Introduction  Distributed generation (DG) has a significant impact on the operational characteristics of the load side of the power grid. However, current research focuses mainly on analyzing and modeling the characteristics of a single type of distributed generation, and there is limited research on general models that can uniformly describe DGs with certain similarities.

  Method  This article constructed an inverter-interfaced distributed generator (IIDG) model and employed a novel optimization algorithm. Firstly, based on the analysis of the characteristics and common features of IIDG, a comprehensive load model containing IIDG was constructed; According to the unified model, analytical calculations were performed to derive the state differential equation of the IIDG system and the output equation of the system model. To calculate the state and response of the system at each moment through continuous iteration and switch function updates, a formula for calculating the initial value of the system's state was provided. Combined with the sample data, the unified model identification process was given. Finally, the white shark optimizer (WSO) algorithm was employed to identify the parameters of the model; considering the voltage drop disturbance, the system model was sampled and analyzed.

  Result  The simulation results show that the proposed unified model can better reflect the IIDG characteristics in the case of different levels of voltage drop.

  Conclusion  The modeling error and parameter identification results show that the proposed unified model has good self-describing ability and parameter stability.