A phase sequence detection method, system and device for three-phase voltage

Abstract

The invention discloses a phase sequence detection method, system and device for three-phase voltage. The phase sequence detection method for the three-phase voltage comprises the following steps: collecting the three-phase voltage value of a power grid in real time, and transforming the three-phase voltage value by a preset coordinate transformation formula to obtain an [Alpha]-axis component anda [Beta]-axis component of the power grid voltage in an [Alpha]-[Beta] two-phase stationary coordinate system; confirming a specific quadrant of a composite vector of the [Alpha]-axis component and the[Beta]-axis component in the [Alpha]-[Beta] two-phase stationary coordinate system in real time according to the plus or minus of the [Alpha]-axis component and the[Beta]-axis component; and judgingwhether the quadrant in which the composite vector is located changes in the counterclockwise direction or not; if so, the phase sequence of the power grid is determined to be correct; if not, the phase sequence of the power grid is determined to be incorrect. The phase sequence detection disclosed by the application is less sensitive to the three-phase voltage value, therefore, the accuracy of phase sequence detection in the case of three-phase voltage distortion or asymmetry is improved; and in the application, in the process that the quadrant in which the composite vector is located is rotated from the first quadrant to the first quadrant again, the quadrant changes for four times, so that the judgment basis of the phase sequence is increased in the voltage cycle, therefore, the accuracy of the phase sequence detection is improved.

Description

technical field [0001] The invention relates to the field of grid power supply, in particular to a phase sequence detection method, system and device for three-phase voltage. Background technique [0002] With the development of power electronic technology, the application of power electronic equipment in the power grid is gradually increasing. For the equipment that needs to be connected to the grid in the power electronic equipment, the correctness of the phase sequence of the three-phase voltage of the grid (correct: positive sequence voltage, wrong: negative sequence voltage) is particularly important. Once the phase sequence of the grid connected to the power electronic equipment Mistakes will directly lead to the failure of power electronic equipment to be connected to the grid, and even cause bombing and equipment damage in serious cases. [0003] In the prior art, the phase sequence detection method of the three-phase voltage usually uses the three-phase voltage val...

AI Technical Summary

Problems solved by technology

However, since the detection basis of this phase sequence detection method is the three-phase voltage value, it is relatively sensitive to the voltage value. When the three-phase voltage is distorted or asymmetrical, it will cause a gap between the detected three-phase voltage value and the standard three-phase voltage value There are errors, which affect the accuracy of phase sequence detection; moreover, this phase sequence detection method only detects the three-phase voltage value when the voltage crosses zero, resulting in less basis for judging phase sequence within the voltage cycle, which also affects the accuracy of phase sequence detection. accuracy

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