RU118102U1 - ELECTRIC CABLE FOR INSTALLATION OF SUBMERSIBLE ELECTRIC PUMPS - Google Patents

Abstract

1. An electrical cable for submersible electric pump installations, containing conductive conductors twisted together or laid in parallel, each of which is covered with an insulation layer made of polyether ketones, and an additional insulating sheath, having a common cushion for armor and armor made of metal tape, characterized in that extruded polyetheretherketone is used as polyetheretherketone, and the shell is made of extruded fluorocopolymer. ! 2. An electric cable according to claim 1, characterized in that a tetrafluoroethylene copolymer is used as the fluorocopolymer.

Description

The inventive utility model relates to cable technology and can be used mainly to power the electric motors of submersible electric pumps.

Known electrical cable for the installation of submersible electric pumps containing parallel conductive conductors, each of which is coated with insulation, enclosed in a common armor of metal tape, the insulation consists of heat-treated four layers of polyamide-fluoroplastic film, applied directly to the conductive core, over which a layer is applied from extrudable fluoropolymer [RF patent No. 62478, H01B 7/00, 04/10/2007]. The cable is designed for operating temperatures up to 250 ° C and operates at high pressures up to 25 MPa.

The disadvantages of this cable include the complexity of the winding due to the need to bake four layers of a polyamide-fluoroplastic film imposed on a conductive core, as well as the insufficient mechanical strength of a polyamide-fluoroplastic film baked from four layers.

Due, in particular, to high heat resistance, they have found application, for example, in the automotive industry, multilayer electrical insulation coatings for cables; for example (copper conductor / polycarboransiloxane-based coating / polyetheretherketone-based (PEEK) coating) [Y. A. Mikhailin. Heat-resistant polymers and polymeric materials. St. Petersburg: PROFESSION, 2006 - 624 p., P.174].

Polyetherketones are aromatic polymers (polyarylene), the molecular chains of which are built from phenylene rings, carbonyl groups and oxygen atoms. Several types of polyaryletherketones were synthesized, the properties of which are determined by the content of ketone groups [Yu.A. Mikhailin. Heat-resistant polymers and polymeric materials. St. Petersburg: PROFESSION, 2006 - 624 p., Pp. 131-182].

Also known is a prototype selected electric cable for submersible electric pump installations, containing conductive wires twisted together or stacked in parallel, each of which is coated with two layers of insulation, having a common cushion for armor and armor made of metal tape, the first layer of insulation made of polyesterketons (PEK), and the second insulation layer is made, for example, of carbon fiber-reinforced polyetherketone (PEK) or polyether ether ketone (PEEKK) [RF patent No. 84618, H01B 1/14, 07/10/2009]. The prototype cable is designed for operating temperatures up to 260 ° C and has other high performance characteristics.

However, the insulating layers of the prototype cable, with high heat resistance, have insufficiently high electrical characteristics due to their implementation from polyetherketones.

The problem being solved and the expected technical result are to increase the cable efficiency for submersible electric pump installations by increasing the electrical characteristics of the outer insulating layer - the sheath. In turn, an increase in the electrical characteristics of the sheath provides an improvement in the corresponding operational characteristics of the cable, in particular, an increase in the reliability of the cable under conditions of voltage drops. The proposed cable withstands high load currents.

The problem is solved in that the electric cable for the installation of submersible electric pumps, containing twisted together or stacked in parallel conductive wires, each of which is covered with an insulation layer made of polyetherketones, and an additional insulating sheath, having a common cushion for armor and armor made of metal tape, characterized in that the extrudable polyetheretherketone is used as the polyetherketone, and the shell is made of extrudable fluoropolymer. As a fluoropolymer used, for example, a copolymer of tetrafluoroethylene brand F-4MB (TU 301-05-73-90):

(the polymer of tetrafluoroethylene PTFE itself complies with GOST 10007-80).

