MT 8 - TC 115/MT 8

IEC TS 62344:2022 applies to the design of earth electrode stations for high-voltage direct current (HVDC) links. It is intended to provide necessary guidelines, limits, and precautions to be followed during the design of earth electrodes to ensure safety of personnel and earth electrodes, and reduce any significant impacts on DC power transmission systems and the surrounding environment. This edition includes the following significant technical changes with respect to the previous edition:
- Changed the requirement of earthing resistance limit for short-time unipolar earth system in 5.1.3.
- Corrected the coefficient before ρs from 0,015 9 to 0,008 in touch voltage limit calculation formula (3) in 5.1.5.
- Deleted the analytical calculation formulas of earthing resistance for sea and shore electrodes in 6.1.3.
- Changed the current density limit from 100 A/m2 to 40 A/m2 ~ 50 A/m2 for the sea electrodes that are not accessible to human beings or to marine fauna in 6.1.7.
- Extended some detailed technical requirements for the measurement of ground/water soil parameters in 6.2.5.
- Reformulated the types and characteristics of electrode element material for sea and shore electrodes in 6.3.2.
- Added an informative Annex B: Earth electrode design process.
- Added an informative Annex C: Test results of human body resistance.
- Deleted the formula for calculating the average soil resistivity using harmonic mean when processing the measurement data in D.2.6 of Annex D.
- Extended some detailed technical requirements of electrode online monitoring system in Annex H.
- CIGRE 675:2017 is added to the bibliography.
- Terminology and way of expressions are modified using more commonly used terms in the HVDC electrode design industries and English-speaking countries, so as to make the readers understand the content more easily.