This application is being filed on 26 July 2013, as a PCT International Patent application and claims priority to U.S. Patent Application Serial No. 61/675,878 filed on 26 July 2012, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

[001] Over the past few years technological innovations, changing economic conditions, changing regulatory environments, shifting of environmental conditions, and social priorities have spurred interest in Distributed Generation (DG) systems. Distributed Generation is a new model for power systems that is based on the integration of small and medium-sized generators into a utility grid. Such generators may be associated with new and renewable energy technologies, such as solar, wind, and fuel cells, into the utility grid. The generators may be

interconnected through a fully interactive intelligent electricity network. Most DG resources are primarily used to supplement the traditional electric power systems. For example, DG resources can be combined to supply nearby loads in specific areas with continuous power during disturbances and interruptions of the main utility grid.

[002] Conventional distributed and centralized renewable energy sources are hard to predict and their energy performance is highly correlated with weather parameters. The dynamic nature of the weather parameters raises a concern regarding the amount of energy expected to be generated from different renewable energy sources, and prevents utilities and customers from investing in this field, and harness free energy.

[003] The increased power fluctuations, resulting from the dynamic weather conditions is placing more demand for ancillary services, such as power regulation services. Power regulation services track and minimize moment to moment fluctuations in load and generation, as well as maintain a constant frequency. The power regulation service is traditionally provided by conventional generators such as steam and gas turbines. However, due to slow response time and limited ramp rates, the conventional generators are increasingly challenged to meet the needs of a system with a growing capacity of intermittent generation sources such as wind and solar.

SUMMARY OF THE INVENTION

[004] Systems and methods for managing electrical distribution system are provided. Energy storage devices, having a control unit are provided. The control unit is configured to enable the energy storage device to provide ancillary services to the electrical distribution system. An aggregator may be configured to receive a charge status from the energy storage devices. The aggregator may further receive electrical

characteristics data of the electrical distribution network. The aggregator may determine, based on the received charge status and the electrical characteristics data, at least one energy storage device, to provide the ancillary services to the electrical distribution network. The aggregator may send instructions to the control unit of the at least one energy storage device to enable the at least one energy device to provide the ancillary services. BRIEF DESCRIPTION OF THE DRAWINGS

[005] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate various embodiments of the present invention. In the drawings:

[006] FIG. 1 is a diagram of a system for managing electrical distribution system;

[007] FIG. 2 is diagram of smart storage energy module (SSEM);

[008] FIG. 3 is a diagram illustrating an architecture of a system for providing ancillary services to an electrical distribution system;

[009] FIG. 4 is flow diagram of a method for providing ancillary services to an electrical distribution system; and

[0010] FIG. 5 is another flow diagram of a method for providing ancillary services to an electrical distribution system.

DETAILED DESCRIPTION

[0011] The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar elements. While embodiments of the invention may be described, modifications, adaptations, and other implementations are possible. For example, substitutions, additions, or modifications may be made to the elements illustrated in the drawings, and the methods described herein may be modified by substituting, reordering, or adding stages to the disclosed methods. Accordingly, the following detailed description does not limit the invention. Instead, the proper scope of the invention is defined by the appended claims.

[0012] Systems and methods for managing electrical distribution system are provided. More specifically systems and methods of providing power regulation services to an electricity distribution system are provided. The systems may include a plurality smart storage energy module (SSEM) distributed along the electrical distribution system. Each of the plurality of SSEM may include an energy storage device, a battery management system, and a control unit. The control unit may include a communication unit configured to communicate with an aggregator. The aggregator may be configured to receive electrical characteristics data of the electrical distribution system and status of charge of the plurality of SSEM. Based on the received electrical characteristics data, the aggregator may be configured to select a SSEM and send instructions to the control unit of the SSEM to commission the SSEM to provide ancillary services to the electrical distribution system. Based on the received instructions, the control unit of the SSEM may configure the energy storage device to provide up or down regulation to the electrical distribution system via a power conversion unit.

[0013] FIG. 1 is a schematic diagram of a system 100 where embodiments of the disclosure may be employed. As an example, system 100 may be an electrical power distribution system. As shown in FIG. 1 , the system 100 may include one or more smart storage energy modules (SSEM) 102a, 102b, 102c (collectively referred to as SSEM 102), one or more aggregators 104a, 104b, 104c (collectively referred to as aggregator 104), one or more energy resources (ERs) 106a, 106b, 106c (collectively referred to as ER 106), and a Network Operations Center (NOC) 108.

