Rectangular coordinate Newton method load flow calculation method with changeable Jacobian matrix

A technology of Cartesian coordinates and power flow calculation, applied to AC network circuits, electrical components, circuit devices, etc., can solve problems such as increased iterations, non-convergence, and poor convergence

CN104037764AActive Publication Date: 2014-09-10SUWEN ELECTRIC ENERGY TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-09-10

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Abstract

The invention discloses a rectangular coordinate Newton method load flow calculation method with a changeable Jacobian matrix. The method includes the following steps that original data input and voltage initialization are conducted; a node admittance matrix is formed; power and voltage deviations are calculated, and the maximum amount of unbalance delta Wmax is obtained; the Jacobian matrix J is formed; a correction equation is solved and a real part e and an imaginary part f of voltage are corrected; node and circuit data are output. According to the rectangular coordinate Newton method load flow calculation method, a Jacobian matrix calculation method different from that used in the following iteration processes is adopted in the initial iteration process, and the convergence problem of rectangular coordinate Newton method load flow calculation in analyzing a system with a small-impedance branch circuit is solved. When misconvergence happens with conventional rectangular coordinate Newton method load flow calculation, the rectangular coordinate Newton method load flow calculation method with the changeable Jacobian matrix can achieve reliable convergence, and the number of iterations is fewer compared with the prior art. The rectangular coordinate Newton method load flow calculation method with the changeable Jacobian matrix can effectively solve the convergence problem of the conventional rectangular coordinate Newton method load flow calculation in analyzing the system with the small-impedance circuit branch, and meanwhile load flow calculation can be performed on normal systems, and adverse effects are avoided.
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Description

technical field

[0001] The invention relates to a power flow calculation method of a Cartesian coordinate Newton method in a power system, which is particularly suitable for the flow calculation of a branch system with small impedance. Background technique

[0002] Power system power flow calculation is a basic calculation for studying the steady-state operation of the power system. It determines the operating state of the entire network according to the given operating conditions and network structure. Power flow calculation is also the basis of other power system analysis, such as safety analysis, transient stability analysis and so on. Due to the advantages of reliable convergence, fast calculation speed and moderate memory requirements, Newton's method has become the mainstream algorithm for power flow calculation. The Newton method is divided into two algorithms: the polar coordinate form and the rectangular coordinate form. Among them, the flow calculation of the rect...

Examples

Embodiment Construction

[0159] The present invention will be further described below in conjunction with the accompanying drawings. according to figure 1 The small impedance transformer model shown, using image 3The flow chart of the Cartesian coordinate Newton method power flow calculation is shown, and the power flow calculation is carried out on an actual large-scale power grid. The actual large grid has 445 nodes and contains a large number of small impedance branches. Among them, there are 118 small impedance branches with x≤0.01, 49 small impedance branches with x≤0.001, 41 small impedance branches with x≤0.0001, and 22 small impedance branches with x≤0.00001. Among them, the smallest impedance value is the small impedance branch between node 118 and node 125 , x=0.00000001, transformation ratio k=0.9565, and k is located on the side of node 118 . The convergence accuracy of the power flow calculation is 0.00001.

[0160] As a comparison, the conventional Cartesian Newton method power flow...