Unfilled materials based on polyetheretherketone (PEEK) are described in detail: [Yu.A. Mikhailin. Heat-resistant polymers and polymeric materials. SPb .: PROFESSION, 2006 - 624 p., P.141-147]. They can be powders - for extrusion or granules - for injection molding or extrusion. They are used, for example, in the automotive industry for cable insulation [ibid, p. 174].

According to the proposed technical solution, extrudable PEEK grades 151G are used for the manufacture of the insulating layer; 351G, representing granules and having unique heat resistance and resistance to influence of hostile environment, characteristic of all PEEK in general.

Figure 1 presents a diagram of a cross section of the inventive cable. Here:

1 - conductive (for example, copper) core;

2 - insulation from extruded polyetheretherketone (PEEK);

3 - a shell of extruded fluoropolymer;

4 - pillow, for example, from tapes of a nonwoven fabric;

5 - armor, for example, of galvanized steel tape.

Table 1 presents the preferred design parameters of the claimed cable.

Table 1 Design parameter Value Number of cores 3 Nominal cross section, mm ² 16 Nominal diameter of a vein, mm 4.45 Maximum deviations on the core diameter, mm ± 0.04 Nominal radial insulation thickness (first layer made of PEEK), mm 0.20 Limit deviations from the nominal radial insulation thickness (first layer), mm ± 0.05 Nominal design diameter for the first layer, mm 4.85 Nominal radial shell thickness, mm 1,0 Limit deviations from the nominal shell thickness (second layer made of fluoropolymer), mm ± 0.2 Nominal design diameter on the shell, mm 6.85 Nominal sizes of non-woven fabric tape, mm 60 × 0.60 Nominal dimensions of armor tape, mm 15 × 0.45 Maximum outer cable dimensions, mm 11.49 × 26.27

The materials used for the manufacture of the cable must comply with the requirements of table 2.

table 2 Cable component Name of material Normative document conductive core round copper wire TU 16-705.492-2005 insulation extrudable polyetheretherketone Brands 151G, 351G shell fluoropolymer GOST 10007-80; TU 301-05-73-90 pillow heat-bonded non-woven fabric tape TU 8390-008-05283280-96 armor galvanized steel strip type Apr II-1 GOST 3559-75

Fluoropolymers (fluoroplastics) designed for a maximum working temperature of 230 ° C must meet the requirements set forth in table 3.

Table 3 Parameter Value Melt flow rate, g / 10 min 4-8 Mechanical tensile strength, MPa, not less 22 Relative elongation,%, not less 200 Dielectric strength with a thickness of 0.2 mm, kV / mm, not less 60 Dielectric loss tangent at a frequency of 1 MHz, no more 0.001

Table 4 shows a comparison of the characteristics of the fluoroplast (fluoropolymer) * and PEEK **, which confirms the advantages of making the external insulating layer - the sheath - of the fluoroplastic (fluoropolymer) to increase the electrical characteristics of the shell. In turn, an increase in the electrical characteristics of the sheath provides an improvement in the corresponding operational characteristics of the cable, in particular, an increase in the reliability of the cable under conditions of voltage drops, as well as a high permissible load current of the cable.

Table 4 Parameter Peek * fluoroplast (fluoropolymer) ** Dielectric Strength kV / mm 16 20-40 (better) Dielectric constant at 50 Hz 3.2 2.1 (better) Dielectric loss tangent at 50 Hz 3,2 × 10- ³ 3 × 10- ⁴ (better) Volume resistivity ohm · cm 5 × 10 ¹⁶ 10 ¹⁸ -10 ²⁰ (better) Glass transition temperature, ° C Plus 143 Minus 90 (better) Water absorption at 23 ° C,% 0.5 0.01 (better) * Yu.A. Mikhailin. Heat-resistant polymers and polymeric materials. SPb .: PROFESSION, 2006 - 624 p., Pp. 131-182; www.victrex.com. ** Yu.A. Mikhailin. Heat-resistant polymers and polymeric materials. St. Petersburg: PROFESSION, 2006 - 624 p., Pp. 32-77.

