الفهرس | Only 14 pages are availabe for public view |
Abstract This dissertation addresses some of the technical challenges raised by the integration of wind power into weak power systems. The main objective is to investigate the dynamic interactions between the wind power generators and interconnected power systems, pinpoint the constraints and operational limitations and meanwhile propose potential solutions to maximize wind power penetration and improve the dynamic stability of the network. First of all, this work investigates the characterization and assessment of voltage and power constraints raised by connecting a DFIG WT to a weak network. As a basis of investigation, a simplified system model is utilized and the respective POC voltage, active and reactive power stability issues are evaluated and identified based on a steady-state study for DFIG WT system. Secondly, a detailed megawatt-level variable speed wind turbine with partial scale converters connected to a weak network with widely varying parameters, i.e., short circuit capacity ratio SCR and X/R ratio is modeled in MATLAB/SIMULINK environment and investigated. An adaptive voltage control AVC scheme based network parameters and operating point is proposed to continually retain voltage constancy and smoothness at the point of connection POC in order to maximize the wind power penetration. Besides, a proposed reactive power dispatch to handle the reactive power sharing between the DFIG inherent stator reactive power and an oversized grid side converter is presented. The AVC showed pronounced mitigation capability with better damped performance particularly at very weak grid condition compared to traditional PI controllers. Thesis objectives: Propose an adaptive voltage control system to maintain voltage constancy and smoothness at the point of connection. Propose a reactive power dispatch strategy to handle reactive power sharing between the DFIG and the grid side converter Propose a generalized fault ride-through for WPPs connected to stiff as well as weak networks. |