WO2012040670A1

WO2012040670A1 - Configurable switchboard for electrical submersible pump

Info

Publication number: WO2012040670A1
Application number: PCT/US2011/053160
Authority: WO
Inventors: Julian Alexander Watt; Thomas Charles Gmuer
Original assignee: Dynapar Corporation
Priority date: 2010-09-25
Filing date: 2011-09-24
Publication date: 2012-03-29

Abstract

A switchboard (40) for powering a submersible pump (44) which is configurable for a wide range of input voltages. Control circuitry (60) of the switchboard requiring a specified low voltage (58) is powered by a step-down transformer (52) with first and second primary windings (P1, P2). Jumpers (J1, J2) on a terminal board (20) selectively connect the two primary windings to a medium voltage power supply (42) in either a series configuration or in a parallel configuration. A step-down secondary winding (S1 ) provides multiple output voltage taps (XN). A selected position of the jumpers and a selection among the output taps provide the specified low voltage for a wide range of input voltages while maintaining a safe creepage distance (C1 ) between terminals on the terminal board.

Description

CONFIGURABLE SWITCHBOARD FOR ELECTRICAL SUBMERSIBLE PUMP

This application claims benefit of the 25 September 201 0 filing date of United States provisional patent Application Number 61 /386,478.

FIELD OF THE INVENTION

This invention relates generally to the field of electrical submersible pumps and more specifically to an electrical switchboard that can be configured for use with such pumps over a wide range of medium voltages.

BACKGROUND OF THE INVENTION

Electrical submersible pumps (ESP) are used in a wide range of applications, such as for on-shore and off-shore horizontal and vertical wells ranging in production from 100 to 100,000 barrels per day. The surface electrical equipment for powering and controlling such down-hole pumps are typically housed in an electrical switchboard which may contain a safety disconnect switch, an over-current protection device, a contactor that controls the pump, and a transformer that converts the medium voltage (over 600 VAC) incoming power to a low voltage (typically 1 20 VAC) for powering the control circuitry within the switchboard. Because the performance demands are so diverse, ESP's are provided in a broad range of power and voltage ratings, and thus the incoming power may vary over a wide range of medium voltages, such as 700 VAC to 5000 VAC for example. However, the voltage requirement for the control circuitry within the switchboard for these various applications remains the same, typically 120 VAC. Thus, a large number of different switchboards may be needed to accommodate all ESP applications.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following description in view of the drawings that show:

FIG. 1 is a schematic view of a transformer with series-connected dual primaries.

FIG. 2 is a schematic view of a transformer with parallel-connected dual primaries. FIG. 3 shows a table of secondary taps that provide about 120 volts for each of several ranges of medium input voltages in the series configuration of FIG 1 .

FIG. 4 shows a table of secondary taps that provide about 120 volts for each of several ranges of medium input voltages in the parallel configuration of FIG 2.

FIG. 5 shows a terminal board for two transformers with jumpers configured for serial-connected dual primary windings per FIG 1 for each transformer.

FIG. 6 shows a terminal board for two transformers with jumpers configured for parallel-connected dual primary windings per FIG 2 for each transformer.

FIG. 7 shows a terminal board with captive jumpers configured for serial- connected dual primary windings per FIG 1 on two transformers.

FIG. 8 shows a terminal board with captive jumpers configured for parallel- connected dual primary windings per FIG 2 on two transformers.

FIG. 9 shows blockage of an attempted misconnection of a jumper.

FIG. 10 shows creepage distances on the terminal board.

FIG. 1 1 shows a gully in terminal board to increase creepage distance.

FIG. 12 shows the use of cuts in the terminal board to increase creepage distance.

FIG 13 shows a configurable switchboard that controls a medium voltage supply for a submersible pump in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present inventors have recognized a need in submersible pump applications for a switchboard which can accept a large range of incoming power voltages with a single control power transformer design. One solution is to provide a switchboard having a transformer with multiple taps on the primary winding and one or a small number of taps on the secondary winding, thereby accommodating more than one incoming power voltage with a single design. This increases the input voltage range, but the number of taps required can make it impossible to maintain defined minimum clearance distances between the primary winding taps and to grounded components as required for safety certification. Thus, an alternative approach is needed.

