Arbitrage control system for two or more available power sources

The present invention provides an arbitrage control system for two or more available power sources (106, 108) that enables the automatic or manual control of one or more multi-source systems (202) to take advantage of price differentials across commodities, locations and/or time. The present invention selects a power source for a device or delivery point (110) from two or more available power sources (106, 108) by analyzing market and operational data (406). A power source (106 or 108) for the device or delivery point (110) is then selected from the two or more available power sources (106, 108) based on a set of financial parameters (408). If the device or delivery point (110) is not already connected to the selected power source, one or more signals are sent (418) to switch the device or delivery point (110) to the selected power source. The arbitrage controller (102) includes a user interface (300), market interface (302), multi-source interface (304), database (306) and processor (308). The processor (308) is communicably coupled to the user interface (300), the market interface (302), the multi-source interface (304) and the database (306).

FIELD OF THE INVENTION

The present invention relates generally to the field of control systems and, more particularly, to an arbitrage control system for two or more available power sources.

BACKGROUND OF THE INVENTION

Arbitrage is the capture of profits by taking advantage of price differentials across commodities, locations and/or time. Individuals and companies have long engaged in arbitrage in the commodity and financial sectors. More recently, individuals and companies have engaged in arbitrage in the energy sector. As a result, sophisticated analysis and trading systems have been developed to facilitate energy related transactions involving natural gas and electrical power. Although these systems facilitate energy sector arbitrage, they do not physically control the field equipment used to generate, store and transmit the subject of the arbitrage, e.g., natural gas or electricity. Accordingly, there is a need for an arbitrage control system for two or more power sources.

SUMMARY OF THE INVENTION

The present invention provides an arbitrage control system for two or more available power sources that enables the automatic or manual control of one or more multi-source systems to take advantage of price differentials across commodities, locations and/or time. More specifically, the present invention provides a method for selecting a power source for a device or delivery point from two or more available power sources by analyzing market and operational data related to the two or more available power sources, and the device or delivery point. A power source for the device or delivery point is then selected from the two or more available power sources based on a set of financial parameters. If the device or delivery point is not already connected to the selected power source, one or more signals are sent to switch the device or delivery point to the selected power source. The present invention may also determine whether it is profitable to switch the device or delivery point to the selected power source and only send the one or more signals when it is profitable to switch the device or delivery point to the selected power source. Moreover, these steps may be periodically repeated and performed on more than one multi-source system. Furthermore, this method can be implemented as a computer program embodied on a computer readable medium wherein each step is performed by one or more code segments.

In addition, the present invention provides an apparatus for selecting a power source for a device or delivery point from two or more available power sources that includes a user interface, a market interface, a multi-source interface, a database and a processor. The processor is communicably coupled to the user interface, the market interface, the multi-source interface and the database. The processor analyzes market and operational data related to the two or more available power sources and the device or delivery point, selects the power source for the device or delivery point from the two or more available power sources based on a set of financial parameters and sends one or more signals via the multi-source interface to switch the device or delivery point to the selected power source whenever the device or delivery point is not already connected to the selected power source. The processor may also determine whether it is profitable to switch the device or delivery point to the selected power source and only send the one or more signals when it is profitable to switch the device or delivery point to the selected power source. Moreover, the processor may periodically repeat these steps and perform these steps for more than one multi-source system.

Other features and advantages of the present invention shall be apparent to those of ordinary skill in the art upon reference to the following detailed description taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention. The present invention provides an arbitrage control system for two or more available power sources that enables the automatic or manual control of one or more multi-source systems to take advantage of price differentials across commodities, locations and/or time.

Referring now toFIG. 1A, a block diagram of an arbitrage system100in accordance with one embodiment of the present invention is shown. The arbitrage system100includes an arbitrage controller102and a multi-source system (collectively104-114). The arbitrage controller102can be a processor, computer, programmable logic controller or other control device that is local or remote to the multi-source system. Moreover, the arbitrage controller102can be combined, integrated or added to the multi-source control system104as hardware, software or a combination thereof. In addition, the arbitrage controller102can be operated as an automated, semi-automated or manual system. For example, the arbitrage controller102can be manually controlled by an operator based on an off-system analysis of market and operational data. Furthermore, the multi-source system is not limited to the embodiments illustrated inFIGS. 1A, 1B and 1Cand only requires that two or more power sources (106and108) can be selectively connected to a device or delivery point110in any desirable manner.

As shown, power source one106is selectively connected to device or delivery point110with switch or coupling112. Similarly, power source two108is selectively connected to device or delivery point110with switch or coupling114. Selectively connecting one of the power sources106or108to the device or delivery point110means that selected power source106or108is providing electrical or mechanical power to the device or delivery point110. Note that the unselected power source106or108can still be physically connected to the device or delivery point110even though it is not providing power to the device or delivery point110(e.g., free wheeling drive shaft running through an engine or motor). The multi-source control system104monitors and controls (as indicated by the dashed lines) power source one106, power source two108, device or delivery point110, and switch or couplings112and114. Typically, the delivery point110will be an electrical connection to an electrical network and the device110will be a compressor, pump or other machine. Likewise, the available power sources106and108can be an electricity source or a mechanical source. The typical electrical sources include electrical network connections, combustion turbine generators, steam turbine generators, batteries, fuel cells, solar cells, wind generators, biomass generators or hydroelectric generators. The typical mechanical sources include engines, motors, motor/generators or turbines. The type of switch or coupling112and114used will depend on the specifics of the corresponding power source and device or delivery point. For example, an electrical source will typically be connected to an electrical switching device and a mechanical source will typically be connected to a clutch, coupling (e.g., fixed, magnetic, etc.) or gearbox. For example, switch or coupling112and114can be a fixed coupling with an overrunning clutch. Moreover, the switch or coupling112and114can be designed to interface with more than one power source.

Now referring toFIG. 1B, a block diagram of an arbitrage system130in accordance with another embodiment of the present invention is shown. The arbitrage system130includes an arbitrage controller102and a multi-source system (collectively104-112). The previous description of the arbitrage controller102, multi-source control system104, power source one106, power source two108, device or delivery point110and switch or coupling112in reference toFIG. 1Aare also applicable toFIG. 1B. As shown, power source one106and power source two108are selectively connected to device or delivery point110with switch or coupling112. The multi-source control system104monitors and controls (as indicated by the dashed lines) power source one106, power source two108, device or delivery point110, and switch or coupling112.

Referring now toFIG. 1C, a block diagram of an arbitrage system160in accordance with another embodiment of the present invention is shown. The arbitrage system160includes an arbitrage controller102and a multi-source system (collectively104-114). The previous description of the arbitrage controller102, multi-source control system104, power source one106, power source two108, device or delivery point110and switch or couplings112and114in reference toFIGS. 1A and 1Bare also applicable toFIG. 1C. As shown, power source two108is selectively connected to device or delivery point110with switch or coupling114. Power source one106is selectively connected to device or delivery point110with switch or coupling112(via power source two108and switch or coupling114). When power source one106is connected to the device or delivery point110, the power from power source one106is passed through power source two108. For example, power source one106can be an engine, power source two108can be a motor, device or delivery point110can be a compressor and switch or coupling112and114can be fixed couplings with overrunning clutches to selectively transfer mechanical power from the engine106or motor108to the compressor110. In another example, power source one106and power source two108can be two different electrical networks that are connected together via switch or coupling112. The multi-source control system104monitors and controls (as indicated by the dashed lines) power source one106, power source two108, device or delivery point110, and switch or couplings112and114.

Now referring toFIG. 2, a block diagram of an arbitrage system200in accordance with another embodiment of the present invention is shown. Arbitrage system200provides an arbitrage controller102that controls more than one multi-source system202,204,206and208. As previously stated, each multi-source system202,204,206and208contains two or more power sources that are selectively connected to a device or delivery point. The multi-source systems202,204,206and208can be located in a single location, grouped into several locations or individually located at different locations. The arbitrage controller102can be located at any of the multi-source systems202,204,206or208or be located remotely at a central or regional control center. Depending on the arrangement, the arbitrage controller102can communicate with the multi-source systems202,204,206and208via a computer network, communications network, wireless communications link, direct connection or combination thereof. The arbitrage controller102is also communicably coupled to a system database210, user interface212and a market data source214.

