Usage: laying cables through walls, floors, descendants of structures of lead-in or bushing insulators. The essence of the invention: the device contains a cylindrical body 1 embedded in the concrete of the wall of the reactor compartment of the nuclear power plant, to the ends of which flanges 2 and 3 are welded with conical threaded holes 4 for the installation of sealing units. Each sealing unit includes a bushing 5 with a cone-shaped diaphragm shell 6 installed inside it, the wall of which is made corrugated. The sheath 6 is filled with a sealing compound 7 with conductors 8 of the cable 9 passing through the latter, having sections 10 with stripped insulation. The corrugated surface of the shell 6 is made along a helical line and corresponds to the pitch of the internal thread of the sleeve 5, with which it forms a common threaded connection. Sleeve 5 also has an external thread designed for connection with end flanges, such as flange 2, 2 z.p.f-ly, 1 silt. sl s sl s s s

S „1753528 Al

UNION OF SOVIET

SOCIALIST

REPUBLIC (st) s H 02 G 3/22

STATE COMMITTEE

FOR INVENTIONS AND DISCOVERIES

PRI SCST USSR MvSchshchr

M 1352578, class. H 02 G 3/22, 1987. (54) CABLE ENTRY (57) Use: laying cables through walls, floors, ceilings of bushing or insulator structures. The essence of the invention: the device contains a cylindrical body 1 embedded in the concrete of the wall of the reactor compartment of the nuclear power plant, to the ends of which flanges 2 and 3 are welded with conical threaded holes 4 for the installation of sealing units. Each sealing unit includes a bushing 5 with a cone-shaped diaphragm shell 6 installed inside it, the wall of which is made corrugated. The sheath 6 is filled with a sealing compound 7 with conductors 8 of the cable 9 passing through the latter, having sections 10 with stripped insulation. The corrugated surface of the shell 6 is made along a helical line and corresponds to the pitch of the internal thread; bushing 5, with which it forms a common threaded connection. Sleeve 5 also has an external thread designed for connection with end flanges, such as flange 2, 2 z.p.f-ly, 1 silt.

SUBSTANCE: invention relates to electrical engineering, in particular to devices for laying cables through walls, floors, ceilings of lead-in or bushing structures, and can be used when laying control cables through the walls of nuclear power plants.

A cable gland is known, containing a hollow body with a sealing assembly installed in it, made in the form of a cylindrical sleeve with holes through which cable cores pass, filled with a sealing polymeric material. outer surface either along the generatrix of the cylinder, or along the helical line, grooves are made connected to the said blind holes. " twenty

However, such a complication of the structural and technological implementation of the forming elements of the sealing assembly does not exclude the main drawback of cable entry: shrinkage and delamination phenomena that inevitably occur under the operating conditions of nuclear power plants under the influence of large temperature drops polymer material from the walls of the bushing and cable cores, leading to a loss of tightness of the input and a decrease in its operational reliability. In addition, the replacement of a cable gland of this design is very laborious, since it requires intervention in the design of the penetration itself., The closest in technical essence and the achieved result to the proposed one is cable gland containing a cylindrical body and end flanges, in the openings of which sealing units are installed, each of which is made in the form of a bushing with a sealing composition placed in it and cable cores passed through the latter, having sections with stripped insulation. The bushings of the sealing units in this device are a massive body with holes for accommodating individual cable cores. The holes in the bushings are made two-stage, and the diameter. one step corresponds to the diameter of the insulation of the cable wires, and the diameter of the other step, located on the peripheral sections of the bushing, is greater than the diameter of the insulation of the cable wires. Gaps between the surface of the sections of cable cores with stripped insulation and the inner surface of the corresponding steps of the holes in the sleeve25

50 ki filled with adhesive sealing material.

A disadvantage of the known device is its low reliability, since even with such a design, due to the natural shrinkage of the polymerizing material, it peels off from the walls of the elements of the sealing assembly with the formation of gaps that worsen the tightness of the cable entry.

In addition, during the operation of such a cable gland under conditions of elevated temperatures and radiation, the sealing material is prepolymerized and other negative changes in its structure up to cracking occur, leading to an additional increase in gaps and practical depressurization of the cable gland, as a result of which it becomes necessary to urgently replace it directly under conditions operation. However, such a replacement in the well-known cable entry design, although provided, is very complex and time-consuming, since it is associated with the need to replace the end flanges. This is a significant drawback of the known device. The aim of the invention is to increase reliability while improving the repairability of constituent parts by providing non-destructive replacement when they fail.

