UA68546A - Method for producing solid-cast polymer casing of an insulator - Google Patents

Abstract

The proposed method for producing solid-cast polymer casing of an insulator consists in providing roughness of the surface of the insulator stick made of glass fiber plastic, degreasing the said surface, placing the stick in a heated die, filling the die with a mix of high-molecular-weight siloxane rubber, and providing the single-stage vulcanization of the said mix.

Description

Description of the invention

The invention relates to the field of electrical engineering, in particular, to polymer insulators, and can be used in the manufacture of structures of high-voltage external devices.

There is a known method of manufacturing a ribbed polymer insulator shell, which consists in the manufacture of an insulating element and an electrically insulating fiberglass rod, connecting them together with a binder. At the same time, the binder is applied to the surface of the electrical insulating rod along its entire length, the electrical insulating rod is placed in a casting mold, to form an insulating element in 70 mold, elastomer is fed under pressure and treated at a temperature of 100-1407C for 5-15 min. At the same time, additive/quick vulcanization silicone rubber is used as an elastomer, which contains both vinyl and hydrogen-containing siloxanes cross-linked under the influence of a platinum catalyst (11.

The disadvantage of the analogue method is insufficient operational reliability of insulators. that are obtained, as well as the complexity of their formation. 12 As a prototype, the method of manufacturing (forming) a ribbed polymer shell of an insulator in the form of an insulator body was chosen, which consists in creating roughness and degreasing the outer surface of a fiberglass rod, placing it in a casting press heated to 1257"C, the inner surface of which determines the ribbed configuration of the outer Then the mixture of high-molecular siloxane rubber is introduced into the mold connected to the hydraulic system of the syringe-apparatus, and the mixture is vulcanized in one step at a temperature of 115-185" to form the inner layer. The outer layer of the shell is formed by the method of paint and varnish technology (21.

The disadvantage of the prototype method is the lack of selection of effective ratios of the geometric sizes of its component elements, which does not allow to achieve an increase in the operational reliability of the polymer insulator, a decrease in energy consumption and labor intensity, and an increase in the manufacturability of its manufacture, as well as an increase in the electrical and mechanical strength of the boundary layer between the electrical insulating rod and the insulating element. "

The invention is based on the task of increasing the operational reliability of the polymer insulator, reducing the energy consumption, labor intensity and increasing the manufacturability of its manufacture, as well as increasing the electrical and mechanical strength of the boundary layer between the electrical insulating rod and the insulating element by improving the method of manufacturing the structure and establishing effective ratios of the formation of ee, geometric dimensions constituent elements of the one-piece protective ribbed shell of the polymer insulator. "Her

This goal is achieved by the fact that in the method of manufacturing a solid polymer shell of an insulator, which consists in creating roughness and degreasing the outer surface of a fiberglass rod, placing it in a heated casting mold, the inner surface of which determines the ribbed configuration of the outer surface of the shell, introducing a mixture of high molecular siloxane rubber into a mold and one-stage 3o vulcanization of the mixture at a temperature, the formation of a cone-shaped recess in the lower part of the annular ribs, ee, as well as the inner and outer layers of the shell, the geometric dimensions of the inner surface of the casting mold are chosen with the possibility of obtaining an insulator for the formed annular rib the value of the diameter of the ring rib in the range from 80 to 160 mm, the step between adjacent ring ribs in the range from 20 to 60 mm, the width of the ring rib at its base in the range from 5 to 21 mm, as well as a dimensionless value that determines the ratio of the length of the leakage path of the element to the step between adjacent ring ribs, in the range from s 2.35 to 3.5.

From" The geometric dimensions of the inner surface of the casting mold are determined experimentally and by calculation.

A casting mold is made with several typical dimensions of the inner surface, which determine the geometric dimensions of the formed annular rib of the insulator shell. b The ratio of the diameter of the edge of the sheath to the diameter of the sheath trunk is determined based on the analysis of the experimental dependences of the electric field voltage, during which a discharge occurs on the surface of the insulator sheath in a contaminated and moistened state, at different values of the diameter of the sheath trunk. i-th The ratio of the length of the rib leakage path to the interrib distance is determined on the basis of measurements of the electric field voltage at which a discharge occurs on the surface of the insulator in a contaminated and moistened state at an alternating voltage at a frequency of 50 Hz and when the surface of the shell is contaminated with salt fog and kaolin. c The thickness of the shell is chosen under the condition of ensuring moisture protection of the fiberglass electrical insulating rod and erosion resistance of the polymer shell.

