Research on optimal scheduling of an IEGS considering the flexibility of gas turbine units

Abstract

With the continuous increase in the installed capacity of gas turbine units， the coupling between electric grids and gas networks has become increasingly tight， forming an integrated electricity-gas system （IEGS）. As the proportion of renewable energy generation continues to rise and the discrepancy between peak and off-peak loads widens， the supply-demand imbalance in the IEGS becomes more severe. Therefore， the economic dispatch model of a two-stage IEGS considering the flexibility of gas turbine units is constructed. Firstly， given the constraints of gas network pressure on line pack， this paper proposes a flexibility evaluation model for gas turbine units that takes into consideration the impact of the natural gas system. It also establishes a modulation range index for the gas turbine units to assess their maximum adjustability. Then， the maximum adjustability of the gas turbine units is incorporated into the output constraints of the gas turbines in the power system. Based on the power system dispatch model， the paper aims to minimize the total operational cost. Lastly， the effectiveness of the proposed model is verified using the IEEE 39-node power system and Belgium 20-node natural gas system.

Keywords

• integrated electricity-gas system
• gas turbine unit
• flexibility
• line pack
• dispatch