RU187629U1 - Power cable for laying in the ground - Google Patents

Abstract

The utility model relates to cable technology, namely, to the design of power cables intended for laying in the ground and operation in conditions of transmission and distribution of electrical energy in stationary installations with alternating voltage from 6 kV to 20 kV and a frequency of up to 50 Hz. The cable contains sequentially placed elements: a conductive core (1), a semiconducting screen (2) of tapes of electrically conductive cable paper along a conductive core, phase insulation (3) of heat-resistant insulating paper with a heat resistance temperature of at least 105 ° C, impregnated with a non-leaking insulating impregnating composition with kinematic viscosity at a temperature of 120 ° C at least 30 centistokes, with a dropping point of at least 108 ° C and with a dielectric constant at a temperature of 60 ° C of at least 2.0, a semiconducting screen (4) made of linen conductive cable paper for phase insulation, a metal sheath (5), an anticorrosive layer (6) of oil distillation products, a layer of polymer tapes (7) and an outer sheath (8) of a polymer material with a Shore hardness of D scale of at least 40. Technical the result is increased cable resistance to damage. 3 s.p. f-ly. 1 ill.

Description

Technical field

The utility model relates to cable technology, namely, to the design of power cables intended for laying in the ground and operation in conditions of transmission and distribution of electrical energy in stationary installations with alternating voltage from 6 kV to 20 kV and a frequency of up to 50 Hz.

State of the art

A power cable with a long-term permissible heating temperature of a conductive conductor, non-burning, of low fire hazard, comprising a conductive conductor, a semiconducting screen along a conductor of tape of conductive cable paper, with phase paper insulation made of heat-resistant insulating paper with a temperature of at least 90 ° C using non-leaking insulating impregnating composition with a kinematic viscosity of at least 30 cst (centistokes) at a temperature of 120 ° C, floor a conductive screen made of tape of electrically conductive cable paper on top of the insulation, a lead sheath, a layer of heat-resistant tapes on top of the lead sheath and an outer sheath of slow-burning polymer compositions (see RF Patent for Utility Model No. 172840, July 26, 2017), based on the set of essential features, taken as the closest analogue (prototype) of a utility model.

The disadvantage of this analogue is that the operational characteristics of the power cable do not fully provide reliability and durability when laying and operating in the ground, in particular at temperatures up to minus 15 ° С. This is due to the lack of the necessary protection of the cable from moisture, its low corrosion resistance, as well as insufficient hardness and resistance of the flame-retardant polymer sheath compositions to mechanical stresses that occur when laying the cable in the ground. In addition, the lower limit of the value of the long-term permissible heating temperature of the conductive core of such a cable is 80 ° C, which is not sufficient in all cases when operating at high power. The indicated design flaws of the analogue can lead to cable damage during installation and / or operation.

Utility Model Essence

The objective of the claimed utility model is to develop a cable design that would have high reliability both when laying and when operating in the ground.

The technical result of the utility model is to increase the resistance of the cable to damage.

The specified technical result is achieved in the claimed utility model due to the fact that the cable contains sequentially placed elements: a conductive core, a semiconducting screen of tapes of conductive cable paper on the core, phase paper insulation made of heat-resistant insulating paper with a heat resistance temperature of at least 105 ° C, impregnated with non-leaking insulating impregnating composition with kinematic viscosity at a temperature of 120 ° C at least 30 centistokes, with a dropping point of at least 108 ° C and a dielectric at a temperature of 60 ° C of at least 2.0, a semiconducting screen of conductive cable tapes on top of the insulation, a metal sheath, a layer of polymer tapes, and an outer sheath of polymer material, while between the metal sheath and the layer of polymer tapes are sequentially placed: anti-corrosion layer from oil distillation products, the outer shell is made of a polymer material with a shore hardness of D scale of at least 40, phase insulation is made of heat-resistant insulating paper with a temperature agrevostoykosti not less than 105 ° C, and nestekayuschy insulating impregnating composition has a dielectric constant at 60 ° C is not less than 2.0.

According to private options for implementing the utility model:

- as an impregnating composition of phase paper insulation used composition of the brand ND-424;

- the metal shell is made of an alloy of lead or aluminum.

In the claimed cable design due to the presence of a conductive core, layers of semiconducting shields, phase insulation from heat-resistant insulating paper with a heat resistance temperature of at least 105 ° C, impregnated with a non-leaking insulating impregnating composition with a kinematic viscosity at a temperature of 120 ° C of at least 30 centistokes, with a dropping point at least 108 ° C and a dielectric constant at a temperature of 60 ° C of at least 2.0, provides a high long-term allowable heating temperature of the conductive cable core (at least 90 C) and the maximum conductor temperature during a short circuit is equal to 250 ° C. This allows you to prevent premature aging of the insulation and subsequent damage as a result of thermal destruction during the entire period of operation.

