SU1679422A1 - Method of diagnostics of high-voltage solid insulation - Google Patents

Abstract

The invention relates to the diagnosis of high-voltage insulation of electrical products, based on the registration of partial discharges. The purpose of the invention is to expand the functionality and increase the reliability of diagnostics of solid high-voltage insulation. This goal is achieved by the fact that the test object is subjected to a high test voltage and simultaneously record the amplitude spectra of signals proportional to the apparent charge of partial discharges and signals. proportional to the light emission of partial discharges developing on the surface of the insulation. In this case, the in-phase signals correspond to a surface defect, the internal defect is characterized by the absence of a signal in the optical channel and the presence of a signal in the electrical channel, and the presence in the insulation of both internal and external defects is characterized by both in-phase and non-phase optical and electrical signals. 2 Il. LO C

Description

The invention relates to electrical engineering, in particular to the diagnosis of solid high-voltage insulation of electrical products, based on the registration of partial discharges (PD).

The purpose of the invention is to increase the reliability of diagnostics of solid high-voltage insulation and expand the functionality achieved by combining optical and electrical diagnostic operations, followed by determining surface, internal and joint defects (surface and internal at the same time).

Figure 1 shows the structural diagram of the device that implements the proposed method; figure 2 - diagrams of the nature of the CR signals, following the optical and electrical measurement channels.

A device that implements the proposed method consists of a source of test voltage 1, made in the form of a high voltage transformer, a coupling capacitor 2 of the test chamber 3 into which the test isolator 4 is placed, a measuring resistor 5 intended for measuring the apparent PD charge, objective 6, an optical sensor 7 for converting a light signal into an electrical one, a high-frequency filter 8, an amplifier 9, a two-beam oscilloscope 10.

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The diagnostic method is carried out as follows.

The test object is located in a darkened, sealed chamber, then filled with electrically high-strength gas, with the help of a special high-voltage input to the chamber a test voltage is applied to the object, usually an alternating voltage of industrial frequency. The test voltage smoothly rises to a value at which partial isolations are observed in the object insulation, the magnitude of this voltage should not be more than a certain value 1) test, normalized for a particular product, the signal from the optical sensor is proportional to the surface radiation Dov, is fed to one of the inputs of a dual-beam storage oscilloscope. A signal from the measuring resistor is simultaneously applied to the other input of the oscilloscope. In this common situation, the presence of signals through both electrical and optical measurement channels is present. In this case, the wire is identified by the phase of occurrence, it can be concluded whether the defect is inside the insulator or on its surface. Rotating the test object relative to the optical sensor and fixing such an object position at which the ratio of the optical signal to the in-phase signal following the electrical channel is maximum, it can be concluded that there is a defect on the surface of the insulator opposite the lens of the optical sensor.

The diagram (Fig. 2) is schematically depicted: a sinusoid of alternating voltage (I) following an electrical channel, a type of PD (II) signals both in electrical and optical channels, some constant signal (111) following an optical signal channel in the absence of signals CR. The diagram shown in Fig. 2a corresponds to the variant when the defect is only on the surface of the insulator and there are no defects inside. In this case, CR signals like

Optical and electric channels appear in-phase on the oscilloscope screen. The circuit shown in FIG. 26 describes an embodiment where the defect is thicker than the insulator and the surface of the insulator is free from defects. In this case, the CR signals on the oscillogram are visible only through the electrical channel, the optical channel is free from the signals of the RCR signals

The diagram shown in Figure 2b describes the most general case when defects are located both inside and on the surface of an insulator. In this variant, it is necessary to carry out identification of CR signals by

phase of occurrence. Due to this, it is possible to distinguish from the spectrum of signals traveling along an electrical channel, signals corresponding to surface defects, and, accordingly, signals corresponding to

internal defects. Only then can a conclusion be made about the degree of danger of defects and to predict the service life of the insulation.

Claims (1)

Invention Formula A method for diagnosing solid high-voltage insulation, which implies that a test object is subjected to a test voltage and an amplitude spectrum of partial discharges is recorded, characterized in that, in order to enhance the functionality and increase the reliability of diagnostics, the amplitude spectra of the signals proportional to the light emission of the surface partial discharges and the signals proportional to the apparent charges of the partial discharges, identify them according to the origin phase, with the in-phase signals corresponding to the surface defect, the internal defect is characterized by the absence of a signal in the optical channel and the presence of a signal at The electrical channel, the presence of both internal and external defects in the insulation, is characterized by both in-phase and non-in-phase optical and electrical signals. v / oi / 6 U M eleven eleven ll II t, tz t, l t, -i, 4-4 fig / 6