A universal high voltage SF6 circuit breaker for HVDC and HVAC systems

High voltage alternating current (HVAC) and high voltage direct current (HVDC) transmission systems have acted as the pillars for the transmission field in power networks. Thus, two types of circuit breakers (CBs) existed; HVDC-CB and HVAC-CB. This imposed a burden on manufacturers by requiring them to set up a separate production line for each type of them, increasing production time and overall cost. This paper proposes a solution for this problem by combing both types into a single universal frame termed as UHAD-CB that could be utilized in both systems. Achieving this aim would reduce the manufacturing obstacles and benefit the entire industry. The proposed UHAD-CB was based on the structure of HVDC-CB which utilizes SF6 interrupter equipped with shunt L-C branch. The UHAD-CB is tested in both HVDC and HVAC systems and the results proved its reliability in both systems. The evaluation analysis for the performance of UHAD-CB showed its ability to reduce the transient recovery voltage by 28% in comparison to conventional HVAC-CB. This increase in performance rates allowed the usage of SF6 interrupter with lower cooling power than that for HVAC-CB which compensates for the added cost for L-C branch. In addition, the overall reduction in cost from the manufacturing point of view would add to that benefit. Finally, the optimum L and C values were found to be in range of 0.1 mH and 50 µF respectively for the selected systems.