Design and verification of shell reactor for retrofit of light triggered thyristor valve

In LCC valve, each module contains at least one saturable reactor（SR）, which protects the thyristors from being damaged by excessive di/dt and d V/dt. There are two types of SR called core-type and shell-type,which are used in LTT and ETT valves respectively. However, due to design defects, iron core sinking and water leakage had occurred in few core-type SRs, while shell-type SRs are more reliable. Therefore, it is very important to develop new shell-type SR for replacement of core-type SRs in LTT valve. Firstly, the structural installation,electrical and water connections of the new shell-type SR are designed to make it fully compatible with LTT valve.Secondly, The influence law of the model and parameters on the output characteristics is analyzed, and the design principle of the main parameters of new shell-type SR is obtained. Finally, iron core temperature measurement and substitutable verification of the new shell-type SR are carried out. The test results show that the new shell-type SR has reasonable heating and better protection for thyristor, which can meet the needs of LTT valve retrofit.