Abstract-The paper investigates the use of frequently discussed battery energy storage system (BESS) models for frequency regulation studies. Integration of a large number of renewable generation sources results in increased uncertainty in electric power generation, requiring, among the others, more frequency regulation services than before. The battery energy storage system models are compared and evaluated to assess their suitability for frequency regulation studies. The accuracy and complexity of BES models reported in the past are also discussed.
Index Terms-Battery energy storage systems, Load frequency control (LFC), Battery models
I. INTRODUCTIONhe operation of an electric power system is a complex process of forecasting the demand for electricity, and scheduling and operating a large number of power plants to meet that varying demand in real time. At every instant, electrical power generation should match power consumption to keep system frequency constant.The integration of renewable energy sources reduces the dependence on fossil fuels and greenhouse gas emission but increases variability and uncertainty in electric power generation. It is estimated that for every 10% wind penetration, a balancing power from other generation sources equivalent to 2% to 4% of the installed wind capacity is required for a stable power system operation [1]. Thus, with more penetration of intermittent renewables, the power system operation will become more complex and will require additional balancing power. As a result of this, there have been serious concerns over the safe and reliable operation of power systems with large penetration of renewable sources and reduction in conventional generation.Effective energy storage can match total generation to total load precisely on a second by second basis. Energy storage can facilitate load leveling for generators, load leveling for postponement of grid upgrade, frequency regulation, and power quality. Conventional generators may take several minutes or even hours to come online and will consume fuel