Breeding as a Science of Selection Methods
ENERGY • ELECTRICAL COMPLEXES AND SYSTEMS
UDC 621.315: 621.314
D. V. MAKSUDOV, E. M. FEDOSOV
PARTIAL DISCHARGE SIGNAL SELECTION METHODS IN ISOLATION OF POWER TRANSFORMERS
The analysis of methods for selecting partial discharge signals is presented. The analysis of the shape of the pulse partial discharge. A method for selecting partial discharge pulses by means of wavelet analysis is proposed. The basic requirements for the basis function of the wavelet transform are given. Equipment diagnostics – power transformers – partial discharges – wavelet transform
The reliability of modern high voltage equipment is largely determined by the reliability of its insulation.
The optimal method for the diagnosis of power transformers with solid insulation seems to be a non-destructive method for diagnosing insulation by the characteristics of partial discharges (PD). In this case, it is possible to provide control of the current state of the equipment under operating voltage.
This method is widely used in factory and laboratory tests in Russia.
and many foreign countries [1_3]. Not
less, while monitoring existing equipment, PD measurements are still relatively rare. This is primarily due to the presence of various kinds of interference, the level of which at operating facilities is much higher than during bench tests, and the intensity of the interference often exceeds the intensity of the measured PD. Thus, the main task when measuring PD signals under operating conditions is to separate PD signals that arise in the high-voltage isolation of the controlled equipment from external and internal interference of various origins (corona signals, RF communications, various kinds of commutation, etc.).
1. ANALYSIS OF EXISTING METHODS OF SELECTION OF SIGNALS OF THE CR
The main methods that separate PD signals from interference signals include seven methods.
1. The frequency method. This method is based on the correct choice of the frequency range in which the signal-to-noise ratio is maximum, i.e., registration is not performed in the frequency bands characteristic of interference signals.
The disadvantage of this method is that different frequency spectra of interference are possible at various monitored objects, which in the general case requires a determination of the frequency characteristics of the interference present at this object during each measurement.