Small-impedance branch PQ endpoint variable Jacobian matrix newton-method power flow calculation method

Abstract

The invention discloses a small-impedance branch PQ endpoint variable Jacobian matrix newton-method power flow calculation method, which comprises the following steps: determining the type T of a branch connected by two-end nodes according to branch resistance and reactance; for a small-impedance branch PQ endpoint and other nodes, adopting different methods to calculate a Jacobian matrix; and solving a correction equation. In the iteration process, the small-impedance branch PQ endpoint adopts a Jacobian matrix calculating method different from those of other nodes, thereby solving the problem of convergence of rectangular coordinate newton power flow calculation when analyzing an electrical power system having a small-impedance branch. If non-convergence occurs when a conventional rectangular coordinate newton power flow calculation method is adopted, the method in the invention can realize reliable convergence and is smaller in iteration times than existing patent technology; and since the method not only can solve the problem of convergence of conventional rectangular coordinate newton power flow calculation when analyzing the electrical power system having the small-impedance branch, but also can carry out power flow calculation on a normal power system, no bad influence is caused.

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

[0058] 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 resistances. When the small impedance branch is small, the number of iterations increases and the convergence becomes poor

[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 in the power system containing multiple small impedance branches with non-zero resistance. However, the number of iterations is still large and needs further improvement

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