The listed features of the method constitute the essence of the invention. 29 The presence of a cause-and-effect relationship between the set of essential features of the invention and the technical result, v. what is achieved is the following.

Features of operation of insulators in contact networks and power transmission lines put forward increased requirements for their reliability. Based on many years of operational experience, today it can be said that polymer insulators best meet these requirements. 60 Now the use of polymer insulating structures is a qualitatively new direction in the development of high-voltage insulator construction. Polymer structures are highly resistant to surface electric discharges, solar radiation, dust, pollution, temperature changes, shocks, operational electrical and mechanical influences.

In addition, polymer insulators have high hydrophobicity and low contamination of insulating surfaces, do not require washing, cleaning, defecting, preventive work.

The specified properties of polymer insulating structures ensure their high reliability and durability, and, therefore, a reduction in costs during their installation, transportation and operation, as well as an increase in the reliability of power supply to objects.

The novelty of the proposed design in the manufacture of insulators consists in the use of insulators made of an integrally cast protective polymer shell, which does not have joints between individual ribs.

Making the insulating element in the form of a one-piece polymer shell allows to increase the operational reliability of the polymer insulator, as well as to increase the electrical and mechanical strength of the boundary layer between the electrical insulating rod and the insulating element, to eliminate the depressurization of the 7/0 insulator between the ring ribs due to the exclusion of connectors, to reduce energy consumption, labor-intensiveness and increase the manufacturability of its manufacture due to the exclusion of installation operations.

In turn, the formation of a solid polymer shell with an effective ratio of the geometric parameters of the ribs and the shell allows to achieve optimal operational and technological characteristics of polymer insulators.

The main operational characteristics of polymer insulators include: Evrn - electric field strength at which a discharge occurs on the surface of the insulator in a contaminated and moistened state (kKV/cm); t - tracking and erosion resistance. This is the time from the start of operation to the moment of the formation of a conductive path (track), into which carbon was introduced, or the erosion of the shell surface to a critical depth.

The track and erosion are formed under the simultaneous influence of an electric field and fog formed by spraying salt water of a given electrical conductivity (hours). The tracking-erosion resistance of the insulator models was determined in the salt fog chamber according to the GOST 28856-90 method.

The technological characteristics of polymer insulators include: resistance (ability) to pull out the shell (ribs) from the casting mold without tearing off the ribs and tearing the rubber at the junction of the rib and the shell trunk.

At the same time, the totality of the parameters of the rib and the barrel of the shell should be such as to ensure obtaining the highest specified operational and technological characteristics.

It was established that the above-mentioned geometric parameters of the integrally cast polymer shell of the insulator are interrelated. The need to observe the above-mentioned ratios when forming an integral polymer shell is determined by the elastic-strength properties of the material of the integral shell (such as conventional strength, relative elongation and residual deformation). "

The invention is illustrated by graphic material, where fig. 1 shows the general view of the formed integral polymer shell of the insulator; IF) in fig. 2 shows the graphical dependence obtained experimentally and by calculation, which justifies the choice of parameters of the method, namely, experimental graphs of the dependence of the voltage of the electric field Evrn.o at which the discharge occurs on the surface of the insulator in a contaminated and moistened state, on (Ce) the ratio of the diameters of the rib of the shell 0 and the barrel of the insulator sg, i.e. Oga, at different diameters of the insulator barrel (i; Fig. C schematically shows the element of the annular rib of the integral polymer shell of the insulator; Fig. 4 shows a graphical dependence showing the influence of the angle of inclination of the rib Ж on the tracking -erosion pt") with stability T and on the coefficient of safety margin for separation K, when pulling the insulator from the casting mold. h The protective ribbed shell of the polymer insulator is made in the form of a solid cylindrical » polymer shell 1, which has a body 2 with annular ribs 3 having a cone-shaped recess 4 in the lower part, as follows.

