Identification method for abnormal state of three-phase asynchronous motor at industrial site

A three-phase asynchronous, abnormal state technology, applied in the direction of motor generator testing, etc., can solve the problems of comprehensive utilization, no data, high data acquisition requirements, etc.

Active Publication Date: 2013-09-04
ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD +1
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

According to relevant statistics, after the implementation of condition-based maintenance, the failure rate of equipment can be reduced by 75%, and the comprehensive maintenance cost can be reduced by 30% to 50%. However, it has higher requirements for data collection of equipment, and there are many non-electrical parameters, such as: Pressure, flow and vibration, etc., also have certain requirements on the test conditions of the equipment, and it is easy to affect the normal production behavior of the enterprise. Therefore, how to eff

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  • Identification method for abnormal state of three-phase asynchronous motor at industrial site
  • Identification method for abnormal state of three-phase asynchronous motor at industrial site
  • Identification method for abnormal state of three-phase asynchronous motor at industrial site

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Experimental program
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Effect test

Embodiment 1

[0029] The output power P of the three-phase asynchronous motor can be directly measured online at the industrial site out or output power P out =f 1 (λ 1 ,λ 2 ...λ n ) parameter λ 1 ,λ 2 ...λ n , then select energy efficiency evaluation for abnormal state identification:

[0030] Measure the applied voltage, frequency, load rate, output torque, motor actual speed and input power, etc., according to In the formula, η is the online energy efficiency, P out is the output power, P in is the input power, n is the actual speed of the motor, and T is the output torque. The calculated online energy efficiency is 0.86. In this embodiment, when the applied voltage is 220v, the frequency is 50Hz, and the load rate of the motor is 0.6, according to the load rate-efficiency curve of the motor, the theoretical energy effect during normal operation is 0.88; the threshold value is set to 5 %, the deviation between online energy efficiency and theoretical energy efficiency It me...

Embodiment 2

[0032] It can directly measure the characteristic quantities that characterize the operation of three-phase asynchronous motors: power factor and efficiency, and select characteristic parameters to identify abnormal states:

[0033] When the applied voltage is 220v and the frequency is 50Hz, the load rate is 0.6, and other working conditions remain unchanged. The power factor is measured 30 times during normal operation, and the calculated average value is 0.84, and the standard deviation is 0.025. The power factor obtained from a certain measurement is 0.86, according to the double deviation criterion, |0.86-0.84|=0.02<0.025×2, indicating that the motor is running normally and there is no abnormality; the power factor obtained from a certain measurement is 0.78, according to the double deviation Criterion, 0.025×2<|0.78-0.84|=0.06<0.025×3, indicating that there is an abnormality in the motor, but no danger has occurred; the power factor obtained from a certain measurement is 0...

Embodiment 3

[0035] If the physical model can be established based on the measured values ​​of the three-phase asynchronous motor, the physical model identification is selected for abnormal state identification:

[0036] Keep the applied voltage at 220v and the frequency at 50Hz. According to the historical data during normal operation, the load rate-power factor curve (β-cosθ 1 ) for cosθ 1 =0.3804+0.2001β+0.42β 2 , and according to the actual measured data, the load rate-power factor curve (β-cosθ 1 ) for cosθ 1 =0.3789+0.2092β+0.4184β 2 , the two model errors are Δ=|-0.0015+0.0091β-0.0016β 2 |≤0.0015+0.0091+0.0016=0.0122 (when β≤1), it can be seen that the changes of the polynomial coefficients before and after are small, indicating that the motor is running normally.

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Abstract

The invention discloses an identification method for the abnormal state of a three-phase asynchronous motor at an industrial site; energy efficiency assessment is selected for carrying out abnormal state identification if the output power of the three-phase asynchronous motor can be directly measured at the industrial site in an on-line mode; characteristic parameter discretion is selected for carrying out abnormal state identification if the characteristic quantity representing the operation of the three-phase asynchronous motor can be directly measured; physical model discretion is selected for carrying out abnormal state identification if a physical model can be established according to a measured value; and predicting model discretion is selected for carrying out abnormal state identification when above conditions are all not applicable. Compared with a currently used empirical method, the method has scientificity and practicability, thus being convenient for an enterprise to grasp the operation state of the three-phase asynchronous motor, helping the enterprise to evaluate when the three-phase asynchronous motor enters an accident-prone period, and further enhancing the enterprise monitoring on the three-phase asynchronous motor and preventing safety loophole.

Description

technical field [0001] The invention relates to the field of industrial equipment diagnosis, in particular to an abnormal diagnosis method of a three-phase asynchronous motor. Background technique [0002] In order to ensure the safe operation of equipment, the health of equipment has long attracted people's attention. With the development of time, the maintenance cost of modern equipment accounts for an increasing proportion of the life cycle cost. At the same time, the requirements for safe operation of equipment are also increasing. Higher and higher. Therefore, a set of feasible and effective equipment abnormal state identification methods is proposed, which can not only facilitate the equipment management personnel to understand the equipment performance status in a timely manner, improve the safety of equipment operation, but also provide decision-making for the daily operation, maintenance, repair and update of equipment. support on . [0003] After going through th...

Claims

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Application Information

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IPC IPC(8): G01R31/34
Inventor 王凯卞龙江高赐威李扬
Owner ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD
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