Rectangular coordinate newton method power flow calculation method based on improved jacobian matrix

Abstract

The invention discloses a rectangular coordinate newton method power flow calculation method based on an improved jacobian matrix; a jacobian matrix calculation method which is different between the first time of iteration and the rest time of iteration process is adopted, so that the problem of convergence of the rectangular coordinate newton method power flow calculation in a small-impedance branch power system is solved. During the first iteration, a PQ node adopts a current vector real part and virtual part obtained by an injected power given value to calculate jacobian elements; a PV nodeadopts a current vector real part and virtual part obtained by an active power given value and a reactive power given value to calculate jacobian elements, without using a power supply reactive powergiven value, so that the adverse effect to the power flow calculation convergence caused by the PV node power supply reactive given value can be avoided. When the conventional rectangular coordinatenewton method is adopted for calculation, the flow calculation is not converged; and compared with the prior art, the method disclosed by the invention has the advantages that the convergence is reliable, and the number of iterations is less than that of the prior art. The method can also carry out power flow calculation on a normal electric power system without adverse effects.

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

[0063] 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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