IEC/TS 62672-1:2013(E) applies to all line-commutated high-voltage direct current (HVDC) transmission systems used for power exchange in utility systems. HVDC stations with voltage sourced converters (VSC) are not covered. The purpose of this part of IEC 62672 is to define a standardized reporting protocol so that data collected from different HVDC transmission systems can be compared on an equitable basis. It covers point-to-point transmission systems, back-to-back interconnections and multi-terminal transmission systems. For point-to-point systems and back-to-back interconnections, i.e. two-terminal systems, statistics are to be reported based on the total transmission capability from the sending end to the receiving end measured at a given point. If, however, the two terminals are operated by different users/owners, or are composed of equipment of different vintage or of equipment from different suppliers, statistics can be reported on an individual station basis if so desired by those responsible for reporting. In such a case, the outage should only be reported under the originating converter station taking care not to report the same event twice. For distributed multi-terminal systems, i.e. systems with more than two terminals, statistics are to be reported separately for each converter station based on its own individual capability.