Power distribution network load flow calculation method based on improved forward-backward sweep method

Abstract

The invention discloses a power distribution network load flow calculation method based on an improved forward-backward sweep method, which belongs to the field of power distribution. Firstly, a corresponding power distribution network related parameter table is generated, all nodes of a power distribution network are numbered in a full-automatic mode, a matrix A and a matrix B are generated through iterative node scale simplification processing, and then special processing on PV nodes is achieved; and the node injection power is replaced with the node injection current to avoid calculation ofbranch power loss during each iterative calculation. A power distribution network can be changed into a simple single-line diagram, so that the system scale is reduced; node injection current is usedfor replacing node injection power in a back substitution process, so that branch loss calculation time can be saved; through the reactive power correction equation of the PV nodes, the power distribution network containing the PV nodes is effectively processed, and the problem that the PV nodes in the power distribution network system cannot be processed in the existing technical scheme is avoided; under the condition of calculating the same configuration network, the method has the advantages of smaller error, better accuracy and higher calculation speed. The method can be widely applied tothe field of distribution network planning and management.

Description

technical field [0001] The invention belongs to the field of power distribution, and in particular relates to a calculation method for power flow of a power distribution network. Background technique [0002] With the rapid development of my country's power industry, the structure of the power system is becoming more and more complex, but the development of the distribution network is at a relatively lagging level. Therefore, the automation construction of the distribution network has become one of the important topics in the current power system research. Power flow calculation, as one of the most basic calculations in power system research, not only provides operating status information for scheduling, but also determines the performance of all other advanced application software that depends on its calculation results. [0003] The current distribution network power flow calculation methods mainly include: improved Newton-Raphson method, improved PQ decoupling method, loo...

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Problems solved by technology

[0004] The Newton-Raphson method and the improved PQ decoupling method have poor convergence and large calculation errors when they are directly applied to the power flow calculation of the distribution network due to their definite principles; the loop impedance method is mainly used to deal with the ring network structure, and the convergence It has good performance, but its node and branch numbers are complicated to deal with, and the amount of calculation is large; and for the characteristics of the radial structure of the distribution network, the forward push-back method is one of the optimal algorithms for power flow calculation of the distribution network, and has good performance. Convergence and Computational Speed

[0005] The traditional push-forward method needs to number the nodes and branches of the network before calculation, and there is a possibility of error in the complex distribution network. "Forward push-back generation method" (Li Xinran et al. "Journal of Electric Power System and Automation" 2017,29(12):121-125.) and "Forward push-back generation method suitable for low-voltage distribution network power flow calculation" (Zhang Xiaomin et al. "Hydropower Energy Science" 2016,34(09):183-186+70.), proposed an automatic numbering method, but this method did not consider the impact of the increasing distributed power generation on the distribution network; literature [ 7] It is pointed out that the reactive power value of the traditional forward push-back substitution method is often different from the actual value, which will increase the final calculation error and affect the iterative result. Therefore, it is necessary to convert the PV node into a PQ node, and then adjust the However, converting all PV nodes to PQ nodes will lead to poor convergence of power flow calculations

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