Detection method of three-phase mains supply power failure

A technology of mains power failure and detection method, which is applied in the direction of power supply testing, etc., can solve the problems of prolonged judgment time, unstable judgment time, and inability to adapt, and achieve the effects of improving stability, precise detection, and improving accuracy

Active Publication Date: 2016-02-03
KEHUA DATA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method can be applied to three-phase four-wire system and three-phase five-wire system; but because this method is to ensure reliable performance, the lower limit of the fixed voltage range is usually set relatively low, so when the three-phase input voltage is high, the single-phase After power-on, the calculated amplitude takes a longer time to be lower than the lower limit of the fixed voltage range, resulting in significantly longer judgment time and unstable judgment time, which cannot adapt to the fast switching system of static switching switches.

Method used

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  • Detection method of three-phase mains supply power failure
  • Detection method of three-phase mains supply power failure

Examples

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Embodiment 1

[0028] A detection method for three-phase mains power failure, such as figure 1 shown, including the following steps:

[0029] Step S1: sampling the instantaneous values ​​Ua, Ub, and Uc of the three-phase mains voltage in real time;

[0030] Step S2: Real-time calculation of the voltage difference Ux between the maximum value and the minimum value of the three-phase mains voltage instantaneous values ​​Ua, Ub, and Uc;

[0031] Step S3: Judging whether Ux is smaller than the set voltage threshold Ud, if Ux

[0032] Step S4: add 1 to the power-down counter count value Cnt;

[0033] Step S5: Clear the count value Cnt of the power-down counter, and return to step 1;

[0034] Step S6: Determine whether the power-down counter count value Cnt is greater than or equal to the power-down count threshold Cmax, if Cnt≥Cmax, t=2ms, f=20kHz, then Cmax=40, then judge that the mains power is off, otherwise return to step S1.

[0035] In this ex...

Embodiment 2

[0040] A detection method for three-phase mains power failure, such as figure 1 shown, including the following steps:

[0041] Step S1: sampling the instantaneous values ​​Ua, Ub, and Uc of the three-phase mains voltage in real time;

[0042] Step S2: Real-time calculation of the voltage difference Ux between the maximum value and the minimum value of the three-phase mains voltage instantaneous values ​​Ua, Ub, and Uc;

[0043] Step S3: Judging whether Ux is smaller than the set voltage threshold Ud, if Ux

[0044] Step S4: add 1 to the power-down counter count value Cnt;

[0045] Step S5: Clear the count value Cnt of the power-down counter, and return to step 1;

[0046] Step S6: Determine whether the power-down counter count value Cnt is greater than or equal to the power-down count threshold Cmax, if Cnt≥Cmax, t=3ms, f=20kHz, then Cmax=60, then judge that the mains power is off, otherwise return to step S1.

[0047] In this ex...

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PUM

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Abstract

The invention relates to a detection method of a three-phase mains supply power failure, wherein instant values of a three-phase mains supply voltages are sampled in real time, simple logic computation is carried out to the instant values of the three-phase mains supply voltages, and a voltage difference is obtained; and a correct threshold interval of the three-phase mains supply voltage is determined according an effective value of the three-phase mains supply voltage, and whether the voltage difference stays within the threshold interval is determined in order to quickly determine whether the three-phase mains supply voltage is powered off. The invention provides a method for quickly and reliably detecting mains supply abnormities, wherein whether the power failure or a default phase happens to a mains supply can be quickly determined through the simple computation based on real-time sampling of the mains supply voltages.

Description

technical field [0001] The invention relates to the field of abnormal detection methods of electric power sources, in particular to a detection method for three-phase mains power failure. Background technique [0002] The static switching switch in the uninterruptible power supply system is usually in the working state of the main power supply. When the main power supply is abnormal (such as power failure, phase loss), the static switching switch quickly switches to the working state of the backup power supply. Therefore, how to quickly and accurately detect AC The input source is powered off and the detection time is reduced as much as possible, which are the technical points and difficulties in the application of static transfer switches. If the detection time is too long, it will cause the load to stop working; if the detection is too fast, it is easy to make a misjudgment, resulting in frequent switching of the main and standby power supplies, reducing the service life o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/42
Inventor 黄国伟易龙强
Owner KEHUA DATA CO LTD
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