Control, Modeling, and Analysis of Inverter-Based Resources

Abstract

The increased penetration level of Inverter-Based Resources (IBR) presents new challenges to the planning and operation of electric grids traditionally designed, protected, and operated based on the inherent characteristics of synchronous machines. Inverters do not have the same inherent properties as synchronous machines and respond based on their control algorithms. The inverter control and design are proprietary, resulting in black-box models provided by inverter manufacturers for proposed interconnections. This work develops a generic model specification and model prototype implementation in an electromagnetic transients simulator of an inverter applied in large IBR plants. The inverter control is designed and tuned to meet the voltage ride-through response performance requirements specified in IEEE P2800 Draft Standard for Interconnection and Interoperability of Inverter-Based Resources Interconnecting with Associated Transmission Systems. The control objective, process model, control implementation, and analytical tuning approach are detailed for each controller. Instantaneous sequence component detection methods proposed in the literature are investigated and modified to allow controlled negative sequence current injection. A current limit logic is developed to ensure the current in each phase is limited to the inverter’s current limit and the prioritization of the incremental sequence components of the current is consistent with the performance requirements in IEEE P2800. Time-domain simulations in PSCAD™ show that the inverter model’s low voltage ride-through response meets the performance specifications for symmetrical and asymmetrical faults. Further, comparisons of the time-domain simulations to laboratory testing measurements of a 2.2 MVA battery storage inverter verify the capability of the model to predict the controlled response of a commercial inverter for terminal voltages consistent with symmetrical and asymmetrical faults.