A comparative study on electrical and thermal stress distribution across fundamental components of conventional and superconducting hybrid type HVDC circuit breakers

Super grids are considered to be the technology of the future that will allow transmission and trade of huge volumes of electricity over long distances. HVDC is the preferred choice for developing super grids as HVAC transmission of bulk power over long distances is less efficient. However, the key obstacle in developing HVDC super grids is the absence of HVDC circuit breakers (DCCB) which can quickly detect and isolate the fault. The huge electrical and thermal stresses subjected to DCCB during DC current interruption are one of the primary challenges in developing DCCB. Especially, IGBT valves in hybrid DCCB are the most expensive and sensitive part and their cost drastically increase with their maximum rating. This research paper presents a comparative study on the electrical and thermal stress distribution across IGBT valves of conventional hybrid DCCB (CDCCB) and Superconducting hybrid DCCB (SDCCB) during fault conditions. Realistic CDCCB and SDCCB models were developed by considering the characteristic values of commercially available IGBT module. To create the electrical and thermal stress profiles, CDCCB and SDCCB were placed in HVDC test bed model and transient simulations were performed. The voltage distribution, current distribution and energy dissipation profiles across IGBT valves were developed for CDCCB and SDCCB. Comparative analysis of the profiles showed that the SDCCB components were subjected to relatively lower electrical and thermal stresses.