Key Parameter Design of Smart Grounding Distribution Systems

Abstract

To make full use of smart grounding system to solve single-phase grounding fault in the neutral non-effectively grounding distribution systems, based on the simple description of basic principles, the transient process during the closing and opening period of the grounding switch and inhibition measures are analyzed in detail, the techniques of transient process reduction and grounded phase identification error correction are described with the corresponding analysis, the design parameters of intermediate resistance of grounding are obtained. The method of identification and location of the single-phase grounding position in permanent single-phase grounding fault for systems with neutral ungrounded and with neutral grounded through an arc-suppression coil are investigated, respectively, together with their design considerations. A method of identifying the disconnected feeder is put forward based on the ratio of zero sequence current before and after accessing the pulse grounding transformer. The simulation and experimental results are in consistent with the theoretical analysis, which shows the feasibility and effectiveness of the proposed method.