With a high penetration level of wind generation, it's critical to establish a robust dynamic equivalent model of the wind farm for the system's stability analysis and smart grid development. Since wind farms may have a multi-stage development and are installed with different wind turbines from different technologies and/or venders, in this paper, a wind farm model with different types of wind generators is constructed according to Western Electricity Coordinating Council (WECC) generic wind generator models. In order to describe the dynamic behavior of the wind farm during system disturbances, by applying the data from phasor measurement units (PMUs), a multi-stage hierarchical parameters identification process based on heuristic algorithms is proposed to develop a dynamic equivalent model for the wind farm. Different scenarios are simulated to validate the effectiveness and robustness of the proposed equivalent model. In addition, the modal analysis is performed to further validate the proposed approach by comparing the eigenvalues between the detailed wind farm model and the equivalent model.

In this paper, a three-phase four-wire harmonic power flow analysis technique using a direct ZBUS method for distribution networks (DNs) is proposed. In this method, component models for three-phase four-wire DNs are developed considering neutral wires and grounding. In addition, harmonic loads are represented as equivalent injection currents. Finally, the outcome of a series of tests is used to verify the solutions of three-phase four-wire harmonic power flow problems.