Test bench development for functional testing of DC protection relays

HVDC systems that interconnect large generation and load centres are expected to facilitate the massive expansion of offshore wind energy. These HVDC systems combine vendor-specific technical designs and operation concepts. The successful operation of these HVDC systems requires well-defined functional specifications and test procedures for all the components of the protection system. To validate the performance of DC protection relays, a test bench for DC relays is necessary. However, existing requirements for DC relay tests are unclear, and no standardized procedures exist to validate the functionality of HVDC protection. Currently, real-time simulation is the most advanced testing method available, but it has accuracy limitations for high bandwidth testing, and its practicality and cost-effectiveness can vary based on the application. This paper presents a novel design of a DC protection relay test bench and discusses key considerations and hardware specifications for a suitable test bench. The presented test bench meets future testing requirements and includes high sample rates, accurate models, and necessary automation controls. Finally, several case studies are presented to demonstrate the practical implementations and test limitations of the test bench.