WO2018055594A1

WO2018055594A1 - Micro-grid having a hybrid battery-supercapacitor power storage system and control method therefor

Info

Publication number: WO2018055594A1
Application number: PCT/IB2017/055824
Authority: WO
Inventors: Giandomenico Testi
Original assignee: Abb Schweiz Ag
Priority date: 2016-09-26
Filing date: 2017-09-26
Publication date: 2018-03-29

Abstract

In aspects, the present invention discloses a method (400) for controlling and operating a power storage subsystem (110) in a micro grid. The method comprises receiving power generation profile of a first power generation source (111) and power demand profiles of the one or more electrical loads (130) connected to the first power generation source (111), from a historian server; determining a combination of battery modules (113) and supercapacitor modules (116) for supporting a first power generation source (111) based on the power generation profile of the first power generation source (111) and power demand profiles of one or more electrical loads (130) connected to the first power generation source (111), and operating the power storage subsystem (110) based on combination of battery modules (113) and supercapacitor modules (116) in a first ratio for supporting a first power generation source (111).

Description

MICRO-GRID HAVING A HYBRID BATTERY-SUPERCAPACITOR

POWER STORAGE SYSTEM AND CONTROL METHOD THEREFOR

FIELD OF INVENTION

[0001] The present invention relates to micro-grids and more specifically to a micro- grid having a hybrid battery-supercapacitor and operation of the hybrid battery- supercapacitors.

BACKGROUND

[0002] In a number of countries, electrical loads may suffer from unavailability of public electric supply for long periods, and poor quality of power supply such as unstable supply voltage, harmonics, high losses, etc., and undeveloped distribution grids geographical reach such that sustainable supply of power to the loads is not effectively achieved. As a consequence, residential, commercial and industrial loads are jeopardized in achieving a continuity and quality of supply which is necessary for their operation. Resort to islanded diesel generation has been historically the solution to the above mentioned problems.

[0003] Since recently, more affordable prices in solar -based generation, wind power and other renewables have opened up opportunities for alternative economic options which additionally have minimal environmental impact. It is common to find such power source options provided in a Micro-grid environments. Micro-grids, are localized grids (or electrical networks) which can operate autonomously and are capable of optionally connecting and disconnecting with the traditional grids.

[0004] Micro-grids includes automation systems for power management, for effective powering of various loads connected to the micro-grid through the various power sources connected to the micro-grid, in addition to operating with connection to a public electric distribution network or managing power in an island operation. As commonly micro-girds rely on renewable source energy for power generation and since renewable source energy is intrinsically stochastic both in time and in amount, there exists a need to store surplus energy versus load consumption over time.

[0005] In this regard it important to note electrochemical battery storage is well established and continues to make substantial progress by increasing efficiencies as well by enhancing the technology portfolio. However, storage costs are still at the border of viability and return of investment depends on specific situations and cannot be generalized.

[0006] Moreover, in conventional micro-grids, battery storage solutions are rated/specified according to the observed/expected maximum difference between highest peaks in output power generated and lowest load power requirements. This often leads to usage of batteries having large capacities, which are not cost effective.

[0007] Moreover, due to transient and frequent / large fluctuations in output power from renewable sources and load power requirements, battery storages are often subject to multiple fast charging and discharging shallow cycles. The transients and large fluctuations are also common for small industries and household loads, which particularly need to be considered for micro-grid applications for a small set of loads / consumers supported with low capacity power generation sources.

[0008] Such fluctuations may not be beneficial to the battery lifecycle and thus to the battery life expectancy. Thus, battery storage would need to be designed in consideration of the energy balance, the power transients and the associated impact on the life of the battery. Sometimes this may lead to a complex tradeoff. Additionally, upon change in power sources or loads (e.g. additions, removal or long-term nonfunctional/seasonal power sources) the initial design of the battery storage may not be optimal. [0009] There have been several approaches which have attempted to solve the problems mentioned above. However, there is a need for an improved system and method that solves the problems mentioned above.

SUMMARY OF THE INVENTION

[0010] The above-mentioned shortcomings, disadvantages and problems are addressed herein which will be understood by reading and understanding the following specification.

[0011] The present invention discusses the usage of supercapacitors along with battery storage and its management in a micro-grid environment.

