SU1337837A1 - Method of nondestructive check of production quality of h.v.insulation - Google Patents

Abstract

The invention serves to improve the accuracy of determining the location of insulation defects. The voltage on sample 4 of the insulation is raised to a value at which partial discharges in sample 4 with a frequency of at least 100 pulses per second, measured by a counter of 8 pulses. In this case, the voltage should be no more than 1.5 voltages, adopted as a working for this sample. Using the amplitude analyzer of 7 pulses and the two-coordinate recorder 9, the amplitude spectra of the signal of the positive and then negative polarities of the partial bits are obtained and the values of the amplitude of the pulses of the partial bits (q and q) are determined. The equality q and d means that the gas pore is in the thickness of the insulation. If q / P, then the gas pore is located near one of the electrodes, and in the case of q P about that, which is connected directly to the output of the secondary winding of the transformer 1. The absence of partial bits or the value of the frequency of the sequence is less than 100 pulses per second testifies to the high quality of the sample. 1 il. F cl with co 00 00

Description

one

The invention relates to instrumentation engineering and can be used in devices for quality control of manufacturing solid high voltage insulation of electrical products, for example high voltage transformers, etc.

The aim of the invention is to improve the accuracy of determining the location of insulation defects, such as gas pores, and the type of insulation defect during its manufacture.

The drawing shows a block diagram of the device that implements the proposed method.

The device comprises a test voltage source 1, made in the form of a high voltage transformer connected to a voltage regulator (not shown). One of the findings of the secondary winding of the transformer 1 is connected to one of the measuring electrodes (not shown). The second electrode (not shown) is connected through the measuring resistor 2 to the common terminal and the second terminal of the secondary winding of the transformer 1. A capacitor 3 is connected in parallel with the secondary winding. A controlled sample 4 of the insulation is placed between the electrodes. The terminals of the resistor 2 are connected to the corresponding inputs of the high-frequency filter 5, the output of which through the amplifier 6 is connected to the input of the amplitude analyzer 7 pulses, the first and second outputs of which are connected respectively to the counter 8 pulses and the two-coordinate recorder 9.

one

The device that implements the method works as follows.

The voltage on a sample of insulation is raised to a value at which partial discharges in the sample are followed at a frequency of at least 100 pulses per second, which is measured by a counter of 8 pulses, but not more than 1.5 voltages taken for this sample as working voltage. In this voltage, using an amplitude analyzer of 7 pulses and a two-coordinate recorder 9, the amplitude spectra of the signal of a positive, then negative polarity of partial discharges, having a shape close to the normal distribution, are obtained. For each spectrum, pulse amplitude values are determined.

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The actual bits (q and q) correspond to the cycle of each amplitude spectra obtained. In this case, IF q P the gas pore does not adjoin to any of the measuring electrodes and is located in the thickness of the insulation (corresponding to such a defect, a possible violation of the technology of making the insulation is a violation of impregnation, vacuum, pressure testing). If q / q ,, then the gas pore is located near one of the electrodes, and at (f. - about that which is connected directly to the output side of the secondary winding of the transformer 1. At q P - the gas pore is located at the opposite electrode, i.e. which, via measuring resistor 2, is connected to a common pin, while a probable violation of the technology may be, for example, poor-quality application of an adhesive sublayer to the current-carrying core or violation of the temperature regime of the insulation.

If partial bits are absent (which will be detected by counter 8) or their frequency is less than: 100 pulses per second, then we can conclude that the quality of the insulation is high, that there are no violations of its manufacturing technology and there is a low probability of its failure during operation.

The invention makes it possible to increase the accuracy of determining the location of defects in the insulation and thereby determine the type of defects caused by a violation of the technology for making the insulation. In addition, the invention reduces the risk of destruction of the insulation during the test, since the value of the test voltage is assumed to be lower.

Claims (1)

Invention Formula The method of non-destructive quality control manufacturing high voltage gQ of isolation, consisting in that a test voltage of industrial frequency is applied to a test sample, the amplitudes of partial discharges are measured, the quality is determined gg of insulation by the value of measured amplitudes, characterized in that, in order to increase the accuracy of determining the location of insulation defects, such as gas pores, 35 40 45 31337837 act as a test voltage. insulation, record the amplitude industrial frequency of this magnitude, the spectrum separately for positive and so that the frequency of following the partial negative polarities of the partial bits in the event of their occurrence were bits, and the measurement amplitude at least 100 pulses per second, but non-particle bits are produced for more than 1.5 voltages received at each of the two peaks of the indicated working quality for a given sample of spectral spectra.