A casting mold is pre-manufactured with several typical dimensions of the inner surface, which (2) determines (mirrors) the ribbed configuration of the outer surface of the protective one-piece polymer o shell that is being formed. The geometric dimensions of the inner surface of the casting mold are determined experimentally and by calculation. o These type-dimensions, in particular, include the diameter of the annular rib, the step between adjacent annular ribs, the width of the annular rib at its base, a dimensionless value that determines the ratio of the length of the leakage path of the element to the pitch between adjacent annular ribs, the angles of inclination and declination vertices of ribs, corners

I) the inclination of the lower surface of the rib to the horizontal plane, the radii of the connection of the rib with the upper and lower parts of the cylindrical shell, as well as the thickness of the wall of the cylindrical shell.

In particular, the ratio of the diameter of the edge of the shell to the diameter of the shell barrel is determined based on the analysis of the experimental dependences of the electric field voltage, at which a discharge occurs on the surface p» of the insulator shell in a contaminated and moistened state, at different values of the diameter of the insulator barrel; the thickness of the shell is chosen under the condition of ensuring moisture protection of the fiberglass electrical insulating rod and erosion resistance of the shell; the optimal ratio of the length of the rib leakage path to the interrib distance is determined on the basis of measurements of the voltage of the electric field, during which a discharge occurs on the surface 60 of the insulator in a contaminated and moistened state at an alternating voltage at a frequency of 50 Hz and when the surface of the insulator is contaminated with salt fog and kaolin.

The inner surface of the casting mold is lubricated with anti-adhesion grease. The binder is applied to the surface of the electrically insulating fiberglass rod (not shown in Fig. 1) along its entire length. Next, the electrically insulating rod is placed in a casting press-form, the inner surface of which 65 determines the ribbed configuration of the outer surface of the integrally cast polymer shell.

For the formation of an insulating element (an integrally cast polymer shell of an insulator), an elastomer is fed into the mold under pressure, and processed at a certain temperature-time dependence and pressure. As an elastomer, as a rule, silicone rubber of additive/quick vulcanization containing both vinyl and hydrogen-containing siloxanes, which are crosslinked under the influence of a platinum catalyst, is used.

The diameter of the rib of the cylindrical shell C of the insulator is chosen in the range from 80 to 160 mm, the step between adjacent ribs n" (or n. ) is chosen in the range from 20 to 60 mm, the width of the annular rib C at its base AP is chosen in the range from 5 to 21 mm, and the dimensionless ratio of the length of the leakage path of the element (1) to the step between the adjacent edges is n, i.e. the ratio of V schi schi y is chosen in the range from 2.35 to 3.5. 70 The angle of inclination 2: the ring rib 3 of the insulator is chosen (performed) in the range from 13 to 25", the angle of inclination 8 of the top 5 of the ring rib is chosen in the range from 6 to 7", and the angle of inclination of the lower surface of the ring rib

From to the horizontal plane is chosen in the range from 6 to 18".

The connection radii (g and g") of the annular rib of the insulator with the upper 6 and lower 7 parts of the cylindrical shell 2 of the insulator are selected in the ranges of -1-3 mm and gv-5-8 mm, respectively. The thickness of the wall A of the cylindrical shell 1 is chosen (formed) in the range from 5 to 7 mm.

As it was experimentally established, the above-mentioned parameters of the ribs of the integral polymer cylindrical insulator shell affect its operational and technological characteristics.

According to the invention, the ratio of the diameter of the edge of the shell to the diameter of the shell barrel, i.e. PO, is determined on the basis of the analysis of the experimental dependences of the electric field voltage, during which a discharge occurs on the surface of the insulator shell in a contaminated and moistened state, at different values of the diameter of the insulator barrel. In fig. 2 shows the experimental graphical dependences of the voltage of the electric field

Evrn o» at which discharge occurs on the surface of the insulator in a contaminated and moistened state, from the ratio of Pa at different diameters of the insulator barrel: and -12 mm (1); and - 20 mm (2) and - 36 mm (3).

In order to be as close as possible to real operating conditions, the tests are carried out when the insulators are contaminated with kaolin with a specific surface conductivity of 5 µS. From the graphs in fig. 2 it follows that the effective (optimal) diameter of rib 0 is in the range of 80-160 mm.

The maximum voltage of the electric field Evrn ", at which a discharge occurs on the surface of the insulator in Ge contaminated and moistened state, in the range of C-880-180 mm is explained by the fact that at OO "x 80 mm ribs " do not effectively protect the insulator from continuous wetting of the shell during rain .

At the same time, at 0 o» 160 mm, due to the decrease in the required number of ribs, the number of dried-up leakage current zones in the space between the ribs decreases, which leads to an increase in the surface conductivity of the insulator and a decrease in the overlap voltage (surface breakdown).