A switchboard for submersible pump applications is described herein which includes a medium voltage dual primary windings and multiple output taps along with a separate configurable terminal board. The terminal board allows an easy reconfiguration of the primary windings between parallel and series connection to accommodate different input voltage ranges while maintaining creepage and clearance distances. FIG 1 schematically shows a transformer T1 with two primary windings P1 , P2 connected in series via a conductive jumper J1 between terminals H2 and H3.

Terminals H 1 and H4 are also provided. A step-down secondary winding S1 has multiple taps XN. For example it may have more than 6, or at least 10, or 14 taps in various embodiments, including X1 , X2, X5, X1 1 , and X14. These multiple secondary taps are on the low voltage side of the transformer. They may provide a given nominal output voltage, for example 120 volts at a given tap XN for a given higher voltage on the primary windings P1 , P2, as later shown.

FIG 2 schematically shows the transformer T1 with its two primary windings P1 , P2 connected in parallel via a first jumper J1 between terminals H1 and H3 and a second jumper J2 between terminals H2 and H4. The two primary configuration options of FIGs 1 and 2 offer a wide range of medium input voltages in a safe and certifiable configuration. The given output voltage may be the same voltage for any input voltage in the range of input voltages. For example, the output voltage may be in the range of 25-1000 volts, or especially 25-500 volts, such as 120 or 230 volts.

FIG 3 shows a table of secondary taps X2-X1 1 that provide about 120 volts for each of several ranges of medium input voltages in the series configuration of FIG 1 where X1 is always a common output connection point. FIG 4 shows a table of secondary taps X5-X14 that provide about 120 volts for each of several ranges of medium input voltages in the parallel configuration of FIG 2 where X1 is always a common output connection point. FIGs 3 and 4 show that the reconfigurable dual primaries of the transformer T1 can provide about 1 20 volts output over a very wide range of selectable input voltages from 700V to 5000V with the same transformer.

Multiple taps on the low voltage side are safer than multiple taps on the medium voltage side of the transformer. Thus, a transformer with a wide medium voltage input range can now be made safe at reasonable cost. The secondary taps X2-X14 may be spaced closely enough to achieve a desired nominal output tolerance over a wide range of input voltages. Examples of nominal output voltages include 120 volts ± 5%, 100- 127 volts, and 230 volts ± 5%. The input divisions shown in FIGs 3 - 4 have ranges of about 10% per division, which allow output tolerances such as ± 5%. Herein, "nominal output voltage" means a given voltage ± 10% unless otherwise specified.

FIG 5 shows a transformer terminal board 20 for two transformers. The terminal board may be made of an electrical insulator material as known in the art. There may be advantages of combining two or more transformers in one housing with one terminal board; however, such a combination is not a requirement of the present invention. Conductive jumpers connect pairs of input terminals on the board to configure each transformer for series-connected dual primary windings corresponding to FIGs 1 and 3, or alternatively, for parallel-connected dual primary windings corresponding to FIGs 2 and 4. Transformer 1 has terminals T1 H1 , T1 H2, T1 H3, and T1 H4. In FIG 5 jumper J1 connects terminal T1 H2 to T1 H3, which provides the circuit configuration of FIG 1 . Jumper J2 may also connect T1 H2 to T1 H3 simply for storage of J2 on the terminal board, with alternative use of jumper J2 being described below. Terminals T1 H1 and T1 H4 are not connected in this configuration (except for connection to the incoming source line in field application and respective transformer winding connections as shown in Figure 1 ). Transformer 2 has terminals T2H 1 , T2H2, T2H3, and T2H4.

