(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2017/0222409 A1
`Oehring et al.
`(43) Pub. Date:
`Aug. 3, 2017
`
`US 20170222409A1
`
`(54) SWITCHGEAR LOAD SHARING FOR OIL
`FIELD EQUIPMENT
`(71) Applicant: US Well Services LLC, Houston, TX
`(US)
`(72) Inventors: Jared Oehring, Houston, TX (US);
`Brandon N. Hinderliter, Houston, TX
`(US)
`
`(73) Assignee: US Well Services LLC, Houston, TX
`(US)
`
`(21) Appl. No.: 15/487,694
`
`(22) Filed:
`
`Apr. 14, 2017
`
`Related U.S. Application Data
`(63) Continuation-in-part of application No. 15/235,788,
`filed on Aug. 12, 2016, which is a continuation-in
`part of application No. 15/202,085, filed on Jul. 5,
`2016, which is a continuation of application No.
`13/679,.689, filed on Nov. 16, 2012, now Pat. No.
`9,410,410, Continuation-in-part of application No.
`15/145,491, filed on May 3, 2016, which is a con
`tinuation-in-part of application No. 13/679,.689, filed
`on Nov. 16, 2012, now Pat. No. 9,410,410.
`
`(60) Provisional application No. 62/323,168, filed on Apr.
`15, 2016.
`
`Publication Classification
`
`(2006.01)
`(2006.01)
`(2006.01)
`
`(51) Int. Cl.
`HO2B 7/06
`E2IB 43/26
`E2IB 4I/00
`(52) U.S. Cl.
`CPC ............... H02B 7/06 (2013.01); E2IB 4I/00
`(2013.01); E2IB 43/26 (2013.01)
`ABSTRACT
`(57)
`A hydraulic fracturing system for fracturing a Subterranean
`formation is disclosed. In an embodiment, the system may
`include a plurality of electric pumps fluidly connected to a
`well associated with the subterranean formation and pow
`ered by at least one electric motor, and configured to pump
`fluid into a wellbore associated with the well at a high
`pressure so that the fluid passes from the wellbore into the
`Subterranean formation and fractures the Subterranean for
`mation; at least one generator electrically coupled to the
`plurality of electric pumps so as to generate electricity for
`use by the plurality of electric pumps; and at least one
`Switchgear electrically coupled to the at least one generator
`and configured to distribute an electrical load between the
`plurality of electric pumps and the at least one generator.
`
`
`
`-300-a
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`FIG. 1
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`O
`C
`CN
`
`
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`t
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`-300-a
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`FIG. 4
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`500
`
`<To Auxiliary>
`
`CTO TransformerS>
`
`CTO TransformerS>
`
`FIG. 5
`
`600
`
`
`
`<To Transformers>
`<To Auxiliary>
`
`<TO TransformerS2
`<To Auxiliary>
`
`FIG. 6
`
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`700
`
`725-a
`
`725-b-1
`
`725-b-2
`
`<To TransformerS2
`<To Auxiliary>
`
`<TO TransformerS>
`<To Auxiliary>
`
`FIG. 7
`
`800
`
`
`
`<TO TransformerSY
`
`<To Auxiliary>
`
`<TO TransformerS2
`<To Auxiliary>
`
`FIG. 8
`
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`
`
`<To TransformerS2
`<To Auxiliary>
`
`<To TransformerS2
`<To Auxiliary>
`
`FIG. 9
`
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`Aug. 3, 2017 Sheet 11 of 13 US 2017/0222409 A1
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`1200
`
`1205-a
`
`1205-b
`
`1205-C
`
`1205-0
`
`1225-a-1
`
`LOng Distance
`Transmission Line
`
`1225-a-2
`
`1225-b-1
`
`1225-b-2
`
`<TO TransformerS>
`<To Auxiliary>
`
`<TO TransformerS>
`<To Auxiliary>
`
`FIG. 12
`
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`Aug. 3, 2017. Sheet 12 of 13
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`*~009)
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`1400
`
`1407-b
`1407-a
`-1N- Ya
`
`
`
`<To Utility GridZ
`
`<TO TransformerS>
`<To Auxiliary>
`
`<TO TransformerS2
`
`FIG. 14
`
`1500
`
`<To Utility Grid
`
`1505-a
`
`1505-b
`
`1545-a
`
`1545-b
`
`1525-a
`
`1525-b-1
`
`1525-b-2
`
`<To Transformers>
`<To Auxiliary>
`
`<TO TransformerSl
`<To Auxiliary>
`
`FIG. 15
`