For each multi-source system202,204,206and208, the arbitrage controller102analyzes market and operational data related to the two or more available power sources and the device or delivery point, selects the power source for the device or delivery point from the two or more available power sources based on a set of financial parameters and sends one or more signals via the multi-source interface to switch the device or delivery point to the selected power source whenever the device or delivery point is not already connected to the selected power source. The market and operational data may include historical operating data, current operating data, contract data, market data or financial data obtained from the multi-source systems202,204,206,208, the system database210, the user interface212or the market data source214. The set of financial parameters may include one or more operating models, operational cost data, relative efficiency of the power sources, switching cost data, minimum return, projections, market buy/sell prices, contract buy/sell prices, fuel costs, electricity costs, target demand, maximum demand, minimum connect times for each available power source, maximum switching cycle over a specified period of time, emission limits, audible noise limits or user input data.

Referring now toFIGS. 3A and 3B, a block diagram (FIG. 3A) and a functional diagram (FIG. 3B) of an arbitrage controller102in accordance with one embodiment of the present invention are shown. The arbitrage controller102includes a user interface300, a market interface302, a multi-source interface304, a database306and a processor308. The processor308is communicably coupled to the user interface300, the market interface302, the multi-source interface304and the database306. The processor308analyzes market and operational data related to the two or more available power sources and the device or delivery point, selects the power source for the device or delivery point from the two or more available power sources based on a set of financial parameters and sends one or more signals (operational instructions366) via the multi-source interface304to switch the device or delivery point to the selected power source whenever the device or delivery point is not already connected to the selected power source. Typically, the processor308receives market data356via the market interface302, and operational data350and352from the multi-source interface304or the database306. The market and operational data may include historical operating data350, current operating data352, contract data354, market data356, financial data358or other data360obtained from the user interface300, market interface302, multi-source interface304or database306. The set of financial parameters may include one or more operating models362, operational cost data, switching cost data, minimum return, projections, market buy/sell prices, contract buy/sell prices, fuel costs, electricity costs, target demand, maximum demand, minimum connect times for each available power source, maximum switching cycle over a specified period of time, emission limits, audible noise limits or user input data364. The analysis and selection process can be periodically repeated, user initiated or repeated whenever new market or operational data related to the two or more available power sources is received.

As part of the analysis, the processor308may determine whether it is profitable to switch the device or delivery point to the selected power source and send the one or more signals (operational instructions366) only when it is profitable to switch the device or delivery point to the selected power source. For example, it may not be profitable to switch the power source too frequently because switching typically stresses the equipment, has some overhead cost and risk associated with it, and increases maintenance costs. Moreover, the amount of time that a particular power source is the selected source may not be long enough for the switch over to be profitable. As a result, the profitability analysis will typically project the potential revenue and costs associated with the switch and determine whether the net revenue is above specified guidelines. Naturally, a user can override a recommended switching operation or manually cause a switching operation via user interface300. Data is input from and output to364the user via the user interface300. This may input/output364may include updating a display based on user inputs, new data or new analysis.

The multi-source interface304can also be a multi-source control system or one or more interfaces to the two or more available power sources, and the device or delivery point. In these cases, the processor308also monitors and controls the two or more available power sources, and the device or delivery point via the multi-source interface. In addition, the multi-source interface304can communicate with the multi-source systems via a computer network, a communications network, a wireless communications link, a direct connection or combination thereof.

Now referring toFIG. 4, a flow chart400of an arbitrage control system in accordance with one embodiment of the present invention is shown. The process400begins in block402and receives input data in block404. Input data, such as market and operational data related to the two or more available power sources, and the device or delivery point is then analyzed in block406and the best power source for the device or delivery point is selected from the two or more available power sources based on a set of financial parameters in block408. The market and operational data may include historical operating data, current operating data, contract data, market data, financial data or other data. The set of financial parameters may include one or more operating models, operational cost data, switching cost data, minimum return, projections, market buy/sell prices, contract buy/sell prices, fuel costs, electricity costs, target demand, maximum demand, minimum connect times for each available power source, maximum switching cycle over a specified period of time, emission limits, audible noise limits or user input data.

If the device or delivery point is already connected to the selected power source, as determined in decision block410, a display is updated in block412and the process repeats the data acquisition, analysis and source selection processes in blocks404,406and408. If, however, the device or delivery point is not already connected to the selected power source, as determined in decision block410, a determination of whether it is profitable to switch the device or delivery point to the selected power source is made. For example, it may not be profitable to switch the power source too frequently because switching typically stresses the equipment, has some overhead cost and risk associated with it, and increases maintenance costs. Moreover, the amount of time that a particular power source is the selected source may not be long enough for the switch over to be profitable. As a result, the profitability analysis will typically project the potential revenue and costs associated with the switch and determine whether the net revenue is above specified guidelines.

If it is not profitable to switch, as determined in decision block414, a display is updated in block412and the process repeats the data acquisition, analysis and source selection processes in blocks404,406and408. If, however, it is profitable to switch, as determined in decision block414, a determination of whether a user has overridden the selection is made. If there is a user override, as determined in decision block416, an optional display is updated in block412and the process repeats the data acquisition, analysis and source selection processes in blocks404,406and408. If, however, there is no user override, as determined in decision block416, one or more signals or operational instructions are sent to switch the device or delivery point to the selected power source in block418. These signals can be sent via a computer network, a communications network, a wireless communications link, a direct connection or combination thereof. Note that the user override in decision block416is applicable to an automatic or semi-automatic system. The present invention can be implemented in a manually operated system wherein an operator decides to implement or send the source change instruction based on an analysis of market and operational data (blocks406and408). The optional display is then updated in block412and the process repeats the data acquisition, analysis and source selection processes in blocks404,406and408. These steps may be repeated periodically, repeated when new data is received, repeated upon user request and performed on more that one multi-source system.

The control system of present invention will now be described in relation to two specific examples. The first example is a redundant prime mover system and is described below in relation toFIGS. 5-10. The second example is an electricity transfer station and is described below in relation toFIGS. 11-19.

The prime mover system described in relation toFIGS. 5-10can be operated in three or four different operating modes, which increases the reliability, versatility and efficiency of the system. The redundant prime mover system includes an engine or turbine, a motor/generator and a machine, such as a compressor or pump. The four different operating modes are: driving the machine with the engine or turbine; driving the machine with the motor/generator; driving the machine and the motor/generator with the engine or turbine such that the motor/generator generates electricity; and driving the machine with both the engine or turbine and the motor/generator in a load sharing arrangement. The system can be selectively switched between these modes depending on one or more parameters. As a result, the redundant prime mover system can be set to run in the most cost effective mode or can arbitrage the price differences between electricity and the fuel used by the engine.

Referring now toFIG. 5, a block diagram of a redundant prime mover system500in accordance with one embodiment of the present invention is shown. The redundant prime mover system500includes a motor/generator502coupled to a compressor504with a first coupling506(also referred to as the “M/G-COMP Coupling”) and a engine or turbine508coupled to the compressor504with a second coupling510(also referred to as the “E/T-COMP Coupling”). Couplings506and510can be a clutch, coupling (e.g., fixed, magnetic, etc.), gearbox or other suitable device to selectively engage/disengage the shaft of the compressor or pump504. For example, couplings506and510can be fixed couplings with an overrunning clutch. The motor/generator502and engine508can be variable speed devices. In one embodiment of the present invention, the engine508is oversized so that some amount of electricity can be generated using the motor/generator502even with the compressor504is operating at peak load. In small to medium applications, the motor/generator502, compressor504and engine or turbine508are typically mounted on a skid512to form a package that can be transported and set up more quickly and economically than individually installing components502,504,506,508and510in the field. As will be appreciated by those skilled in the art, other equipment (not shown), such as coolers, cooler drivers, scrubbers and application specific devices, may be connected to the motor/generator502, compressor504or engine508.

The motor/generator502is electrically connected to an electrical network connection514, which is used as a source of electricity to run the motor/generator502and drive the compressor504and a delivery point for the electricity generated by the motor/generator502when the engine508is supplying more output power than is required to drive the compressor504. The exact interface between the electrical network connection514and the transmission or distribution system516will vary from one installation to another. One possible interface may include a step-down/step-up transformer518connected to the transmission or distribution system line516via breaker520. The step-down/step-up transformer518can be isolated with switches522and524. A meter526records the energy flow to and from the step-down/set-up transformer518. Meter526is connected between the step-down/step-up transformer518and the electrical network connection514, and may be isolated with switches528and530or bypassed with switch532. Other metering and protective devices may also be used, such as protective relays (not shown), lightning arrestors534and536, potential transformers538, etc.