[0014] SSEM 102 may be a device configured to provide ancillary services to the electrical distribution system. As an example, SSEM 102 may be configured to absorb or inject active and reactive power to the electrical distribution system when commissioned. Although the system 100 of FIG.1 is shown to include only three SSEM 102a, 102b and 102c, it will be apparent to those skilled in the art that system 100 may include any number of aggregators. An electrical distribution system, such as system 100, may include multiple SSEM 102 spread across the grid. As an example, SSEM 102 may be placed throughout the grid based on local load conditions, type of local load, etc. Each SSEM 102a, 102b, and 102c may be pole mounted and configured to communicate with at least one aggregator 104a, 104b, and 104c. SSEM 102 may communicate with aggregator 104 either directly or indirectly (hoping through another SSEM). SSEM 102 is described in detail with respect to FIG. 2 of this disclosure.

[0015] Aggregator 104 may be a device configured to manage power regulation in the electrical distribution system. Aggregator 104 may be configured to receive electrical characteristic data of the electrical distribution system. As an example, aggregator 104 may receive the electrical characteristics data from NOC 108, an energy market system, and grid management system, such as SCADA. Aggregator 104 may analyze the electrical characteristics data to determine if the electrical distribution system requires power regulation. Aggregator 104 may further be configured to receive notification for power regulation from the grid management system. If the electrical distribution system does require power regulation, aggregator 104 may interact with the SSEM 102 to provide the required power regulation. A method of providing power regulation is described with reference to FIG. 4 and FIG. 5.

[0016] Although the system 100 of FIG.1 is shown to include only three aggregators 102a, 102b and 102c, it will be apparent to those skilled in the art that system 100 may include any number of aggregators. A number of aggregators installed in an electrical distribution system may depend on a number of SSEM 102, types of SSEM 102, geographical distribution of SSEM 102, range of communicator on SSEM 102, if communicator is a wireless device, range of aggregator 104, if aggregator 104 is a wireless device, etc. One aggregator may be able to collect energy generation and other telemetry data from a predetermined number of SSEM 102.

Aggregator 104 may be further configured to act as a relay point to facilitate delivery of the energy generation data and other telemetry data from ER 106 to NOC 108. NOC 108 may be a computer system having a memory and a processor. The functionalities of aggregator 104 are described in detail with respect to FIG. 3 and FIG. 4 in the later parts of the description.

[0017] ER 106 may include either traditional energy resources or renewable energy sources, or both traditional and renewable energy resources. As an example, ER 106 may include, but not limited to fossil fuels, nuclear, hydro, wind, photovoltaic, batteries, and geo-thermal based energy resources. The energy generated from ER 106 may be consumed locally, i.e. within premises of ER 106, or may be supplied to an electrical distribution system by connecting ER 106 to the electrical distribution system. Each Energy Resource 106 may be configured to report the amount of energy generated by it to the aggregator 104 and NOC 108.

[0018] In one embodiment, each ER 106 may be configured to communicate, either directly or indirectly (hoping through another ER), with aggregator 104. ER 106 may be able to communicate with aggregator 104 through a first communication system (not shown). The first communication system may include ZigBee, WiFi, power-line communications, GSM, Fiber, or any other reliable communication protocol. Each ER 106 may include a device, for example an electricity metering device, configured to measure an amount of energy being produced by the ER. The measured energy generation data may be temporarily stored on a local memory at the ER with an associated time stamp.

[0019] FIG 2 is a diagram illustrating SSEM 102. As shown in FIG. 2, SSEM 102 may include a plurality of energy storage devices (ESDs) 202a, 202b (collectively referred to as ESD 202). ESDs 202a, 202b, and 202c may be connected to each other through a DC bus 204, either in series or in parallel or in combination of series and parallel. SSEM 102 may further include a battery management system (BMS) 206 configured to manage ESD 202, and a control unit 208 configured to control commissioning and decommissioning of ESD 202 to the electrical distribution system. SSEM 102 may be connected to the electrical distribution system through AC contactor 214.

[0020] ESD 202 may be energy storage devices configured to store energy and decimate the stored energy. ESD 201 may be configured to store or decimate energy by control unit 208. ESD 202 may include one or more electrochemical cells that convert stored chemical energy into electrical energy, and vice versa. As an example, ESD 202 may be at least one of galvanic cells, electrolyte cells, fuel cells, flow cells, and voltaic piles.

[0021] ESD 202 may be connected to BMS 206 through DC bus 204. BMS 206 may be configured to monitor status of charge (SOC) and other operating parameters of ESD 202. As an example, BMS 206 may be configured to determine a charging rate, and a discharging rate of ESD 202. As another example, BMS 206 may be configured to manage transition between charging modes, and monitor charge discharge rate limits for ESD 202. In addition, BMS 206 may be configured to protect ESD 202 from over charging and under charging. BMS 206 may communicate with control unit 208.