[0012] In one aspect, the present invention discloses a method for controlling and operating a power storage subsystem in a micro grid. The micro grid comprises electrical loads electrically connectable to the power storage subsystem, and power generation sources. The power storage subsystem comprises one of more battery modules and one or more super-capacitor modules electrically connectable to the one or more battery modules via one or more electrical equipment.

[0013] The method comprises receiving at least one of power generation profile of a first power generation source and power demand profiles of the one or more electrical loads connected to the first power generation source, from a historian server; determining a first combination of battery modules and supercapacitor modules in a first ratio for supporting a first power generation source based on at least one of a power generation profile of the first power generation source and power demand profiles of one or more electrical loads connected to the first power generation source; and operating the power storage subsystem based on first combination of battery modules and supercapacitor modules in a first ratio for supporting a first power generation source, wherein operating the power storage subsystem includes one of receiving power from the first power generation source and supplying power to the one or more electrical loads connected to the first power generation source.

[0014] In an embodiment, the power generation profile of the first power generation source is determined by the server based on a first set of measurements from a first set of sensors measuring a plurality of electrical parameters associated with the first power generation source, and a second set of measurements from a second set of sensors measuring a plurality of non-electrical parameters associated with the first power generation source.

[0015] In an embodiment, the controller of the power storage subsystem is configured to coordinate with a central controller for determining the first combination of battery modules and supercapacitor modules in the first ratio, based on meteorological information associated with a location of the first power generation source. In another embodiment, the controller of the power storage subsystem is configured to coordinate with a central controller for determining the first combination of battery modules and supercapacitor modules in the first ratio, based on one of power tariff information of a traditional power grid and electrical information of section of a second micro -grid, wherein an electrical bus of the section of the second micro-grid is electrically connectable to the one or more electrical loads of the micro-grid for supplying power.

[0016] The plurality of non-electrical parameters associated with the power generation source includes at least one of solar light intensity, temperature of the power generation source, and wind velocity.

[0017] In another aspect, the present invention discloses a control system for controlling one or more power storage subsystems in a section of the micro grid, the micro grid comprising one or more electrical loads electrically connectable to the one or more power storage subsystems, and one or more power generation sources, a first set of sensors for measuring a plurality of electrical parameters associated with the power generation sources and the electrical loads, and a second set of sensors for measuring a plurality of non-electrical parameters associated with the one or more power generation sources.

[0018] The control system comprises one or more controllers for controlling the one or more power storage subsystems; and a server connectively coupled to the one or more controllers. The historian server stores one or more power generation profiles of the power generation sources and one or more power demand profiles of the electrical loads.

[0019] At least one power storage subsystem comprises one of more battery modules and one or more super-capacitor modules electrically connectable to the one or more battery modules via one or more electrical equipment. The controller of the at least one power storage subsystem determines a first combination of battery modules and supercapacitor modules in a first ratio based on at least one of a power generation profile of a first power generation source and power demand profiles of one or more electrical loads connected to the first power generation source, for operating the at least one power storage subsystem for supporting the first power generation source.

[0020] In an embodiment, the controller associated with the control of the at least one power storage subsystem is configured to determine an electrical configuration for connecting the one or more battery modules and the one or more super-capacitors based on the determined combination of battery modules and supercapacitor modules in a first ratio, and operate the electrical equipment for connecting the battery modules and the supercapacitor modules according to the determined electrical configuration.

[0021] Systems and methods of varying scope are described herein. In addition to the aspects and advantages described in this summary, further aspects and advantages will become apparent by reference to the drawings and with reference to the detailed description that follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 illustrates a section of micro-grid having modular power generation subsystems connected to an exemplary load, in accordance with various embodiments of the present invention;

[0024] Figure 2 is a graphical representation of actual and average power generation output and power demand profile in an exemplary section of the micro-grid, in accordance with various embodiments of the present invention; and

[0025] Figure 3 illustrates a section of micro-grid having modular power generation subsystems connected to an exemplary load, in accordance with various embodiments of the present invention; and

[0026] Figure 4 illustrates a method for controlling and operating a power storage subsystem in the section of the micro-grid, in accordance with various embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0027] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments, which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken in a limiting sense.