Based on this, it was established that the effective diameter of the rib 0 of the cylindrical insulator isolator shell is chosen in the range from 80 to 160 mm.

In this method, the optimal ratio of the length of the rib leakage path to the interrib distance, i.e., the ratio В «I ,/Н,., is determined on the basis of measurements of the voltage of the electric field, at which a discharge occurs on the surface of the insulator in a contaminated and moistened state at an alternating voltage of its frequency - 50 Hz w-v s when the surface of the insulator is contaminated with salt fog and kaolin.

Determination of the optimal ratio of the length of the leakage path of rib 1. to the interrib distance n. . ," are carried out on the basis of measurements of the voltage of the electric field, during which a discharge occurs on the surface of the insulator in a contaminated and moistened state Evrya - t(V) with an alternating voltage at a frequency of 50 Hz and with contamination

F 45 with salt fog and kaolin.

The effective range of the B I 4 /H ratio is sought. determined on the basis of the data given in the table. 1, where со 1 μС (microsiemens) - 1 Сми10 - the specific surface conductivity of the contaminated and moistened polymer os insulator. in Table 1

Ratio E 1.11.67)2 235 2.51 3 3.35 3541440 4") In in.

In salt fog with a specific surface conductivity of 0.5 µS 29 Kaolin with a specific surface conductivity of 4 µS in. Kaolin with a specific surface conductivity of 17 μS 0.9 1.2111.35/2.25 2.282.25|2.09 2.081.84.

It follows from Table 1 that the effective ratio is sought. In "Iya ./N. lies in the range from 2.35 to 3.5. From in the table. 1 shows that the deviation from this effective range leads to the deterioration of the operational and technological characteristics of solid-cast polymer shells of insulators.

The thickness of the shell A is chosen under the condition of ensuring moisture protection of the fiberglass electrical insulating rod (not shown in Fig. 1-4) and erosion resistance of the shell 1. The desired thickness was

Atp Z 9 MM; Atah Z 7 MM. 65 The width of the annular rib at its base Ap is determined as follows. Thus, the values of Anrpig and Aptah were determined for a shell with a rib diameter of 0 - 100 mm. In this case, Ani - 8 MM; Idaho - 8.4 mm

For a shell with a rib diameter of О and - 80 mm, determine:

R Eud, sob 2319. soz257 MM.

Ap yan - y A I Ol t p lo nasho sr sr 4.5

For a shell with a rib diameter of O tah - 160 mm, we got:

E. Ed. sov 1029 . soz257

Antip I ---- - - 02 V'sov g -20.7 821 70 sr sr 4.5

Thus, it was established by calculation and experiment that the effective size of the base of the edge AP for angles c. - 13 - 252, respectively, is: Andip - 5 MM; lach 7 21 mm.

The step between the ribs of n. are also determined by calculation and experiment. The corresponding calculated /5 ratio for determining No has the following form: zip 3, (10) zip

Nz - - zip B -th where 2 is the angle of inclination of the upper plane of the rib (not shown in Fig. 1-4), which is equal to a - Ch0--s,, degrees; a' is the angle of inclination of the lower plane of the rib (not shown in Fig. 1-4), which is determined as follows: degrees (11 -- ad b TR di (11) p2 where p. is the height of the inner cone of the rib, which is determined as follows:

On - p. seeds "(mm) 2 zipe where C is the protrusion of rib Z (see fig. 3).

The effective range of n values determined by calculation and experiment turned out to be as follows:

Drink - 20 MM; Note - 60 mm. "t

The thickness of the edge of the shell Ai at its base, that is, at the point of connection with the cylindrical part of the shell, is determined based on the following considerations.

When pulling the insulator from the casting mold, the rib must not break away from the trunk of the shell and d) there must not be tearing of the rubber at the point of contact A of the base of the rib with the cylindrical body of the shell (see Fig. 3), i.e. at the point of connection of the annular rib of the insulator with the lower part of the cylindrical shell.

