Interaction analysis between MMC-based VSC-HVDC links and DFIG-based WPPs within the AC network

Abstract

This paper deals with a detailed interaction anal- ysis between a wind power plant (WPP) including Doubly Fed Induction Generators (DFIG) and a Voltage Source Converter High Voltage Direct Current (VSC-HVDC) link based on Modular Multilevel Converter (MMC) technology, which are connected nearby. This analysis is approached obtaining the small-signal model of the WPP including a specific model of the generator, the partial scale converter including its control loops, the WPP grid and the transformers. Besides, the MMC- based VSC-HVDC link is modeled including the converter dynamics, the inner current controllers, the internal energy controllers and the outer control loops. Based on this model, the oscillation modes of the system are highlighted and a participation factor analysis is performed to identify which variables can be problematic. This analysis is carried out for different grid strength conditions. The derived linear model and the subsequent mathematical analysis results are validated through time domain simulations