Although a compressor504is depicted, compressor504could also be a pump or other machine that is driven by large engines, turbines or motors. Input line540and output line542are connected to compressor504. As will be appreciated by those skilled in the art, the connection of the lines540and542to the compressor504will also include various valves, regulators and other flow protection/regulation devices. These lines540and542may be taps off of a pipeline, such as natural gas or other petroleum product, or part of a processing plant. If input line540contains a product that can be used as fuel for the engine or turbine508, a first fuel supply line544having a regulating valve546will connect the input line540to the engine or turbine508. In such cases, first fuel supply line544will serve as the primary fuel supply for the engine or turbine508. A second fuel supply line548having a regulating valve550will typically connect the engine or turbine508to an alternate fuel supply. If input line540does not contains a product that can be used as fuel for the engine or turbine508, second fuel supply line548will be the primary source of fuel to the engine or turbine508.

Now referring toFIG. 6, a block diagram of a control system600for a redundant prime mover system in accordance with one embodiment of the present invention is shown. A controller602is communicably coupled to the engine or turbine508, the second coupling510, the compressor504, the first coupling506and the motor/generator502. The controller602monitors and controls the operation of these components502,504,506,508and510. The controller602can be installed on the skid512(FIG. 5) or in a remotely located control room or building (not shown). The controller602may also be communicably coupled to one or more input/output (“I/O”) devices602and data storage devices604. The system600can be controlled and monitored from the controller602or from a remote terminal606communicably coupled to the controller602via a network608or a direct communication link (not shown). The controller602can also send and retrieve data or commands from a remote server610communicably coupled to the controller602via network608.

In this embodiment, the two or more available power sources106and108(FIG. 1) include an engine508and a motor/generator502. The device or delivery point110(FIG. 1) includes a machine (compressor)504and/or an electrical connection. The engine508is coupled to the machine504. The motor/generator502is coupled to the machine504and the electrical network connection. The arbitrage controller102can be located with, combined with or integrated in the controller602as illustrated by arbitrage controller102b. Alternatively, the arbitrage controller102can be at a remote site as illustrated by arbitrage controller102aand communicate with the controller602via network608.

Referring now toFIG. 7, a block diagram of a controller602for a redundant prime mover system in accordance with one embodiment of the present invention is shown. The controller602includes one or more processors702communicably coupled to a memory704. Memory704can be read only memory (“ROM”) and/or random access memory (“RAM”). The one or more processors702are communicably coupled to an engine control interface706, a compressor control interface708, a motor/generator control interface710, an I/O interface712and a remote interface714. The controller602controls and monitors the engine or turbine508(FIG. 6) using the engine control interface706. The second coupling510(FIG. 6) can be automatically controlled (e.g., fixed coupling with an overrunning clutch), or controlled and monitored using engine control interface706, the compressor interface708or a separate interface (not shown). Similarly, the controller602controls and monitors the motor/generator502(FIG. 6) using the motor/generator control interface710. The first coupling506(FIG. 6) can be automatically controlled (e.g., fixed coupling with an overrunning clutch), or controlled and monitored using motor/generator control interface710, the compressor interface708or a separate interface (not shown). The controller602controls and monitors the compressor504(FIG. 6) using the compressor control interface708. Note that some or all of these three interfaces706,708and710can be combined into a single interface. Moreover, each interface706,708and710can be individually wired connections. The I/O interface712communicably couples the processor720to the I/O devices602(FIG. 6) and data storage devices604(FIG. 6). Similarly, the remote interface714communicably couples the processor720to the remote terminal606(FIG. 6) and data server610(FIG. 6). The I/O interface712and remote interface714can be a serial, parallel, universal serial bus (“USB”), Ethernet, telephone or other type of computer interface. As will be appreciated by those skilled in the art, the interfaces706,708,710,712and714include the necessary hardware, software and drivers to establish communication between the processor and the connected devices.

Now referring toFIG. 8A, a flowchart of a control process800for a redundant prime mover system in accordance with one embodiment of the present invention is shown. The control process800starts in block802and the system determines whether it is in manual or automatic mode in decision block804. If the system is not in automatic mode, as determined in decision block804, an operating mode is selected in block806. If the system is in automatic mode, as determined in decision block804, one or more parameters, such as operational data, are obtained and the proper operating mode is determined in block808. The one or more parameters may include an estimated operational cost for the engine, an estimated operational cost for the motor/generator, a selling price for electricity, a fuel cost for the engine, an electricity cost for the motor/generator, a time period, an emission limit, an audible noise limit, or any other operational data.

Once the operating mode has been selected or determined in either block806or block808, and if the operating mode is new (initial operating mode or different from the current operating mode), as determined in decision block810, and if it is not time to re-determine the operating mode, as determined in decision block812, the system waits a predetermined amount of time in block814before it re-determines the operating mode. If, however, it is time to re-determine the operating mode, as determined in decision block812, operating data is obtained and the proper operating mode is determined in block816. If the system is set to automatic, as determined in decision block818, the process loops back to decision block810to determine whether the re-determined operating mode is new. If, however, the system is not set to automatic, as determined in decision block818, the system recommends that the operating mode be changed in block820and then loops back to block806where the operating mode is selected. If a new operating mode is not selected in block806, the re-determination process can be repeated.

The control process800of the present invention operates the motor/generator502(FIGS. 5 and 6), compressor504(FIGS. 5 and 6) and engine508(FIGS. 5 and 6) in three or four operating modes. The operating modes can be selected manually or automatically. The first operating mode drives the machine with the engine. The second operating mode drives the machine with the motor/generator. The third operating mode drives the machine and the motor/generator with the engine such that the motor/generator generates electricity for delivery to the electrical network connection. Alternatively, the third operating mode drives the machine with both the engine and the motor/generator. This alternate operating mode can also be included as a fourth operating mode.

For example, the present invention can be set to operate in the most cost efficient manner using three operating modes based on these parameters: a first estimated operational cost for the engine, a second estimated operational cost for the engine, an estimated operational cost for the motor/generator and a selling price for the electricity. The first estimated operational cost for the engine corresponds to the operating costs to drive the compressor504(FIGS. 5 and 6) with the engine508(FIGURES 5 and 6). The second estimated operational cost for the engine corresponds to the incremental cost to drive the compressor504(FIGS. 5 and 6) and the motor/generator502(FIGS. 5 and 6). The first operating mode occurs whenever a first estimated operational cost for the engine508(FIGS. 5 and 6) is less than an estimated operational cost for the motor/generator502(FIGS. 5 and 6). The second operating mode occurs whenever an estimated operational cost for the motor/generator502(FIGS. 5 and 6) is less than or equal to the first estimated operational cost for the engine508(FIGS. 5 and 6). The third operating mode occurs whenever a selling price for the electricity is greater than the second estimated operational cost for the engine508(FIGS. 5 and 6). The processor702(FIG. 7) can calculate the first operational cost for the engine508(FIGS. 5 and 6), second operational cost for the engine508(FIGS. 5 and 6), operational cost for the motor/generator502(FIGS. 5 and 6) and selling price for the electricity using current and/or historical data. These operating modes can be manually controlled, preprogrammed, or determined in real-time, near real-time or from historical and/or projected data. For example, the operating modes could be triggered by selected time periods to operate in the first operating mode during the summer months (excluding electrical peaking periods), the second operating mode during the remaining months, and the third operating mode during the electrical peaking periods.

If the operating mode is new (initial operating mode or different from the current operating mode), as determined in decision block810, and the new operating mode is the first operating mode, as determined in decision block822, the E/T start process is executed in block824. The E/T start process824is described below in reference toFIG. 8B. After completion of the E/T start process in block824, the process loops back to decision block812to determine whether it is time to re-determine or update the operating mode. If, however, the new operating mode is not the first operating mode, as determined in decision block822, and the new operating mode is the second operating mode, as determined in decision block826, the M/G start process is executed in block828. The M/G start process828is described below in reference toFIG. 8C. After completion of the M/G start process in block828, the process loops back to decision block812to determine whether it is time to re-determine or update the operating mode. If, however, the new operating mode is not the second operating mode, as determined in decision block826, and the new operating mode is the third operating mode, as determined in decision block830, the generation start process is executed in block832. The generation start process832is described below in reference toFIG. 8D. After completion of the generation start process in block832, the process loops back to decision block812to determine whether it is time to re-determine or update the operating mode. If, however, the new operating mode is not the third operating mode, as determined in decision block830, and the new operating mode is the fourth operating mode, as determined in decision block834, the load sharing start process is executed in block836. The load sharing start process836is described below in reference toFIG. 8E. After completion of the load sharing start process in block836, the process loops back to decision block812to determine whether it is time to re-determine or update the operating mode. If, however, the new operating mode is not the fourth operating mode, as determined in decision block834, and the shut down process has not been ordered, as determined in decision block838, a error process will commence in block840. The error process840may include various system checks, diagnostics and reporting functions, and may or may not initiate a shut down process or “safe” operating mode. If, however, the shut down process has been ordered, as determined in decision block838, the shut down process will be executed in block842and the process ends in block844.

