Abnormal detection method and device for AC power supply

Abstract

The present invention is applicable to the technical field of electric power supply, and provides a method and device for abnormality detection of an AC power supply, wherein the method includes: acquiring the phase-locked frequency of the AC power supply, and respectively acquiring the correspondence between the latest two zero-crossing points of each phase in the AC power supply. time information; calculate the maximum frequency difference of the AC power supply according to the phase-locked frequency and time information; determine whether the maximum frequency difference is greater than or equal to the preset threshold; when the maximum frequency difference is greater than or equal to the preset threshold, determine that the AC power supply is abnormal. The AC power abnormality detection method and device provided by the embodiments of the present invention use the zero-crossing information of each phase in the AC power supply to judge whether the AC power is abnormal, so that the zero-crossing point is directly applied to the AC power detection, which solves the problem of the existing technology in AC power detection. The zero-crossing point in the system is the problem of detecting blind spots, which can completely, accurately and quickly detect the AC power supply.

Description

technical field [0001] The invention belongs to the technical field of electric power supply, and in particular relates to a method and device for detecting an abnormality of an AC power supply. Background technique [0002] The static transfer switch in the uninterruptible power supply system is generally in the working state of the main power supply. When the main power supply is abnormal (such as power failure, phase loss), the static transfer switch needs to quickly switch to the standby power supply working state to ensure continuous and stable power supply. How to quickly and accurately detect the power failure of the AC input source and reduce the detection time as much as possible is the technical key to the application of static transfer switches. If the detection time is too long, it will cause the load to stop; if the detection is too fast, it is easy to make a misjudgment, resulting in frequent switching of the main and standby power supplies, and shortening the...

AI Technical Summary

Problems solved by technology

[0005] In view of this, the embodiment of the present invention provides a method and device for abnormal detection of AC power supply, so as to solve the problem of zero-crossing detection blind spot existing in the detection of AC power supply in the prior art

[0007] The AC power abnormality detection method provided by the embodiment of the present invention uses the zero-crossing information of each phase in the AC power supply to judge whether the AC power is abnormal, so that the zero-crossing point is directly applied to the AC power detection, which solves the problem of the existing technology in the AC power detection. The zero-crossing point is the problem of detecting blind spots, which can perform complete, accurate and fast detection of AC power

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