Analysis of an Abnormal Electronic Current Transformer Measurement and Optimization Strategy

An exhaustive analysis was conducted on an anomalous electronic current transformer (CT) measurement event observed within a VSC-HVDC back-to-back converter station. To unravel the underlying cause, a DC partial discharge test was performed alongside industrial CT scanning, revealing a mismatched discharge phenomenon stemming from the insulation dielectric resistivity. Based on this diagnosis, the study delves into the interplay between the identified fault mechanism and its consequences on the control and protection of the operational integrity. Consequently, a set of remedial measures is proposed, encompassing the enhancement of the system architecture through the addition of remote modules and spare optical fibers, coupled with the implementation of an improved S-bend insulator type.