Rectangular coordinate Newton method load flow calculation method for small-impedance-branch-containing power grid based on compensation method

Abstract

The invention discloses a rectangular coordinate Newton method load flow calculation method for a small-impedance-branch-containing power grid based on a compensation method. Before performing load flow calculation, a small-impedance branch is processed firstly; the small-impedance branch is changed into two series branches, wherein the impedance of one branch is z1 which is equal to r<ij>+j(x<ij>+x<c>) while the impedance of the other branch is z2 which is equal to -jx<c>, wherein x<c> is a normal electric reactance average value x<av> of an electric power system. One small-impedance branch is changed into two branches with relatively high impedance through series compensation, so that the convergence of load flow calculation can be improved. By adoption of the load flow calculation method, the small-impedance branch of any impedance can be calculated, or even a branch with zero impedance also can be calculated; the small-impedance branch data is processed before the load flow calculation is performed; and the data is preprocessed, so that a load flow calculation program is not changed, so that the rectangular coordinate Newton method load flow calculation method is particularly suitable for transforming an old load flow calculation program.

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 method for power flow calculation. Newton's method is divided into two forms: polar coordinates and rectangular coordinates. B...

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Problems solved by technology

[0059] Chinese patent ZL201611094297.8 proposes a Newton method power flow calculation method that changes the Jacobian matrix with iterations and node types. In the first iteration of the method, all PQ nodes use different Jacobian matrix calculation methods from the subsequent iterations. All PQ nodes calculate the Jacobian element by the given value P is and Q is Calculated a i and b i value, all PV nodes in the first iteration and all nodes in the subsequent iterations still use the traditional method to calculate the Jacobian elements, which effectively solves the divergence problem of the power flow calculation with small impedance branches in the power system, but the number of iterations is still large. needs further improvement

Some programs may be written in older programming languages ​​and are not easy to modify. Some versions of power flow calculations do not even have source files and cannot be modified.

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