Curve fitting method for duration of multiple voltage sags, and voltage sag severity assessment method

Abstract

The invention discloses a curve fitting method for duration of multiple voltage sags, and a voltage sag severity assessment method. The curve fitting method comprises the steps: obtaining the change rule of the voltage value of a power grid with time in a unit time, and obtaining a voltage change time sequence curve; obtaining the number of voltage sags of the voltage in the unit time and the data of each voltage sag according to the voltage change time sequence curve, wherein the data of each voltage sag comprises the time period of the voltage sag and the voltage value corresponding to the voltage sag; taking a plurality of voltage values Vi between the maximum voltage value Vst and the minimum voltage value Vmin of each voltage sag; calculating the time duration values corresponding to the plurality of voltage values Vi; superposing the time duration of all voltage sags corresponding to the same voltage value Vi, so as to obtain the total time duration under the same voltage value Vi, and to carry out the fitting of the total time duration curve according to the total time duration corresponding to the plurality of voltage values Vi.

Description

technical field [0001] The invention relates to a duration curve fitting method for multiple voltage sags per unit time and a method for evaluating the severity of different equipment caused by multiple voltage sags based on the fitted duration curves. Background technique [0002] With the increasing sensitivity of electrical equipment to power quality, voltage transient has become one of the main power quality problems that affect the reliable power supply of loads and the normal operation of equipment. Especially for precision process control equipment using computer, power electronics and automation technology, new energy generator sets and electric vehicle charging facilities, voltage sag accidents will cause inestimable losses in equipment production, operation and maintenance, etc. For computers and semiconductor manufacturing equipment, the Computer Business Equipment Manufacturers Association (CBEMA) was later changed to the Information Technology Industry Council (...

AI Technical Summary

Problems solved by technology

from image 3 It can be seen that the traditional method can only obtain the duration after a single voltage sag, and when using the duration to perform relevant evaluation and statistical analysis in the subsequent period, only the single duration can be used for statistical analysis, and the result of the analysis is not Considering the impact of the three voltage sags on the equipment at the same time, it is not comprehensive

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