prEN IEC 60071-12:2021

This standard applies guidelines on the procedures for insulation co-ordination of line commutated converter (LCC) stations for high-voltage direct current (HVDC) project, whose aim is to give guidance for the determination of the specified withstand voltages for equipment. The content of this document strictly follows the flow chart of the insulation co-ordination process and give detailed information on the concepts governing the insulation co-ordination process which leads to the establishment of the specified withstand voltage levels. This document emphasizes the necessity of considering, at the very beginning, all origins, all classes and all types of voltage stresses in service. At the end of the process, when the selection of the specified withstand voltages takes place, does the principle of covering a particular service voltage stress by a specified withstand voltage apply. The annex contains examples of insulation co-ordination for LCC HVDC converters which support the concepts described in the main text, and the basic analytical techniques used.