Jumper J3 connects terminal T2H2 to T2H3, which provides the circuit configuration of FIG 1 . Jumper J4 may also connect T2H2 to T2H3 simply for storage of J4 on the terminal board. Terminals T2H 1 and T2H4 are not connected in this configuration (except for connection to the incoming source line in field application and respective transformer winding connections as shown in Figure 1 ). Fuses F1 , F2, F3 may be mounted on the terminal board as known in the art.

FIG 6 shows the transformer terminal board 20 with the jumpers reconfigured for parallel-connected dual primary windings corresponding to FIGs 2 and 4. Jumper J2 now connects terminal T1 H1 to T1 H3. Jumper J1 now connects terminal T1 H2 to

T1 H4. These two connections provide the circuit configuration of FIG 2 for transformer 1 . Jumper J4 connects terminal T2H1 to T2H3. Jumper J3 connects terminal T2H2 to T2H4. These two connections result in the circuit configuration of FIG 2 for transformer 2.

FIGs 7 and 8 show a transformer terminal board 20 with captive jumpers J1 , J2,

J3, and J4. These jumpers are retained on respective terminals T1 H2, T1 H3, T2H2, and T2H3. Jumper J1 pivots about terminal T1 H2 along with Jumper J2 which pivots around T1 H3 to alternately connect T1 H2-T1 H3 for a serial configuration of transformer 1 (FIG 7) or J1 pivots to connect T1 H2-T1 H4 along with J2 which pivots to connect T1 H3- T1 H1 for a parallel configuration (FIG 8). Similarly, jumper J3 pivots about terminal T2H2 along with Jumper J4 which pivots around T2H3 to alternately connect T2H2-T2H3 for a serial configuration of transformer 2 (FIG 7) or J3 pivots to connect T2H2-T2H4 along with J4 which pivots to connect T2H3-T2H1 for a parallel

configuration (FIG 8). Captive jumpers may prevent loss of the jumpers and help prevent misconnection.

Each jumper may have one or more tabs 22, 23 on one side of the jumper to prevent misconnections. For example, an upturned tab 22 may extend away from the jumper board, and a downturned tab 23 may extend toward the jumper board. If these tabs are located on the stopped side of the two jumpers J1 , J2 when both jumpers are connected between the same two terminals T1 H2, T1 H3 as shown, the tabs will allow this connection, but will block misconnections as shown in FIG 9. Herein "stopped side" means the side toward which the rotation of each jumper J1 , J2 is stopped by the mutually connected terminals T1 , T2.

FIG 9 shows the rotation 26 of jumper J1 in an attempt to misconnect J1 to T1 H3 when jumper J2 is already connecting T1 H 1 , T1 H3. The downturned tab 23 on jumper J2 prevents this misconnection by blocking J1 at point 25. The user should now realize that this connection should not be made. If the user tries to make J1 ride over J2, then the upturned tab 22 on J2 will block it. The only way to connect J1 between T1 H2 and T1 H3 is to also connect J2 between T1 H2 and T1 H3 as seen in FIG 7. Likewise, the only way to connect J2 between T1 H2 and T1 H3 is to also connect J1 between T1 H2 and T1 H3. The upturned tab 22 and downturned tab 23 may be formed by bending tabs of the jumper sheet metal in opposite directions if the jumper is formed from sheet metal. All of the jumpers J1 -J4 as shown may be of the same part number in different respective orientations except for different labeling, if any. A tab is upturned 22 or downturned 23 depending on which side of the jumper part is up. Alternately, the tabs 22, 23 may be formed by casting, by a metals joining process, or by other means, in which case the tabs can be co-located, rather than spaced from each other along the side of the jumper as shown. FIG 10 shows that all contacts on the terminal board may have at least the minimum required creepage distance for a given voltage. For example, Underwriter's Laboratories specifies clearance distance (air distance) and creepage distance (surface distance) for given voltages. The clearance distance should be measured between the nearest mutual points between pairs of jumpers in their closed positions on different terminals. Specification UL347 specifies 1 .0" clearance and 2.0" creepage distance for voltages up to 2500V. This first creepage distance is represented in FIG 10 by C1 . UL347 further specifies 2.0" clearance and 3.5" creepage distance for voltages up to 7200V. This second creepage distance is represented in FIG 10 by C2. The fuse holders can be staggered as shown to increase the distance between them.

