A Study Of Transient Equivalent Circuit Of Single-phase Earth Fault

As a result of the weakness of fault signals, it is difficult to detect faults. Compared with current fault detection (fault line detection and fault location) methods, the protections based on transient information fit the development demands of future network. It will be the develop direction of fault detection. So the transient characteristics of single-phase earthed fault should be analyzed systematically and deeply which will improve the reliability of transient fault detection methods.The fault transient essence can not be analyzed deeply without quantifies calculation. However, one of the current transient equivalent circuits ignores the influence of linear module component and the other ignores the influence of zero module inductance and resistance. So the models themselves are not currency. So it is necessary to establish an equivalent circuit with high accuracy in order to analyze the transient quantitatively.As a result of disadvantages and demands above, the phase-frequency and amplitude-frequency characteristics are analyzed in this paper. And also the simplification criterion is proposed. According to it, the simplification criterion is proposed as a RLC serises circuit which takes over the line model and zere model. And the simulation is more exact than current models.According to the characteristics of transient signals and the requirement of analysis, the evaluated method for error analysis is established which is benefit for model improvement. And the frequency, phase, amplitude and the linear weighted method is used to analyze the comprehensive error of indexes.In this paper, the high-precision models of single-phase earth fault base on distributed parameters and transient equivalent circuit are established by ATP software. Finally, simulations vertified the feasibility of the simplification and evaluated methods.The simplification of single-phase earth fault model can be established based on the simplification criterion. And the distributed characteristics are provided, so it can be use for fault location, enlarging the applicability. It can be used valuably and will be the driving force for correlation technique.