Modeling of smart inverter functions executed by photovoltaic systems for power flow analysis

The significant growth of variable renewable generation might cause adverse technical impacts on the power grid. Smart inverter functions, recommended by the IEEE 1547-2018 standard, help mitigate those impacts with inverter-based resources, including photovoltaic systems, yet traditional steady-state power flow modeling of generation is inadequate to represent these controls. This work proposes a new model for smart inverter functions that includes fixed power factor, volt-var, and volt-watt, based on single-phase Newton-Raphson power flow, useful for analyzing its benefits with reliable simulation results. The model incorporates key photovoltaic system components and employs smooth functions and complementarity problems for representing limits and piecewise linear curves via a fully unified approach. The solution results in photovoltaic system internal variables for dynamic model initialization and control center operations. A review of control and limit inclusion in power flow is also provided. Computational simulations validated the model, demonstrating its advantage in the Newton-Raphson convergence characteristic while maintaining a viable computational cost between 2 and 3 times the traditional power flow simulation time. Comparisons with OpenDSS modeling revealed the proposed modeling requires fewer and more regular iterations, around 8, and maintains similar numerical robustness.