FIG 1 1 shows a way to increase the creepage distance between conductors such as terminals and fuse holders by adding a discontinuity in the surface between the conductors, for example a non-planar region such as gully 28 in the terminal board 20 between the contacts. This may alternately be a protrusion to produce the same effect.

FIG 12 shows an alternate way to add a discontinuity in the surface between the conductors to increase the creepage distance between conductors such as terminals and fuse holders. In this example, the discontinuities are slots 30 in the terminal board 20 between the contacts.

FIG 13 illustrates a configurable switchboard 40 that controls a medium voltage supply 42 for a remote load such as a submersible pump 44 in accordance with an aspect of the invention. The switchboard 40 may form an enclosure that houses a safety disconnect switch 46, an over-current protection device 48, and a contactor 50 that controls the pump 44. A terminal configuration board 20 as described herein may be connected to the medium voltage lines 54 in the switchboard 40. Medium voltage power leads 56 interconnect the terminal board 20 to a control power transformer 52. The terminal board 20 selectively interconnects terminals connected to these leads 56 to configure the primary windings of the control power transformer 52 in series or parallel as described herein. The control power transformer 52 converts the medium voltage input 56 to low voltage output 58 that powers control components 60 such as a motor protective circuit and contactor control circuit. This arrangement supplies the control components 60 with a specified low voltage such as 120 VAC over a broad range of medium input voltages such as 700-5000 VAC. The control power transformer 52 includes first and second primary windings P1 , P2 and multiple output taps X1 -XN as described above with respect to FIGs. 1 and 2. The terminal board 20 may be configured as described above with respect to FIGs. 5-12. The winding wire used in the transformer 52 to wrap the primary windings may be connected within or at the transformer 52 to the medium voltage power leads 56.

The medium voltage power leads 56 extend to the terminal board 20 where they are connected to the terminals H1 -H4 respectively as described above with respect to FIGs. 1 and 2. The jumpers J1 , J2 as described herein are easily field configurable on the terminal board 20 as described herein, and the appropriate output taps XN are field selectable to convert the available supply voltage to the specified control voltage.

A benefit of having multiple taps X1 -XN on the low-voltage side of the control power transformer 52 instead of on the medium-voltage side P1 , P2 is that the taps X1 - XN can be closer together without arcing than if they were on the medium-voltage side. This allows close enough spacing of the ranges X2-X1 1 in FIGs 3 and 4, to meet a required voltage tolerance of the specified control power voltage such as plus or minus 5 volts. If the taps were on the primary side, they could not be so close together. This configuration allows closely spaced output taps X1 -XN, while minimizing the number of medium-voltage terminals on the terminal board 20. Since only four medium-voltage terminals H1 -H4 are needed on the terminal board 20 per transformer 52, the terminals can be adequately spaced on the terminal board as described herein to meet creepage certification standards.

While various embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions may be made without departing from the invention herein. For example, it is possible to use more than two primary windings in the invention using appropriate terminals and jumpers.

Claims

The invention claimed is: 1 . A configurable electrical switchboard for a submersible pump as may be used in a down-hole well application, the switchboard comprising;

a medium voltage power input configured for connection to any one of a plurality of medium voltage power supplies having different voltages;

a medium voltage power output configured for connection to a medium voltage submersible pump;

a contactor selectively connecting the power input to the power output for powering the pump;

a control circuit of the switchboard requiring power at a specified low voltage; a power transformer comprising first and second primary windings and further comprising a step-down secondary winding with multiple output taps;

medium voltage power leads having respective first ends connected to the first and second primary windings;