The resistance of the silicone rib to detachment and tearing is determined experimentally and computationally, that is, the obtained calculated values were later tested experimentally. Below is the sequence of the calculation. " 20 1) Calculate the force E necessary to pull out the rib from the casting half-form, based on the following w-v ratio: - v NTO) h E-shiu.t.-- y? 2 where "U is the friction pair coefficient "rubber - metal"; taking into account the use of anti-adhesive U - 0.1; 45. - the internal pressure of vulcanized rubber in the casting form before opening, MPa; the value 7 is taken

Ge) such that it is equal to the modulus of elasticity of rubber under compression Erozh, which is equal to Erozh. t 5 MPa - 51105 N/m; o 5 - the area of the lower surface of the rib of the insulator: 2821 Im?) (2 sl vyr-va) mo) 4 y s, y - 2) Calculate the force P,, per unit length of the semicircle at the point of contact of the rib with the cylindrical part 4) of the shell ( barrel): in ..E NO)

poison where r - 9/2 - the radius of the protective polymer shell. vn C) Calculate the force of separation of the rib from the insulator P when pulling it out of the mold, as well as the tearing force Pv in the corner part of the connection (point A, see Fig. 3):

Ra - Bud sov, N/mm (4) 60 Rv - Bdovipe o, N/mm (5) 4) Calculate the required thickness Ap:

Oh Im! (6 days in MI)

Iv 65 where | gr) - strength limit of rubber at separation (stretching); for rubber NM 1760/65 the value || x 4.5 N/mm7.

Define auxiliary parameters! (thickness of the rib near the surface of the cylindrical part of the shell) and 7: 1- АН.в8ипа, у- (0

K- where o r is the radius of the rib. 2

Thus, the thickness of the rib near the surface of the cylindrical part of the shell !, while maintaining the same stiffness of the ribs with an increase in their diameter 0, is proportional to the protrusion of the rib 7, calculated using the empirical expression: so ke as -k) (8) where 7 - 0.2- 0.25. 5) Determine the coefficient of safety margin of the rubber against tearing at the point of connection of the rib with the trunk of the shell: well, sq (9)

IS,

R o, where H is the tearing strength of rubber, N/mm.

Table 2 shows the calculated and experimentally verified values of KE and Ed for the annular ribs of the solid polymer insulator shell with effective dimensions.

Table 2 8m2 EE, N , Nimm ov vd (80 000437 1092.5) 23/19 (lo 000714 1785) 37.89 00136 3400 728 00194 4847) 102.9 «

It should be noted that the force of separation of the rib from the insulator and the tearing force of the rubber material in the zone of the base of the rib 3, which lies between positions 6 and 7, depend on the angle of inclination of the lower surface of the rib 5, which, in turn, is related to the angle Ж. Therefore, the specified ratios are found experimentally and by calculation. "Her

Note that the initial effective values of the angle of inclination of the rib 5 are found under the condition of simultaneous provision of high values of tracking-erosion resistance (t) and the reserve of mechanical strength of the rib against tearing and separation. with

The dependence of t -th(«) is determined experimentally. Coefficient of safety margin for separation when pulling out, . o, and of an insulator from a casting mold (Kr - NI; , where Н - breaking strength, Р, - tearing force) are determined by calculation.

In fig. 4 shows the graphical dependence obtained by experimental and computational methods, which shows the influence of the angle of inclination of rib 2 on the tracking-erosive resistance t and on the coefficient of safety margin on

Detachment when pulling the insulator from the casting mold k, (kr - No, where H is the breaking strength, N/mm, which for rubber NM 1760/65 is H - 4.5 N/mm; 1-7; 2- K,). From the graphs shown in fig. 4, it follows that in the case of small angles of inclination of the ribs (2 " 8") tracking-erosion resistance

T decreases significantly below the norm (norm - 182 hours). On the other hand, increasing the angle 5 leads to

Reduction of the margin of tear strength. b It is known that the norm of tracking-erosion resistance according to GOST 28856-90 is 182 hours, which, as can be seen from fig. 4, corresponds to the angle of inclination of the rib 5 - 137. The ratio of the tear strength of the rubber to the force Br» THAT is equal to (ee) and . oh 1, corresponds to the angle of inclination of the edge - 257 (see Fig. 4). 1 Thus, the following ranges of Я» 50 changes in the angle of inclination of the ring rib of the insulator were established experimentally and by calculation: yt 13", ydldh - 25". These angles correspond to 5: angles of inclination

F of the lower surface of the rib is 67 and bach is 18".

