Conventional generation emulation for power grids with a high penetration of wind power

Abstract

Abstract Integrating large-scale wind plants with the electricity grids has many challenges for grid operators. Besides the variability and uncertainty of wind power, coordinating between different technologies of generation in the same grid can be considered the main problem, specifically for short-term frequency stability. Therefore, a large penetration of wind power generation in modern power grids has a risky influence on the power-system frequency. Wind-generation plants have contradictory behaviour compared to classic thermal plants, especially in active generated power-shortage events due to the variable nature of wind power. Existing experience in wind plants keeps part of the available wind power unloaded, using what are known as deloading techniques. Different deloading techniques are usually applied to emulate the thermal-plant-governor function and confirm a proper spinning reserve for any active-power shortages. These techniques decrease the generated power from wind plants continuously from maximum point tracking ones. Consequently, the practical capacity, annual generated energy and economical income of wind plants are reduced. In addition, grid-protection and control sub-schemes are set and designed according to the well-known conventional responses of thermal plants, which increase the need for thermal-plant-behaviour emulation. In this paper, instead of the usual deloading methods, a supercapacitors scheme is proposed with wind turbines to emulate the response of conventional power plants. The study discusses the technical and economic benefits of the proposed addition of supercapacitors in the wind-plant-planning phase. Restricted frequency grid-code indices are selected to evaluate studied behaviours. Simulation results of the IEEE four-generation two-area system determines the effectiveness of suggested schemes technically. The System Advisor Model (SAM) program estimates the economic benefits of a typical US study case compared with the existing wind-deloading technique.