Demand-side contribution to secondary frequency control in an isolated wind-aluminum system

High penetration of wind power with the characteristics of randomness and fluctuation will affect grid frequency stability, especially in an isolated power system. Taking an isolated industrial power system which is a recycling economy demonstration project owned by China Power Investment Corporation as the studied system, the frequency response characteristic of power system with demand side contribution is modelled. The returning negative feedback signals from the AGC reset the power output reference of the power plants and the ASLs to maintain the grid frequency at 50 Hz. This paper takes wind power fluctuations as a stochastic process rather than a deterministic signal to assess grid frequency deviation based on the power spectrum density (PSD) theory. Finally, the proposed control strategy is used to assess the permitted wind power penetration while meeting the requirement of deviations limit in an actual industrial isolated power system. Results in this paper can be useful in improving wind power penetration level and providing valuable information for power system restructuring process.