Newton method power flow calculation method which changes Jacobi matrix with iteration and node types

Abstract

The invention discloses a Newton method power flow calculation method which changes a Jacobi matrix with iteration and node types. A PQ node calculates a Jacobi matrix element by using an ai value and a bi value which are calculated by given values Pis and Qis in the first-time iteration. A PV node and all nodes in the subsequent iteration calculates the Jacobi matrix element by using a conventional method. The method solves a convergence problem of a rectangular coordinate Newton method power flow calculation method in the analysis of a power system containing a low impedance branch in such a way that the PQ node adopts the Jacobi matrix calculation method in the first iteration process and which is different from that in the subsequent iteration processes. The method of the invention can be reliably converged when he conventional rectangular coordinate Newton method are not convergent, is less than the number of iterations than the prior art. The Newton method power flow calculation method can not only solve the convergence problem of the rectangular coordinate Newton method power flow calculation method in the analysis of a power system containing a low impedance branch, but also can calculate the power flow of the normal power system without any adverse effect.

Description

technical field [0001] The invention relates to a power flow calculation method of a power system with a small impedance branch, in particular to a power flow calculation method of the Cartesian coordinate Newton method of the power system. 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 coordinates and rectangular coordinates...

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Problems solved by technology

[0060] 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 b 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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