationship among neutral-point displacement voltage

line asymmetry and system detuning degree is verified.