Referring now toFIG. 8B, a flowchart of the engine or turbine start process824ofFIG. 8Afor a redundant prime mover system in accordance with one embodiment of the present invention is shown. The E/T start process824begins in block850. If the engine or turbine508(FIG. 5) is not on, as determined in decision block852, the engine or turbine508(FIG. 5) is started in block854. If the engine or turbine508(FIG. 5) is not up to the proper speed to engage the E/T-COMP coupling510(FIG. 5), as determined in decision block856, and the start process has not exceeded a specified period of time (“timed out”), as determined in decision block858, the process will wait in block860for a period of time before the engine or turbine508(FIG. 5) speed is checked again in decision block856. If, however, the start process has timed out, as determined in decision block858, an error process will be initiated in block862. The error process862may include various system checks, diagnostics and reporting functions. The error process862may also shut the engine or turbine508(FIG. 5) down and disable the E/T start process824and generation start process832until a technician services the control system and the engine or turbine508(FIG. 5). If the engine or turbine508(FIG. 5) is up to the proper speed, as determined in decision block856, the E/T-COMP coupling510(FIG. 5) is engaged in block864. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. If the motor/generator502(FIG. 5) is not on, as determined in decision block866, the system suspends further processing until a transition delay period has expired in block868and the process returns in block870. The transition delay period can be a minimum time to run the engine or turbine508(FIG. 5) in the first operating mode based on the costs and equipment wear and tear associated with changing operating modes. For example, the system may be specified to prevent changing operating modes every few minutes or even every hour. Alternatively, there may be a maximum number of changes allowed per day, week or month.

If, however, the motor/generator502(FIG. 5) is on, as determined in decision block866, the M/G-COMP coupling506(FIG. 5) is disengaged in block872and the motor/generator502(FIG. 5) is shut down in block874. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. As before, the system suspends further processing until the transition delay period has expired in block868and returns to the main process (FIG. 8) in block870. If, however, the engine or turbine508(FIG. 5) is on, as determined in decision block852, and the motor/generator502(FIG. 5) is not on, as determined in decision block876, the process returns in block870to the main process (FIG. 8) because the system is already in the first operating mode. If, however, the motor/generator502(FIG. 5) is on, as determined in decision block876, the M/G-COMP coupling506(FIG. 5) is disengaged in block878and the motor/generator502(FIG. 5) is shut down in block880. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. The speed of the engine or turbine508(FIG. 5) is reduced in block882to only drive the compressor instead of both the compressor and motor/generator. The system suspends further processing until the transition delay period has expired in block868and returns in block870to the main process (FIG. 8).

Now referring toFIG. 8C, a flowchart of the motor/generator start process828ofFIG. 8Afor a redundant prime mover system in accordance with one embodiment of the present invention is shown. The M/G start process828begins in block890. If the motor/generator502(FIG. 5) is not on, as determined in decision block892, the motor/generator502(FIG. 5) is started in block894. If the motor/generator502(FIG. 5) is not up to the proper speed to engage the M/G-COMP coupling506(FIG. 5), as determined in decision block896, and the start process has not timed out, as determined in decision block898, the process will wait in block900for a period of time before the motor/generator502(FIG. 5) speed is checked again in decision block896. If, however, the start process has timed out, as determined in decision block898, an error process will be initiated in block902. The error process902may include various system checks, diagnostics and reporting functions. The error process902may also shut the motor/generator502(FIG. 5) down and disable the M/G start process828and generation start process832until a technician services the control system and the motor/generator502(FIG. 5). If the motor/generator502(FIG. 5) is up to the proper speed, as determined in decision block896, the M/G-COMP coupling506(FIG. 5) is engaged in block904. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. If the motor/generator502(FIG. 5) is not on, as determined in decision block906, the system suspends further processing until a transition delay period has expired in block908and the process returns in block910. The transition delay period can be a minimum time to run the motor/generator502(FIG. 5) in the first operating mode based on the costs and equipment wear and tear associated with changing operating modes. For example, the system may be specified to prevent changing operating modes every few minutes or even every hour. Alternatively, there may be a maximum number of changes allowed per day, week or month.

If, however, the motor/generator502(FIG. 5) is on, as determined in decision block906, the E/T-COMP coupling510(FIG. 5) is disengaged in block912and the engine or turbine508(FIG. 5) is shut down in block914. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. As before, the system suspends further processing until the transition delay period has expired in block908and returns to the main process (FIG. 8) in block910. If, however, the motor/generator502(FIG. 5) is on, as determined in decision block892, and the engine or turbine508(FIG. 5) is not on, as determined in decision block916, the process returns in block910to the main process (FIG. 8) because the system is already in the second operating mode. If, however, the engine or turbine508(FIG. 5) is on, as determined in decision block916, the speed of the engine or turbine508(FIG. 5) is reduced in block918so that the system is not generating electricity. The E/T-COMP coupling510(FIG. 5) is disengaged in block920and the engine or turbine508(FIG. 5) is shut down in block922. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. The system suspends further processing until the transition delay period has expired in block908and returns in block910to the main process (FIG. 8).

Referring now toFIG. 8D, a flowchart of the generation start process832ofFIG. 8Afor a redundant prime mover system in accordance with one embodiment of the present invention is shown. The generation start process832begins in block930. If the engine or turbine508(FIG. 5) is not on, as determined in decision block932, the engine or turbine508(FIG. 5) is started in block934. If the engine or turbine508(FIG. 5) is not up to the proper speed to engage the E/T-COMP coupling510(FIG. 5), as determined in decision block936, and the start process has not timed out, as determined in decision block938, the process will wait in block940for a period of time before the engine or turbine508(FIG. 5) speed is checked again in decision block936. If, however, the start process has timed out, as determined in decision block938, an error process will be initiated in block942. The error process942may include various system checks, diagnostics and reporting functions. The error process942may also shut the engine or turbine508(FIG. 5) down and disable the E/T start process824, generation start process832and load sharing start process836until a technician services the control system and the engine or turbine508(FIG. 5). If the engine or turbine508(FIG. 5) is up to the proper speed, as determined in decision block936, the E/T-COMP coupling510(FIG. 5) is engaged in block944. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. If the motor/generator502(FIG. 5) is on, as determined in decision block946, the speed of the engine or turbine508(FIG. 5) is increased in block948so that the system generates electricity. The system suspends further processing until a transition delay period has expired in block950and the process returns in block952. The transition delay period can be a minimum time to run the motor/generator502(FIG. 5) and engine or turbine508(FIG. 5) in the third operating mode based on the costs and equipment wear and tear associated with changing operating modes. For example, the system may be specified to prevent changing operating modes every few minutes or even every hour. Alternatively, there may be a maximum number of changes allowed per day, week or month.

If, however, the motor/generator502(FIG. 5) is not on, as determined in decision block946, the motor/generator502(FIG. 5) is started in block954. If the motor/generator502(FIG. 5) is up to the proper speed, as determined in decision block956, the M/G-COMP coupling506(FIG. 5) is engaged in block958and the speed of the engine or turbine508(FIG. 5) is increased in block948so that the system generates electricity. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. The system suspends further processing until a transition delay period has expired in block950and the process returns in block952. If, however, the motor/generator502(FIG. 5) is not up to the proper speed to engage the M/G-COMP coupling506(FIG. 5), as determined in decision block956, and the start process has not timed out, as determined in decision block960, the process will wait in block962for a period of time before the motor/generator502(FIG. 5) speed is checked again in decision block956. If, however, the start process has timed out, as determined in decision block960, an error process will be initiated in block964. The error process964may include various system checks, diagnostics and reporting functions. The error process964may also shut the motor/generator502(FIG. 5) down and disable the M/G start process828, generation start process832and load sharing start process836until a technician services the control system and the motor/generator502(FIG. 5).

