Newton method load flow calculation method based on node type and modified Jacobian matrix

Abstract

The invention discloses a Newton method load flow calculation method based on a node type and a modified Jacobian matrix, and solves a problem of convergence when rectangular coordinate Newton methodload flow calculation is used for solving a branch power system comprising a small impedance through employing a Jacobian matrix calculation method difference from each iteration process in the firstiteration. In the first iteration process, a PQ node employs real and virtual parts of a current phasor calculated through a node injection power given value for calculating Jacobian elements, and a PV node does not use the real and virtual parts of the current phasor for calculating the Jacobian elements, thereby avoiding the adverse impact on the load flow calculation convergence from a reactivepower given value of the PV node. When the rectangular coordinate Newton method load flow calculation is not convergent, the method can achieve the reliable convergence. Moreover, compared with the prior art, the number of iteration times is reduced. The method can perform the load flow calculation of a normal power system, and caused no adverse impact.

Description

technical field [0001] The invention relates to a flow calculation method of a Cartesian coordinate Newton method in a power system, which is particularly suitable for calculating a Cartesian coordinate Newton method 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 power system according to the given operating conditions and network structure of the power system. The power flow calculation is also the basis of other analysis of the power system, such as safety analysis, transient stability analysis, etc., all use power flow calculation. 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. Newton's method is divided into two forms: polar coord...

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Problems solved by technology

[0062] Chinese patent ZL201410315785.1 proposes a Cartesian coordinate Newton method power flow calculation method with Jacobian matrix changes. The first iteration and subsequent iterations of this method use different Jacobian matrix calculation methods. The Jacobian elements are calculated by the given Fixed value P is and Q is Calculated a i and c i value, the traditional method is still used in subsequent iterations to calculate the Jacobian elements, which effectively solves the divergence problem of power system power flow calculations with small impedance branches with non-zero resistance. When it is too large, the number of iterations increases and the convergence becomes poor

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