This goal is achieved by the fact that the cable gland contains a cylindrical body and end flanges, in the holes of which sealing units are installed. each of which is made in the form of a sleeve with a sealing compound placed in it and cable cores passed through the last one, having sections with stripped insulation, provided with a cone-shaped diaphragm shell located in the bushing, the walls of which are made with corrugations, and the sealing compound is placed inside the shell.

The cone-shaped diaphragm shell can be made of a rigid springy material or an elastic polymeric material.

The drawing shows circuit diagram the proposed cable entry.

The cable entry contains the walls of the reactor compartment embedded in concrete

AE S cylindrical body 1, to the ends of which flanges 2 and 3 are welded with conical threaded holes 4 for the installation of sealing units, Each sealing unit includes a sleeve 5 with

1753528 with a cone-shaped diaphragm shell 6 installed inside it, the wall of which is made with corrugations, the shell 6 is filled with a sealing compound 7 with cable 9 cores 8 passing through the latter, having sections 10 with insulation removed 5. The corrugated surface of the shell 6 is made along a helical line and corresponds to the pitch of the internal thread of the sleeve 5, with which it forms a common threaded connection. The sleeve 5 also has an external thread intended for connection with end flanges, for example, flange 2. In the proposed cable gland the pitches of the taper threads of all three parts; flange 3, bushing 5 and shell 6 are made both with the same pitches of all threads, and without their coincidence, while dx taper reaches 2 ... The cone-shaped diaphragm shell 6 is made either from a rigid spring material, for example, structural steel with a given (experimentally selected) wall thinning up to 0.3-0.5 mm, providing it

25 elastic properties, or from a heat-resistant and radiation-resistant polymer elastic material without imposing restrictions on the choice of its wall thickness. The large base of its cone shell 6 faces the inside of the body

1, and its height exceeds the height of the sleeve 5.

The input is also equipped with end caps 11. The assembly and operation of the proposed cable gland is carried out in the following way. working conditions one of the main elements of the proposed input is made - a corrugated sheath 6 filled with a sealing compound 7 cut ends of the cores 8 of the cable 9. To do this, a measured piece of cable 9 is cut, its ends are cut by removing the insulating sheath from both ends, as well as removing the insulation from metal cores

8 cable 9. The number of bare areas can be from one to several and is determined from the condition of ensuring optimal adhesion of the sealant and the metal conductor (core), since in the bare areas the degree of adhesion of the sealant to the conductor increases significantly. stacks are left for that; so that there is no closure. After that, cable 9c is exposed. 10 on the cores 8 is inserted into a detachable form with a pre-installed in the last corrugated oGolochka 6.

The detachable form is compressed with force along the parting line. The sealing composition 7 is poured through the special technological openings of the external plugs 11 of the sheath 6 into the free space between the walls of the said sheath 6 and the cores 8 of the cable 9. After the polymerization of the sealing composition 7, the form is disassembled along the parting line: and a similar operation is repeated with the other end of the cable 9.

Upon completion of the technology of prefabrication and casting of each such element of the cable gland, the subsequent assembly of the proposed design is carried out in the housing 1 or the embedded pipe of the wall of the reactor compartment. At the same time, from the side of the flange 3 welded to the body 1 (embedded pipe) on the tapered thread (with a taper angle of 2) of the shell 6, the wall of which is made with corrugations, with the cores 8 of the cable 9 filled with a sealing compound 7, the sealing sleeve 5 is screwed. the conical thread of the shell 6 is simultaneously screwed into the conical thread of the hole in the end flange 3; In this case, the sheath 6 with the sealant sealed in it with the cores 8 of the cable 9 and the flange 3 due to the taper angle of the thread within

2O with a different (not coinciding) pitch of all three threads, it will turn no more than 360-720O. Twisting of the cores 8 of the cable 9 practically does not occur with such a twist. With the same (identical) pitch of all three threads, the rotation is significantly reduced and amounts to only 3090O, i.e. cores 8 of cable 9 and flange 3 remain practically motionless; —:

In the region of the flange 2, the assembly is carried out in a similar way by screwing the sealing sleeve 5 onto the tapered thread of the shell 6, the walls of which are made with corrugations.

When the threaded parts of the input are screwed in, due to the elastic deformation of the wall, the inner corrugated surface of the shell 6 is pressed against the surface of the sealing composition 7 in contact with it. .Leaking due to shrinkage both in the process of polymerization of the composition, and during the entire operational period.

