Study On Energy Flow Calculation And State Estimation Of Electric-Gas Combined System

With the advance of energy revolution caused by the energy crisis,it has promoted the transformation of energy system form and upgrading of technology.In the trend of the change of energy system form,the traditional power system based on coal is gradually ignored by people,and the natural gas network which uses natural gas as consumption is studied instead.Compared with traditional coal-fired units,natural gas has gradually become one of the supporting energy sources in the power network due to its advantages of cleanliness and efficiency.The interconnection of the power-gas network is bound to be the trend of the next generation of energy supply,and the energy flow model of the power-gas network is the foundation.Only by accurately controlling the equipment state in the two internet works can the optimization decision be made effectively.In addition,the error will inevitably exist in the measurement,and the appearance of the measurement error will first interfere with the data in the database,and then affect the operation control personnel’s decision correctness.Therefore,in order to cater for the operation development and optimization research of power-gas combined system,it is essential to develop the power flow calculation and state estimation algorithm of power-gas combined system.The main work is as follows:The electricity-gas combined system is taken as the research object,and its mathematical model is built based on the equipment in the two networks.It specifically relates to special processing components such as circuits and transformers in power networks.Pipelines,compressors and coupling equipment P2 G and gas turbines in the natural gas network,It lays a foundation for energy flow calculation and state estimation calculation.An initial value search method for radiation branch in natural gas system is proposed.The method using the relationship between flow of traffic and compressor loss preliminary calculation its loss,reuse without air flow loss in pipeline gas flow statistics source point,finally from front to back pressure at various points in the gradually calculate initial value,the proposed method is effective to solve the gas system,the difficulty of initial value,improve the convergence of the algorithm.The effectiveness of the proposed strategy is verified by grid 9-gas grid 5-node system and grid 14-gas grid 14-node system.This algorithm is suitable for energy flow calculation of electric-gas combined system and energy optimization calculation of electric-gas combined system.An improved weight function robust estimation algorithm is proposed for the combined electric-gas system.This method can accurately estimate the state variables in the joint system and reduce the influence of uncontrollable errors to some extent.Compared with the traditional robust algorithm,the proposed algorithm can correct the weight through the residual iteration,accelerate the convergence of the algorithm and improve the computational efficiency of the algorithm on the premise of ensuring the accuracy of the calculation.It is found that the convergence speed of the proposed algorithm is increased by 3 times in the combined system,which verifies the effectiveness of the proposed algorithm.This algorithm can be applied to the state perception of electric-gas system and can reduce the influence of random error.