Research On Static Security Region Calculation And Safety Correction Method Of Integrated Gas And Power Systems

Along with the increasingly outstanding of the energy and environmental issues,the new energy structure and energy supply mode have been the principal matters that need to be solved in the present international society.In order to absorb a large number of distributed energy,a comprehensive energy system that integrates multiple energy sources such as electricity,gas,heat/cooling has emerged.However,with the deepening of the coupling degree between multiple energy sources,the fluctuations caused by the internal uncertainties of each system are easily transmitted to other systems through the coupling equipment,which brings risks to the safe operation of integrated energy system.In this thesis,the static security analysis of integrated gas and power system with micro gas turbine coupled is analyzed and the safety correction strategy is developed.The main work is as follows:(1)Based on the knowledge of graph theory,the commonality of power system and natural gas system is analyzed,that is,they have the same topological matrix description and obey the generalized Kirchhoff’s law.The characteristics of each system are analyzed according to the physical characteristics of different fluid,and the steady-state model of the coupled system is established.The physical equipment in the coupling system is divided into independent equipment and coupling equipment,and the model is established respectively.On this basis,the general steps of energy flow solution are given,which lays the foundation for the following safety analysis and the formulation of correction strategy.(2)This thesis studies and proposes a method for the static security analysis of the integrated gas and electric system,safety region method,which comes from the power system security analysis,and it is improved to make it suitable for coupling system.The static security region model is constructed for the integrated gas and electric system coupled micro gas turbine,with the node injections used as the variable space.The safety state under disturbance of the coupling system is analyzed using static security region,and the simulation results are verified by the point by point method.Compared with the point by point method,the computational complexity of this model is greatly reduced.What’s more,the safety status and safety margin can be obtained by judging whether the current operating point is in the safety region or not after only one time calculation of the safety region,which is simple and effective.(3)In view of the integrated gas and electric system connected to photovoltaic,wind power and other renewable energy,the security correction optimization model is developed based on security region and considering source-load coordination.Firstly,a selection strategy of control quantity is established.Based on the concept of sensitivity,the sensitivity of safety margin is established,and the key control variables that affect the safety margin are identified.Following the principle of equal and opposite quantities in pairs in power system,the control quantity pairs in coupling system are formed dynamically in the process of security correction.Taking the lowest total operating cost and the minimum total load shedding of the coupled system as the objective function and the safety range of state variable as constraints,the optimization model of security correction is established to restore safety state,and the plant growth simulation algorithm is improved to solve the model.Because the security region method can reflect the optimal control direction,it is more intuitive,efficient and cost-effective than traditional optimal operation considering security constraints.