Research On Heat-Electricity Combined Scheduling Method Of Peak Load Regulation Considering The Characteristices Of The Heat Network

In northwest,north and northeast parts of China,the power system mainly consists of cogeneration,and a large proportion of wind power.During the winter heating period,the high power outputs of the cogeneration units and the wind power units lead to the difficulty of peak regulation and seriously wind power abandon.Scholars at home and abroad put forward a variety of proposals for optimal scheduling combined heat and power system,decoupling the cogeneration units' "power subject to heat" constrain,which include a solution of curtailed wind power accommodation based on electric boiler for distributed daily peak-load regulation at secondary heat supply network.The proposals are proved to enhance wind power consumption rate of the power grid,but they assume that the heat transfer is an instant process when it comes to the modeling and simulation of the heat network.In fact,the heat network has delay and attenuation characteristics,which results in a big deviation between the simulation results and the actual running state of the network.The paper puts forward a solution of curtailed wind power accommodation based on electric boiler for distributed daily peak-load regulation at secondary heat supply network.The paper also studies the construction of the thermoelectric system considering the characteristics of the delay and attenuation.Furthermore,discusses the influence cost by the characteristics of the thermal network on the wind power consumption capability of the system.At first,the paper presents a practical thermal network based on the existing hydraulic model,the thermal model and the actual structure and operation characteristics of the thermal network.The model is simple and convenient to take into account the electric heating equipment such as electric boiler,and also be transformed to the thermal network constraint equation.In this paper,the main factors influencing the delay characteristics and attenuation characteristics of the thermal network are studied,and the calculation model of the delay time and thermal attenuation rate is established.Secondly,the paper studies the operating characteristics of the cogeneration units and the thermal power units,then establishes the characteristics equations of the thermoelectric coupling equipment.On this basis,the heat-electricity combined scheduling model of peak load regulation considering the characteristics of the heat network is established.The model includes the constraints of heating network characteristic constraint,thermoelectric coupling constraint,system power supply and heating constraint,and so on.Finally,an improved particle swarm optimization algorithm is proposed to solve the problem that the traditional mathematical optimization method is slow to converge and hard to get the feasible solution because of the equality constraints and the inequality constraints in the optimal scheduling model.The algorithm includes the penalty function and the self-adjustment section,which has the advantages of high precision and fast convergence.The simulation results show that the method based on electric boiler for distributed daily peak-load regulation at secondary heating network considering the heating network characteristics is helpful to improve the wind power consumption of the system and reduce the abandoned wind power.The heating network delay characteristics can reduce the coal consumption of the system and increase the reserve of the power grid to enhance wind power accommodation.The heating network attenuation will increase the heat supply and the coal consumption of the system,which do harm to the wind accommodation.The work in the paper has been funded by national science and technology project of power grid corporation,"Research and application of key technologies of the heat-electricity combined scheduling considering safety and economy".