Research On Parallel Power Flow Computing In Power Grids Based On GPU

Power flow calculation is the basis of power system safety and stability analysis,fault calculation,economic dispatch and other problems.Accurate and fast power flow calculation is an important guarantee for the safe and reliable operation of power grid.The scale and complexity of power flow calculation increase dramatically with the continuous expansion of regional power grid interconnection scale,the large-scale interconnection of renewable energy and the large-scale application of power electronic equipment.At the same time,the process of power grid intelligence is deepening and the requirements for fine operation of power grid are improving.Hence,there exist higher requirements for power system power flow calculation accuracy and efficiency.In order to solve the large-scale power flow problem accurately and quickly,an inexact Newton method with a two-step preconditioned bi-conjugate gradient stabilized(BICGSTAB)method based on the CPU-GPU heterogeneous platform is proposed.The main research contents of this paper are as follows:The efficiency of power flow computing can be effectively enhanced by improving the solving efficiency of the correction equations which are the most time-consuming part of Newton-Raphson method.Inexact Newton method is used to calculate power flow.The correction equations are solved approximately using the iterative method which is used to solve the linear equations instead of using the direct method to solve them exactly.Then,different iterative methods of solving the correction equations are analyzed,and the BICGSTAB method is adopted to solve the correction equations according to the asymmetric and indefinite characteristics of Jacobian matrix.Next,in order to improve the convergence performance of the BICGSTAB method,a two-step preconditioner for Jacobian matrix is proposed according to the characteristic that the Jacobian matrix is analogous to sparse diagonally dominant matrix.And the convergence performance of BICGSTAB method can be improved with the two-step preconditioner that consists of the improved PPAT(Preconditioner with sparsity Pattern of AT)preconditioner and the improved Jacobi preconditioner.Finally,the above power flow algorithm is deployed to CPU-GPU heterogeneous platform to achieve the power flow parallel computing.Different test systems are further used to verify and analyze the performance of the proposed method.The results validate that the proposed power flow algorithm can solve the power flow equation accurately and quickly.