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`US 2017/0222409 A1
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`Aug. 3, 2017
`
`SWITCHGEAR LOAD SHARING FOR OL
`FIELD EQUIPMENT
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`0001. This application claims priority to and the benefit
`of U.S. Provisional Application Ser. No. 62/323,168, filed
`Apr. 15, 2016, and is a continuation-in-part of, and claims
`priority to and the benefit of co-pending U.S. application
`Ser. No. 15/235,788, filed Aug. 12, 2016, which is in turn a
`continuation-in-part of, and claims priority to and the benefit
`of co-pending U.S. application Ser. No. 15/202,085, filed
`Jul. 5, 2016, which is a continuation of, and claims priority
`to and the benefit of, U.S. Pat. No. 9,410,410, filed Nov. 16,
`2012, and is further a continuation-in-part of and claims
`priority to and the benefit of co-pending U.S. application
`Ser. No. 15/145,491, filed on May 3, 2016, which is a
`continuation-in-part of, and claims priority to and the benefit
`of, U.S. Pat. No. 9,410,410, filed Nov. 16, 2012, the full
`disclosures of which are hereby incorporated by reference
`herein for all purposes.
`
`BACKGROUND
`0002 1. Technical Field
`0003. This disclosure relates generally to hydraulic frac
`turing and more particularly to systems and methods for
`spare turbine power generation, which is sometimes referred
`to as reserve power.
`0004 2. Background
`0005 With advancements in technology over the past
`few decades, the ability to reach unconventional sources of
`hydrocarbons has tremendously increased. Horizontal drill
`ing and hydraulic fracturing are two Such ways that new
`developments in technology have led to hydrocarbon pro
`duction from previously unreachable shale formations.
`Hydraulic fracturing (fracturing) operations typically
`require powering numerous components in order to recover
`oil and gas resources from the ground. For example, hydrau
`lic fracturing usually includes pumps that inject fracturing
`fluid down the wellbore, blenders that mix proppant into the
`fluid, cranes, wireline units, and many other components
`that all must perform different functions to carry out frac
`turing operations.
`0006. Usually in fracturing systems the fracturing equip
`ment runs on diesel-generated mechanical power or by other
`internal combustion engines. Such engines may be very
`powerful, but have certain disadvantages. Diesel is more
`expensive, is less environmentally friendly, less safe, and
`heavier to transport than natural gas. For example, heavy
`diesel engines may require the use of a large amount of
`heavy equipment, including trailers and trucks, to transport
`the engines to and from a wellsite. In addition, such engines
`are not clean, generating large amounts of exhaust and
`pollutants that may cause environmental hazards, and are
`extremely loud, among other problems. Onsite refueling,
`especially during operations, presents increased risks of fuel
`leaks, fires, and other accidents. The large amounts of diesel
`fuel needed to power traditional fracturing operations
`requires constant transportation and delivery by diesel tank
`ers onto the well site, resulting in significant carbon dioxide
`emissions.
`0007 Some systems have tried to eliminate partial reli
`ance on diesel by creating bi-fuel systems. These systems
`
`blend natural gas and diesel, but have not been very Suc
`cessful. It is thus desirable that a natural gas powered
`fracturing system be used in order to improve safety, save
`costs, and provide benefits to the environment over diesel
`powered systems. Turbine use is well known as a power
`Source, but is not typically employed for powering fractur
`ing operations.
`0008 Though less expensive to operate, safer, and more
`environmentally friendly, turbine generators come with their
`own limitations and difficulties as well. As is well known,
`turbines generally operate more efficiently at higher loads.