At the same time, the combination of a metal sheath, an anticorrosive layer, a layer of polymer tapes and an outer sheath with the indicated hardness provides high cable strength, its corrosion resistance and moisture resistance, which prevents damage to the cable when laying in the ground and its subsequent operation (as a result of exposure to the external environment).

Thus, all the indicated features of the utility model are aimed at achieving a single technical result, which consists in increasing the cable resistance to damage.

These particular cases of the implementation of the utility model are also aimed at achieving the specified technical result. However, they are not the only possible forms of embodiment of the proposed design, but show the most preferred, from the point of view of this result, options.

Brief Description of the Drawings

The invention is illustrated by a figure, which schematically shows the structure of the cable in section.

Utility Model Disclosure

The claimed power cable contains the following sequentially (in layers) placed elements of a conductive core (1), a semiconducting screen (2) along the core, phase insulation (3), a semiconducting screen (4) on insulation, a metal sheath (5), an anticorrosive layer (6) , a layer of polymer tapes (7) and the outer shell (8).

The conductive core (1) can be made, for example, of copper or aluminum.

The semiconducting screen (2) along the conductive core is made of a tape of electrically conductive cable paper, superimposed overlapping. In particular, BECDm-150 paper can be used.

Phase insulation (3) is made of heat-resistant insulating cable paper with a heat resistance temperature of at least 105 ° C, impregnated with a non-draining composition of high viscosity. Preferably, a composition with kinematic viscosity at a temperature of 120 ° C of at least 30 cSt (centistokes), with a dropping point of at least 108 ° C and a dielectric constant at a temperature of 60 ° C of at least 2.0 is used. As an example, the composition of the brand ND-424 can be used. The combination of these materials will provide the best protection for the cable from overheating over the entire life cycle.

The semiconductor screen (4) for phase isolation is also made of wound tapes of electrically conductive cable paper.

The metal shell (5) may be made of aluminum or lead. Depending on the diameter of the cable under the metal sheath, the nominal thickness of the metal sheath can range from 1.05 to 1.96 mm.

The anticorrosion layer (6) is made of oil distillation products with a brittle temperature not higher than minus 15 ° С, in particular bitumen, and has a thickness, as a rule, of up to 1 mm.

The layer of polymer tapes (7) can be made in particular of polyethylene terephthalate. The thickness of the tape, as a rule, is up to 0.05 mm.

The outer shell (8) is made of a polymer material with a Shore hardness of D scale of at least 40. In particular, cable polyethylene compositions can be used for its manufacture. Depending on the diameter of the cable under the outer sheath, the nominal thickness of the outer sheath can range from 1.8 to 3.0 mm.

The claimed cable is made in the following way.

The conductive conductors of the conductor (1) are produced by any of the technologies known to the specialist in the cable industry.

The flooring of conductors, screens (2), (4) and phase isolation (3) is carried out on insulating machines of the M4-BP8 type. The impregnation of the insulation is carried out by means of a technology well known to a person skilled in the cable industry.

The overlay of the metal shell (5) is carried out on presses of the Hanson-Robertson or P-6034 type.

The imposition of the outer shell (8) is carried out on extrusion lines.

The anticorrosion layer (6) and the layer of polymer tapes (7) are applied on equipment for applying protective coatings.

Thus, the cable of the above construction has several advantages associated with an increased long-term allowable heating temperature of the conductive core, high tightness and strength during installation, which determine the high resistance of the cable to damage during thermal, corrosion and mechanical stress.

It should be noted that the utility model is not limited to the specific implementation examples given in the description. Other options for the execution of the cable layers are possible within the framework of the given set of essential features that are understandable to a person skilled in the art.

Claims (4)

1. A power cable for laying in the ground, containing sequentially placed elements: a conductive core (1), a semiconducting screen (2) of tapes of conductive cable paper along a conductive core, phase insulation (3) of heat-resistant insulating paper impregnated with a non-leaking insulating impregnating composition with kinematic viscosity at a temperature of 120 ° C of at least 30 centistokes, with a dropping point of at least 108 ° C, a semiconducting screen (4) made of tapes of electrically conductive cable paper for phase insulation, metal sheath at (5), a layer of polymer tapes (7), and an outer shell (8) of polymer material, characterized in that between the metal shell (5) and the layer of polymer tapes (7) there is: an anti-corrosion layer (6) of products oil distillation, the outer shell (8) is made of a polymeric material with a shore hardness of D scale of at least 40, phase insulation (3) is made of heat-resistant insulating paper with a heat resistance temperature of at least 105 ° C, impregnated with a non-draining insulating impregnating composition with a dielectric constant at temperament D 60 ° C is not less than 2.0. 2. The cable according to claim 1, characterized in that the composition of the ND-424 brand is used as an impregnating composition of phase insulation (3). 3. The cable according to claim 1, characterized in that the metal sheath (5) is made of lead alloy. 4. Cable according to claim 1, characterized in that the metal sheath (5) is made of an aluminum alloy.

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