Power grid voltage temporary drop weak region identification method and device

Abstract

The invention discloses a power grid voltage temporary drop weak region identification method and device. The method includes the following steps that: the fault type of each fault line is obtained, and a corresponding voltage equation is selected; the drop amplitude of a sensitive load access point which is caused by a head end point and tail end point fault of each fault line is solved according to the voltage equation, and a weak index vector corresponding to each fault line is calculated; and a weak region corresponding to each fault line is determined through using a golden section method and / or secant line iteration method and on the basis the numerical value of the weak index vector. According to the power grid voltage temporary drop weak region identification method and device of the invention, the corresponding voltage equation is selected, so that the drop amplitude of the sensitive load access point which is caused by any point fault of each fault line is calculated; the weak region corresponding to each fault line is determined through using the golden section method and / or secant line iteration method; and a golden section method and secant line iteration method-combined method can be adopted to calculate a critical point, and therefore, the voltage temporary drop weak region of a power grid can be determined.

Description

technical field [0001] The invention relates to the field of power quality evaluation of power systems, in particular to a method and device for identifying weak areas of grid voltage sags. Background technique [0002] With the development of high-tech in modern society, the number of sensitive equipment in the power system is gradually increasing, and the voltage sag of the power grid will lead to the tripping or misoperation of sensitive equipment, affecting the entire end-user process, resulting in huge production and economic losses. According to the definition of the Institute of Electrical and Electronics Engineers IEEE, the voltage sag refers to the reduction of the root mean square of the voltage to between 0.1 and 0.9 times the rated voltage under the condition of power frequency, and the duration is 0.5 cycles (calculated at the power frequency of 50Hz in my country, 1 cycle It is a short-term voltage fluctuation phenomenon from 20ms) to 1min. Voltage sag consists...

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Problems solved by technology

[0004] In the prior art, the identification methods for weak areas, such as critical distance method and fault location method, often have many defects or are too time-consuming for the calculation of critical points and weak areas of large-scale power systems, and in some cases will It leads to disagreement when calculating the critical point, and cannot accurately and quickly identify the weak area of ​​the grid voltage sag

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