`Many power plants or industrial plants steadily operate
`turbines at 98% to 99% of their maximum potential to
`achieve the greatest efficiency and maintain this level of use
`without significant difficulty. This is due in part to these
`plants having a steady power demand that either does not
`fluctuate (i.e., constant power demand), or having Sufficient
`ing if a load will change (e.g., when shutting down or
`starting up a factory process).
`0009. In hydraulic fracturing, by contrast, the electrical
`load constantly changes and can be unpredictable. This
`unpredictability is due to the process of pumping fluid down
`a wellbore, which can cause wellhead pressure to spike
`several thousand PSI without warning, or can cause pressure
`to drop several PSI unexpectedly (sometimes called a
`“break.' as in the formation broke open somewhere). In
`order to maintain a consistent pump rate, the pump motors
`are required to “throttle' up or “throttle' down (applying
`more or less torque from a variable frequency drive), draw
`ing either more or less electrical power from the turbines
`with little to no notice in many situations.
`0010 Concurrently with pressure variations, fluid rate
`variations can also occur. At any moment, the contracting
`customer may ask for an extra 5 barrels per minute (bpm) of
`pump rate or may request an instantly decreased pump rate
`with little to no warning. These power demand changes can
`vary from second to second—unlike industrial power
`demands, which may vary from hour to hour or day to day,
`allowing for planning and coordination.
`0011
`Hydraulic horsepower (HHP) can be calculated
`with the following relationship:
`
`HHP
`
`(Wellhead Pressure)x (Pump Rate)
`40.8
`
`HHP also directly correlates with the power demand from
`the turbines, where:
`HHPsElectrical Power Demand
`Therefore, if both variables (rate and pressure) are con
`stantly changing, maintaining a steady power demand can be
`difficult. Due to this, it is impossible to design the equipment
`and hold the turbine output at 98%-99% of full potential
`because a minute increase in power demand may shut the
`turbines down and may result in failure of the fracturing job.
`To prevent such turbine shutdown from happening, fractur
`ing equipment S designed to only require approximately
`70% of the maximum output of the turbine generators during
`normal and expected operating conditions. This allows the
`fleet to be able to operate against changing fracturing
`conditions, including increased fluid rate and increased
`wellhead pressure.
`
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`
`0012. There are also other small loads which contribute
`to changing power demand. These include turning on or off
`Small electrical motors for hydraulic pumps, chemical
`pumps, cooling fans, valve actuators, Small fluid pumps,
`etc., or power for metering instrumentation, communication
`equipment, and other Small electronics. Even lighting or
`heating can contribute to the fluctuating power load.
`0013 Therefore it tray be desirable to devise a means by
`which turbine power generation can be managed at an output
`usable by fracturing equipment.
`
`SUMMARY
`
`0014. The present disclosure is directed to a method and
`system for providing electrical load sharing between Switch
`gear trailers acting as power hubs to combine the output of
`multiple electrical generators.
`0015. In accordance with an aspect of the disclosed
`Subject matter, the method and system of the present dis
`closure provide a hydraulic fracturing system for fracturing
`a Subterranean formation. In an embodiment, the system can
`include a plurality of electric pumps fluidly connected to the
`formation and configured to pump fluid into a wellbore at
`high pressure so that the fluid passes from the wellbore into
`the formation and fractures the formation; at least one
`generator electrically coupled to the plurality of electric
`pumps so as to generate electricity for use by the plurality of
`electric pumps; and at least one Switchgear electrically
`coupled to the at least one generator and configured to
`distribute an electrical load between the plurality of electric
`pumps and the at least one generator.
`0016. In an embodiment, the system including the plu
`rality of electric pumps, the at least one generator, and the at
`least one Switchgear can be a single electrical microgrid.
`0017. In an embodiment, the system making up the single
`electrical microgrid can be split into two or more electrical
`banks. In an embodiment, each of the two or more electrical
`banks can include at least one generator and at least one
`Switchgear. In an embodiment, when one or more of the two
`or more electrical banks is shut down, each of the other
`active electrical banks can be configured to distribute the
`electrical load between the plurality of electric pumps and
`the at least one generator associated with each active elec
`trical bank.
