IEC 62823:2015+A1:2019 defines routine and type tests on thyristor valves used in thyristor controlled series capacitor (TCSC) installations for a.c. power transmission. The tests specified in this standard are based on air insulated valves operating in capacitive boost mode or bypass mode. This consolidated version consists of the first edition (2015) and its amendment 1 (2019). Therefore, no need to order amendments in addition to this publication.