Based on the above analysis, a control strategy based on cooperative frequency modulation of thermal power units and an energy storage output control system is proposed to improve the frequency stability of the power grid.
The dynamic frequency modulation model of the whole regional power grid is composed of thermal power units, energy storage systems, nonlinear frequency difference signal decomposition, fire-storage cooperative fuzzy control power distribution, energy storage system output control and other components. Fig. 1.
The challenges of large-scale energy storage application in power systems are presented from the aspect of technical and economic considerations. Meanwhile the development prospect of global energy storage market is forecasted, and application prospect of energy storage is analyzed.
Due to rapid development of energy storage technology, the research and demonstration of energy storage are expanding from small-scale towards large-scale. United States, Japan, the European Union have proposed a series of policies for applications of energy storage technology to promote and support industrial development [12 – 16].
Under the four control strategies of A, B, C and D, the hybrid energy storage participating in the primary frequency modulation of the unit |Δ fm | is 0.00194 p.u.Hz, excluding the energy storage system when the frequency modulation |Δ fm | is 0.00316 p.u.Hz, compared to a decrease of 37.61 %.
The application of energy storage technology in power system can postpone the upgrade of transmission and distribution systems, relieve the transmission line congestion, and solve the issues of power system security, stability and reliability.