Impact of Wind Generation on Grid Frequency Stability

摘要

The integration of renewable energy sources into power systems has gathered significant momentum globally because of its unlimited supply and environmental benefits. Within the portfolio of renewable energy, wind power has been experiencing a steadily increasing growth. Despite its well known benefits, wind power poses several challenges in grid integration. The inherent intermittent and non-dispatchable features of wind power not only inject additional fluctuations to the already variable nature of frequency deviation, they also decrease frequency stability and reliability by reducing the inertia and the regulation capability. To ensure the system security, the integration of wind power must be limited and the wind generation has to operate in the condition that enables wind generator to support the frequency control. As a result, the reliability of wind power must be re-estimated based on the wind power that can be accepted by the system, instead of the total wind production. This research examines the impacts of wind generation on system inertia and the regulation capability as well as the effect on tie-line flows and area control error. The effect of wind power on frequency regulation capability at different penetration levels is also investigated. The mathematical and simulation model to determine maximum wind power penetration level, given a frequency deviation limit, is developed. Based on the proposed mathematical model of wind penetration limit, the negative impact of wind on system reliability is examined. An improved method to coordinate the energy storage with the existing system to improve the wind-integrated system reliability while maintaining the system frequency security is also proposed. An approach to assist the integration of wind power with grid-scale virtual energy storage will be developed and examined. This thesis discusses the pertinent background and state of the art, and describes the proposed approaches and the results obtained.