Geometric Optimization for Efficient Measurement of High-Voltage DC Systems using Shunt Technology with regard to current displacement effects

In response to evolving HVDC system and grid protection requirements, ensuring safe operation requires precise measurement of DC superimposed with AC components. Economically feasible DC measurements rely on shunts - low-ohmic resistors. However, existing naturally cooled shunts have a nonlinear impedance within the required bandwidth (up to 100 kHz). This research addresses the critical need for an innovative shunt design, aiming to balance bandwidth and amperage through geometric properties. The primary objective is to analyze various design options to overcome these challenges. Utilizing finite element analysis and a measuring system capturing real and imaginary impedance components as functions of frequency, different geometries were examined from literature and conceptual sketches. The analysis focuses on current displacement effects. Building upon the findings, an exemplary shunt is presented capable of measuring direct currents up to 6,000 A with a 3dB bandwidth of at least 100 kHz. The shunt design analysis addresses the critical challenges posed by nonlinear impedance, paving the way for enhanced safety and performance in in the latest generation of high-voltage direct current transmission systems.