A Method of Analyzing and Diagnosing Mechanical Faults of On-load Tap-Changers

Abstract

The invention discloses a method for analyzing and diagnosing mechanical faults of an on-load tap changer, which specifically refers to: obtaining the vibration signal of the on-load tap-changer and the current signal of the driving motor; splitting and calculating the current signal; referring to the current segmentation point The vibration signal is split and calculated; the initial diagnosis is performed according to the segmentation parameters; if the first diagnosis finds a definite fault, the diagnosis ends; if the first diagnosis finds an indeterminate fault, or if the initial diagnosis cannot be diagnosed and the state is normal, the EMD decomposition is performed on the vibration signal segment and performed Intensive diagnosis. The invention combines two kinds of signals, divides the vibration signal in the switching process of the on-load tap changer into an energy storage section and a switching section, reduces the analysis difficulty, and improves the real-time performance of the diagnosis algorithm. In the present invention, the initial diagnosis can diagnose general faults, which can reduce the calculation overhead in the diagnosis process and improve the real-time performance of the diagnosis algorithm; if the initial diagnosis fails, the fault characteristics can be extracted by combining EMD and other nonlinear signal analysis methods for precise diagnosis. Improve the accuracy of diagnostic algorithms.

Description

technical field [0001] The invention relates to the technical field of electric equipment monitoring, and more specifically refers to a method for analyzing and diagnosing mechanical faults of on-load tap changers. Background technique [0002] The On-load Tap Changer (hereinafter referred to as OLTC in this application) is a key component of the on-load tap changer, which plays a role in stabilizing the grid voltage, adjusting the reactive power flow, and increasing the flexibility of the grid in the power system. important role. However, OLTC failures occur more frequently. According to the statistics of China Electric Power Research Institute, from 1990 to May 1994, transformer accidents caused by on-load tap changer failures accounted for 18.5% of the total number of transformer accidents nationwide. According to the statistics of international transformer faults, faults caused by on-load tap changers account for more than 20% of the total faults, and the fault rate is...

AI Technical Summary

Problems solved by technology

However, the research shows that the vibration signal in the OLTC switching process shows obvious nonlinear behavior, and the time-frequency analysis method is used to decompose the signal into a smooth signal, which inevitably has certain limitations.

Algorithms such as Empirical Mode Decomposition (EMD) are suitable for the analysis of nonlinear and unsteady signals, but they also have many shortcomings, and the amount of calculation in the decomposition process is large, which affects the real-time performance of diagnosis.

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