Compiled by A. Yudin

Techred M. Morgenthal

Proofreader O. Kravtsova

Editor M, Yankovic

Order 2771 Circulation Subscription

VNIIPI State Committee for inventions and discoveries at the State Committee on Science and Technology of the USSR

113035, Moscow, Zh-35, Raushskaya emb., 4/5

Production and publishing plant "Patent", r. Uzhgorod, street, Gagarin, 101

In addition, in this bushing, the sealing composition is compacted with significant uniformity due to the layer-by-layer crushing of the sealing composition by the corrugations of the elastic wall, which also improves the quality characteristics of the said composition and at the same time increases the tightness and reliability of the cable gland as a whole.

Thus, the proposed design of the cable gland for a long time of operation, due to the design features of its constituent parts, is maintained in the optimal volumetric, polymerizing sealant, and in cases when any part irreversibly fails, it is replaced, for which the sleeve 5 is unscrewed from the threaded hole of the flange 2, and then the sheath 6 with the cable 9 is easily and quickly removed from the sleeve 5.

The installation of a new set of sheath 6 with cable 9 is carried out in the reverse order without any intervention in the design of the penetration. the diameter of the shell 6 is less than the diameter of the holes in the corresponding flanges 2 and 3.

Thus, in comparison with the prototype, the technical and economic advantages of the proposed cable gland are in a simpler design implementation of the parts that make up the design; higher operational reliability due to improved sealing by compensating for shrinkage and aging of the sealing composition, higher durability, as well as improving the repairability of parts without complicating the design and reducing the complexity of assembly and dismantling operations due to simplified interconnections of parts. components of the proposed cable gland, the use of the proposed cable gland in the power industry will dramatically increase the efficiency of maintenance and repair of penetrations for control cables at nuclear power plants.

Except toro. The use of the proposed cable entry at NPPs makes it possible to reduce the permissible level of radionuclide leakage into the environment through the containment and thereby improve the environmental situation in the NPP area.

Claim

1. Cable gland containing a cylindrical body and end flanges, 20 in the holes of which sealing units are installed, each of which is made in the form of a bushing with a sealing compound placed in it and cable cores passed through the latter, having sections with stripped insulation, from l characterized by the fact that, in order to increase reliability while improving the repairability of the parts that make up the structure due to

30 non-destructive replacement when they fail, it is equipped with a cone-shaped diaphragm shell located in the sleeve, the walls of which are made with corrugations, and the sealing compound is placed

35 inside the shell.

2. Input pop.1, different from tea (qi and syatem), that the cone-shaped diaphragm shell is made of a rigid springy material.

40 3. Input according to claim 1. characterized in that the cone-shaped diaphragm shell is made of an elastic polymer material.

Similar patents:

One of the most vulnerable points of any communications is the place where a cable or wire enters the wall of a building, into a switchgear, an actuator, etc. Today, there are many options for protecting cable passages from moisture, we tried to collect the most effective of them for readers site in this article. So, let's figure out now how the sealing of cable entries into a building, cabinet, etc. can be performed.

What are the rules and requirements?

AT normative documents clause 2.1.58 and SNiP 3.05.06-85 describes the requirements for cable passages:

According to the above requirements, it turns out that the cable gland in the building must be able to retain water, not support combustion and prevent the spread of fire. With all this, be able to re-replace the cable or wire, if necessary.

Sealing methods

To seal the input in a private house or cottage, fire-retardant polyurethane foam is most often used, evenly distributing it in the pipe around the cable. After curing mounting foam cut off and partially rammed, pressing into the pipe. The resulting recesses are plastered with cement mortar. An example of such a sealing option for a cable line is shown in the photo below:

You can also try using the old-fashioned method: rags cut into thin rags, liquid cement mortar and a piece of rag soaked in abundance with it are rammed with a wooden stick into the gap between the cable and the pipe.

Another commonly used method is the use of a sealant that fills the bumps and voids between the hole and the embedded sleeve, usually made of fiber cement, metal or plastic. Sealing the cable entry with this technique has the advantage that the sealant does not harden, making the entry hole repairable.

In addition, there are specialized professional materials on the market for sealing and production of hermetic bushings. For a hermetic passage into a switchboard or an actuator, a cable gland is most often used - a PG gland, shown in the photo below:

A large range of models and different sizes make this solution simple and versatile. The collapsible design of the cable gland allows you to install it in completely different and convenient places for maintenance. At the same time, the presence of a rubber seal and a correctly selected size of the cable and a pressure seal will allow achieving high tightness indicators, the degree of protection IP54-IP68.

