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RU-2861311-C1 - METHOD FOR DETECTING AND LOCALISING CORONA DISCHARGE SITES ON HIGH-VOLTAGE ELECTRICAL EQUIPMENT

RU2861311C1RU 2861311 C1RU2861311 C1RU 2861311C1RU-2861311-C1

Abstract

FIELD: technical diagnostics. SUBSTANCE: invention relates to methods for detecting corona discharge caused by various defects in elements of high-voltage electrical equipment. The method is based on registering radiation from the object under study. The radiation is passed through an optical system that ensures the transmission of ultraviolet radiation in a given solar-blind range and suppresses radiation of other wavelengths. An image is recorded on a photodetector array simultaneously in the visible and ultraviolet ranges, wherein the image in the ultraviolet range is formed at a frequency of at least twice the mains frequency of the alternating current. Localisation on the frame of a signal having harmonics of the mains frequency of the alternating current is determined. A combined image is analysed and based on the data obtained, the position of the radiation source is determined, thereby determining the position of the defect causing the radiation. EFFECT: increased reliability of defect detection on high-voltage electrical equipment and improved accuracy of determining their location on the frame. 5 cl, 10 dwg

Inventors

  • Paltsev Andrej Vladimirovich
  • ABEZGAUZ BORIS SAMUILOVICH
  • Lastochkin Anton Petrovich

Dates

Publication Date
20260504
Application Date
20250811

Claims (5)

  1. 1. A method for detecting and localizing corona discharge locations on high-voltage electrical equipment, which consists of passing radiation from the object under study through an optical system that ensures the passage of ultraviolet radiation in a specified solar-blind range and the suppression of radiation of waves of other lengths, characterized in that an image is recorded simultaneously on a camera in the visible and ultraviolet ranges, wherein the image in the ultraviolet range is formed with a frequency of at least twice the industrial frequency of alternating current with mandatory hardware stabilization of the frame rate, frequency filtering is carried out and the localization on the frame of a signal having harmonics of the industrial frequency of alternating current is determined, the joint image is analyzed and, on the basis of the data obtained, the position of the radiation source is determined and thereby the position of the defect that caused the radiation is determined.
  2. 2. The method according to paragraph 1, characterized in that it provides for contactless measurement of the frequency of the high-voltage electrical equipment being diagnosed and determination of phase voltage zeros using capacitive, inductive or radio frequency measurement of the electromagnetic field created by the equipment.
  3. 3. The method according to paragraph 1, characterized in that it provides for wireless transmission to the inspection site of high-voltage electrical equipment of the measured value of the frequency of the monitored network in order to compare the calculated frequency with the measured one and increase the reliability of defect detection.
  4. 4. The method according to paragraph 1, characterized in that it provides for wireless transmission to the inspection site of high-voltage electrical equipment of synchronization pulses coinciding with the zeros of the phase voltage, for measuring the phase shift between the zero of the phase voltage and the moment of ignition of the corona discharge in order to determine the characteristics of the corona discharge.
  5. 5. The method according to paragraph 1, characterized in that it provides for the use of an unmanned aerial vehicle to study the equipment being diagnosed from the closest possible distance and from different angles.

Description

The invention relates to technical diagnostics, namely to methods for detecting corona discharge caused by various defects in elements of high-voltage electrical equipment, and can be used for remote monitoring of their condition. One of the pressing challenges in the electric power industry is developing a method for remotely monitoring the condition of AC overhead power lines (OTLs). Many defects in OPLs are accompanied by the occurrence of corona discharge. Optoelectronic methods offer promising methods for detecting corona discharge. The main challenge with these methods is illumination from external sources, the strongest of which is the sun. The contribution of ultraviolet (UV) radiation to solar radiation at the Earth's surface depends significantly on the current atmospheric transparency. The spectral range from 200 to 315 nm can be characterized as partially free from solar radiation (solar-blind). By analyzing UV radiation in this range, it is possible to develop an effective method for detecting UV radiation from corona discharges caused by current leakage from high-voltage AC power system components. This information can then be analyzed to obtain quantitative and qualitative data on the insulation condition of these components. A known method for detecting and localizing corona discharges is implemented in a device covered by patent RU 106382 U1 (IPC G01R 3/00, published July 10, 2011). This method utilizes an optical filter to filter ultraviolet radiation and digital electronic filtering to isolate the second harmonic of the signal. This filtering is based on the isolation of the second (100 Hz) harmonic of the signal from a photodiode receiving optical radiation from a corona discharge in electrical equipment operating at a standard industrial frequency of 50 Hz. The disadvantage of the known method is that it only provides information about the presence or absence of a defect, but it is impossible to determine its exact location. A method for remote monitoring of the insulation quality of high-voltage AC electrical installations is known under patent RU 2402030 C1 (IPC G01R 31/12, published 20.10.2010), which consists in the fact that radiation from the object under study is passed through an optical system that ensures the passage of ultraviolet radiation in a given solar-blind range and the suppression of radiation of waves of other lengths, individual photons are recorded, they are counted, the time and coordinates of their arrival are determined, based on the data obtained, the position of the radiation source is determined, a time-amplitude characteristic of the radiation is formed, the fundamental frequency of the alternating current is identified, a spectrogram is calculated and, based on its analysis, the presence of partial discharges, the frequency of their sequence and repetition are determined, a correspondence is established between the intensity of photon counting and the instantaneous phase of the alternating voltage, obtaining information on the instantaneous power of ultraviolet radiation at the selected frequency, based on this information, a phase integral characteristic and an amplitude-phase distribution characteristic are constructed, and by analyzing these characteristics, the relative radiation intensity is determined partial discharges in various phases, obtaining qualitative and quantitative characteristics of the quality of the object's insulation. A disadvantage of the known method is the need to create calibration tables to convert the approximate coordinates of the detected photon to the true coordinates. This significantly complicates determining the coordinates of the radiation source, as it requires a two-stage algorithm for determining the defect's coordinates and requires recalibration during repair and maintenance work. Another disadvantage of the method is its low angular resolution and, consequently, low accuracy of defect localization using monophoton time-coordinate-sensitive detectors, compared to defect localization based on the intensity of illuminated pixels in a UV image, as described in this patent. The method known from patent RU 2402030 C1 was selected as the closest analogue. The objective of the invention is to develop a method for detecting and localizing corona discharge locations on high-voltage electrical equipment, ensuring reliable detection and precise determination of the coordinates of corona discharge locations, as well as identification of the radiation source from the image. The technical result of the invention consists in increasing the reliability of detecting defects in high-voltage electrical equipment and increasing the accuracy of determining their location in a frame, which is achieved by combining information from a high-speed UV camera and from a visible range camera, which makes it possible to perform a spectral analysis of a sequence of UV frames with the superposition of the analysis results on a video frame, as well