`0018. In an embodiment, the system can further include
`at least two Switchgear units electrically coupled to the at
`least one generator, and a tie breaker electrically coupled
`between each of the at least two switchgear units.
`0019. In an embodiment, the tie breaker can be config
`ured to evenly distribute the electrical load between the
`plurality of electric pumps and the at least one generator
`when the tie breaker is in a closed position; and isolate one
`or more of the plurality of electric pumps, the at least one
`generator, and the at least two Switchgear units when the tie
`breaker is in an open position.
`0020. In an embodiment, when the tie breaker is in the
`closed position, at least one generator is shut down and at
`least one other generator is active, the electrical load can be
`evenly distributed among the at least one other active
`generators.
`0021. In an embodiment, the tie breaker can include a
`long distance transmission line.
`
`0022. In an embodiment, the at least one switchgear can
`be configured to distribute power among any of one or more
`transformers, auxiliaries, or other Switchgear units, or a
`combination thereof.
`0023. In an embodiment, the one or more auxiliaries can
`include any of a blender, electric wireline equipment, a
`transfer pump, an electric crane, a data van, a work trailer,
`living quarters, an emergency shower, sand equipment, a
`turbine inlet chiller, a compressor Station, a pumping station,
`a second fracturing site, a drill rig, or a nitrogen plant, or a
`combination thereof.
`0024. In an embodiment, the at least one generator can be
`one of a turbine generator or a diesel generator, or a
`combination thereof.
`0025. In an embodiment, the at least one turbine genera
`tor can be powered by natural gas.
`0026. In an embodiment, wherein each component of the
`system can be modular and movable to different locations on
`mobile platforms.
`0027. In an embodiment, the system can further include
`a power connection panel associated vial the plurality of
`electric pumps. In an embodiment, the power cot panel can
`include a plurality of power connections for each of the
`plurality of electric pumps, and a system ground connection
`configured to act as a ground between the plurality of
`electric pumps and a transformer. In an embodiment, the
`transformer can be configured to provide power to the
`plurality of electric pumps.
`0028. In an embodiment, the system can further include
`a variable frequency drive connected to the at least one
`electric motor to control the speed of the at least one electric
`motor. In an embodiment, the variable frequency drive can
`frequently perform electric motor diagnostics to prevent
`damage to the at least one electric motor.
`0029. In accordance with another aspect of the disclosed
`Subject matter, the method and system of the present dis
`closure a hydraulic fracturing system for fracturing a Sub
`terranean formation. In an embodiment, the system can
`include a plurality of electric pumps fluidly connected to the
`formation and configured to pump fluid into a wellbore at
`high pressure so that the fluid passes from the wellbore into
`the formation and fractures the formation; at least one
`turbine generator electrically coupled to the plurality of
`electric pumps so as to generate electricity for use by the
`plurality of electric pumps; at least two Switchgear units
`electrically coupled to the at least one turbine generator and
`configured to distribute an electrical load between the plu
`rality of electric pumps and the at least one turbine genera
`tor; a tie breaker electrically coupled between each of the at
`least two Switchgear units and configured to evenly distrib
`ute the electrical load between the plurality of electric
`pumps and the at least one turbine generator when the tie
`breaker is in a closed position; and a variable frequency
`drive connected to the at least one electric motor to control
`the speed of the at least one electric motor, wherein the
`variable frequency drive frequently performs electric motor
`diagnostics to prevent damage to the at least one electric
`motor.
`0030. Other aspects and features of the present disclosure
`will become apparent to those of ordinary skill in the art
`after reading the detailed description herein and the accom
`panying figures.
`
`LIBERTY EXHIBIT 1006, Page 16
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`Aug. 3, 2017
`
`BRIEF DESCRIPTION OF DRAWINGS
`0031. Some of the features and benefits of the present
`disclosure having been stated, others will become apparent
`as the description proceeds when taken in conjunction with
`the accompanying drawings, in which:
`0032 FIG. 1 is a schematic example of a turbine gen
`erator in communication with an electronic equipment room,
`which connects to a Switchgear according to an embodiment
`of the disclosure.
