A Novel Control Strategy for Transmission Level Interconnection of Large Scale Renewable Energy Generations

Abstract

This thesis illustrates novel voltage control strategies applied for large scale renewable energy generations in order to overcome the issues related to the integration in the electric grid. Designed control strategies are applied to large scale wind parks and photovoltaic power plants connected to the grid at transmission level and are compared to the existing voltage control strategies. The designed online supervisory voltage control scheme for the photovoltaic power plants allows them to participate in the voltage control, by means of reactive power injection or absorption depending on the grid conditions. As for the designed adaptive secondary voltage control for the wind parks, it also utilizes the capacity of voltage support provided by doubly-fed induction generators. In addition, to enhance the transient stability of the system, automatic gain controllers are included. Both algorithms take into account the intermittency of wind and solar irradiance in order to maximize the reactive power support and minimize the loading of individual generation units. The effectiveness of the proposed algorithms is tested in a weak power grid with low X/R ratio at different short circuit ratios. To evaluate the dynamic performance of the proposed algorithms the system is stressed to contingencies, such as sudden load change and three-phase to ground fault. As the designed strategies rely on a wide area measurement system, impact of communication time delay is taken into consideration.

Date of Award	Jun 2013
Original language	American English
Supervisor	Mohamed El Moursi (Supervisor)