33results about How to "Enhanced fault signature" patented technology

The invention discloses a method for strengthening weak faults of rolling bearings based on matrix recovery, which belongs to the technical field of fault diagnosis of rotating machinery. By constructing the fault information matrix, the collected one-dimensional vibration signal is expressed in the form of a two-dimensional fault information matrix, so as to meet the input requirements of the matrix recovery theory, and use the matrix recovery algorithm to restore the shock characteristics from the two-dimensional fault information matrix. Based on the low-rank matrix, the cumulative average algorithm is used to restore the vibration signal without noise interference from the low-rank matrix. At the same time, considering the inevitable tail truncation phenomenon when constructing the fault information matrix, the positive sequence and reverse sequence fault information matrices are respectively constructed for the positive sequence and reverse sequence vibration signals, and the above three steps are carried out for the two fault information matrices respectively, and The denoising information obtained through the above two fault information matrices is synthesized to obtain a final denoising signal. The method is applicable to the analysis of vibration signals of rotating machinery in the field of fault diagnosis of rotating machinery.

The invention relates to a distribution network single-phase grounding protection method based on active and passive joint detection of weak faults, and belongs to the technical field of electric power system relay protection. When the distribution network is running abnormally, use the bus zero-sequence voltage wavelet transform mutation energy in the low frequency band to judge whether the system has a single-phase ground fault, and start protection; if a fault occurs, the bus zero-sequence voltage when the neutral point is not regulated The zero-sequence current is sampled, decomposed by 6-layer wavelet, and the characteristic frequency band is determined by using the energy and maximum principle; the fault passive detection criterion is constructed after the wavelet coefficients under the characteristic frequency band are cross-overlapped and differentially transformed. According to whether the first non-zero value of the passive detection discriminant exceeds the threshold, it is judged whether a single-phase ground fault occurs in the feeder. The present invention utilizes whether the zero-sequence voltage can be continuously detected multiple times within a fixed time limit, can preliminarily judge the nature of the fault, and avoid repeated tripping to reduce power supply reliability.

The invention relates to a diagnosis method for impact type failure between a rolling bearing and a gear based on an optimal self-adaptive wavelet filter, which comprises the following steps: firstly establishing an exponentially damped sinusoidal impact type failure signal model, using a mode self-adaptive wavelet generation algorithm publicly disclosed by Hector Mesa to generate a self-adaptive wavelet filter which is matched with the signal model, then utilizing a fast FIR (finite impulse response) filtering algorithm to execute the wavelet filter to obtain the filtering result, then calculating the kurtosis value of the filtering result, and using an evolution differential algorithm to repeat the steps so as to finally obtain an optimized envelope spectrum. By adopting the method, impact failure characteristics in vibration signals can be precisely extracted, and a clearer envelope spectrum can be given out, thereby ensuring that failure symptoms can be displayed more clearly.