It should be additionally noted such a method of sealing the cable entry as the use of a sealant, which is concreted in the formwork, and a system cover. In appearance, such a method of protection looks like this:

There are also specialized seals that allow you to reliably seal the cable entry with inflatable passages, gloves, etc. All these devices, as a rule, are imported, so the cost of this method of protection is quite high. In this case, it is more rational to consider simple, but effective and time-tested options.

Cable glands or cable glands are used to fix the cable and seal the entry point into the housing of electrical equipment or the protective sheath during piping. Often this connecting element is considered insignificant and does not pay enough attention to its selection, or pay it mainly to the cost. This approach is erroneous and can lead to serious consequences.

In addition to the main tasks indicated above, cable glands perform a number of other important functions:

• protection of cable and equipment from external influences (moisture, dust, etc.)
• Ensuring the tightness of the housing when used in an explosive environment;
• preventing breakage of the connection during mechanical impact on the cable.

The use of low-quality cable glands often leads to temporary inoperability of electrical equipment due to a lack of contact or its failure as a result of foreign particles entering the housing, as well as to the occurrence of fires and other emergencies. As a result, insufficient attention to a small detail leads to big troubles, especially when it comes to a large and responsible object or process.

Careful selection of cable glands by parameters allows minimizing the risks of emergency situations at the facility and increasing the safety of technological processes. The use of original certified parts also helps to reduce operating costs by reducing equipment downtime and the resulting reduction in production.

Selection of cable glands

In order for cable glands to ensure the fulfillment of all the tasks assigned to them, it is important to choose them correctly in accordance with the operating conditions, the type of equipment and the cable on which they will be installed. In this case, it is desirable to adhere to a certain algorithm.

Main selection criteria for cable glands:

1. Type of cable (armored or unarmoured).
2. cable laying method.
3. IP protection class.
4. Operating environment.
5. Availability of requirements for explosion protection.

Currently, manufacturers of cable glands produce a wide range of products that differ in a number of ways:

• case material;
• sizes;
• seal type;
• connection type;
• level of protection;

This allows you to choose the most suitable product for a particular case in compliance with the requirements, eliminating unreasonable costs. At the same time, it should be taken into account that the current regulations and standards do not cover all the characteristics of cable glands. In this regard, some companies apply their own design solutions and innovative materials to improve product quality and service life in difficult conditions. It is the products that have additional benefits should be preferred.

The invention relates to sealed cable glands of electrical conductors in the electrical equipment of deep-sea vehicles. The cable gland contains a metal cylindrical body with holes for electrical conductors, equipped with conductive contact rods and nuts fixing them, insulating bushings and centering bushings. Each of the centering bushings is welded into one of the holes of the metal cylindrical body. An insulating bushing is introduced into the hole of each centering bushing, into the hole of which a conductive contact rod is inserted and pressed. The free space of the hole between each conductive rod and the metal cylindrical body is filled with an insulating compound. EFFECT: invention improves the efficiency of cable entry sealing. 1 ill.

Drawings to the RF patent 2502145

Field and state of the art to which the invention relates

The present invention relates to the field of electrical engineering, including ship electrical installations, electrical connections of systems, installations and devices using electrical connectors, glands, cable glands. Specifically, the proposal refers to sealed cable glands of electrical conductors in the electrical equipment of deep-sea vehicles.

Sealed connectors and bushings in the electrical engineering of surface and especially underwater vessels are a widely used technique. Complicated sealing tasks. It is required to guarantee the reliable operation of electrical conductors of electrical equipment, the applicability of materials. The technologies for their production and application are rapidly developing, the level of development of the technology of hermetic connections and bushings is increasing.

There are known pressure seals according to OSTV5.8707-85 “The pressure seals. Design, dimensions and technical requirements". The standard applies to pressure seals operating in the aquatic environment at hydrostatic pressure from 0 to 6.0 MPa. The standard is somewhat outdated, its requirements are lower than modern needs. We need pressure seals operating in the aquatic environment in a wider range of hydrostatic pressures up to 20.0 MPa and above.