[0022] Control unit 208 may configured to control commissioning and decommissioning of ESD 202 to the electrical distribution system. As an example, control unit 208 may be configured to commission/decommission ESD 202 to the electrical distribution system based on control signals received from aggregator 104. Control unit 208 may further be configured to provide SOC of ESD 202 to aggregator 104. Control unit 208 may be configured to communicate with aggregator 104 through communication module 216. Control unit 208 may include control and data acquisition module 210 and a power conversion module 212.

[0023] Control and data acquisition module 210 may be configured to receive control signals from aggregator 104. Control and data acquisition module 210 may further be configured to receive status of charge (SOC) data of ESD 202, charging rate of ESD 202, and discharging rate of ESD 202 from BMS 206. Based on received control signals from aggregator 104 and SOC data from BMS 206, control and data acquisition module 210 may be configured to generate control signals to power conversion unit 212. As an example, control and data acquisition module 210 may generate control signals to power conversion unit 212 to configure SSEM 102 to provide active power to the electrical distribution system. As another example, control and data acquisition module 210 may generate control signals to power conversion unit 212 to change a rate of discharge or a rate of charge based on reports from BMS 206.

[0024] Power conversion unit 212 may be configured to control flow of energy to and from ESD 202. As an example, power conversion unit 212, depending based on control signals received from control and data acquisition unit 210, may commission ESD 202 either in charging mode or discharging mode. As an example, power conversion unit may commission ESD 202 to absorb reactive power from the electrical distribution system to stabilize power factor. As another example, power conversion unit 212 may commission ESD 202 to provide active power to the electrical distribution system to support load balancing. Power conversion unit 212 may include a bi-direction AC/DC inverter/charger.

[0025] Communication module 216 may be configured to enable exchange of messaged between SSEM 102 and aggregator 104.

Communication module 216 may include ZigBee, WiFi, power-line communications, GSM, Fiber, or any other reliable communication protocol. Communication module 216 may include a memory device to temporarily store control signals received from aggregator 104 and SOC received from BMS 206. Communication module 216 may further include a receiver and a transmitter. The receiver may be configured to receive data from aggregator 104. The transmitter may be configured to send data to aggregator 104, and forward the SOC received from BMS 206 to aggregator 104.

[0026] FIG. 3 illustrates system architecture of SSEM 102 deployment in electrical distribution system. Multiple units of SSEM 102 may be distributed along a distribution system, preferably near to loads. Each SSEM 102 unit is configured to communicate with an aggregator 104, responsible for grouping and encapsulation of SSEM 102 deployment as a single harmonious system through a low bandwidth communication network.

[0027] As shown in FIG. 3, aggregator 104 may include a market interface engine 302 and an aggregation engine 304. Aggregator 104 may include a separate box that hosts market interface engine 302 and aggregation engine 304. Aggregation engine 302 may be configured to summarize performance data and status updates for presentation to a energy market system 306, and to NOC 108. Aggregation engine 302 may further be configured to distribute the regulation work load to the individual SSEM 102 units to most efficiently satisfy market commitments.

[0028] Market interface engine 304 may also be hosted on aggregator 104, and may be responsible for interfacing with the ISO/RTO energy market system 306 or other supervisory systems, which may be a standard interface provided by ISO/RTO to facilitate integration of resources into its market. Market interface engine 304 may send bids and operating reports, and receive prices and regulation commands from the ISO/RTO energy market system in certain format over a communication network such as the Internet connection.

[0029] Network Operations Center (NOC) 108 may be leveraged to provide support to the system, and maximize its up-time. NOC 108 may fetch weather data from online services and forward to market interface engine 306. NOC 108 may further monitor the operating data of the system, collect diagnostic information, and send firmware upgrades when necessary. A method for providing ancillary services to the electrical distribution system using system architecture of FIG. 3 is described with reference to FIG. 4 and FIG. 5.

[0030] FIG. 4 is a flow diagram illustrating a method 400 for providing ancillary services to an electrical distribution system. The method 400 may be implemented at aggregator 104 or a computing device accessible to aggregator 04. As an example method 400 may be implemented at NOC 108.

[0031] At block 402 of FIG. 4, charge status from energy storage units may be received. The charge status may include an amount of charge available on the energy storage units. As an example, aggregator 104 may receive charge status from all SSEM 102 within its domain. Control unit 208 may be configured to communicate the charge status to aggregator 104.

