IEC 60700-1: 2008 applies to thyristor valves with metal oxide surge arresters directly connected between the valve terminals, for use in a line commutated converter for high voltage d.c. power transmission or as part of a back-to-back link. It is restricted to electrical type and production tests. The tests specified in this standard are based on air insulated valves. This consolidated version consists of the first edition (1998),its amendment 1 (2003) and its amendment 2 (2008). Therefore, no need to order amendments in addition to this publication.