Development of High Renewable Penetration Test Cases for Dynamic Network Simulations using a Synthetic Model of South-East Australia

Power system studies rely on trusted benchmark models to test new theories and technologies. While many such models exist for small networks, realistic benchmark models for full-scale networks are less available due to data confidentiality. Synthetic models offer a solution to this issue by allowing the public release of network models through data obfuscation. One such transmission network model, based on Australia's National Electricity Market (NEM), has recently been made available, however, it lacks modelling details that are required to capture the dynamics of inverter-based generators (IBGs). This paper extends the existing synthetic model by incorporating dynamic models of IBGs. A Julia package is developed that applies generation and demand forecasts, as provided by the Australian Energy Market Operator (AEMO), and incorporates planned transmission network expansions. Initial attempts to solve AC optimal power flow (OPF) problems revealed convergence challenges. To address these issues, we propose a methodology to identify additional on load tap-changing transformers and reactive power compensation devices that enable successful AC OPF solutions. The modifications enabled successful AC OPF solutions for the first 144 half-hourly intervals of the projected 2050 network state. These operating points provide a foundation for analyzing the dynamic performance of IBGs in the future NEM. Analysis of both steady-state and dynamic performance validates the effectiveness of the enhanced model. Steady-state stability is observed in 134 mainland NEM scenarios. A comprehensive analysis of the stability and frequency performance of the model demonstrates its utility in studying power grids with high IBG penetration.