Assessing the impact of a pumped-storage power station on the normal operation of the Mongolian power system

The paper is aimed at assessing the impact of integrating pumped-storage power stations on the steady-state operation of the Mongolian central power system, as well as its operational reliability, in the context of growing power consumption and the increasing share of renewable energy sources. The study was conducted employing the machine learning method (specifically, ensemble models and statistical ranking models) to build a model of the daily load curve, as well as the power generation of wind and solar power plants. The computations were performed using the Pandapower software, which provided a means to take into account the actual technical characteristics of power grid equipment, analyze normal conditions, and optimize the operating conditions. The modeling results indicate that the integration of four pumped-storage power stations with a total capacity of 250 MW significantly smoothes out the irregularity of the daily output curve of thermal power plants. The irregularity factor indicating the minimum-to-maximum daily load ratio increased from 0.8 to 0.96. An analysis of operating conditions did not reveal overloading of backbone transmission lines or unacceptable node voltage deviation. The total power losses in the central energy system of Mongolia were shown to increase insignificantly with the integration of pumped-storage power stations amounting to 5.54% (5.36% without taking them into account). This fact confirms that the redistribution of significant amounts of power associated with the growing share of renewable energy sources in the Mongolian power system requires a thorough analysis of the technical status of equipment and an increase in transmission line capacity. Thus, the integration of pumped-storage power stations by 2030 will make the control of the Mongolian central power system more flexible. This will increase domestic power generation, reduce ohmic losses in the grid, decrease the volume of power imports from Russia, lower the risks of outages in the central region of Mongolia, and effectively solve the power shortage problem.