It was also established that in order to increase the margin of safety of the rib against tearing forces (Пр) and separation (Р, ), the connection point of the rib Z with the cylindrical part of the shell (barrel 2 of the shell and not and not and 1) must be made with the following radii: in the lower part of g, 2 2 mm; in the upper part of gu 2 5 mm.

P» Practice has shown that the increase in radii is 2 mm and g; - 5 mm is impractical, since the margin of strength at these values of the radii is quite sufficient, and the further increase of t and g; leads to an increase in the consumption of GUMA boron.

Thus, the ranges of change of the radii of the connection of the rib with the upper (tn) and lower (gk) parts of the cylindrical shell of the insulator were established, namely: гу 5153 MM; g, 5-6 MM.

It was experimentally confirmed that these dimensions make it possible to exclude the deformation of the ribs when the mold is opened and to avoid the possible separation of the ring-shaped rib from the body of the insulating element or the shell.

If the upper values of these parameters are exceeded, the edge may detach from the shell body, and if the values are lower than the lower limit values, the cost of the casting mold increases significantly and the strength of the finished shell significantly deteriorates.

The thickness of the shell -khd is chosen under the condition of ensuring moisture protection of the fiberglass electrical insulating rod (not shown in Fig. 1-4) and erosion resistance of the shell 1. The selected thickness was

At Z 9 MM; Atah Z 7 MM.

The method of manufacturing a one-piece polymer shell of the claimed insulator has passed successful experimental tests in the manufacture of insulators that were tested in high-voltage laboratories in 70 cases. in the EEZ named after Paton. Currently, documentation is being prepared for the industrial use of the method for the formation of insulators operated at nominal voltages from З5 to 110 kV (at the voltage of a lightning impulse, which can withstand, according to the requirements of the standard, from 220 to 450 kV).

Sources of information: 1. Polymer insulator and its manufacturing method (Polymer insulator and its manufacturing method). IPC 7 15. НО1 В 17/00. Patent Ukraine! (ША) Мо 52084А, 2002. 2. Insulator, overvoltage limiter and method of manufacturing a polymer shell. IPC 7 H 01 B 17/50, H 01 B 19/04, H 01 C 17/12. Patent of the Russian Federation (Ky)Mo 2203514, 2003

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Claims (4)

30 Formula of the invention " 1. The method of manufacturing a one-piece polymer shell of an insulator, which consists in roughening and degreasing the outer surface of a fiberglass rod, placing it in a heated casting mold, (2.0) 35 the inner surface of which determines the ribbed configuration of the outer surface of the shell, introducing a mixture of high molecular weight of siloxane rubber into a mold and one-stage vulcanization of the mixture at a temperature, forming a cone-shaped recess in the lower part of the annular ribs, as well as the inner and outer layers of the shell, which is characterized by the fact that the geometric dimensions of the inner surface of the casting mold are selected with the possibility of obtaining for the formed annular insulator ribs, the diameter of the ring rib is in the range from 80 to 160 mm, the step between adjacent ring ribs is in the range from 20 to 60 mm, the width from c of the ring rib at its base is in the range from 5 to 21 mm, as well as a dimensionless value that determines the ratio of the length of the leakage path of the element to the cro ku between adjacent ring ribs, ranging from 2.35 to 3.5. and - . . . . and а а 2. The method according to claim 1, which differs in that the geometric dimensions of the inner surface of the casting mold are determined experimentally and by calculation. Q. The method according to claim 1, which is characterized by the fact that a casting mold is made with several standard dimensions of the FO of the inner surface, which determine the geometric dimensions of the formed annular rib of the insulator shell. 4. The method according to claim 1, which differs in that the ratio of the diameter of the edge of the shell to the diameter of the barrel of the shell is determined on the basis of the analysis of the experimental dependences of the electric field voltage, at which a discharge occurs on the surface of the insulator shell in the contaminated and moistened states, at different 5r Values shell diameter. - 5. The method according to claim 1, which differs in that the ratio of the length of the rib leakage path to the interrib distance Ф is determined on the basis of measurements of the voltage of the electric field, during which a discharge occurs on the surface of the insulator in a contaminated and moistened state with an alternating voltage at a frequency of 50 Hz and when the shell surface is contaminated with salt fog and kaolin. b. The method according to claim 1, which differs in that the thickness of the shell is chosen under the condition of ensuring moisture protection of the fiberglass electrical insulating rod and erosion resistance of the polymer shell. Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2004, M 8, 15.08.2004. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. in U r b5