Method of detecting defects in tightness of electric insulation

IPC classes for russian patent Method of detecting defects in tightness of electric insulation (RU 2250473):

G01R31/08 - Locating faults in cables, transmission lines, or networks (emergency protective circuit arrangements H02H)

G01M3 - Investigating fluid tightness of structures (investigating permeability of porous material, investigating the presence of flaws in general G01N)

Another patents in same IPC classes:

Method of measuring distance to point of single-phase short circuit onto ground in radial distribution circuits / 2250472
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FIELD: electric engineering; measurement technology.

SUBSTANCE: method can be used for inspection of integrity of electric insulation. According to the method item is placed into transparent chamber filled with special liquid and is subject to physical action. Tightness of item is judged from bubbles of gas. Physical action concludes in applying physical load during 10-600 seconds and electrical load is set within range of 500-2500 V. Transformer oil is used as technical oil with water content of 0,01-0,1%.

EFFECT: nondestructive detection of defects in tightness.

The invention relates to the field of electrical engineering, in particular to the field of measuring and control equipment, and can be used to diagnose the condition of electrical insulation products without further destruction.

A known method of drying and moisture protection electrical isolation machines by connecting the vehicle body and current-carrying elements of the winding to the poles of the DC voltage source, wherein the current-carrying elements of the winding is connected to the negative pole of the DC voltage source and the positive pole of the constant voltage source connected directly to the machine body (SU, 1365266, CL H 02 To 15/12, 07.01.88).

In the known method, the electric field causes the free movement of charged particles that capture the neutral molecules of moisture and carry them in the direction of the positive pole, i.e. housing, resulting in the selection of air on the surface eliminates the penetration of moisture into the insulation of the winding.

However, the known method carried out in air, cannot detect the destruction of electrical insulation products.

There is a method of impregnating the insulation of windings of electrical products, which consists in the fact that the product is placed in a chamber filled with technical liquid, place the insulation of the windings of a DC electric the OLE by connecting the “plus” source and “minus” to the engine block and finish the impregnation process when reaching the steady-state values of electricity consumption (EN, 2174279, CL H 02 To 15/12, 27.09.01).

At the same time as the fluid used, comprising a varnish, the solvent and the electrolyte, and the shutter speed taking into account the overall dimensions of the equipment is 30-120 minutes

A known method can improve the efficiency of the impregnation process isolation electrical products. However, the existence of the integrity of electrical insulation products to install in a known manner possible.

The closest analogues of the present invention is a method of detection of violations in the integrity of electrical insulation products, which consists in the fact that the product is placed in a transparent chamber filled with technical fluid, and reported physical effects, and the presence of the integrity of the product is judged by the appearance of gas bubbles (Lanes VP, Levin LA “Technique vacuum test”, L., SEI, 1963, p.132-137).

In a known way as a physical impact on product use impact pressure and give the product an excessive pressure of the control gas.

The known method provides a defect is detected in the winding insulation of electrical products.

However, in a known manner by creating excessive pressure now is should to check the electrical insulation products for tightness without further destruction.

Object of the invention is the provision of opportunities for defect detection electrical isolation without further destruction.

A new technical result is achieved in that in the method for detecting the integrity of electrical insulation products, which consists in the fact that the product is placed in a transparent chamber filled with technical fluid, and reported physical effects, and disorders integrity of the product is judged by the appearance of gas bubbles, according to the invention, the physical impact is applied by overlaying the electrical load for 10-600 sec, and the electric load set in the range of 500-2500, the technical fluids used transformer oil with a water content of 0.01-0.1%.

The electric field created in isolation of the product by applying a constant voltage between the windings and the frame of the device by connecting the positive pole of the DC voltage to the housing, and the negative to the conductors of the winding.

The electrical load is set in the range of 500-2500, which is selected depending on the operating voltage of the machine:

- machines for voltage up to 1000 V - load is set at 500;

- for machines voltage up to 3 kV - load is set at 1000;

- for machines voltage is about 6 kV the load is set at 2500 C.

At the same time as oil use technical oil, transformer oil, petroleum oil, etc. All oil must contain moisture (water content of from 0.01 to 0.1%).

The proposed method is implemented as follows: the test article is placed in a transparent chamber filled with technical fluid, creating an electric field with a certain electric load for 10-600 sec, and about the presence of a defect is judged by the gas bubbles, resulting in damaged areas of the product.

The proposed method allows to determine the number of insulation defects on the amount of emitted air garlands and the degree of the defect on the number of bubbles in the air the garland.

In places where damage to electrical isolation of the product in the proposed method stands out hydrogen gas, which rises to the surface of the fluid in the form of garlands clearly visible bubbles, indicating the location of the defect. If you damage a few, there are several such garlands.

Hydrogen gas is formed at the damage site electrical isolation of the product in the recovery of hydrogen ions found in moist oil and formed by dissociation of water molecules in the oil. Hydrogen ions that carry a positive charge, the move is conducted to the winding, to which is supplied a negative charge, and the conductive part is the recovery of hydrogen ions to molecular hydrogen (in places where broken insulation).

Thus, the proposed method can be used to determine the defects in the insulation of electrical products quick and economical way without destroying the insulating material that allows you to “heal” thus revealed defects in various known ways, for example by electrophoresis method.

The method of detection of violations in the integrity of electrical insulation products, which consists in the fact that the product is placed in a transparent chamber filled with technical fluid, and reported physical effects, and disorders integrity of the product is judged by the appearance of gas bubbles, wherein the physical impact is applied by overlaying the electrical load for 10-600 s, and the electric load set in the range of 500-2500, the technical fluids used transformer oil with a water content of 0.01-0.1%.