Optimal stability-oriented protection coordination of smart grid’s directional overcurrent relays based on optimized tripping characteristics in double-inverse model using high-set relay

[Display omitted] •Proposing a new optimal transient stability-oriented protection coordination method;•Smartly selecting characteristics for double-inverse relays equipped with HS relay;•Increasing the speed of stability-oriented protection scheme;•33.7% improvement in the sum of operating times of DOCRs compared to available methods;•Validating the optimum results and their CTI and CCT constraints in the DIgSILENT. Many studies have been devoted to developing the optimized protection schemes of smart grids. However, there is a research gap about studying the transient stability constraints in smart grids’ optimized protection schemes. Also, there is a major challenge in the transient stability-oriented protection system's speed due to increased coordination constraints and transient stability for synchronous distributed generations (DGs). This paper tries to fill such a research gap by developing a new transient stability-oriented method for optimized settings of directional overcurrent relays (DOCRs), smartly selecting relay curves in double-inverse relays equipped with high-set (HS) relays. This study's main advantage is achieving a fast and optimal protection system, while all transient stability constraints have been concerned. The proposed method has been studied in the IEEE 33-bus test system, while the GA and PSO algorithms solve the optimization problem. The comparative analysis of the test results with those of other available methods illustrates that 33.7% improvement in the sum of DOCRs’ operating time appears, while there is no stability constraint violation. The validation of speed and both coordination and stability constraints violations using the DIgSILENT simulations is another contribution of this research work.