Abstract: [Objectives] The high proportion of renewable energy generation connected to the grid and the operation of combined heat and power units ‘based on heat’ have led to insufficient peaking of the power system. Therefore, it proposes the configuration of electric thermal storage boilers in large-scale thermal power plants and the use of heat storage characteristics of the heating network to jointly participate in power system peaking. [Methods] Firstly, the feasible domain mathematical model of thermoelectric decoupling is established by combining the electric thermal storage boiler with the thermal storage system and the area of the feasible domain is used as a flexibility evaluation index to analyse the flexibility of peaking. Secondly, the resistance of thermal inertia to power fluctuation and the delayed response characteristics are analyzed, and a model of thermal inertia on the primary side of the heating network is constructed based on the second-order windward implicit format of Taylor expansion, and the heat storage capacity of the heating network is quantitatively corrected for the output of combined heat and power units. Finally, with the objective of minimizing the daily operating cost, an optimal operation model is established to participate in the deep peaking of the power system using the heat storage characteristics of the electric thermal storage boiler and the heat supply pipe network.[Results] Through scene comparison, it is verified that this model expands the range of electrothermal power regulation of cogeneration units and increases the range of the feasible operation region.[Conclusions] The model can improve the depth and flexibility of peak regulation of cogeneration units, reduce daily operating costs, and increase wind power consumption.

Key words: cogeneration unit;thermoelectric decoupling, electric thermal storage boilers, pipe network heat storage, quantitative heat storage, deep peak regulation, optimal operation, wind power accommodation