WO2013140341A1

WO2013140341A1 - Electric cable

Info

Publication number: WO2013140341A1
Application number: PCT/IB2013/052181
Authority: WO
Inventors: Valery BARSUKOV; Evgeny BARSUKOV; Denis KURASHOV
Original assignee: Energiya Scientific Production Company, Ltd.; Sevan, Ltd.
Priority date: 2012-03-20
Filing date: 2013-03-19
Publication date: 2013-09-26

Abstract

An electric cable for submersible electric pump devices, comprises conductors made of aluminum or of copper-plated aluminum or its alloys, conductor serving and insulation, and also serving is made of bedding and armor, characterized in that the conductors are made of aluminum or copper-plated by galvanic method aluminum or its alloys, containing the rare or rare-earth metals: zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium or their compounds.

Description

ELECTRIC CABLE

The present invention is in the field of cable constructions and, more particularly, relates to an electric cable for supplying electric power to submersible electric pumps for oil extracting devices, water lifting and liquid pumping-over from derrick cellars . Russian patent No . 14473 describes an electric cable construction having three copper conductors which are laid in parallel or inter-stranded with respect to each other and provided with a polymeric insulation and a covering. A steel galvanized tape serves as an armor, with a bedding being applied under the armor.

This electric cable construction is disadvantageous in that it is heavy-weight and causes high costs in the production process. Furthermore, there is a negative influence of copper on the polymeric insulation resulting in an increased destruction of the insulation.

Russian patent No. 57959 describes an electric cable construction which by its parameters is nearest to the electric cable of the invention. It has conductors made of aluminum, copper-clad aluminum or its alloys. The electric cable consists of conductors, a conductor insulation, a conductor covering, a bedding under an armor, and the armor. The electric cable is manufactured by the following technology: the (double-layer polymer) insulation and (polymer) covering are applied over each of the conductors by extrusion. Then the bedding made of polymer tapes and steel galvanized tapes serving as armor are applied over the conductors which are laid parallel or inter-stranded. This electric cable construction is disadvantageous in that it has a reduced long-run admissible temperature of conductor heating (up to 90°C) and a reduced long-run admissible load current .

The drawbacks of the above-cited electric cable essentially reduce the cable performance characteristics and the application area for submersible pumps, especially in oil wells. Specifically, electric cables with aluminum conductors are not allowed to explore in oil wells of great depth and environmental tem^¬ peratures of more than 90°C as the presently available grades of electro-technical aluminum and its alloys loose strength and become considerably fragile at such high temperatures. Fur^¬ thermore, the application of the preset heat-resistant aluminum alloys for the conductors is problematic because of their high specific electric resistance and low effectiveness.

The present invention has been achieved in view of the above problems. It is an object of the invention to provide an improved electric cable for supplying electric energy to submersible pumps which has better performance characteristics with respect to conventional electric cables. Furthermore, the electric cable should be reliable in use and be produced in a cost-efficient manner. These and further objects are met by an electric cable according to the independent claim. Preferred embodiments are given by the sub-claims.

According to the invention, a new electric cable for supplying electric energy to submersible electric pumps for oil extracting devices, water lifting and liquid pumping-over from derrick cellars is proposed. The electric cable for submersible electric pump devices ac^¬ cording to the invention comprises conductors made of aluminum or of copper-plated aluminum or its alloys, a conductor serving and an insulation, wherein the serving is made of a bedding and an armor. According to a characterizing feature, the conductors are made of aluminum or copper-plated by galvanic method aluminum or its alloys, containing the rare or rare-earth metals:

zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium or their compounds.