If, however, the engine or turbine508(FIG. 5) is on, as determined in decision block932, and the motor/generator502(FIG. 5) is on, as determined in decision block966, the process returns in block952to the main process (FIG. 8) because the system is already in the third operating mode. If, however, the motor/generator502(FIG. 5) is not on, as determined in decision block966, the motor/generator502(FIG. 5) is started in block954and the process continues as previously described.

Referring now toFIG. 8E, a flowchart of the load sharing start process836ofFIG. 8Afor a redundant prime mover system in accordance with one embodiment of the present invention is shown. The load sharing start process836begins in block970. If the engine or turbine508(FIG. 5) is not on, as determined in decision block972, the engine or turbine508(FIG. 5) is started in block974. If the engine or turbine508(FIG. 5) is not up to the proper speed to engage the E/T-COMP coupling510(FIG. 5), as determined in decision block976, and the start process has not timed out, as determined in decision block978, the process will wait in block980for a period of time before the engine or turbine508(FIG. 5) speed is checked again in decision block976. If, however, the start process has timed out, as determined in decision block978, an error process will be initiated in block982. The error process982may include various system checks, diagnostics and reporting functions. The error process982may also shut the engine or turbine508(FIG. 5) down and disable the E/T start process824, generation start process832and load sharing start process836until a technician services the control system and the engine or turbine508(FIG. 5). If the engine or turbine508(FIG. 5) is up to the proper speed, as determined in decision block976, the E/T-COMP coupling510(FIG. 5) is engaged in block984. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. If the motor/generator502(FIG. 5) is on, as determined in decision block986, the output of the engine or turbine508(FIG. 5) and motor/generator502(FIG. 5) are adjusted to share the load of the compressor504in block988. The system suspends further processing until a transition delay period has expired in block990and the process returns in block992. The transition delay period can be a minimum time to run the motor/generator502(FIG. 5) and engine or turbine508(FIG. 5) in the fourth operating mode based on the costs and equipment wear and tear associated with changing operating modes. For example, the system may be specified to prevent changing operating modes every few minutes or even every hour. Alternatively, there may be a maximum number of changes allowed per day, week or month.

If, however, the motor/generator502(FIG. 5) is not on, as determined in decision block986, the motor/generator502(FIG. 5) is started in block994. If the motor/generator502(FIG. 5) is up to the proper speed, as determined in decision block996, the M/G-COMP coupling506(FIG. 5) is engaged in block998and the speed of the engine or turbine508(FIG. 5) and motor/generator502(FIG. 5) are adjusted to share the load of the compressor504in block988. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. The system suspends further processing until a transition delay period has expired in block990and the process returns in block992. If, however, the motor/generator502(FIG. 5) is not up to the proper speed to engage the M/G-COMP coupling506(FIG. 5), as determined in decision block996, and the start process has not timed out, as determined in decision block600, the process will wait in block602for a period of time before the motor/generator502(FIG. 5) speed is checked again in decision block996. If, however, the start process has timed out, as determined in decision block600, an error process will be initiated in block604. The error process604may include various system checks, diagnostics and reporting functions. The error process604may also shut the motor/generator502(FIG. 5) down and disable the M/G start process828, generation start process832and load sharing start process836until a technician services the control system and the motor/generator502(FIG. 5).

If, however, the engine or turbine508(FIG. 5) is on, as determined in decision block972, and the motor/generator502(FIG. 5) is on, as determined in decision block606, the process returns in block992to the main process (FIG. 8) because the system is already in the third operating mode. If, however, the motor/generator502(FIG. 5) is not on, as determined in decision block1006, the motor/generator502(FIG. 5) is started in block974and the process continues as previously described.

The following data illustrates an example of some of the equipment that can be used to implement the present invention. The applicable data for compressor654is:

The applicable data for the engine508is:

The applicable data for the motor/generator502is:

The first and second couplings506and510can be fixed couplings or couplings that incorporate an overrunning clutch into the driven hub that mounts the motor shaft. In order to use the engine or turbine508, the engine or turbine508is started allowed to warm up at idle speed. The engine or turbine508is then sped up to run speed. When the engine or turbine508speed becomes faster than the motor/generator502speed, the overrunning clutch engages and the engine or turbine508becomes the prime mover.

The applicable data for the cooler (not shown) is:

The applicable data for the cooler driver (not shown) is:

Relief valves for discharge and the fuel system are Mercer or Equal—Spring Operated. The relief valve exhaust is piped above cooler. Process piping is built in accordance with ANSI B31.3 Code. Suction and Discharge pulsation bottles are ASME Code Stamped. Scrubber and Pulsation Bottle sizes and working pressures apply to typical design conditions.

The applicable data for the programmed logic controller (“PLC”) control panel is:

The skid512is a heavy duty oil field type with 3/16″ checkered floor plate, four main runners and leveling jack screws. Skid members support all vessels and piping, and are provided with pipe ends for skidding and lifting. The skid512will be concrete filled under the engine, compressor frame & distance pcs. The skid512also includes an environmental drip rail with four drain sumps. The skid512has estimated package dimensions of fourteen feet (14′) wide by thirty-five feet (35′) long and an estimated weight of 125,000 lbs. The cooler has estimated package dimensions of twenty-one feet (21′) wide by fifteen feet (15′) long and an estimated weight of 20,000 lbs.

Now referring toFIG. 9, a block diagram of a redundant prime mover system1050in accordance with another embodiment of the present invention is shown. The redundant prime mover system1050includes a motor/generator1052coupled to a compressor1054with a first coupling1056(also referred to as the “M/G-COMP Coupling”) and a engine or turbine1058coupled to the compressor1054with a second coupling1060(also referred to as the “E/T-COMP Coupling”). Couplings1056and1060can be a clutch, coupling (e.g., fixed, magnetic, etc.), gearbox or other suitable device to selectively engage/disengage the shaft of the compressor or pump1054. Note that depending on the type of coupling used, the coupling may always be engaged and it is an overrunning clutch that is actually engaged or disengaged. The motor/generator1052and the engine1058can be variable speed devices. In one embodiment of the present invention, the engine1058is oversized so that some amount of electricity can be generated using the motor/generator1052even with the compressor1054is operating at peak load. In small to medium applications, the motor/generator1052, compressor1054and engine or turbine1058can be mounted on a skid (not shown) to form a package that can be transported and set up more quickly and economically than individually installing components1052,1054,1056,1058and1060in the field. As will be appreciated by those skilled in the art, other equipment (not shown), such as coolers, cooler drivers, scrubbers and application specific devices, may be connected to the motor/generator1052, compressor1054or engine1058.

The motor/generator1052is electrically connected to an electrical network connection1062, which is used as a source of electricity to run the motor/generator1052and drive the compressor1054and a delivery point for the electricity generated by the motor/generator1052when the engine1058is supplying more output power than is required to drive the compressor1054. The exact interface between the electrical network connection1062and the transmission or distribution system1064will vary from one installation to another. The electrical network connection1062may include some of the equipment described inFIG. 5, such as step-down/step-up transformer, breaker or switches.

Although a compressor1054is depicted, compressor1054could also be a pump or other machine that is driven by large engines, turbines or motors. Input line1066and output line1068are connected to compressor1054. As will be appreciated by those skilled in the art, the connection of the lines1066and1068to the compressor1054will also include various valves, regulators and other flow protection/regulation devices. These lines1066and1068may be taps off of a pipeline, such as natural gas or other petroleum product, or part of a processing plant. If input line1066contains a product that can be used as fuel for the engine or turbine1058, a first fuel supply line1070having a regulating valve1072will connect the input line1066to the engine or turbine1058. In such cases, first fuel supply line1070will serve as the primary fuel supply for the engine or turbine1058. A second fuel supply line1074having a regulating valve1076will typically connect the engine or turbine1058to an alternate fuel supply. If input line1066does not contains a product that can be used as fuel for the engine or turbine1058, second fuel supply line1074will be the primary source of fuel to the engine or turbine1058.

In this embodiment, the two or more available power sources106and108(FIG. 1) include an engine1058and a motor/generator1052. The device or delivery point110(FIG. 1) includes a machine (compressor)1052an electrical network connection1062. The engine1058is coupled to the motor/generator1052. The motor/generator1052is coupled to the machine1054and the electrical network connection1062.

