Sizing of Synchronous Condensers to Strengthen a Large-Scale Network Model

This paper presents a method for the optimization of the size and location of synchronous condensers (SCs) to meet a grid strength requirement defined by a minimum effective short-circuit ratio at monitored buses. It is proposed to use the Nelder-Mead algorithm (NMA) to minimize the total short-circuit contribution of SCs installed at candidate buses. The Basin Hopping algorithm is used to iteratively run the NMA so as to guarantee that possible solutions around of the global minimum are identified. The proposed approach was applied for the sizing of SCs in a large-scale model of the National Electricity System of Chile in a scenario with extremely high penetration of inverter-based resources. It is verified that the problem has several solutions leading to similar values of total short-circuit power contribution but different allocations to the candidate buses. Sensitivity analysis are run to asses the impact of converting existing thermal generating units to allow their operation as SCs.