A major advantage of the new electric cable is given by the broad availability of aluminum conductors or the ones made of cop^¬ per-plated aluminum or its alloys. At the same time the proposed electric cable differs from the currently ones by utilizing aluminum conductors or the ones made of copper-plated by galvanic method aluminum or its alloys containing rare or rare-earth metals: zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium or their compounds. Specifically, small additives (up to 1 mass percent) of the above-mentioned rare or rare-earth metals make it possible to increase strength, heat resistance and corrosion resistance of aluminum and its alloys without losing electrical conductivity. As usual, the content of the rare or rare-earth metal in mass percent (mass.%) is calculated as the mass of the rare or rare-earth metal divided by the total mass of the mixture, multiplied by 100%.

For example: the addition of cerium in a quantity of 0.5 mass . ~6 increases the aluminum strength and heat resistance nearly twice. At the same time corrosion diminishes 10 times and its electric conductivity increases essentially. An addition of 0.3 m.cL S S · "6 of yttrium increases the electrical conductivity by 7.5% and also increases its strength and heat resistance. The addition of 0.4 mass . ~6 scandium increases the aluminum strength by 35%. At the same time, electrical conductivity of aluminum and heat re^¬ sistance increases. The addition of zirconium up to 0.5 mass . ~6 allows essentially (2-2.5 times) increasing the heat resistance of aluminum and its alloys without diminishing its electric conductivity. Under-load creeping of aluminum and its alloys containing rare or rare-earth metals is practically absent. The galvanic technology of applying copper over aluminum allows an essential increase of copper coat adhesion strength to aluminum conductor due to molecular cohesion force. Thereby, the resistance of the copper-plated conductor to corrosion increases essentially .

Advantages of the new cable are the following:

high performance characteristics,

enhanced reliability and service life,

a wider range of application.

The specific requirements for manufacturing, assembling, stripping and cable service involved with electric cables for supplying electric energy to submersible electric pump devices impose constraints on the choice of aluminum and its alloys grades for conductors:

manufacturing of conductors out of a rod by drawing;

cable service in oil wells of great depth in hostile environment at the temperature up to 160°C;

required physical-mechanical conductor characteristics: maximal break-down force and percent elongation, minimal creeping, minimal electric resistance, maximal heat resistance and long service life;

price. As a matter of fact, aluminum and copper-plated aluminum or its alloys, provided with the above-cited rare or rare-earth metals or their compounds meet the mentioned above requirements.

Broadly available and cheapest are aluminum alloys provided with zirconium. It is preferred to use a heat-resistant aluminum alloy for manufacturing cable conductors out of a rod, in particular having grade TAC according to standard specification TU

1712-043-50289046-2012, issued 2012, Russia, wherein the heat-resistant aluminum alloy is provided with zirconium.

The essence of the proposed electric cable is illustrated by the following examples. Variants of wire samples for conductors of aluminum and aluminum alloys and their main characteristics are given in Table 1. A rod with a diameter 9-9.5 mm was used for wire manufacturing :

- rod according to standard specification GOST 13843-78, Russia, made of electro-technical aluminum (grade A5E) ;

- rod according to standard specification GOST 20967-75, Russia, made of aluminum alloy (grade AVE) ;

- rod according to standard specification TU

1712-042-50289046-2012, year of introduction 2012, Russia, made of heat resistant aluminum alloy grade TAC, provided with zirconium, mass.%: 0.05; 0.25; 0.35.

Quality indexes of three-conductor cable samples are given in Table 2:

- of grade KPvTBP-160 3*16 according to standard specification TU 3542-015-10995863-2005, year of introduction 2006, Russia, with copper conductors with cross-section 16 mm² (comparative example 1 according to Russian patent No. 14473); - of grade AKPvTBP-90 3*25 according to standard specification TU 3542-015-10995863-2005, with conductors of aluminum alloy of grade AVE with cross-section 25 mm² (comparative example 2 according to Russian patent No. 57959);

- of grade AKPvTBP-160 3*25 ELKA according to standard spec^¬ ification TU 3542-044-50289046-2012, year of introduction 2012, Russia, with conductors of heat-resistant aluminum alloy of grade TAC, provided with Z Ϊ X^"COΠϊυ.ΓΠ_r m.cLSS . "6 : 0.05; 0.25; 0.35 (examples of the invention) .