Referring now toFIG. 10, a block diagram of a redundant prime mover system1100in accordance with another embodiment of the present invention is shown. The redundant prime mover system1100includes a motor/generator1102coupled to a gearbox1104with a first coupling1106(also referred to as the “M/G-COMP Coupling”), a compressor1108coupled to the gearbox1104with a third coupling1110and a engine or turbine1112coupled to the gearbox1104with a second coupling1114(also referred to as the “E/T-COMP Coupling”). Couplings1106,1110and1114can be a clutch, coupling (e.g., fixed, magnetic, etc.), gearbox or other suitable device to selectively engage/disengage the shaft of the motor/generator1106, compressor or pump1108and engine or turbine1112. The motor/generator1106and the engine1112can be variable speed devices. In one embodiment of the present invention, the engine1112is oversized so that some amount of electricity can be generated using the motor/generator1102even with the compressor1108is operating at peak load. In small to medium applications, the motor/generator1102, gearbox1104, compressor1108and engine or turbine1112can be mounted on a skid (not shown) to form a package that can be transported and set up more quickly and economically than individually installing components1102,1104,1106,1108,1110,1112and1114in the field. As will be appreciated by those skilled in the art, other equipment (not shown), such as coolers, cooler drivers, scrubbers and application specific devices, may be connected to the motor/generator1102, gearbox1104, compressor1108and engine or turbine1112.

The motor/generator1102is electrically connected to an electrical network connection1116, which is used as a source of electricity to run the motor/generator1102and drive the compressor1108and a delivery point for the electricity generated by the motor/generator1102when the engine1114is supplying more output power than is required to drive the compressor1108. The exact interface between the electrical network connection1116and the transmission or distribution system1118will vary from one installation to another. The electrical network connection1116may include some of the equipment described inFIG. 5, such as step-down/step-up transformer, breaker or switches.

Although a compressor1108is depicted, compressor1108could also be a pump or other machine that is driven by large engines, turbines or motors. Input line1120and output line1122are connected to compressor1108. As will be appreciated by those skilled in the art, the connection of the lines1120and1122to the compressor1108will also include various valves, regulators and other flow protection/regulation devices. These lines1120and1122may be taps off of a pipeline, such as natural gas or other petroleum product, or part of a processing plant. If input line1120contains a product that can be used as fuel for the engine or turbine1112, a first fuel supply line1124having a regulating valve1126will connect the input line1120to the engine or turbine1112. In such cases, first fuel supply line1124will serve as the primary fuel supply for the engine or turbine1112. A second fuel supply line1128having a regulating valve1130will typically connect the engine or turbine1112to an alternate fuel supply. If input line1120does not contains a product that can be used as fuel for the engine or turbine1112, second fuel supply line1128will be the primary source of fuel to the engine or turbine1112.

Now turning to the second example, an electricity transfer station is described below in relation toFIGS. 11-19. Electricity suppliers have traditionally sold electricity to large customers, such as large commercial and industrial customers, rural electric cooperatives and municipalities, based on a demand charge and the customer's actual electricity usage. The demand charge is based on the customer's expected or actual peak demand (normally measured in kilowatts (“KW”)) over a short period of time (normally 15 to 30 minutes) during a contractual billing period. The customer's peak demand and electricity usage (normally measured in kilowatt-hours (“KWH”)) charges are typically specified in long term contracts. As a result, the customer pays a periodic fee, usually monthly, for the ability to draw its peak demand from the electricity supplier via a transmission network even though that peak demand may only occur once during the contractual billing period, if at all. Moreover, if the customer's actual demand exceeds the contractual demand, significant excess demand charges and/or penalties may be imposed on the customer.

Some customers, such as rural electric cooperatives and municipalities, have negotiated long term, low cost electricity purchase contracts with their electricity suppliers. As the re-delivery market for electricity has developed over the years through deregulation and diversification, some of these customers and third-party electricity suppliers have seen an opportunity to purchase additional electricity under existing electricity purchase contracts and re-deliver that additional electricity to other customers at a profit. The sale of such additional electricity is, however, limited and reduced in value if it cannot be sold on a firm basis. For example, the customer may limit the amount of electricity that can be re-delivered based on the economics of the electricity purchase contract. Furthermore, the additional electricity may be reduced in value because it is sold under an interruptible contract, which means that the availability of the additional electricity is not guaranteed during peak demand periods. In order to provide non-interruptible electricity, the customer or third-party electricity supplier would risk setting a new peak demand for the customer, which may be financially unacceptable.

The electricity transfer station allows electricity to be secured by a customer of an electricity supplier via a transmission network under an existing electricity supply contract and re-delivered by that customer to another party under a non-interruptible supply contract without risk of increasing the customer's peak demand above a desired value. This system affords the customer more flexibility, and thus more opportunity to extract value from its supply contracts as well as its distribution, transmission and generation equipment.

Referring now toFIG. 11, a block diagram showing an electricity transfer station1220connected to an electricity customer1222, and to one or more electricity suppliers1224and other electricity customers1226via a transmission network1228is shown. The electricity customer1222, which may be a large commercial or industrial customer, rural electric cooperative or municipality, purchases electricity from an electricity supplier(s)1224via the transmission network1228at an electricity delivery point1230, also referred to as a second network connection. The electricity delivery point1230can be at nominal transmission voltages, such as 69 kilovolts (“KV”), 138 KV, 230 KV or 345 KV, or at nominal distribution voltages, such as 15 KV or 25 KV. Although these voltages are commonly used, the present invention can be designed to operate at any desired voltage. Note also that the electricity customer's metering point may not be at the same point as the electricity delivery point1230. For example, the delivery voltages may be at 138 KV, but the metering point may be at 25 KV because the metering equipment is less complex and expensive. Adjustments are then made to convert the metering data to a 138 KV equivalent.

The electricity delivery point1230will typically be located in or near a substation. The ownership of the equipment in the substation will depend on the contractual agreement between the owner of the transmission network1228, the electricity supplier(s)1224and the electricity customer1222. Typically, the substation will contain circuit breakers, step-down transformers, metering equipment, distribution circuit breakers/reclosers, switches and various protective and metering devices. The electricity transfer station1220of the present invention is typically installed within or next to the electricity customer's substation. Accordingly, the capacity of the electricity transfer station1220is affected by the ratings of the equipment within the substation and by any restrictions imposed by the electricity customer1222, including but not limited to a maximum electricity flow at the electricity delivery point1230.

The electricity transfer station1220includes one or more electricity transfer devices1232, one or more electricity sources1234, an electricity transfer controller1236and an arbitrage controller102. The arbitrage controller102can be physically located with the electricity transfer controller1236, integrated within the electricity transfer controller1236, or located at a remote location. The electricity transfer station1220is connected to the transmission network1228or some other transmission network at the electricity re-delivery point1238, also referred to as a first network connection. As indicated by arrow1240, also referred to as a second electricity flow, electricity flows from the transmission network1228through electricity delivery point1230to the electricity customer1222and the electricity transfer station1220. As indicated by arrow1242, also referred to as a first electricity flow, electricity flows from the electricity transfer station1220through electricity re-delivery point1238to the transmission network1228.

The one or more electricity transfer devices1232may be a phase-shifting transformer, a static transfer device (AC to direct current (“DC”) to AC conversion system), a motor-generator package (AC to DC converter, DC motor and AC generator) or other suitable devices that can regulate the electricity flow through the electricity transfer device1232. The one or more electricity sources1234may be combustion turbine generators, steam turbine generators, batteries, fuel cells, solar cells, wind generators, biomass generators, hydroelectric generators or other type of electricity source. The one or more electricity sources1234generate reliable electricity during peak demand periods and are economical to purchase, lease, operate and/or maintain.

In this embodiment, the two or more available power sources106and108(FIG. 1) include a second network connection, one or more electricity sources1234, and a combination of the second network connection1230and the one or more electricity sources1234. The one or more electricity transfer devices1232are connected to the one or more electricity sources1234. The device or delivery point110(FIG. 1) includes one or more third network connections1244, the one or more third network connections1244connected to the second network connection1230and the one or more electricity transfer devices1232. In this case, the processor308(FIG. 3A) can determine whether to provide electricity from the one or more electricity sources1234to a first network connection1238connected to the one or more electricity sources1234and the one or more electricity transfer devices1232.

