Critical Review of Cigrè Technical Brochure 852

In November 2021 the Cigrè WG B1.61 issued Technical Brochure 852, entitled “Recommendations for testing DC extruded cable systems for power transmission at a rated voltage up to and including 800 kV”. In some respects, this TB is mostly in line with previous TB 219:2003 and TB 496:2012, but it has also introduced novelties, like revisions of test criteria, regimes and methods, and special Temporary Overvoltage tests. Nevertheless, TB 852:2021 has several gaps and weak points. First and foremost, despite the statement “Wherever possible, the tests are based on existing recommendations, standards and practices”, TB 852:2021 neglects IEEE stds. 1732:2017 and 2862:2020, relevant respectively to space charge measurements on HVDC cables and AC voltage test with Partial Discharge (PD) measurement; such topics are very important for the performance and reliability of HVDC cable systems. The gaps and weak points of TB 852:2021 are treated here, aiming at improving it, also in view of future IEC standards and forthcoming HVDC cable projects at increasing levels of voltage, power and length.