Relationship between Supply-demand Balance and Domain of Existence of the Number of Connected Generators for Determining Unit Commitment in Power System with a Large Integration of Renewable Energy Sources

Abstract

In general, conventional power generators, which are scheduled to operate in unit commitment (UC) planning based on power generation and demand forecasts, have their output regulated to maintain the power balance and to minimize their operational cost for demand and supply operation in power systems. The number of operating (connecting) generators determines whether the power balance can be maintained or not. During load dispatch, it is difficult to start-up or stop generators at once for securing regulating capacity. A power surplus occurs if outputs less than the minimum outputs are requested of the connected generators, whereas a power shortfall occurs if outputs greater than the maximum outputs are requested. In this study, we analyze the relationship between the supply-demand balance and the domain of the existence of the number of connected generators for determining UC in a power system with a large integration of renewable energy sources. Moreover, we discuss quantitatively the impact of the power system conditions on the supply-demand balance using two-dimensional diagrams and numerical simulations.

Coordinated operation of a battery energy storage system and thermal generators for supply–demand balance maintenance and efficient use of photovoltaic energy

“…Available capacities of nuclear power, hydropower, and thermal power are given in Table . The data for thermal generators are cited from the literature with regard to the Improved Power System Standard Model . Thermal generators are assumed to be committed in the descending order of fuel cost at rated output, and 5% rated output is utilized as LFC regulation capacity.…”