Now referring toFIG. 12, a block diagram showing electricity flow in and out of an electricity transfer station1220in accordance with the present invention is shown. As described inFIG. 11and indicated by arrow1240, electricity flows from the electricity delivery point1230to primarily serve one or more customer network connections1244, also referred to as a third network connection. Accordingly, the electricity customer's load is connected to the one or more customer network connections1244. The electricity flow to the electricity customer1222(FIG. 11) is represented by arrow1246.

When second electricity flow1240is less than an a first value, the one or more electricity transfer devices1232will cause a electricity to flow into the electricity transfer station1220, as indicated by arrow1248and referred to as a third electricity flow. The first value is a maximum electricity flow determined by the electricity customer1222(FIG. 11), which may be based on the contractual and/or physical limitations of the electricity customer's substation. The first value may also be the electrical customer's contractual peak demand or other peak demand limit set by the electricity transfer station1220. The amount of electricity transfer1248is controlled by the electricity transfer controller1236so that the first electricity flow1242back into the transmission network1228(FIG. 11) through electricity re-delivery point1238is the desired amount without having the second electricity flow1240exceed the first value. Whenever electricity transfer1248is insufficient to meet the desired amount for first electricity flow1242, the electricity transfer controller1236will activate and control the one or more electricity sources1234to supply the deficiency as indicated by arrow1250. As a result, the one or more electricity sources1234are used to provide additional electricity during the customer's peak demand periods when the second electricity flow1240and the third electricity flow1248(electricity transfer) cannot be increased to supply the desired amount of first electricity flow1242.

Note that the one or more electricity sources1234could be used to provide electricity back through the one or more electricity transfer devices1232or a bypass around the one or more electricity transfer devices1232to the electricity customer1222(FIG. 11). In such a case, the third electricity flow1248would be in the opposite direction and flow into the one or more third network connections1244. Thus, the one or more electricity sources1234could supply electricity to the electricity customer1222(FIG. 11) during emergency or peak conditions.

FIG. 13is a graph showing peak and off-peak demand curves1252and1254, respectively, for electricity customer1222(FIG. 11). The peak demand curve1252and off-peak demand curve1254correspond to different electricity flows (daily and/or seasonal) to the electricity customer1222(FIG. 11) represented by arrow1246(FIG. 12). Much of the time, the customer's off-peak demand curve1254is well below the contractual peak demand1256. As a result, the difference between lines1254and1256represents the available electricity that can be re-delivered without setting a new peak demand for the electricity customer1222(FIG. 11). As previously mentioned, setting a new peak demand or exceeding the contractual peak demand1256may be financially undesirable. For example, the electricity customer1222(FIG. 11) may have to pay significant excess demand charges and fees if the peak demand curve1252exceeds the contractual peak demand1256as indicated by shaded area1258. In such a case, the contractual peak demand1256is equivalent to the first value described above. But, the contractual peak demand1256may be any maximum electricity flow determined by the electricity customer1222(FIG. 11) or other peak demand limit set by the electricity transfer station1220.

As shown during peak demand periods, there is less available electricity that can be re-delivered, the difference between lines1252and1256, without setting a new peak demand for the electricity customer1222(FIG. 11). As a result, any re-delivered electricity must be sold as interruptible electricity, meaning that delivery of the re-delivery electricity cannot be guaranteed and that the electricity will probably not be available during peak demand periods in which it is most often needed. Interruptible electricity is typically sold at a discount as compared to non-interruptible or firm electricity.

Referring now toFIG. 14, a graph showing a customer off-peak demand curve1254and a total demand curve1260using the electricity transfer station1220(FIGS. 11 and 12) in accordance with the present invention is shown. As mentioned in reference toFIG. 13, the electricity transfer station1220(FIGS. 11 and 12) can transfer and re-deliver electricity, without having to generate any additional electricity, as long as the total demand curve1260is less than the first value or contractual peak demand1256. Note that the off-peak demand curve1254corresponds to arrow1246(FIG. 12) and the total demand curve1260corresponds to the second electricity flow1240(FIGS. 11 and 12). The re-delivery demand1262, which is the difference between the total demand curve1260and the off-peak demand curve1254, therefore, represents the first electricity flow1242(FIGS. 11 and 12). So, as long as the re-delivery demand1262or second value is not set too high, the electricity transfer station1220(FIGS. 11 and 12) can operate much of the time without having to generate any additional electricity.

Now referring toFIG. 15, a graph showing a customer peak demand curve1264and a total demand curve1266without using the electricity transfer station1220(FIGS. 11 and 12) in accordance with the present invention is shown. Note that the peak demand curve1264corresponds to arrow1246(FIG. 12) and the total demand curve1266corresponds to the second electricity flow1240(FIGS. 11 and 12). The re-delivery demand1268, which is the difference between the total demand curve1266and the peak demand curve1264, therefore, represents the first electricity flow1242(FIGS. 11 and 12). If the electricity transfer station1220(FIGS. 11 and 12) of the present invention is not used, the total demand curve1266or second electricity flow1240(FIGS. 11 and 12) will exceed the second value or the electricity customer's contractual peak demand56during peak demand periods, as indicated by shaded area1270. Since the advantages of the electricity re-delivery would most likely be affected if the second value or target peak demand1256, which may or may not be the contractual peak demand, is exceeded, the first electricity flow1242(FIGS. 11 and 12) must be provided as interruptible electricity. If, however, the electricity transfer station1220(FIGS. 11 and 12) of the present invention is used, the first electricity flow1242(FIGS. 11 and 12) can be provided as non-interruptible electricity.

For example,FIG. 16is a graph showing a customer peak demand curve1264and total demand curve1266using one or more electricity transfer devices1232(FIGS. 11 and 12) and one or more electricity sources1234(FIGS. 11 and 12) in accordance with the present invention. As before, the peak demand curve1264corresponds to arrow1246(FIG. 12) and the total demand curve1266corresponds to the second electricity flow1240(FIGS. 11 and 12). The electricity supplied by the one or more electricity transfer devices1232(FIGS. 11 and 12) is indicated by shaded area1272, which corresponds to electricity transfer1248(FIG. 12). The electricity supplied by the one or more electricity sources1234(FIGS. 11 and 12) is indicated by shaded area1274, which corresponds to arrow1250(FIG. 12). Thus, the combination of shaded areas1272and1274corresponds to the first electricity flow1242, which can be provided as non-interruptible electricity. Preferably, an appropriate safety factor, indicated by the difference between lines1256and1276, will be incorporated into the control of the one or more electricity transfer devices1232(FIGS. 11 and 12) and the one or more electricity sources1234(FIGS. 11 and 12) so that the contractual peak demand1256or first value is not exceeded.

Referring now toFIG. 17, a flow chart for the electricity transfer controller1236(FIGS. 11 and 12) in accordance with the present invention is shown. The electricity transfer controller1236(FIGS. 11 and 12) receives operating data from the electricity delivery point1230(FIGS. 11 and 12) and the electricity re-delivery point1238(FIGS. 11 and 12). As recognized by a person skilled in the art, the electricity transfer controller1236(FIGS. 11 and 12) will also receive data from other sources to monitor operating conditions, protective relaying, metering, check for fault or overload conditions, etc. Thereafter, the electricity transfer controller1236(FIGS. 11 and 12) will analyze the operating data in block1304and determine whether any electricity adjustments to the system need to be made in decision block1306. If no adjustments are necessary, the process loops back to block1302where new operating data is received. Note that the electricity transfer controller1236(FIGS. 11 and 12) can be programmed to provide a predefined, variable electricity flow at the electricity re-delivery point1238(FIGS. 11 and 12).

If, however, electricity adjustments are required, as determined in decision block1306, the electricity transfer controller1236(FIGS. 11 and 12) will make the appropriate adjustments as illustrated in ovals1308,1310or1312. If the second electricity flow1240(FIGS. 11 and 12) at the electricity delivery point1230(FIGS. 11 and 12) is too high, as indicated by oval1308, the electricity transfer controller1236(FIGS. 11 and 12) will decrease the electricity output of the one or more electricity transfer devices1232(FIGS. 11 and 12) in block1314and will increase the electricity output of the one or more electricity sources1234(FIGS. 11 and 12) in block1316. Thereafter, the process loops back to block1302where new operating data is received.

