Motor rotor turn-to-turn short circuit fault detection method based on frequency response analysis

Abstract

The invention relates to a motor rotor turn-to-turn short circuit fault detection method based on frequency response analysis. The method comprises the following steps of: S1, establishing a frequency response analysis model, which is a passive linear two-port network, wherein N over-the-ground distributed capacitances C with unit length are connected between an input end and an output end of the two-port network in parallel; S2, sequentially inputting sine-wave voltage signals Vs with different frequencies; S3, digitally recording over-the-ground voltage signals Vi (n) and Vo (n) on two ends of the two-port network; S4, obtaining a transfer function H (n) being equal to 20log [Vo (n) / Vi (n)]; and S5, plotting frequency responses into a curve according to frequency, and computing a correlation coefficient between frequency response curves measured by two times, wherein if the correlation coefficient is smaller than 1, a turn-to-turn short circuit is proved to exist in a motor rotor winding. According to the motor rotor turn-to-turn short circuit fault detection method based on frequency response analysis, the accuracy for judging the motor rotor turn-to-turn short circuit fault can be improved, and the reliability of motor operation is improved.

Description

technical field [0001] The invention relates to a fault detection method for electric equipment, in particular to a fault detection method for an inter-turn short circuit fault of a generator rotor based on frequency response analysis. Background technique [0002] With the rapid growth of the national economy, the power system is developing towards an ultra-high-voltage large-capacity multi-machine interconnection system. Large-scale generators with a capacity of 300MW, 600MW and above have become the main units of my country's power grid. As the heart of the power system—the generator, with the continuous increase of the unit capacity, the operation reliability is particularly important and prominent. In the various components of a large turbogenerator set, the rotor is in a state of high-speed rotation and bears huge mechanical stress and thermal load. When the rotor winding has an inter-turn short circuit, the rotor current increases and the winding temperature rises, li...

AI Technical Summary

Problems solved by technology

However, under the load condition of the generator, the detection effect is not obvious due to the armature reaction, and the detection accuracy is also low due to the large interference of on-site detection

Other methods, such as voltage drop method, open transformer method, AC impedance and power loss analysis method, direct resistance measurement, no-load and short-circuit characteristic test, etc., have low accuracy and sensitivity, and cannot be directly used as the basis for judging inter-turn short-circuit faults.

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