Research On Wind Accommodation Method By Source-Network-Load Coordination Of Combined Heat And Power System Considering Pipe Network Heat Storage

In the "Three North" area,the single power source structure,the large proportion of CHP(combined heat and power)units,and the large number of wind power connected to power grid make it difficult to regulate peak load.CHP units are constrained by the working condition of “power subject to heat”,power grid is lack of other flexible regulating power sources,and wind power has characteristics of randomness,intermittentity and peak-valley opposite to power load.These factors lead to the difficulty of peak-regulation in CHP system during the peak period of wind power,resulting in a large number of abandoned wind.Therefore,this paper studies the heat storage capacity calculation method of thermal system pipe network,and the abandoned wind absorption method by source-network-load coordination in CHP system,which uses pipe network heat storage instead of heat storage device,to cooperate with peak-shaving electric boilers to decouple the “power subject to heat” constraint of CHP units.Firstly,the model establishment method of thermal system is studied.The electrothermal characteristic and consumption characteristic of CHP units are studied,and heat power calculation model of CHP units is established.On the basis of considering the attenuation and delay characteristics of heat network,equivalent heat storage tanks are proposed to simulate heat storage and release characteristics of pipe network at the midpoint of each pipe,and the equivalent model and calculation model of heat storage of thermal system pipe network are established.Secondly,the abandoned wind absorption effect of centralized source-side and distributed load-side electric boilers is compared and analyzed.Similarities and differences of eliminating abandoned wind mechanism between two different electric boiler configurations are qualitatively analyzed from aspects of the influence of heat network attenuation and delay characteristics on heat power of heat source,and the influence of heat network delay characteristic on heat power and filling power load valley effect of electric boilers.CHP dispatching models of two different electric boiler configurations is established.The simulation results quantitatively prove that the abandoned wind absorption effect of distributed load-side electric boilers scheme is better.Next,the optimal dispatching method of CHP system based on source-network-load coordination of thermal system is studied.The coordinated heat release strategy of thermal system pipe network and electric boiler is given,and the mechanism of coordinated heat release of pipe network and electric boiler decoupling “power subject to heat” of CHP units is analyzed.The heat storage and discharge model of pipe network,the interruptible power load and adjustable heat load model of load-side electric boiler have been established.Based on t hese models,the dispatching model of CHP system based on source-network-load coordination of thermal system is constructed.The simulation results show that the coordination of pipe network heat storage and electric boiler can reduce the configured capacity of electric boilers,and source-network-load coordination of thermal system has higher abandoned wind absorption ability than single-side method of source-network-load.Finally,the abandoned wind absorption effect of pipe network heat storage and load-side electric boiler with heat storage device is compared and analyzed.The abandoned wind absorption mechanism of two heat storage methods is compared,and the influence of heat network attenuation and delay characteristics on the abandoned wind absorption effect of two heat storage methods is analyzed and compared.The source-load coordinated dispatching model of CHP system considering electric boiler with heat storage device is constructed.The simulation results of source-network-load coordination method and source-load coordination method are compared and analyzed,which show that in the condition of same heat storage capacity,pipe network heat storage can replace heat storage device of electric boiler with heat storage device,and pipe network heat storage is more flexible,has larger actual heat storage amount and better abandoned wind absorption effect.