`0033 FIG. 2 is a perspective view of an example of a
`turbine generator and electronic equipment room according
`to an embodiment of the disclosure.
`0034 FIGS. 3A and 3B are perspective views of a
`Switchgear trailer according to an embodiment of the dis
`closure.
`0035 FIG. 4 is a perspective view of cables connecting
`to a hydraulic fracturing pump trailer according to an
`embodiment of the disclosure.
`0036 FIGS. 5-15 are block diagrams of portions of a
`microgrid having a plurality of turbine generator sets and
`Switchgear units according to various embodiments.
`0037. While the disclosure will be described in connec
`tion with the preferred embodiments, it will be understood
`that it is not intended to limit the disclosure to that embodi
`ment. On the contrary, it is intended to cover all alternatives,
`modifications, and equivalents, as may be included within
`the spirit and scope of the disclosure as defined by the
`appended claims.
`
`DETAILED DESCRIPTION
`0038. 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 disclo
`sure 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.
`0039. 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 embodi
`ments and, although specific terms are employed, they are
`used in a generic and descriptive sense only and not for the
`purpose of limitation.
`0040. Described herein is an example of a method and
`system for providing electrical load sharing between Switch
`gear trailers acting as power hubs to combine the output of
`multiple electrical generators. Adding a tie breaker between
`two switchgear trailers can eliminate the need for a third
`switchgear trailer, while still retaining the ability to evenly
`distribute power between all of the equipment, and to
`concurrently evenly distribute the electrical load between a
`plurality of turbine generator sets.
`0041. A feature of the switchgear configurations
`described herein is the capability selectively choose between
`
`either load sharing, to provide efficiency and flexibility; or
`having isolated banks of equipment, to provide protection
`and redundancy. In an embodiment, the Switchgear option
`ally includes a tie breaker. The tie breaker can synchronize
`three-phase power of a similar voltage and frequency from
`different sources to act as a common bus, and can evenly
`distribute the electrical load between a plurality of electric
`pumps and turbine generators when the tie breaker is in a
`closed position. The tie breaker will isolate one or more of
`the plurality of electric pumps, the turbine generator, and the
`Switchgear units when the tie breaker is in an open position.
`The use of a tie breaker can provide an advantage over
`previous load sharing systems because use of a tie breaker
`provides more options for the equipment operators and
`allows the fleet to be more versatile as to which mode of
`operation protection and redundancy, or efficiency and
`flexibility—is more desirable at any given moment.
`0042 Another favorable aspect of load sharing is the
`ability to shutdown turbines when peak power output is not
`required. If the power load is distributed evenly between all
`of the generator sets in the fleet, then it can be possible to
`shut down unnecessary power generation as long as the
`remaining generator sets can compensate for the loss and
`pick up the extra load placed on them. This flexibility for
`partial shutdown can allow the remaining turbines to operate
`at a higher efficiency, which can reduce wear on the fleet by
`not running every turbine continuously, and increase effi
`ciency while reducing emissions by allowing fewer turbines
`to run in a lower emissions mode. The lower emissions mode
`is called SoloNox, and can be performed due to load sharing
`using a Switchgear, because the turbines can only operate in
`this mode while operating above a 50% load. In some
`embodiments, directly powering fracturing pumps can
`involve using all turbines regardless of the required power
`load.
`0043. In an embodiment, a variable frequency drive
`(VFD)—and in Some cases, an A/C console used to keep the
`VFD from overheating can be utilized to control the speed
`of an electric motor associated with a pump powered by the
`turbine(s).
`0044. In some examples, certain tasks can be accom
`plished with fewer turbines. Instead of having redundancy or
`spare power generation available to isolated power banks,
`the reserve power generation capability can be consolidated
`across the entire fleet. Requiring fewer turbine generators
`means the equipment can now fit on Smaller well sites which
`reduces the need to clear more land and disrupt the Sur
`rounding environment to create a larger pad, and reduces the
`costs associated with Such clearing and construction.
