Research Of Sparse Technique For Power Flow Calculation

Power flow calculation is one of most important electrical operation applied in the electrical system analysis, of which the Newton flow and the Fast Decoupling power flow are the most popularized operation. Therefore, it is meaningful to improve the two calculations'efficiency. Currently, the sparse technique has been widely used in the areas of power flow calculation, the safety analysis and the optimization. Therefore, to improve the efficiency of sparse technique by combing the two calculations features could enhance the efficiency of the power flow calculation as well as other electrical operations. In this paper, we devoted to make three improvements which were.Firstly, we proposed a new kind of two-layer linked list to make the bus admittance matrix and the bus block jacobian matrix stored, and the function of location searching between the two matrixes implemented under the same structure. And the efficiency of the formation and modification of jacobian matrix has been largely improved, so dose the solving of linear equations. The research then used the symmetry of the symmetric matrix during the factorization, halved the amount of the layer two linked list storage cell, and formed the lower triangular and two-layer linked list. At the mean time, through exacting the elements from the being revised jacobian matrix and the unbalanced power to reduce the operation so as to enhance the efficiency.Secondly, The improved minimum degree algorithm (MD) has been used in the paper to enhance the effectiveness and efficiency of the optimal ordering algorithm. In the MD, the amount of one bus'connected branch was called its degree. This paper defined the sum of the degree as the bus's QUANTITY and presented that in the MD less input elements would be realized by eliminating the bus with minimum QUANTITY in the first under the premise of the minimum buses'degree. Besides, after choosing the pivot element, using the method of gauss decomposition without permutation of both the rows and columns of the matrix to achieve the MD and to improve the minimum degree bus positioning approach and the efficiency applied by the sparse technique. Numerical results indicated that the node ordering method proposed in this paper is suitable for power simulation as it can get less input elements and cost less time.Thirdly, Based on the MD calculation, the paper proposed the Upstream Minimum Degree, which realized the radial distribution networks by dealing with the nodes which only have one connected branch batching to carry out the upstream bus-labeling technique. Based it, Upstream Minimum Degree used in ordinary network was proposed, it can distinguish the nodes whether in the structure of radial distribution or not, which numbered the ring network by MD, numbered the radial distribution network by UMD. The merits of different numbering methods have been fully used.The experiments and analysis have proved the validity of the methods proposed in the paper. It is meaningful for improving the power flow calculation.