Identification of Fault Line Selection and Section for Single-Phase Ground Fault in Small Current Grounding System

The fault characteristics of the small current grounding system are not obvious when the fault occurs. Currently, it is hard to accurately select and locate the ground fault in the small current grounding system. Therefore, in this paper, a scheme of fault grounding line selection and location is proposed based on the characteristic of the zero-sequence current matrix. As the zero-sequence current phase always lags behind the zero-sequence voltage when the amplitude of zero-sequence current increases. Based on this, we developed a State Matrix S. It can effectively reflect the degree of each region that is affected by the fault. Based on the State Matrix S, we can draw out the regional fault state value through a formula we created to quantify the influence of fault. Fault line selection and ground fault location can be accurately measured by calculating and comparing the regional fault state value of each region. The scheme proposed in this paper applies to a variety of the small current grounding system. The effectiveness and reliability of this scheme have been amply demonstrated through PSCAD/EMTDC simulations and experiments.