Power flow calculation method for three-phase unbalanced low-voltage power distribution system

Abstract

The invention discloses a power flow calculation method for a three-phase unbalanced low-voltage power distribution system. The method is characterized in that firstly, for a three-phase structurallysymmetric power distribution system under various wiring conditions, establishing a simplified circuit model and determining the binary coded phase sequence configuration strategy of a node load access scheme are performed; secondly, the topological structure is reasonably numbered, and raw data is stored in a matrix form; and lastly, algebraic operation of matrix elements is directly utilized tosolve the power flow of various branches of a power distribution system and the voltage of load nodes. As the logical relationship of structural connections in the circuit model is intelligible and clear through introducing 0-1 logic variables to represent a three-phase load access scheme and utilizing the matrix form to represent the topology of the circuit, programmatic implementation of the calculation process is easy, the raw data in the matrix form is inputted as the only data, algebraic operation of the matrix elements is directly utilized in the calculation process for solving, the consumed computing time is made to be less, and the convergence speed is faster.

Description

technical field [0001] The invention relates to the technical field of low-voltage power distribution, in particular to a power flow calculation method for a three-phase unbalanced low-voltage power distribution system. Background technique [0002] At present, distribution network power flow calculation is an important basis for distribution network system analysis and economic operation. Distribution network network reconfiguration, fault handling, reactive power optimization, state estimation, and line loss analysis all require the results of distribution network power flow calculations. A power flow calculation method with good performance is the key to power distribution system management. As the power sector pays more and more attention to distribution network management, research on power flow calculations for distribution networks has been widely carried out. Since the voltage level of the low-voltage distribution network is lower than that of the transmission netw...

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Problems solved by technology

However, the Newton method needs to form an admittance matrix, and the diagonal advantage of the Jacobian matrix no longer exists, so it is difficult to converge; the improved PQ decoupling method introduces compensation technology for lines with large R / X values, and this algorithm is complicated and lost The advantage of fast decoupling is that the original calculation amount is small and the convergence is reliable; the loop impedance method requires complex node and branch numbers, which is time-consuming

In comparison, the forward-backward power flow algorithm makes full use of the radial structure of the network. The physical concept of this method is clear, but due to the large distribution network structure and many branches, the search for network structure data in the calculation process has an impact on The calculation speed of the power flow is reduced, and the power loss of the branch is calculated every time the data is pushed forward, which involves direct calculation of the data matrix, which takes up a lot of space and is time-consuming

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