Study On The Economy Of Electric Boiler Configuration In Thermal Power Plant Under Load Regulation Market

In recent years,with the large-scale development of wind power,a large-scale windcurtailment occurred during the heating period in Northern China.The main reason is that the high proportion of the units in thermal power plant in the system must generate electricity at a high level due to heating,and it is impossible to reduce the power output to make room for the wind power to access the power grid.In order to improve the operation flexibility of heat-power units to reduce its power output to receive wind power,the country is actively promoting the "heat-power decoupling" remoulding of thermal power plants,at the same time,many regions have also established load regulation auxiliary service markets to motivate the units to participate in load regulation.However,in the current load regulation market,there is still a lack of systematic and in-depth research on the economy of participating in load regulation of the remoulding of the thermal power plant,the factors that affect it,the investment risks and the incentive mechanism.For this reason,taking the load regulation market in Northern China as the background,taking the mainstream heat-power units configured with direct-heating electric boiler in thermal power plant as the object to study the above problems.The main work and results are as follows:(1)The current mechanism,adjustment process,driving factors and operation of the peak shaving market in Northern China are analyzed,and the differences with other regional load regulation markets are compared,the mechanism environment for thermal power plants to participate in load regulation remoulding by direct-heating electric boilers is clarified.(2)Based on the mechanism of steam extraction heating units,the conversion model of heat-power units from steam extraction heating working condition diagram to heat-power operation region is established;based on the mechanism of coordinated peak regulation between heat-power units and electric boilers,an overall electric heating operation region model of the combined system composed of heat-power units and electric boilers is established;furthermore,in order to provide deep load regulation capacity during the period of curtailed wind,the coordinated operation model of heat-power units and electric boilers is established for a given depth load regulation capacity;based on the results of coordinated operation,a coal-saving model for deep load regulation by electric boilers in thermal power plants is established,and the characteristics of marginal coal-saving rate are analyzed.(3)Based on the results of coordinated operation and the rules of load regulation market in Northern China,the operating cost and benefit model for load regulation by electric boilers in thermal power plants is established;furthermore,considering the cost of the investment and reconstruction of the electric boiler,and taking the investment payback period as an index,an investment economic analysis model is established.(4)Based on the above model,the calculation example analysis with actual units and actual curtailed wind data shows that the thermal power plant equipped with electric boilers can effectively provide deep load regulation capability,and even reduce the overall output of the power plant to zero,thus giving a large amount of space for the wind power to the power grid;however,under the current market mechanism of load regulation in Northern China,when the heating load is large,the income is negative when carrying out small-scale deep load regulation,and the power plant is unwilling to carry out deep load regulation for small-scale curtailed wind,moreover,when the shared load regulation responsibilities of a single unit become smaller due to the reduction of curtailed wind or the increase of retrofitted power plants,a single heat-power unit needs to configure a larger minimum electric boiler capacity to ensure the economy of investment,which brings great investment risks to the power plant,all of which mean that the existing market mechanism still has certain defects;however,the reduction of the minimum output of the heat-power unit will improve the economy of investment,so the thermal power plant should actively carry out the remoulding of reducing the minimum output while configuring the electric boiler.The above work and achievements can provide effective reference for the thermal power plant to improve the operation flexibility and design the market mechanism.