[0032] At block 404, electrical characteristics data of the electrical distribution system may be received. The electrical characteristics data may include a power factor, power demand on the electrical distribution system, power supply to the electrical distribution system, access power available on the electrical distribution system, shortage of power on the electrical distribution system, cost of electric power in the energy market, etc. The electrical characteristics data may be received from various sources, such as NOC 108, energy market 306, an electrical distribution system management and control center, etc.

[0033] At block 406, a type of ancillary service to be provided to the electrical distribution system may be determined. The type of ancillary service to be provided may be determined based on the received electrical characteristics data of the electrical distribution system. As an example, based on the power factor of the electrical distribution system, it may be determined either to inject or absorb reactive power to the electrical distribution system. As another example, based on the rate of power in the energy market, and demand and supply data from the electrical distribution system, it may be determined to inject or absorb real power in the electrical distribution system.

[0034] At block 408, at least one energy source may be elected to provide ancillary service to the electrical distribution system. The energy source may be elected based on the type of ancillary service to be provided to the electrical distribution system and the charge status of the energy sources. The identified energy source may be commissioned to provide the ancillary service to the electrical distribution system by sending control signals to the control unit configured to control the energy source. The election and commissioning/decommissioning of the energy source is described in detail with reference to FIG. 5 below.

[0035] FIG. 5 is a flow diagram illustrating a method 500 for providing ancillary services to the electrical distribution system. Method 500 may be implemented at aggregator 104 or a computing device connected to aggregator 104.

[0036] At block 502 of FIG. 5, electrical characteristics data from utility grid, such as an electrical distribution system may be received. The electrical characteristics data may be received from grid management systems such as SCADA.

[0037] At block 504, charge status from SSEM 102 may be received. Charge status may be received from each of the SSEM 102. At block 506, type of ancillary services to be provided to the electrical distribution system may be determined. The type of ancillary services to be provided to the electrical distribution system may be determined based on the received electrical characteristics data.

[0038] At block 508, up/down regulation may be determined. The up/down regulation may be determined based on the determination of the type of ancillary service to be provided to the electrical distribution system. As an example, if the type of ancillary service to be provided requires providing active power to the electrical distribution system, it may be determined to be up regulation service. Similarly, if the type of ancillary service to be provided to the electrical distribution system requires absorbing real power, then it may be classified as down regulation service.

[0039] If the ancillary service is classified as down regulation service, method 500 may proceed to block 510a. At block 510a, a pool of energy source may be elected to provide the ancillary service. The pool of energy sources may be elected based on type of ancillary service to be provided to the electrical distribution system and the status of charge on the energy source. As an example, a group of energy sources with charge status approximately in between 20% to 60% having a minimum power rating of 100kw may be elected to provide down regulation service.

[0040] At block 512a, status of charge of the elected energy sources may be monitored continuously. The status of charge may be received from the BMS 206. If there is an energy source with status of charge greater than 60%, at block 514a, such energy source may be removed from the pool. Furthermore, if there is another energy resource outside the pool with charge status between 20% and 60% may be added to the pool to replace the removed energy source. If multiple energy sources are available for replacement, the energy source having a lower charge status may be preferred.

[0041] At block 508, if type of ancillary services is identified as up regulation service, method 500 may proceed to block 510b. As an example, the ancillary service may be identified as to provide real power to the utility grid. At block 510b, a pool of energy source may be elected to provide the up regulation to the utility grid. As an example, a group of energy sources with charge status approximately in between 60% to 100% having a minimum power rating of 100kw may be elected to provide the up regulation service.

[0042] At block 512b, status of charge of the elected energy sources may be monitored continuously. The status of charge may be received from the BMS 206. If there is an energy source with status of charge less than 60%, at block 514b, such energy source may be removed from the pool. Furthermore, if there is another energy resource outside the pool with charge status more than 60% may be added to the pool to replace the removed energy source. If multiple energy sources are available for replacement, the energy source having a higher charge status may be preferred.

[0043] At block 516, method 500 may update a report of the regulation service to a monitoring point, preferably to aggregator 104.

Aggregator 104 may be configured to monitor the status of charge of energy sources involved in providing the ancillary services to the utility grid as well as electrical characteristics of the utility grid.

[0044] At block 518, method 500 may determine if there is a change in regulation for the utility grid. As an example, method 500 may identify if the utility grid still requires up regulation, down regulation or no regulation at all. If the utility grid still requires down regulation, method 500 may loop back to block 512a. If the utility grid requires up regulation, method 500 may loop back to block 512b. If the utility grid requires further regulation, method 500 may loop back to block 506.

