A novel method for accurate ground parameter estimation in MV networks

Abstract This paper presents a novel method for ground parameter estimation that enables the accurate estimation of the total ground capacitance and conductance in MV networks. The novelty of the method is that the effect of the leakage impedance of the inductive voltage transformer can be significantly reduced compared to the prior-art method. The key idea of the novel method is based on dual inductive voltage transformers for resonant earthed neutral networks. Until now, it has been necessary to simplify the equivalent circuit model by neglecting the effect of the inductive voltage transformer leakage impedance to enable ground parameter estimation with the prior-art signal injection-based method. The experimental test results clearly demonstrate the significant effect of the inductive voltage transformer leakage impedance on ground parameter estimation with the prior-art method and show that the proposed method is effective at improving the accuracy of ground parameter estimation, which is beneficial for the security risk assessment of underground cables, the configuration and expansion capacity of the Petersen coil and the detection of high-impedance ground faults.