[0028] The present invention discusses the usage of supercapacitors along with battery storage and its management in a micro-grid environment. Supercapacitors have some intrinsic features that make them complementary to electrochemical batteries. The latter find their optimal use in storing relatively large amounts of energy whereas supercapacitors can supply high power in very short time, though energy content is comparatively much smaller. Thus the two technologies might be used in a combined fashion such that each is used according to its intrinsic merit. The combination of supercapacitors along with batteries able to store and release an amount of energy which is a fraction of battery-based larger storage may entail a number of benefits. Such benefits depend on the specific situation such as type of source, meteo conditions, load curve versus time and finally on the power conditioning devices used along with their implemented control logic. For effective battery management, it is important to reduce the charge / discharge current of batteries over time, and to absorb a limited depth of discharge (DOD) to prolong the battery life. In addition, a suitably lower charging / discharging current permits to effectively exploit the charge of the battery during working cycles. Therefore, the current invention addresses the need to effectively manage individual battery storage systems within a micro-grid environment, thorough proper coordination via the control system considering various sources / load conditions. This need is addressed below.

[0029] Figure 1 illustrates a section 100 of micro-grid having modular power generation subsystems (110, 120) connected to an exemplary load 130 via an electrical bus 150. Additionally, a grid connector 140 is also provided for electrically connecting the micro- grid to the traditional public power grid or another micro-grid (not shown in figure).

[0030] The micro-grid is operated using a control system comprising a plurality of controllers (115, 135) that may be associated with control and/or operation of with power generation subsystems, and electrical loads in the micro-grid. The plurality of controllers (115, 135) can be connected amongst themselves via a communication bus. The operation in the micro-grid are monitored, controlled and managed by a centralized system (e.g. central controller 145, computer servers, monitoring stations, etc.). The centralized system 145 can provide grid-wide power management/ supervision in coordination with the one or more controllers associated with the control of the electrical subsystems/ power equipment (including power sources, power equipment and loads) of the micro-grid. The control system also includes a historian server for storing measurements from a plurality of sensors connected to the components of the micro- grid including power generation subsystems (110, 120), electrical loads (130), power storage subsystems, etc.

[0031] The central controller 145 in the centralized system is responsible for coordinating among the power equipment for connecting and disconnecting power generation sources and / or loads for power management and for controlling the power generation sources, the power storage subsystems and loads and for optimizing power utilization from the power generation sources and so forth for effective power management in the micro-grid.

[0032] The first power generation subsystem 110 in the figure 1 depicts a solar power generation source 111 (also referred to as photovoltaic, "PV"). The solar power generation source 111 is shown as connected to the electrical bus 150 via a power conditioning module 114. Additionally, the first power generation subsystem 110 includes a first power storage subsystem (also referred to as hybrid battery- supercapacitor storage module). The first power storage subsystem or hybrid battery- supercapacitor storage module comprises battery system 113 (also referred to as battery storage or battery modules) and a supercapacitor 116 (also referred to a supercapacitor module) in parallel to the battery storage 113. The battery system 113 and the supercapacitor 116 are connected to an internal DC (direct current) bus of the first power generation subsystem 110. The first power generation subsystem 110 is connected and controlled by a controller 115.

[0033] The power conditioning module 114 allows to transfer the power from the solar power source 111 to the load 130, via the AC Bus 150, in an exemplary embodiment, at 400 V in 3 -phase + Neutral arrangement, by performing necessary power conversion for connecting the solar power source 111 to the electrical bus 150. Additionally, the power conditioning module 114 allows for storing of excess power generated from the solar power source 111 in the first power storage subsystem and also transfer of stored energy from the first power storage subsystem to the electrical bus 150 in situations where sufficient power is not available from the solar power source 111, again through power conversions as needed.

[0034] In an example configuration, the controller 115 along with the power conditioning module 114 is responsible for effective operation of the battery system 113 and the supercapacitor 116, for example for controlled and coordinated charging and discharging of the hybrid battery-supercapacitor storage module including optimized individual operation of battery modules 113 and supercapacitor modules 116. The power conditioning module 114 can support charging the battery modules 113 and supercapacitor modules 116 through the traditional grid by providing necessary power conversion and control.