`0045. The systems described herein are not limited to use
`in processes involving hydraulic fracturing. For example,
`the system includes electric fracturing equipment and power
`generation equipment. The power generation equipment can
`be used to Supply any oilfield equipment including com
`pressor stations, pumping stations, nitrogen plants, CO
`plants, drilling rigs, work-over rigs, barracks, coiled tubing
`units, refineries, or other systems or applications that do not
`have access to a utility provided power grid or that have a
`dynamic power load or low power factor.
`0046 FIG. 1 is a block diagram showing the basic
`components of a hydraulic fracturing well site power gen
`eration system 100 for providing electrical load sharing
`according to an embodiment. A turbine generator 105 can
`include a natural gas turbine engine coupled to a three
`
`LIBERTY EXHIBIT 1006, Page 17
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`US 2017/0222409 A1
`
`Aug. 3, 2017
`
`phase, 60 hertz (Hz) electric generator to produce power as
`the turbine engine rotates. In an alternative, the generator
`can generate electricity at 50 Hz, or at any other power level
`useful for hydraulic fracturing fleets. In the illustrated
`embodiment, the turbine generator 105 is shown being
`electrically connected to an electronic equipment room
`(EER) 115, which can house wiring, breakers, controls,
`monitoring systems, fire Suppression Support, and a battery
`bank for secondary power when the turbine is not operating
`and there is no other power source. In some examples, the
`battery bank can power lighting, fire Suppression, emer
`gency turbine lube pumps, and onboard electronics. The
`combination of a turbine generator 105 and an EER 115 can
`be referred to as a generator set. A switchgear trailer 125 can
`provide power distribution, high Voltage breakers, and
`“lock-out, tag-out” (a safety procedure used to ensure that
`dangerous machines are properly shut off and not able to be
`started up again prior to the completion of maintenance or
`servicing work) capabilities.
`0047 Transformers can optionally be included with the
`equipment of FIG. 1. As illustrated in the embodiment
`shown in FIG. 1, an air intake filter house 110 can be
`positioned on top of or adjacent to the turbine generator 105,
`and a catwalk 120 can connect turbine generator 105 and
`EER 115 for ease of access. The system 100 as a whole can
`define an example of an electrical microgrid.
`0048 FIG. 2 shows a perspective view of an example
`system 200 having a single generator set with a turbine
`generator 205 and an overhanging filter house 210 according
`to an embodiment. A power cable 206 can connect the
`turbine generator 205 to an EER 215 with plugs 204-a,
`204-b. In some embodiments, plugs 204-a, 204-b are
`enclosed and concealed while energized. Between turbine
`205 and EER 215 is an elevated catwalk 220 with Stairs
`leading to the EER 215 for employee access, in the illus
`trated embodiment. Turbine 205 can also include mainte
`nance hatches for purposes of employee access. A plug 202
`can provide a power cable between the EER 215 and a
`Switchgear trailer (not shown).
`0049. An example 300-a of a switchgear trailer 325 is
`shown in an end perspective view in FIG. 3A. Electrical
`connections 302 for turbines and an auxiliary trailer are
`shown in recesses formed on a lateral surface of the trailer
`325. A side opposite the lateral side of the trailer 325, as
`shown in the example 300-b according to an embodiment
`illustrated in FIG.3B, can include electrical connections 302
`for transformers.
`0050 FIG. 3B illustrates in side perspective view a side
`of the switchgear trailer 325 opposite from that of shown in
`FIG. 3A. In the illustrated example, switchgear trailer 325
`can be an example of a switchgear “B” trailer. Four con
`nections 302 are visible, which are for the 13.8 kV cable that
`spans between the Switchgear and the transformers. Each
`connection 302 is a cable that contains all three electrical
`phases, a ground, and a ground check, which is different
`from the cabling configuration of FIG. 4, which relies on the
`use of multiple conductors per phase, as discussed below.
`0051. The switchgear trailer 325 can house large breakers
`and fault protection equipment required for safe operations
`and for "lock-out, tag-out of power going to selected
`equipment. The switchgear is optionally rated for 15 kV
`(1.3.8 kV), and can be designed or reconfigured for different
`voltages, such as 138 kV. 4,160 V, or 600 V, or any other
`voltage suitable for fracturing fleet operations. The switch
`
`gear can include ground fault detection, color coordinated
`cable receptacles, interlock system, and other safety fea
`tures.
