A Novel Online On-State Voltage Drop Measurement Technique for Thyristors

The thyristor is widely applied in industrial applications, for instance, line commutated converter-based high voltage direct current (LCC- HVDC) transmission. The performance of the thyristor directly affects the reliable operation of system and it is closely related to temperature. The on-state voltage of the thyristor can be used for temperature estimation for the thyristor. However, there are few studies about online on-state voltage measurement for the thyristor. Therefore, it is particularly crucial to further study the technique of online on-state voltage measurement of thyristors. In this paper, a novel online measuring method for the on-state voltage of thyristor is proposed. The proposed method can measure the on-state voltage drop of the thyristor with fast response and high accuracy, without disturbing the normal operation. The accurate measurement of the on-state voltage of the thyristor can be utilized for estimating junction temperature. Experiments and simulations verify the feasibility of the proposed technique. The online on-state voltage drop measurement technique proposed is greatly meaningful for condition monitoring and reliable operation.