As illustrated in FIG. 1, all cable samples consisted of three laid-parallel conductors 1 with a cross-linked PE

( Polyoxyethylen) double layer insulation 2, a protective conductor covering 3 of thermoplastic elastomer, a bedding 4 of non-woven cloth tapes, and an armor 5 of steel galvanized tapes. All cable samples construction and manufacturing technology (including comparative example 2 according to Russian patent No. 57959) were similar in the given examples. Table 1 shows that heat-resistant aluminum alloy of grade TAC, provided with zirconium, acquires better characteristics.

Table 2 shows that the new cable according to the invention has better performance characteristics.

The new cable for submersible electric pump devices has passed all-round testing at RF Cable factories with positive results.

Further aspects of the invention are given by the following description: An electric cable for submersible electric pump devices, comprising one or more electric conductors made of aluminum or of copper-plated aluminum or alloys thereof, wherein each conductor contains one or more rare or rare-earth metals selected from the group comprising zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium and compounds thereof. In one embodiment, each conductor contains one rare ore rare-earth metal selected from the group comprising zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium and compounds thereof. In one embodiment, aluminum is copper-plated by a galvanic method. In one embodiment, the electric cable is provided with a conductor serving and insulation. In one embodiment, the conductor serving is made of a bedding and an armor. In one embodiment, the conductors are made of an aluminum alloy, in particular heat resistant aluminum alloy of grade TAC, containing zirconium. In one embodiment, each of the conductors contains the above-cited rare or rare earth metal in an amount of up to 1 mass percent.

Table 1

Characteristics Variants of aluminum and aluminum alloy wire samples

A5E AVE TAC-0,05 TAC-0,25 TAC-0,35

Temporary

resistance to

147 180 182 189 190 rupture, MPa,

accord, to

GOST

10446-80

Relative elongation at rup¬

2 1 ,5 2,5 3 3 ture , %, accord, to GOST

10446-80

Resistivity at

20°C DC,

0,0282 0,0300 0,0285 0,0283

Ohmxmm ²/M, 0,0282 accord, to

GOST 7229-76

Temperature of

recrystallization 320

130 170 210 310

starting, °C

Creep limit at

200°C, MPa,

7 12 30 46 48 accord, to

GOST 3248-81

Table 2

Cable Cable Cable variants AKPbTBP-160 3x25 ELKA with KPvTBP-160 AKPbTBP-90 aluminum alloy conductors, provided with zirco3x16 with 3x25 with nium

Electric cacopper conaluminum

bles quality

ductors alloy conducindexes

(comparative tors AVE

example 1 ) (comparative

example 2)

TAC-0,05 TAC-0,25 TAC-0,35

Estimated

weight 1 km, 1016 872 870

865 867 kg

Admissible

continuous

temperature of 160 90 140 160 160 conductor

heating, °C

Admissible

continuous

load current at

temperature 106 20 92 104 105 90°C, A, accord, to GOST

R 51777-2001

Reference list

1 Conductor

2 Conductor insulation

3 Conductor covering

4 Bedding

5 Armor

Claims

1. Electric cable for submersible electric pump devices, comprises conductors made of aluminum or of copper-plated aluminum or its alloys, conductor serving and insulation, and also serving is made of bedding and armor, characterized in that the conductors are made of aluminum or copper-plated by galvanic method aluminum or its alloys, containing the rare or rare-earth metals: zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium or their compounds.

2. Cable according to claim 1, characterized in that the conductors are made of an aluminum alloy, in particular heat resistant aluminum alloy of grade TAC, containing zirconium.

3. Cable according to claim 1 or 2, characterized in that the conductors contain the rare or rare-earth metals: zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium or their compounds, in an amount of up to 1 mass percent.