OLTC (On-Load Tap Changer) fault diagnosis method based on LCD (Local Characteristic-scale Decomposition) and permutation entropy

Abstract

The invention discloses an OLTC (On-Load Tap Changer) fault diagnosis method based on LCD (Local Characteristic-scale Decomposition) and a permutation entropy. The OLTC fault diagnosis method comprises the steps of: (1) sticking a vibration detection probe at the top end of a box wall of an OLTC, respectively acquiring vibration signals generated in the actuating process of the OLTC in a normal state, a contact loosened state, a contact worn state and a contact burn-down state, and denoising multiple groups of vibration signals in each state, which are respectively acquired; (2) carrying out adaptive decomposition on the denoised vibration signals by utilizing an LCD method, and selecting a plurality of ISCs (Instrinsic scale components) in the front as principal components; (3) calculating permutation entropies of the selected ISCs, and forming a characteristic vector; and (4) inputting the characteristic vector into an established SVM classifier to carry out working mode identification. According to the method, the working state of the OLTC of a transformer can be monitored in real time, and requirements for real-time fault diagnosis on the OLTC are met. Data support is providedfor purposive overhaul, and waste of labor, material resources and time is avoided.

Description

technical field [0001] The invention relates to a fault diagnosis method for electric equipment, in particular to an OLTC fault diagnosis method based on LCD and permutation entropy. Background technique [0002] The on-load tap changer (OLTC) is an important part of the power transformer, and its operating status is directly related to the stability and safety of the transformer and the system. OLTC is one of the components with the highest failure rate of transformers, and its failure not only directly affects the operation of the transformer, but also affects the quality and operation of the power grid. According to statistics in the ditch, the accidents caused by OLTC faults account for about 28% of the total transformer accidents, and the fault types are basically mechanical faults, such as loose contacts, falling off contacts, mechanism jamming, slipping, and refusal to move. Mechanical failure will directly damage the OLTC and the transformer itself, and then cause o...

AI Technical Summary

Problems solved by technology

The power outage maintenance period of on-load tap-changers is often long, and it is difficult to detect early mechanical failures in time. Failures and damages often occur before power outage maintenance, and power outage maintenance affects the normal operation of the transformer, which requires a lot of manpower, material and financial resources

On-line monitoring methods mainly include thermal noise-based diagnosis method and vibration-based on-line monitoring, etc. The thermal noise-based diagnosis is that the thermal noise generated by the heat generated after the transformer tap-changer breaks down spreads to the outside of the transformer, and is detected by installing a noise sensor on the transformer shell. To diagnose the fault of the tap changer, but when the thermal noise is transmitted to the sensor, the energy loss is too large, and various noises interfere with the engineering application, which is difficult to realize

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