Reduction method for short-circuit capacity by unit commitment with network topology optimization

To achieve a carbon-neutral society, it is necessary to penetrate large amounts of variable renewable energy (VRE). Generally, VRE is connected via an inverter so the impedance of the system increases, then the shortcircuit capacity of the system decreases. However, it is necessary to maintain the connection of synchronous generators to ensure the reserve for the uncertain output of VRE. Therefore, there is a concern that the impedance of the system decreases and the short-circuit capacity remains high. Therefore, we propose a method that reduces short-circuit capacity by using network topology optimization, which is one of the methods used to reconfigure network topology in existing power systems. This method is verified by solving the unit commitment problem. Hence, this method is designed to determine the hourly schedule of the generators and the network topology. Furthermore, this method considers bus-splitting, which divides the elements connected to a substation into two groups. This method is verified by using the modified IEEE 14 bus test system based on the two-busbar model. The results show that this method reduces the maximum short-circuit capacity in the test system without changing the hourly schedule of the generators.