GIS mechanical fault diagnosis method and device

A gas insulated switchgear (GIS) mechanical fault diagnosis method, comprising:

• collecting vibration signals to be measured of various excitation sources of GIS in mechanical operation;
• performing wavelet packet-feature entropy vector extraction on the vibration signals to be measured, in response to determining that the vibration signals to be measured are abnormal according to standard vibration signals in normal state;
• and
• inputting extracted wavelet packet-feature entropy vectors into a pre-trained back propagation (BP) neural network for GIS mechanical fault identification, and outputting corresponding fault;
• wherein the vibration signals to be measured comprise vibration signal excited by an operating mechanism and vibration signal excited by electromagnetic force, and the operating mechanism comprises a circuit breaker, an isolating switch, and a grounding switch;
• wherein determining that the vibration signals to be measured are abnormal according to standard vibration signals in normal state comprises:
• extracting an envelope of the vibration signal excited by the operating mechanism to obtain envelope area by using Hilbert method;
• at the same time, extracting vibration energy of the vibration signal excited by the electromagnetic force at set frequency by using fast fourier transform (FFT) method;
• determining that the vibration signals to be measured are abnormal in response to that the envelope area corresponding to the vibration signal excited by at least one operating mechanism satisfies a set first formula, and/or the vibration energy satisfies a set second formula;
• in which,
• the first formula is:
• |ES−ES0|/ES0×100%≥5%
• ES is the envelope area corresponding to the vibration signal excited by a certain operating mechanism, and ES0 the envelope area corresponding to the standard vibration signal excited by the operating mechanism;
• and
• the second formula is:
• |EQ−EQ0|/EQ0×100%≥5%
• EQ is the vibration energy of the vibration signal excited by electromagnetic force at the set frequency, and EQ0 is the vibration energy of the standard vibration signal excited by electromagnetic force at the set frequency;
• wherein the set frequency is 100 Hz;
• a collection time of the vibration signal excited by the electromagnetic force is 2 seconds, and a sampling frequency is 20 KHz;
• and
• a collection period of the vibration signal excited by the operating mechanism is from a start time to an end time of an operation of the operating mechanism and 0.5 second extended.