| The analysis of power system operation state is inseparable from power flow calculation,and power flow algorithm is the core of power flow calculation.In order to analyze the operation state of power grid and adjust the operation mode of power grid more quickly and accurately,and form a power flow calculation method with strong convergence and fast calculation speed,it has always been the focus of power flow calculation.Therefore,based on the generalized Tellegen theorem,combined with the preserved nonlinear power flow algorithm,studing the generalized Tellegen theorem preserved nonlinear power flow algorithm,which has theoretical significance and practical application value.The main contents are as follows:By analyzing the principle of traditional Newton Raphson power flow calculation method,there is still room to improve the accuracy of the algorithm.In order to solve the problem of power flow calculation accuracy,presenting an improved algorithm to retain nonlinear power flow.The algorithm establishes an improved current injection model in the calculation program,and unifies the usage model of PV node and PQ node,which saves the time cost in modeling to a certain extent.Compared with the traditional Newton Raphson method,it has better convergence and accuracy.The improvement of the accuracy of power flow solution makes it difficult to solve all elements of Jacobi matrix in the modified equation,and the solution time of power flow increases accordingly.In order to make up for the problem of increasing the solution time of power flow due to the improvement of accuracy,combining the small disturbance theorem in the generalized Tellegen theorem with the nonlinear power flow.The physical model of the small disturbance theorem in the generalized Tellegen theorem is in line with the modified equation of current injection type which keeps the nonlinear flow.It can solve the power flow correction equation more quickly and improve the solution time of the power flow from the power flow solution method In order to solve the problem of ill conditioned power flow,zero power method of small impedance branch is used to preprocess the initial value of small impedance branch,which is widely used in power system.Considering the actual system,provides a new method for the initial value selection of the generalized Tellegen theorem preserving nonlinear power flow algorithm.Matlab software is used to simulate and analyze the nonlinear power flow retained by the generalized Tellegen theorem,it is verified that the power flow with small impedance branches has good convergence and rapidity when combined with the generalized Tellegen theorem and the current injection type power flow algorithm with nonlinear reservation. |
