Estimation method of capacity exchange ability between large regional grids of electric system

Abstract

The invention discloses an estimation method of capacity exchange ability between large regional grids of an electric system. The method comprises the steps: based on sensitivity analysis of a section exchange capacity-voltage change ratio, carrying out analysis on the section exchange capacity-voltage stability of a tidal current section between the large regional grids, and obtaining the most sensitive node of voltage of a system; and carrying out spline interpolation on a trend of voltage change to sensitivity change, wherein the voltage change is based on the most sensitive node of the voltage of the exchange capacity, carrying out derivation after nonhomogeneous exponential function fitting is conducted on a discrete value obtained by the spline interpolation, obtaining a change rate function of the voltage change to sensitivity, calculating a limit of the exchange capacity according to discrimination conditions of a critical point of voltage stability, analyzing the voltage stability conditions of the system through a voltage stability margin, and carrying out checking and calibration on correctness of an inflection point and an estimation result of the exchange capacity.

Description

technical field [0001] The invention belongs to the field of safe technical operation of electric power systems, and more specifically relates to a method for evaluating capacity exchange capacity between large-area power grids of electric power systems based on improved voltage sensitivity analysis. Background technique [0002] The "Twelfth Five-Year Plan" period is an important stage for the development of my country's UHV power grid. The UHV transmission system has the characteristics of large transmission capacity, large power flow range, and no accident backup in the early stage of operation. The busbars of the 500kV tie-lines in the nearby area are mostly important large-capacity substation nodes and converter station nodes, resulting in the receiving end power grid being greatly affected by the operation status of the UHV transmission system. Once the UHV AC line itself fails, the receiving end The power grid will have the possibility of voltage instability, which will...

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Problems solved by technology

Greene S [1] The sensitivity calculation method proposed by et al. needs to calculate the left eigenvector corresponding to the zero eigenvalue of the power flow Jacobian matrix at the critical point, which requires a large amount of calculation in solving large systems; Jiang Tao [2] pointed out that most of the voltage Stability indicators need to track and judge the singularity of the Jacobian matrix of the power flow or equilibrium point equation, which involves high-dimensional matrix inversion, which requires a large amount of calculation and is difficult to achieve online practical application

Most of the traditional sensitivity analysis methods are based on static power flow calculations. When the system is close to the critical state, there is a problem that the convergence of the power flow equation is difficult. At the same time, there is a lack of adaptive methods for the calculation and analysis of the interval exchange capacity limit.

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