Research On Harmonic Power Flow Of Distribution Network With Distributed Generation

At present,with the access of distributed energy generation to the distribution network,the use of a large number of power electronic devices leads to the increase of harmonic content in the distribution network,which affects the power quality of the distribution network.At the same time,it also increases the complexity of harmonic power flow calculation in the distribution network.Therefore,this paper studies the harmonic power flow calculation of distribution network with distributed generation,and seeks a fast and accurate harmonic power flow algorithm of distribution network,which has practical significance and application value.In order to establish the harmonic power flow calculation model of distribution network with distributed generation,based on the structure and components of distribution network with distributed generation,the harmonic models of generator,transformer,power line and load are established.The operation characteristics of wind power generation system and photovoltaic power generation system are analyzed in detail,and their harmonic models are established,The harmonic power flow synthesis model of distribution network is constructed.In order to improve the rapidity of harmonic calculation method with distributed generation in distribution network,based on the existing Newton method and distribution network power flow calculation method,an improved Newton method power flow algorithm for distribution network is proposed,which reduces the number of iterations and improves the solution speed.The difference form of the generalized Tellegen theorem is discussed and analyzed in detail.An improved Newton method based on the generalized Tellegen theorem is proposed to calculate the harmonics of distribution network.The method is divided into three steps.Firstly,the harmonic admittance matrix is formed according to the characteristics of Newton’s harmonic power flow calculation and distribution network structure.Secondly,in order to improve the speed of the algorithm,the generalized Tellegen theorem is applied to construct the corresponding distribution network harmonic adjoint matrix,and the mathematical model is established.Thirdly,by calculating the sensitivity matrix,the harmonic power flow algorithm based on the generalized Tellegen theorem is obtained.In this thesis,the integrated harmonic power flow algorithm is applied to IEEE34 bus systems with distributed generation.The results show that the calculation speed of the method combining the generalized Tellegen theorem with the current injection Newton method is faster than that of the traditional Newton method.The results show that the method is fast and effective.