Known sealed cable gland according to the patent RU No. 2224312 (analogue). SUBSTANCE: invention relates to electrical engineering and can be used for cable entry into ship hull structures and fire-hazardous premises to ensure tightness of cable entry in case of fire inside premises and ship compartments. Sealed cable gland contains a body with an annular protrusion in the hole for cable passage, a sealing element, a washer and a pressure element. The cable gland contains a fire-resistant material capable of changing its shape under the action of pressure, located in the opening of the housing around the cable and enclosed between the inner and outer conical washers. The fire-resistant material is under pressure from a spring located between the annular protrusion of the body opening and the inner cone washer, which is pressed by a compression nut. Spherical quartz granules with a smooth surface can be used as a fire-resistant material capable of changing its shape under pressure in a cable gland. The disadvantages of this solution are to exclude the possibility of melting and burnout of the cable in the zone of its sealing, maintaining the tightness of the cable gland in case of fire, which is important for fireproof cable glands and is a disadvantage for deep-sea cable glands due to excessive unjustified costs.

Known decision on the application No. JP 20080049384 20080229 (analogue) applicant SUKEGAWAELEC+. The solution provides resistance to the ingress of moisture into the sleeve. It seems that such a solution may not provide the required depth of immersion of a deep-sea vehicle for several kilometers.

Known tight inputs according to patents RU 2259608 dated 11/27/2003 and No. 2291507 dated 08/01/2005 (prototype). The inventions relate to hermetic inputs of electrical conductors in sealed rooms or volumes on nuclear power plants or other objects. The essence of the invention lies in the fact that in a sealed cable gland containing a metal cylindrical body with flanges attached to its ends by electric arc welding, the ends of the cables are sealed with oxide ceramic insulators sprayed onto the insulators at the places of titanium soldering and the insulators are attached to the metal sheath of the cable by the active method. soldering with the AgCuTi system in a vacuum furnace.

Their main disadvantages are determined by the need to perform high-tech complex technological methods of welding and soldering in the conditions of non-serial shipbuilding production, which makes it excessively complicated technological process input sealing.

The listed shortcomings of the prototype and analogues are eliminated in the proposed technical solution for sealed cable entry.

Sealed cable gland containing a metal cylindrical body with holes for electrical conductors, characterized in that it is equipped with conductive contact rods and nuts fixing them, insulating bushings and centering bushings, each of the centering bushings is welded into one of the holes of the metal cylindrical body, into the hole of each an insulating sleeve is inserted into the centering sleeve, a conductive contact rod is inserted and pressed into the hole, the free space of the hole between each conductive rod and the metal cylindrical body is filled with an insulating compound, and the conductive rods pressed into the insulating sleeve are fixed in the holes of the metal cylindrical body with nuts fixing the rods in the body .

The proposed technical solution formulates the main distinguishing features of a sealed connector.

signs

"it is equipped with conductive contact rods and nuts fixing them, insulating sleeves and centering sleeves," provide the possibility of sealing contact connection when entering the cable across the border between the electrical installation circuits of the deep-sea vehicle and circuits outside it. A set of the listed structurally simple rods, bushings and nuts, which are provided with a sealed gland (if the prescribed simple requirements for the assembly of a pressure seal) ensures its tightness.

signs

"Each of the centering bushings is welded into one of the holes of the metal cylindrical body, an insulating bushing is inserted into the hole of each centering bushing, into the hole of which a conductive contact rod is inserted and pressed," provide, with careful implementation of the proposed design solutions, the ability to obtain a reliable sealed contact electrical connection on any depths of application of tight input. Tightness is ensured by hermetic welding of the centering sleeve into the hole metal case, introduction and hermetic pressing of the contact rod into the insulating sleeve.

signs

"the free space of the hole between each conductive rod and the metal cylindrical body is filled with an insulating compound, and the conductive rods pressed into the insulating sleeve are fixed in the holes of the metal cylindrical body with nuts,"

provide additional sealing by filling the free space of the housing hole between each conductive rod and the metal of the cylindrical housing with an insulating compound. In this case, the main sealing is provided by pressing the rods into an insulating sleeve, in which the conductive rods after pressing are fixed in the holes of the metal cylindrical body with nuts that fix the rods in the body. Based on the use of standard materials for shipbuilding, technological methods and the use of original simple products without special expensive tools and fine technologies, a sealed cable gland is proposed.

Therefore, the proposed sealed cable gland meets the criterion of "novelty", as it has distinctive features from the prototype, new structural elements, new connections between elements and new materials used. The given properties do not coincide with the properties that are distinctive features in known technical solutions, and are not the sum of their properties, which allows us to consider the proposed solution as corresponding to the criterion of "significant differences".

Description of the design of sealed cable entry.

The figure shows a drawing of a sealed cable gland.

