The development of 6 kV network models for the study of digital instrument transformers with arc intermittent single-phase ground faults

The Ivanovo State Power Engineering University (ISPEU) and industrial partners have developed combined digital measuring current and voltage transformers (DCVTs). Numerous studies and tests have been carried out on DCVTs, giving experience in their use for commercial electricity metering. However, some applications require additional research, in particular, their use as a primary sensor for relay protection against single phase faults. This article presents an outline for an experimental study of a combined DCVT 6 (10) kV with arc intermittent single-phase ground faults (AISPGF), using “closed cycle” physical and mathematical modeling. Based on statistical data, a simulation model of a section of a 6 kV electric network region in RSCAD RTDS has been developed to simulate transient processes during AISPGF according to known theories. The article presents the results of model verification with the MATLAB Simulink software package and an analytical solution. The results of experimental studies of 6 (10) kV central heating transformers in AISPGF modes are presented in conditions as close as possible to real electrical installations. Conclusions are drawn about the applicability of the resulting models.