Automated Tool to Create Chronological AC Power Flow Cases for Large Interconnected Systems

Abstract

Power system planning engineers currently perform planning studies based on a few snapshots representing typical system operating points, also known as base power flow cases. However, that is not enough to fully understand and evaluate operational impacts of the current and future grid, especially in high uncertainty and extreme events. Time-series analysis must be considered. We developed a procedure for using production cost model (PCM) simulation data for wind, photovoltaic, and load levels to generate chronological, hourly power flow cases. Because the PCM uses a lossless, linear, DC power-flow solution for simulations, AC power flow must be converged to enable reliability planning studies. This paper describes a procedure to handle losses and reactive power planning for large, interconnected systems. The procedure is illustrated with an example using the Western Electricity Coordinating Council (WECC) 2028 Anchor Data Set (ADS) as a PCM and the WECC 2028 High Summer Power Flow case (22,000 bus system) as references. This procedure can be applied to systems with multiple AC and DC grids of any grid topology.

Keywords

• AC/DC
• power flow convergence
• power system analysis
• transmission planning
• reactive power planning
• voltage control