The conductive core should preferably be made of MM brand copper wire and comply with class 1 according to GOST 22483. Tinning of lead wire with tin-lead solder is allowed. PEEK insulation must be extruded over the conductive core. The insulation layer should fit snugly to the core. A fluoropolymer sheath must also be applied over the PEEK insulated core, also by extrusion. The shell should fit snugly against the insulation, not peel off from it and provide longitudinal tightness.

Three insulated and sheathed blanks must be laid in a cable, for example, parallel to each other in the same plane. On top of insulated and in the shell blanks laid in parallel, a pillow should be placed under the armor. The pillow under the armor should be made in the form of a winding with ribbons with an overlap of at least 70%. The pillow should be tightly laid and easy to detach without damage. On top of the pillow, armor made of galvanized steel tape should be applied in nominal sizes: width from 15 mm to 20 mm; thickness 0.45 mm.

When booking a cable, the steel tape must have an anti-seize profile that provides anti-seize cable properties in both directions. No discrepancies, running on each other rounds of armor. Armor should be applied by winding with overlapping (35-50)%. It is possible to manufacture armor using tape made of corrosion-resistant steel.

The electrical parameters of the proposed cable are tested. The electrical resistance of the conductive conductors to direct current, calculated for a length of 1 km and a temperature of 20 ° C, must comply with GOST 22483, while the specific resistance of the core must be no more than 0.001724 Ohm / m. The insulation resistance of the cable conductors, calculated for a length of 1 km and a temperature of 20 ° C, must be at least 2500 MΩ. Insulated cable conductors must pass a DC voltage test for 5 minutes.

The values of the test voltage and leakage current measured at the end of the voltage test and counted at 1 km and a temperature of 20 ° C are shown in table 5.

Table 5 Rated voltage, kV Test voltage kV Insulation leakage current (PEEK layer and fluoropolymer casing) at test voltage, A, not more than 3.3 18.0 1 · 10 ^-5

Permissible cable load currents at a temperature of downhole media and air from 20 ° C are shown in table 6.

Table 6 Temperature ° C Permissible cable load current, A in the downhole environment in the air twenty 145 127 thirty 142 124 40 138 121 fifty 135 118 60 131 115 70 127 111 80 123 108 90 119 104 one hundred 114 one hundred 110 110 96 120 105 92 130 one hundred 88 140 95 83 150 90 79 160 84 74 170 78 68 180 71 62 190 63 56 200 55 48 210 45 39 230 32 28

The cable test results shown in tables 5, 6 confirm the high electrical characteristics of the insulation made of the extrudable PEEK layer and the shell of the extrudable fluoropolymer (fluoroplastic) and the cable as a whole.

The cable is resistant to bending when winding onto a cylinder with a diameter equal to 15 times the maximum cable diameter. The cable can withstand crushing load [plates of size (140 × 140) mm, the crushing moment is determined by a short circuit between the core and armor] of at least 158 kN (16 tf). Insulated cable conductors remain airtight in the longitudinal direction with a differential pressure of liquid (oil) of 0.02 MPa per 1 m of length.

The cable is resistant in the static state to the effects of temperature changes from minus 60 ° C to plus 230 ° C. The permissible minimum bending radius during operation is at least 380 mm. Cable rewinding and hoisting operations are allowed at air temperatures up to minus 40 ° C.

Thus, the proposed cable for the installation of submersible electric pumps is more efficient than the prototype by increasing the electrical characteristics of the outer insulating layer - the sheath. In turn, an increase in the electrical characteristics of the sheath provides an improvement in the corresponding operational characteristics of the cable, in particular, an increase in the reliability of the cable under conditions of voltage drops; the cable has a high permissible load current.

Claims (2)

1. An electric cable for installation of submersible electric pumps, comprising conductive conductors twisted between each other or laid in parallel, each of which is coated with an insulation layer made of polyetherketones and an additional insulating sheath, having a common cushion for armor and armor made of metal tape, characterized in that extrudable polyetheretherketone was used as polyetherketone, and the shell was made of extrudable fluoropolymer. 2. The electric cable according to claim 1, characterized in that a tetrafluoroethylene copolymer is used as the fluoropolymer.