[0035] Similarly, Figure 1 depicts the second power generation subsystem 120 that includes a wind based power generation source 121. The wind power generation source 121 is shown as connected to the electrical bus 150 via another power conditioning module 125. The power conditioning module 125 is responsible for performing necessary power conversion for connecting the wind power generation source 121 to the electrical bus 150. The second power generation subsystem 120 includes a second power storage subsystem (also referred to as hybrid battery-supercapacitor storage module). The second power storage subsystem comprising a battery system 123 (also referred as battery storage module) and a supercapacitor 126 (also referred to as supercapacitor bank or module) in parallel. In exemplary configuration, the second power generation subsystem 120 is shown to directly coordinate with the central controller 145 (without any additional local controller) and is also responsible for optimally operating the second power storage subsystem (i.e. battery system 123 and the supercapacitor 126) comprised in the second power generation subsystem 120. [0036] Additionally, the controller 115 is capable of coordinating with the central controller 145 and also other controllers (such as controller 135 which is responsible for control of the electrical load 130) in the micro-grid for coordinated operation and for performing one or more functions in the micro-grid, together with or independent of the central controller 145.

[0037] In an embodiment, each subsystem as shown in figure 1, are housed in a transportable container, and tested at a factory. The container may be installed at the customer site either on ground or underground or indoors. In an embodiment, the micro- grid consumers are invoiced to their bank account based on their consumption of power via a communication system connected to consumers' meters.

[0038] The working of the battery modules (113, 123) and the supercapacitor modules (116 and 126), is explained using figure 2. For simplicity, the working is explained using the solar power source. Figure 2 shows exemplary power output from the solar power generation source and exemplary power requirement of the load versus time.

[0039] In figure 2, the actual load curve 220 (indicated by dotted line) is shown along with the "smoothed" load curve 225 (indicated by double line) which is obtained by averaging the actual curve. Likewise, the actual output power 210 (indicated solid thin line) is shown, along with "smoothed" output power 215 (indicated by dash line). When the solar power source 111 is generating power and such generated power is higher than the load requirement of the electrical load 130, the surplus power is stored in the battery system 113 and the supercapacitors 116. For example, as seen from the figure 2, in the region approximately represented by R2, output power is higher than the load requirement and according the excess power is stored in the battery system 113 and supercapacitors 116. It will be apparent that the transients and fluctuations will depend on the nature of source / load, and their dependencies on ambient conditions and usage. Therefore, there shall be scenarios where there are extremely large transient / fluctuations and output of power source and load requirements. [0040] Also, when the output power is lower than the load power requirement, the battery module 113 and supercapacitor 116 can be used to supply the load 130 as long as the stored energy is available. For example, as seen from the figure 2, in the regions approximately represented by Rl and R3, output power is lower than the load requirement and according the stored power in the first power storage subsystem (113 and 116) can be used to provide for meeting the load power requirement.

[0041] In an exemplary embodiment, the solar power source 111 is rated as 40 kWp. Correspondingly, the power conditioning module 114 is rated for 40 kW. The battery storage 113 is rated for 100 kWh, CO.10, 15kW, and supercapacitor 116 is rated 2 kWh, 15 kW. Here, the maximum smoothed load is 27 kW, minimum peak is 10 kW, maximum peak is 45 kW, and average peak duration is considered as 15 - 20 minutes.

[0042] By using the supercapacitor module 116 of opportune energy rating, in parallel to the battery module 113 as shown in Fig 2, transient fluctuations are filtered from the battery duty almost completely. Such opportune rating may range from few percent to some percent of the battery's energy rating, depending on the load characteristics, battery type and lifetime, cost objectives, etc. The supercapacitor would absorb the power transients to a very great extent, depending on its size, by supplying/absorbing the energy content of the transients. In this way the battery would only take care of the energy requirements connected to the difference between the "smoothed" curves of PV output and load.

[0043] Accordingly, the power storage system 110 is designed and operated based on statistical considerations about the distribution network availability. Both the battery modules 113 and supercapacitor 116 shall be controlled in such a way that all the potential benefits are actually achieved.

[0044] The size/capacity of the battery storage 113 and supercapacitor 116 are dynamically adjusted (active control with solid state devices) according to the load development over time and/or to the generation source availability based on forecast data available with the central controller 145 and effected through the local controllers/power conditioning modules in order to obtain the most efficient set-up. Thus, the size of the battery system 113 and supercapacitor 116 are adjusted according to the load development over time and / or to the generation source size upgrades in order to obtain the most economic set-up. This is further explained using figures 3 and 4.

