Single-phase voltage sag detection method and system based on EEMD method and two-point method and application

Abstract

The invention provides a single-phase voltage sag detection method and system based on an EEMD (ensemble empirical mode decomposition) method and a two-point method and application. According to the method, a sampling value is utilized to construct a data segment suitable for online calculation, the EEMD method is utilized to extract network voltage fundamental waves, harmonic interference is filtered out, the sage depth and phase jump angle of a current network voltage are calculated through the two-point method, and finally voltage sag online rapid detection is realized. Therefore, an original signal can be decomposed into IMF with different frequencies, and most harmonic components can be filtered out; and in combination with the EEMD method, the problem that the two-point method is notapplicable under the situation that harmonic distortion is contained is solved, and the advantages of rapidity and accuracy of the two-point method are reserved.

Description

technical field [0001] The disclosure belongs to the field of voltage control, and in particular relates to a single-phase voltage sag detection method, system and application based on EEMD and two-point method. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] In recent years, with the application of more and more sensitive power electronic equipment and the rise of modern new power loads, it is no longer enough to deal with steady-state power quality problems such as harmonic pollution, frequency offset, and three-phase imbalance. The focus of electric power workers on power quality has gradually shifted from traditional problems such as harmonic pollution and switch operation overvoltage to transient power quality problems such as voltage sag and transient pulse interference. [0004] Voltage sag brings various effects to sensitive load...

AI Technical Summary

Problems solved by technology

[0007] Among the above methods, the detection method based on the transform domain is suitable for the analysis of voltage sags, but it needs to select an appropriate basis function, the calculation is complicated, it takes a long time, and the requirements for hardware implementation are relatively high, so it is not suitable for the occasion of sag compensation, or It is necessary to use the phase-locked loop to lock the grid voltage synchronization angle, and the three-phase voltage is required to be symmetrical and the measurement is synchronous

The detection method based on time-domain characteristics is a commonly used real-time detection algorithm for voltage sags. According to the characteristics of the algorithm itself, the effective value method needs sampling data of one power frequency cycle, and the transformed average value method also needs half a cycle of data. Avoid affecting the real-time performance of detection

Images