Sealed cable entry contains a metal cylindrical body 1 with holes 2 for electrical conductors. It is equipped with conductive contact rods 3 and nuts 4 fixing them, insulating bushings 5 ​​and centering bushings 6.

Each of the centering sleeves 6 is welded into one of the holes 2 of the metal cylindrical body 1. An insulating sleeve 5 is inserted into the hole 2 of each centering sleeve 6, into the hole of which a conductive contact rod 3 is inserted and pressed. The free space 7 of the hole 2 between each conductive rod 3 and metal cylindrical body 1 is filled with an insulating compound 8. The conductive rods 3 are fixed in the holes 2 of the metal cylindrical body 1 by nuts 4 with washers 9.

The basis of sealing guarantees is provided by constructive solutions of the main units introduced into the design of the sealed bushing, technological methods of their assembly. The tightness of the input is ensured by pressing the contact rods 3 into the insulating bushings 5. This operation is carried out by tightening the nut 4 and fixing it. Additional sealing is performed by filling the free space 7 of the hole 2 of the body 1 with an insulating compound 8 between each conductive rod 3 and the metal cylindrical body 1. The sealing guarantee is determined by the combination of parts designs, their materials and accuracy during assembly. Multiple tests confirm the guaranteed results of tightness of the bushings despite the apparent simplicity of the proposed solution.

Thus, the issues of electrical isolation of rods 3 from each other, from the body, from environment. The technology of hermetic installation of the body 1 of the hermetic cable entry into the body of the underwater vehicle is repeatedly and constantly used and does not require improvement.

CLAIM

Sealed cable gland containing a metal cylindrical body with holes for electrical conductors, characterized in that it is equipped with conductive contact rods and nuts fixing them, insulating bushings and centering bushings, each of the centering bushings is welded into one of the holes of the metal cylindrical body, into the hole of each an insulating sleeve is inserted into the centering sleeve, a conductive contact rod is inserted and pressed into the hole, the free space of the hole between each conductive rod and the metal cylindrical body is filled with an insulating compound, and the conductive rods pressed into the insulating sleeve are fixed in the holes of the metal cylindrical body with nuts fixing the rods in the metal cylindrical body.

In accordance with paragraph 29.13 of the "Scope and standards for testing electrical equipment", power cable lines during commissioning must be tested with an alternating current voltage of frequency 50 Hz 1.00 - 1.73 U nom. Due to the lack of appropriate test equipment in Russia, it is customary to confine ourselves to monitoring partial discharges in the terminations of cable lines under operating voltage at the first start. The acoustic method is the most effective non-destructive diagnostic method under operating voltage. Domestic end couplings of the MKAPV 64/110 type are the most emergency. In the 1990s, Mosenergo had more than 10 accidents of these couplings per year, with a total number of about 300 couplings. However, imported couplings are also prone to accidents. For example, at the City substation in 2007, an accident occurred with a 110 kV Siemens termination. Therefore, acoustic inspection for the presence of partial discharges continues to be relevant.

The reasons for the breakdown of couplings of the MKAPV 64/110 type are the imperfection of the technology.

Typically, an acoustic survey is carried out under operating voltage without shutting down and removing the load. When conducting an acoustic survey, an RChRsh sensor is installed on the grounded base plate of the 110 kV coupling, and its signal is recorded by the Dolphin device. At the same time, the sensitivity of the device to discharge sounds is such that it allows recording entry-level discharges (several picocoulombs). This corresponds to the ignition of the indicator of the first level of the Dolphin device. In the presence of significant acoustic signals exceeding the noise level, an oscillogram of ultrasonic signals is recorded for two periods of the mains frequency. The analysis of acoustic signals is carried out: according to the frequency spectrum, their binding to the voltage phase, amplitude and stability. Signals from electrical discharges have a high-frequency spectrum of 60-130 kHz, occur twice during the mains voltage period, and are unstable in amplitude. The spectrum of the acoustic signal is determined using software oscilloscope "Aktakom" by fast Fourier transform.

Listening to discharges in insulation with the Dolphin device.

Partial discharge hazard criteria and decision-making on the need for repairs are set out in the "Methodology for monitoring the insulation of KRUE-110 kV and terminations of cable jumpers with polyethylene insulation ..." Mosenergo OJSC. The decision to recommend a repair is made at a level of partial discharges of 25-100 pC. Decision on urgent shutdown - at the level of partial discharges more than 100 pC. The sound of such a discharge process causes the ignition of three to five levels of the Dolphin device.