Comparative Stability Analysis of a Combined DFIG-based and PMSG-based Offshore Wind Farm Connected to a Large Power Grid through a LCC-HVDC Link and an HVAC Line

Abstract

This paper presents the comparative dynamic-stability analysis of an integration of a doubly-fed induction generator (DFIG)-based offshore wind farm (OWF) and a permanent-magnet synchronous generator (PMSG)-based OWF fed to a large power grid through a high-voltage AC (HVAC) line and a high-voltage direct-current (HVDC) link based on line-commutated converter (LCC). The operating performance of the studied 60-MW PMSG-based OWF is simulated by an equivalent PMSG driven by an equivalent wind turbine (WT) while an equivalent DFIG driven by an equivalent WT through an equivalent gearbox is used to simulate the operating characteristics of the 80MW DFIG-based OWF. A frequency-domain approach based on a linearized system model using eigenvalue technique and a time-domain scheme based on a nonlinear system model subject to various disturbance conditions are both utilized to compare the damping characteristics contributed by the HVAC line and the proposed LCC-HVDC control scheme. It can be concluded from the simulation results that the proposed LCC-HVDC link is capable of rendering better damping characteristics to stabilize the studied integrated two OWFs fed to power grid subject to a severe fault than the HVAC line.