A time, cost and safety optimized approach for cable impedance measurements

The energy transition is driving rapid growth in the electrical power grid, particularly in Distributed Energy Resources (DER) systems, distribution networks, and industrial plants. Urban medium voltage cable networks often need expansion to accommodate new roof-top solar systems and charging stations for electrical vehicles. Correct impedance values for cables in such networks are crucial for distance protection relays, load flow calculations and fault location indicator functions. Those are often unavailable for legacy or frequently expanded cable systems and needs to be calculated or measured. The shortage of trained personnel further complicates this issue. To address this challenge, there is potential for developing an optimized cable impedance measurement system for such application scenarios. This paper presents an analysis and optimization of key elements in existing cable impedance measurement systems in this respect, validated through practical measurements. The optimized measurement system demonstrated significant advantages, including time savings, weight reduction, higher safety and improved efficiency, highlighting their potential to address the challenges posed by the energy transition and workforce shortages.