This disclosure relates in general to electrical submersible well pumps (ESP), particularly to an electrical power connector for the ESP.
ESPs are often used to pump well fluid from hydrocarbon producing wells. A typical ESP for a hydrocarbon producing well has a pump driven by a three-phase electrical motor. The motor may be an inductive type, or it may be a permanent magnet motor.
A power cable extends from a wellhead to the motor to supply power. The power cable has three insulated electrical conductors, one for each phase. One type of power cable is round, with the three electrical conductors spaced 120 degrees apart from each other. Another type of power cable is flat, having the three conductors located side-by-side.
In some instances a splice may be made in the power cable to lengthen the power cable. Also, in the case of flat power cable, transpositional splices may be made at various points along the length of the power cable to correct for a voltage imbalance. For example, power conductors leading to phase A and phase C windings in the motor in a lower length of the power cable may be on right and left outer side edges of the flat power cable. The power conductor in the lower length of the power cable leading to phase B windings may be in a center position between the phase A and phase C. A transpositional splice may be made thousands of feet from the motor to connect the phase A conductor in the lower length of the power cable to a middle position in a next upward length of the power cable. Also, in that transpositional splice, the phase C conductor in the lower power cable length may connect to the left outer side of the next upward length of the power cable. The phase B conductor in the lower power cable length may connect to the right outer side of the next upward length of the power cable.
A splice may also be required between the power cable and a motor lead extension. In addition, other conductor-to-conductor connections are made in ESP installations. As an example, connections for the power conductors may be required for electrical penetrators extending through packers. Electrical connections are required between the windings within the motor and flex wires, and between the flex wires and motor lead extension wires.
In some instances these electrical connections must be made after the ESP is partially or entirely lowered into the well. Special care must be taken when making an electrical power connection for a permanent magnet motor because if the rotor of the motor is rotated, it can generate a significant electrical charge that could be harmful to the technician making the electrical connection. A variety of electrical connections are known, however, improvements are desired.
An electrical connector comprises an electrical conductor member having a longitudinal axis, a first end with a first opening and a second end with a second opening. First and second grab rings mounted in the first and second openings have inner diameters containing a plurality of teeth protruding toward the axis. The teeth have crests defining a superimposed inner diameter for each of the grab rings. The superimposed inner diameter of the first grab ring is selected to receive a first electrical wire having a larger outer diameter than the superimposed inner diameter of the first grab ring, causing the teeth of the first grab ring to deflect and frictionally engage the outer diameter of the first wire to retain the first wire in the first opening. The superimposed inner diameter of the second grab ring is selected to receive a second electrical wire having a larger outer diameter than the superimposed inner diameter of the second grab ring, causing the teeth of the second grab ring to deflect and frictionally engage the outer diameter of the second wire to retain the second wire in the second opening.
A sleeve of insulation material covers an exterior of the conductor member. The sleeve may have a first end that protrudes past the first opening of the conductor member to closely receive the sleeve of the first wire. The sleeve may have a second end that protrudes past the second opening of the conductor member to receive an insulation layer of the second wire.
A resilient first electrical contact member is in the first opening adjacent the first grab ring. The first electrical contact member has an inner portion sized to be biased into contact with the first electrical wire and an outer portion biased into contact with the conductor member. A resilient second electrical contact member is in the second opening adjacent the second grab ring. The second electrical contact member has an inner portion sized to be biased into contact with the second electrical wire and an outer portion biased into contact with the conductor member. Each of the grab rings may be in electrical contact with the conductor member.
The crest of each of the teeth of each of the grab rings has a curvature with a radius extending from the axis that is equal to a radius of the superimposed inner diameter.
Each of the grab rings comprises a circular rim having an outer surface that defines the outer diameter of each of the grab rings. The rim of each of the grab rings has an inner diameter. Each of the teeth of each of the grab rings has an outer portion joining the inner diameter of the rim.