If the first electricity flow1242(FIGS. 11 and 12) at the electricity re-delivery point1238(FIGS. 11 and 12) is too high, as indicated by oval1310, the electricity transfer controller1236(FIGS. 11 and 12) will determine whether the one or more electricity sources1234(FIGS. 11 and 12) are on in decision block1318. If one or more electricity sources1234(FIGS. 11 and 12) are not on, the electricity transfer controller1236(FIGS. 11 and 12) will decrease the electricity output of the one or more electricity transfer devices1232(FIGS. 11 and 12) in block1320. If, however, the one or more electricity sources1234(FIGS. 11 and 12) are on, as determined in decision block1318, the electricity transfer controller1236(FIGS. 11 and 12) will decrease the electricity output of the one or more electricity sources1234(FIGS. 11 and 12) in block1322. Thereafter, the process loops back to block1302where new operating data is received.

If the first electricity flow1242(FIGS. 11 and 12) at the electricity re-delivery point1238(FIGS. 11 and 12) is too low, as indicated by oval1312, the electricity transfer controller1236(FIGS. 11 and 12) will determine whether the second electricity flow1240(FIGS. 11 and 12) at the electricity delivery point1230(FIGS. 11 and 12) can be increased in decision block1324. If the second electricity flow1240(FIGS. 11 and 12) at the electricity delivery point1230(FIGS. 11 and 12) cannot be increased, the electricity transfer controller1236(FIGS. 11 and 12) will increase the electricity output of the one or more electricity sources1234(FIGS. 11 and 12) in block1326. If, however, the second electricity flow1240(FIGS. 11 and 12) at the electricity delivery point1230(FIGS. 11 and 12) can be increased, as determined in decision block1324, the electricity transfer controller1236(FIGS. 11 and 12) will increase the electricity output of the one or more electricity transfer devices1232(FIGS. 11 and 12) in block1328. Thereafter, the process loops back to block1302where new operating data is received.

Now referring toFIG. 18, a one-line diagram of one possible implementation of the present invention is shown. A wholesale power customer substation1402is connected to a transmission system1238via transmission line1406. A step-down transformer1410is connected to the transmission line1406via breaker1408. The breaker1408can be isolated with switches1416and1418; whereas the step-down transformer1410can be isolated with switches1418and1420. A meter1422at the electricity delivery point1230or the second network connection records the second energy flow from the step-down transformer1410. Meter1422is connected between the step-down transformer1410and the substation distribution bus1424.

Four distribution feeders1432,1434,1436and1438are connected to the substation distribution bus1424via circuit reclosers1440,1442,1444and1446respectively. Thus electricity is distributed to the wholesale customer's system via distribution feeders1432,1434,1436and1438. Distribution feeders1432,1434,1436and1438represents the one or more third network connections1244(FIG. 12). Circuit recloser1440can be isolated with switches1448and1450, and bypassed with fuse1452and switch1454. Circuit recloser1442can be isolated with switches1456and1458, and bypassed with fuse1460and switch1462. Circuit recloser1444can be isolated with switches1464and1466, and bypassed with fuse1468and switch1470. Circuit recloser1446can be isolated with switches1472and1474, and bypassed with fuse1476and switch1478.

The electricity transfer station1404is connected to the wholesale power customer's substation1402via a distribution bus or line1480. More specifically, the distribution bus or line1480is connected to the substation distribution bus1424via circuit recloser1482. Circuit recloser1482can be isolated with switches1484and1486, and bypassed with fuse1488and switch1490. The electricity flow through the distribution bus or line1480is measured by meter1492. A phase shifting/regulating transformer1494is connected between the distribution bus or line1480and transfer bus1502. Phase shifting/regulating transformer1494or some other electricity transfer devices, causes electricity to flow through distribution bus or line1480. Phase shifting/regulating transformer1494can be isolated with switches1496and1498or bypassed with switch1500.

The electricity transfer station1404is also connected to the transmission system148via transmission line1504. Step-up transformer1506is connected between transmission line1504and transfer bus1502. Step-up transformer1506can be isolated with switches1508and1510. A meter1512is connected between the step-up transformer1506and the transfer bus1502, which corresponds to the electricity re-delivery point1238or first network connection.

A first generation bus1514is connected to transfer bus1502via step-up transformer1516and a switch1518. A first generator1520is connected to the first generation bus1514via breaker1522and switch1524. A second generator1526is connected to the first generation bus1514via breaker1528and switch1530. Similarly, a second generation bus1532is connected to transfer bus1502via step-up transformer1534and a switch1536. A third generator1538is connected to the second generation bus1532via breaker1540and switch1542. A fourth generator1544is connected to the second generation bus1532via breaker1546and switch1548.

Now referring toFIG. 19, a block diagram showing electricity flow in and out of an electricity transfer station1600in accordance with another embodiment of the present invention is shown. As inFIG. 11, the electricity transfer station1600is connected to an electricity customer1222, and to one or more electricity suppliers1224and other electricity customers1226via a transmission network1228. The electricity customer1222, which may be a large commercial or industrial customer, rural electric cooperative or municipality, purchases electricity from an electricity supplier(s)1224via the transmission network1228at an electricity delivery point1230, also referred to as a second network connection. The electricity delivery point1230can be at nominal transmission voltages, such as 69 kilovolts (“KV”), 138 KV, 230 KV or 345 KV, or at a distribution voltage, such as 15 KV or 25 KV. Although these voltages are commonly used, the present invention can be designed to operate at any desired voltage. Note also that the electricity customer's metering point may not be at the same point as the electricity delivery point1230. For example, the delivery voltage may be at 138 KV, but the metering point may be at 25 KV because the metering equipment is less complex and expensive. Adjustments are then made to convert the metering data to a 138 KV equivalent.

The electricity delivery point1230will typically be located in or near a substation. The ownership of the equipment in the substation will depend on the contractual agreement between the owner of the transmission network1228, the electricity supplier(s)1224and the electricity customer1222. Typically, the substation will contain circuit breakers, step-down transformers, metering equipment, distribution circuit breakers/reclosers, switches and various protective and metering devices. The electricity transfer station1600of the present invention is typically installed within or next to the electricity customer's substation. Accordingly, the capacity of the electricity transfer station1600is affected by the ratings of the equipment within the substation and by any restrictions imposed by the electricity customer1222, including but not limited to a maximum electricity flow at the electricity delivery point1230.

The electricity transfer station1600includes one or more electricity transfer devices1232, an electricity transfer controller1236and an arbitrage controller102. The arbitrage controller102can be physically located with the electricity transfer controller1236, integrated within the electricity transfer controller1236, or located at a remote location. The electricity transfer station1600is connected to the transmission network1228or some other transmission network at the electricity re-delivery point1238, also referred to as a first network connection. As indicated by arrow1240, also referred to as a second electricity flow, electricity flows from the transmission network1228through electricity delivery point1230to the electricity customer1222and the electricity transfer station1600. As indicated by arrow1242, also referred to as a first electricity flow, electricity flows from the electricity transfer station1600through electricity re-delivery point1238to the transmission network1228.

The one or more electricity transfer devices1232may be a phase-shifting transformer, a static transfer device (AC to direct current (“DC”) to AC conversion system), a motor-generator package (AC to DC converter, DC motor and AC generator) or other suitable devices that can regulate the electricity flow through the electricity transfer device1232.

As indicated by arrow1240, electricity flows from the electricity delivery point1230to primarily serve one or more customer network connections1244, also referred to as a third network connection. Accordingly, the electricity customer's load is connected to the one or more customer network connections1244. The electricity flow to the electricity customer1222is represented by arrow1246.

When second electricity flow1600is less than an a first value, the one or more electricity transfer devices1232will cause a electricity to flow into the electricity transfer station1600, as indicated by arrow1248and referred to as a third electricity flow. The first value is a maximum electricity flow determined by the electricity customer1222, which may be based on the contractual and/or physical limitations of the electricity customer's substation. The first value may also be the electrical customer's contractual peak demand or other peak demand limit set by the electricity transfer station1600. The amount of electricity transfer1248is controlled by the electricity transfer controller1236so that the first electricity flow1242back into the transmission network1228through electricity re-delivery point1238is the desired amount without having the second electricity flow1240exceed the first value.

While the making and using of various embodiments of the present invention have been described in detail, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and does not limit the scope of the invention. It will be understood by those skilled in the art that various modifications can be made therein without departing from the spirit and scope of the invention as set forth in the appended claims