| In order to cope with climate change,a clean and low-carbon energy transition has risen to the national strategy.While a large number of renewable energy grids promote clean substitution on the power generation side,they also impact on the conventional power grid dispatching system,causing problems such as abandoning wind,solar and water power.The renewable energy curtailment is the most severe during the heating season in Three North Areas of China.The reason is that Chinese power supply structure is dominated by coal power.Coal power is an inflexible power source.Thermoelectric power unit is one of the least flexible power sources because heat and power are not decoupled.The uncertainty of the wind and solar power output just puts forward high requirements for the flexibility of the power grid.Therefore,when the system flexibility is insufficient,the phenomenon of abandoning renewable energy will inevitably occur.Aiming at the above problems,especially the problem of electricthermal interaction,this thesis aims to follow the electric-thermal friendly interactive technical route of increasing heat storage capacity on the power demand side,and proposes corresponding models,algorithms and strategies to realize the quantitative analysis and optimal dispatching.First of all,based on the research framework of the adequacy of power generation and consumption in the power system,the electric-thermal interactive system is used as the research category to analyze the power generation principles of fire,wind,and solar and the heating principle of heat storage boiler.The power adjustment flexibilities are modeled according to the operating characteristics.Secondly,the concepts of heat boundary,power boundary,and heat storage feasible range are proposed.Based on these concepts,a quantitative evaluation method for the reserve capacity of heat storage boilers under a certain peak regulation strategy is given.Based on the actual power grid planning scenario,the size of the reserve capacity and the effect of absorbing new energy to the power grid under the high-rate thermal storage boiler heating mode is analyzed and inferred.The effects of factors such as the configuration of the thermal storage tank and the time scale of the electricity market are compared and analyzed.Thirdly,in the context of improving traditional dispatch operation,the reserve capacity of the thermal storage electric boiler is taken into account in the deterministic reserve constraint.Aiming at the objective function of minimizing coal consumption and penalties of abandoning wind and solar,an optimal dispatching model of electricheat interactive system with thermal storage electric boiler is established.The complex problems with continuous and discrete decision variables are turned into mixed integer linear optimization problems.The analysis of a numerical example shows that the configuration of a thermal storage electric boiler can effectively decouple the thermal power unit from “constraining electricity by heat” and make the interaction of the electric heating system more efficient.Finally,a risky dispatching strategy that can be applied to a higher proportion of renewable energy systems and is proposed,taking into account the electric-thermal interaction capability.By introducing the concept of Value at Risk,and taking the total cost of system risk control as the objective function,a risky dispatching optimization model based on multiple scenarios is established and solved.The analysis of examples shows that in the electric-heat system with high-permeability renewable energy,the risk dispatching can more reasonably arrange the unit output of the system than the traditional dispatching.It can obtain smaller expected risky cost in various scenarios with ensuring the reliability of the power grid operation. |
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