In the embodiment shown, the teeth of each of the grab rings define a superimposed conical surface of revolution. The rim of each of the grab rings is located in a plane perpendicular to the axis.
In the embodiment shown, the crest of each of the teeth has a curvature with a radius that defines the superimposed inner diameter. The crest of each of the teeth has a circumferentially extending dimension. The outer portion of each of the teeth of each of the grab rings has a circumferentially extending dimension that is less than the circumferentially extending dimension of each of the crests.
The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes +/−5% of the cited magnitude. In an embodiment, usage of the term “substantially” includes +/−5% of the cited magnitude. The terms “upper” and “lower” and the like are used only for convenience as the well pump may operate in positions other than vertical, including in horizontal sections of a well.
It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.
ESP 11 also includes an electrical motor 19 for driving pump 13. Motor 19 connects to pump 13 via a seal section 21. Motor 19 is filled with a dielectric lubricant, and a pressure equalizer reduces a pressure differential between the dielectric lubricant and the well fluid on the exterior. The pressure equalizer may be within seal section 21 or in a separate module. Intake 17 may be at the lower end of pump 13, in the upper end of seal section 21, or in a separate module. Also, ESP 11 may also include a gas separator, and if so, intake 17 would be in the gas separator.
A power cable 23 is strapped to and extends alongside tubing 15 from a power source at the wellhead. Power cable 23 joins a motor lead extension 25 that extends along ESP 11. Motor lead extension 25 has a plug 27 on its lower end that connects to motor 19. Motor lead extension 25 may have a flat configuration with three power conductors, or it could be comprised of three separate tubes, each having one of the power conductors.
In this example, power cable 23 is in a flat configuration and has transpositional splices 29 (two illustrated) to correct for voltage imbalance.
As an example only, electrical connector 31 will change the position of the conductor for phase A from a right-hand side position (as shown in the drawings) in power cable 23 to a central position in the next portion of power cable 23. Electrical connector 31 will change the position for the conductor of phase C from a central position to a right-hand side in the next portion of power cable 23. Electrical connector 31 keeps the conductor for phase B on the left-hand side of power cable 23.
Electrical connector 31 has a conductor member 41 of an electrical conductive metal such as copper. Conductor member 41 is a cylindrical rod with an opening or bore 43 on each end. Bores 43 could join each other or be separated as shown. A longitudinal axis 45 of conductor member 41 passes through each bore 43. In this embodiment, each bore 43 has an entry section 43a, an intermediate section 43b, a contact member section 43c and a recessed end section 43d. Entry section 43a has a larger inner diameter than intermediate section 43b and contact member section 43c. An outward facing conical wall 46 is located at the recessed end of the entry section 43a. Intermediate section 43b and recessed end section 43d have smaller inner diameters than contact member section 43c. The recessed end of recessed end section 43d may be closed with an outward facing wall 44. A longitudinal axis 45 of conductor member 41 extends coaxially through bores 43. Entry section 43d has a conical wall 46 that inclines to a smaller diameter in a recessed direction toward recessed end section 43d.
In this example, a gripping device, referred to herein as grab ring 47, fits within bore entry section 43a outward from conical wall 46. A snap or retaining ring 49 fits within a groove outward of grab ring 47 to retain grab ring 47 in bore entry section 43a. Snap ring 49 and conical wall 46 prevent grab ring 47 from sliding axially relative to conductor member 41. Grab ring 47 engages and grips wire 37 as wire 37 is pushed into bore entry section 43a, preventing wire 37 from easily being withdrawn. Grab ring 47 may also provide electrical continuity between wire 37 and conductor member 41 in the embodiment shown.