[0045] According to embodiments of the disclosure, the disclosed methods and systems may provide redundancy for the ancillary service support to the electrical distribution system. As an example, in case of a single unit failure or loss of communications, the aggregation engine may dispatch standby units to provide the planned ancillary services. In addition, the redundancy may allow the aggregation engine to shuffle.

[0046] Energy storage devices in and out of the committed pool of resources committed to a given ancillary service to ensure uninterrupted support of that service. For example, in frequency regulation applications and during regulation down intervals, which correspond to having the energy storage devices absorb power (charging state), aggregator may continuously monitor the state of charge (SOC) of the energy storage devices to determine which energy storage device have reached full state of charge (100% SOC) and thus need to be removed from the aggregation resource pool. Those units may be replaced with other available energy storage devices with SOC less than 100%. In addition, aggregator 104 may allocate the energy storage devices to intervals of up regulation (discharge state) or to other ancillary service requiring power injection into the utility grid to reduce their state of charge. An optimal cost function may be implemented to maximize the potential revenue of these resources. An optimal cost function may analyze a spot prize of the energy in the energy market received from energy market interface, a cost of energy generation, a cost of energy transmission from generating sources, etc. Based on the analysis of various parameters, the optimal cost function may determine whether to charge/discharge batteries, or purchase/sale power in the energy market.

[0047] According to embodiments of the disclosure, SSEM 102 may accelerate the photo-voltaic (PV) deployments. In addition SSEM 102 may enable distribution utilities to proactively manage grid effects caused by renewable generation intermittency. As an example, SSEM 102 may leverage existing smart grid communications, network operations center (NOC), and command-and-control capabilities to integrate SSEM 102 into deregulated electricity markets. Furthermore distributed deployment of SSEM 102 may provide increased reliability and system redundancy. As an example, the ability of the system to accommodate unit failure by shifting the operating burden to other units while maintaining normal function may provide the reliability and redundancy.

[0048] According to embodiments of the disclosure, SSEM 102 may be tied directly into the electric grid and may be installed on existing assets such as utility and streetlight poles. SSEM 02 may be installed on secondary circuits near customers' loads. No upgrades may be required in the distribution system thereby eliminating any grid interconnection issues. In addition, SSEM 02 may be suitable for incremental deployment and immediate commission in the electrical distribution system. As an example, the system aggregated power may be increased incrementally with time due to the distributed decentralized nature. Moreover SSEM 102 may be designed to work as a plug and play device. The incremental increase in capacity may be deployed and commissioned quickly to realize the return on investment immediately.

[0049] In addition to providing ancillary services to the electrical distribution system, distributed SSEM 102 may reduce transmission and distribution (T&D) line losses. As example, when SSEM 102 is installed throughout the secondary distribution system of the utility grid, the power drawn from the T&D system may be kept yielding a reduction in the T&D losses because the power -both real and reactive- is generated very close to the load.

[0050] Embodiments of the invention may be practiced in an electrical circuit comprising discrete electronic elements, packaged or integrated electronic chips containing logic gates, a circuit utilizing a microprocessor, or on a single chip containing electronic elements or microprocessors. Embodiments of the invention may also be practiced using other technologies capable of performing logical operations such as, for example, AND, OR, and NOT, including but not limited to mechanical, optical, fluidic, and quantum technologies. In addition, embodiments of the invention may be practiced within a general purpose computer or in any other circuits or systems.

[0051] Embodiments of the invention, for example, may be implemented as a computer process (method), a computing system, or as an article of manufacture, such as a computer program product or computer readable media. The computer program product may be a computer storage media readable by a computer system and encoding a computer program of instructions for executing a computer process. The computer program product may also be a propagated signal on a carrier readable by a computing system and encoding a computer program of instructions for executing a computer process. Accordingly, the present invention may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.). In other words, embodiments of the present invention may take the form of a computer program product on a computer- usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. A computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. [0052] The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical,

electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific computer-readable medium examples (a non-exhaustive list), the computer-readable medium may include the following: an electrical connection having one or more wires, a portable computer diskette, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, and a portable compact disc read-only memory (CD-ROM). Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

[0053] Embodiments of the present invention, for example, are described above with reference to block diagrams and/or operational illustrations of methods, systems, and computer program products according to embodiments of the invention. The functions/acts noted in the blocks may occur out of the order as shown in any flowchart. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionalities/acts involved.

[0054] While the specification includes examples, the invention's scope is indicated by the following claims. Furthermore, while the specification has been described in language specific to structural features and/or methodological acts, the claims are not limited to the features or acts described above. Rather, the specific features and acts described above are disclosed as example for embodiments of the invention.