a terminal board comprising terminals each connected to a second end of a respective one of the medium voltage power leads; and

jumpers selectively connectable between the terminals to configure the two primary windings in either a series configuration or in a parallel configuration for connection to the medium voltage power input;

wherein the control circuit may be powered at the specified low voltage by a power supply in a first range of medium voltages by connection of the control circuit to appropriate ones of the output taps with the jumpers configured to connect the primary windings in parallel; and

the control circuit may be powered at the specified low voltage by a power supply in a second range of medium voltages higher than the first range of medium voltages by connection of the control circuit to appropriate ones of the output taps with the jumpers configured to connect the primary windings in series.

2. The switchboard of claim 1 , wherein the first and second ranges of medium voltages extend from 700-5000 volts and the specified low voltage has a tolerance of ± 5%.

3. The switchboard of claim 1 , wherein the parallel configuration is effected by a first jumper interconnecting a second and fourth terminal on the terminal board and a second jumper interconnecting a first and third terminal; and wherein the series configuration is effected by the first and/or second jumper interconnecting the second and third terminals.

4. The switchboard of claim 3, wherein the terminal board comprises at least a first specified creepage distance between the first and third terminals, between the second and third terminals, and between the second and fourth terminals; and wherein the terminal board comprises at least a second specified creepage distance between the first and fourth terminals; wherein the second specified creepage distance is greater than the first specified creepage distance.

5. The switchboard of claim 4 wherein the first, second, third, and fourth terminals comprise a first set of terminals, and the terminal board further comprises a second corresponding set of terminals for a second transformer, wherein the first terminal is common to both sets of terminals, and the fourth terminal of the first set is spaced from a corresponding fourth terminal of the second set by at least the second specified creepage distance.

6. The switchboard of claim 5 wherein the second set of terminals is configured on the terminal board in a mirror image of the first set of terminals mirrored laterally about the common first terminal.

7. The switchboard of claim 4 wherein the first jumper has a rotatable connection to the second terminal, the second jumper has a rotatable connection to the third terminal, and each jumper comprises a tab on one side thereof that allow the parallel and series configurations and block other connections of the jumpers.

8. The switchboard of claim 7 wherein rotations of the first jumper are stopped in opposite directions by the third and fourth terminals respectively; rotations of the second jumper are stopped in opposite directions by the first and second terminals respectively; the first jumper comprises an upturned tab and a downturned tab on a side of the first jumper that is stopped by the third terminal, and the second jumper comprises an upturned tab and a downturned tab on a side of the second jumper that is stopped by the second terminal, wherein the tabs are positioned to alternately allow the parallel and series configurations, and to block the other connections of the jumpers regardless of which jumper is on top of the other jumper.

9. The switchboard of claim 1 , wherein

the first range of medium voltages comprises 700-1949 volts;

the second range of medium voltages comprises 1950-5000 volts;

the specified low voltage is in a range of 25-500 volts and has a specified tolerance of ± 10%.

10. An arrangement for providing a specified low voltage over a range of medium input voltages, the arrangement comprising;

a power transformer comprising first and second primary windings and further comprising a step-down secondary winding with multiple output taps;

medium voltage power leads having respective first ends connected at the power transformer to respective ends of each of the first and second primary windings, the medium voltage power leads extending away from the power transformer;

a terminal board disposed separate from the transformer and comprising a respective terminal connected to a second end of each of the respective medium voltage power leads;

jumpers selectively connectable between ones of the terminals to configure the two primary windings in either a series configuration or in a parallel configuration for connection to a medium voltage power supply; and

wherein a low voltage device operable at a specified voltage can be powered by any of a first range of medium input voltages by connection of the device to appropriate ones of the output taps with the jumpers configured to connect the primary windings in parallel; and

the same low voltage device operable at the specified voltage can be powered by any of a second range of medium input voltages higher than the first range of medium input voltages by connection of the device to appropriate ones of the output taps with the jumpers configured to connect the primary windings in series.