An optional electrical contact member 51 fits within bore contact member section 43c, which is cylindrical. Contact member 51 has an outward end that abuts an inward facing shoulder of bore contact member section 43c. Contact member 51 has a recessed end that abuts an outward facing shoulder at the outward end of bore contact member section 43c, preventing contact member 51 from axial movement. Electrical contact member 51 is formed of a conductive material, such as copper, and has a central inner portion that is in biased engagement with wire 37 and an outer portion that is biased into engagement with the outer diameter of contact member section 43c. Once wire 37 is pushed into electrical contact member 51, it will provides electrical continuity between wire 37 and conductor member 41.
Conductor member 41 may also have an electrical insulation sleeve 53 on its exterior. Insulation sleeve 53 may cover all three of the electrical connectors of the transpositional splice connector 31 of
Grab ring 47 may have a variety of configurations. In the embodiment of
Each crest 65 is a portion of a circle. Crests 65 have a greater circumferential dimension between flanks 67 than teeth outer portions 63 between flanks 67. Flanks 67 of each tooth 61 diverge from each other from outer portion 63 to crest 65. Teeth 61 are equally spaced apart from each other. As shown in
Teeth 61 thus protrude in an inward direction inclining toward the wall that separates bore entry portion 43a from bore intermediate portion 43b. The inward inclination allows wire 37 (
Electrical contact member 51 may be of various configurations to establish continuity between wire 37 and conductor member 41. As shown in
During installation, a technician will connect insulated conductors 35 by stripping back insulation layer 39, then pushing each wire 37 through one of the grab rings 47 and into one of the contact members 51. The technician may then seal the ends of insulation sleeve 53 to insulated conductors 31 by wrapping with tape.
While making the connection, the technician will grip insulation sleeve 53 to avoid contact with wire 37, which could have an electrical charge, particularly if motor 19 is a permanent magnet motor. The length of the protruding portion of wire 37 may be selected such that it will be substantially recessed within protruding end 53a of insulation sleeve 53 during insertion before the wire tip reaches contact member 51. Protruding insulation sleeve end 53a reduces a chance of inadvertent contact of the protruding portion of wire 37 by the technician; wire 37 could have an electrical charge.
Electrical connector 31 allows a technician to more quickly insulate potentially energized wires, thus reducing exposure time. Electrical connector 31 allows repeated connects and disconnects of a splice without having to cut wires, de-solder, or do other destructive mechanical work. Further if electrical connector 31 is used in a cable splice, it will aid in blocking gas from travelling up the power cable, particularly those with stranded wires 37.
Electrical connector 31 may be used in a variety of places in an ESP 11 assembly in addition to transpositional splices 29. For example, electrical connector 31 could be employed in other types of cable splices, in packer penetrators and within motor 19. A similar electrical connector 31 could be used to connect together the three internal motor wires in a wye configuration of motor 19. Electrical connector 31 would allow repeated connects and disconnects, allowing the wye to be more easily taken apart. This feature would be useful in electrical submersible pump tandem motors, where wyes have to be deconstructed to allow stators normally intended as a bottom motor in a tandem to be used as an upper motor in a tandem. Additionally, electrical connector 31 could be used outside of submersible well pump assemblies for connecting electrical wires to each other in general.
Referring to
Electrical connector 31′ could have both ends with a seal retaining member 83 configured as in
The present disclosure described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While only two embodiments of the disclosure have been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the scope of the appended claims.
For example, grab rings 47 could be mounted out of contact with conductor member 41, and all of the electrical continuity between wire 37 and conductor member 41 could be achieved through contact member 51. Alternately, all of the electrical continuity between conductor member 41 and wire 37 could be provided by grab ring 47, eliminating the need for contact member 51. Also, the grab ring 47 and contact member 51 on one end could have different inner diameters than the grab ring 47 and contact member 51 on the opposite end to connect different diameters of wires 37 to the opposite ends of electrical connector 35.
This application claims priority to provisional application Ser. No. 63/002,677, filed Mar. 31, 2020.
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Number | Date | Country | |
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20210305742 A1 | Sep 2021 | US |
Number | Date | Country | |
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63002677 | Mar 2020 | US |