`Illustrated in a side perspective view in FIG. 4 is an
`0.052
`example 400 of multiple single-conductor cables connecting
`to a fracturing pump trailer 425, according to an embodi
`ment. In the illustrated example, a 600 V power connection
`panel 401 contains power connections for two fracturing
`pumps. Each electrical phase is split into two separate
`cables. An upper row of plugs 402-a can be used to power
`one fracturing pump, while a lower row of plugs 402-b can
`be used to power a second fracturing pump on the same
`fracturing pump trailer 425.
`0053. In the illustrated example, the upper row of plugs
`402-a includes six single-phase cable connections, and the
`lower row of plugs 402-b includes six single-phase cable
`connections, allowing for two cables per phase. The plugs
`can be color-coded based on the electrical phase. The power
`connection panel 401 can also include a control power cable
`404 and a system ground cable 406. The system ground
`cable 406 can act as a ground between the fracturing pump
`trailer 425 and a 13.8 kV to 600 V transformer (not shown)
`providing power to the fracturing pump trailer 425. Addi
`tional cables can span between the 13.8 kV to 600 V
`transformer and the fracturing pump trailer 425.
`0054 FIG. 5 is a block diagram illustrating one example
`500 of a plurality of generator sets 505-a, 505-b, 505-c for
`use with a system for fracturing a Subterranean formation.
`Each generator set 505-a, 505-b, 505-C can include a turbine
`engine with Sufficient mechanical power to rotate an electric
`generator with sufficient electrical power to provide elec
`tricity to a small, closed circuit, electrical grid. This grid can
`be considered part of the microgrid.
`0055 For the sake of discussion herein, certain types of
`Switchgear units have nomenclature based on their applica
`tion; for example a switchgear “A” can distribute power to
`other Switchgear units, a Switchgear “B” can transmit power
`to transformers and auxiliaries, and a Switchgear “C” can
`transmit power to transformers. However, a Switchgear
`trailer is not limited to the previously stated configurations.
`It is possible to power more than four transformers from a
`switchgear “B” or switchgear “C”; and a switchgear “B” can
`Supply more than one auxiliary trailer if needed. Similarly,
`a switchgear “A” is not limited to connections for only three
`or four generator sets and only two Switchgear trailers. The
`denotation of A, B, C, A+, B+ and C+ Switchgear units does
`not reflect industry standards, but is a naming convention for
`use herein.
`0056. In the illustrated embodiment, switchgear “A”
`525-a is an electrical hub combining the power output of
`three 5.7 MW natural gas turbine generators from generator
`sets 505-a, 505-b,505-c. Further in this example, switchgear
`“A” 525-a can supply electrical power to two other switch
`gear units. Switchgear “B” 525-b can receive power from
`switchgear “A” 525-a and distribute the power to an auxil
`iary unit and multiple transformers, as shown. Switchgear
`“C” 525-c can also receive power from switchgear “A”
`525-a and distribute the power to one or more transformers,
`but in the illustrated embodiment does not distribute power
`to an auxiliary unit.
`0057. In this example, the illustrated lines leading
`between the generator sets 505-a, 505-b, 505-c, switchgear
`units 525-a, 525-b, 525-c, and auxiliary units and transform
`ers can be 13,800 volt, three-phase, 60 Hz, power lines. This
`
`LIBERTY EXHIBIT 1006, Page 18
`
`

`

`US 2017/0222409 A1
`
`Aug. 3, 2017
`
`example allows load distribution between all three turbines
`in generator sets 505-a, 505-b, 505-c through switchgear
`“A” 525-a. Optionally, the power demand placed on each
`generator set 505-a, 505-b, 505-c can be equal, and each
`generator set 505-a, 505-b, 505-c can run at an equal output.
`0058 FIG. 6 is a block diagram showing an embodiment
`600 illustrating a plurality of generator sets 605-a, 605-b,
`605-c for use with a system for fractur