[0045] Figure 3 illustrates another exemplary configuration of a section 300 micro-grid having solar power source 311 connected to the electrical bus 350 via a power storage subsystem 310, and wind based power source 321 directly connected to the electrical bus 350 via appropriate power conversion and control as commonly known in the art. Similarly, the micro-grid has a power storage subsystem 320 having one or more battery modules 323 and supercapacitor modules 326 directly connected to the micro-grid with appropriate power conversion and control (shown in the figure a power condition module 325). Also, Figure 3 illustrates use of control system that allow for a plurality of controller (315, 335) of the micro-grid to connect with a remote central controller 345 and a historian server (not shown in figure) via a remote network 380. In an embodiment, the central controller is a virtual controller/system executed on a remote server. A grid connector 340 is provided for establishing electrical connection between the micro-grid and the traditional grid.

[0046] Additionally, the micro-grid has a plurality of sensors provided for measurement of parameters that can support effective power management. The plurality of sensors includes a first set sensors (357) for measuring electrical parameters associated with the power generation sources (311, 321), the power storage subsystems (320), the electrical bus (350) and loads (330). The plurality of sensors includes a second set of sensors (317, 327, 337) for measurement of non-electrical parameters associated with solar power source 311 (e.g. light intensity, temperature), wind based power source 321 (e.g. wind velocity), with battery storage system 323 (e.g. temperature of battery or supercapacitor), ambient conditions (e.g. temperature, humidity, atmospheric pressure etc.) for better coordination and effective power management including use of hybrid battery-supercapacitors.

[0047] The measurements of the non-electrical parameters also help to provide forecast that may be more suitable to manage power including storage according to local ambient conditions and conditions of power equipment and storage system. Figure 3 additionally illustrates various sensors connected with one or more controlling devices including obtaining measurement or status values via remote sensors 367 (e.g. weather condition sensors or weather data sources), neighboring micro-grid to support forecasting and accordingly manage power storage by providing instructions/ set point values to local controlling devices to act as per the provided instruction/ set points. This is further explained in figure 4.

[0048] Figure 4 illustrates a method 400 for controlling and operating a power storage subsystem (310) in a section 300 of the micro grid, by a controller (315). At step 410, the controller 315 receives at least one of power generation profile of a first power generation source (i.e. the solar power source 311) and power demand profiles of the one or more electrical load 330 connected to the first power generation source 311, from a historian server.

[0049] In an embodiment, the power generation profile of the first power generation source 311 is generated based on the measurements of the one or more sensors from first set of sensors connected to the first power generation source 311. The power generation profile of the first power generation source 311 may include actual power generated vs. time trend data and average power generated vs. time trend, as indicated in figure 2 as trends actual output power 210 and smoothed output power 215. Similarly, the power demand profile of the electrical load 330 311 is generated based on the measurements of the one or more sensors from first set of sensors connected to the electrical load 330. The power demand profile of the electrical load 330 may include actual power demand vs. time trend data and average power demand vs. time trend, as indicated in figure 2 as trends actual load 220 and smoothed load 225

[0050] At step 420, the controller 315 determines a first combination of battery modules 313 and supercapacitor modules 316 in a first ratio for supporting a first power generation source 311 based on at least one of a power generation profile of the first power generation source 311 and power demand profiles of one or more electrical loads 330 connected to the first power generation source 311. For example, based on the frequency of and area under regions such as Rl, R2 and R3, the controller 315 determines the ratio of battery modules 313 to supercapacitor modules 316 required to support the first power generation source 311.

[0051] At step 430, the controller 315 operating the power storage subsystem 310 based on first combination of battery modules 313 and supercapacitor modules 316 in the first ratio for supporting a first power generation source 311. Operating the power storage subsystem 310 includes one of receiving power from the first power generation source 311 and supplying power to the one or more electrical loads 330 connected to the first power generation source 311. In an embodiment, the controller 315 along with the power condition module 314 is configured to determine an electrical configuration for connecting the one or more battery modules 313 and the one or more super-capacitors 316 based on the determined combination of battery modules 313 and supercapacitor modules 316 in a first ratio, and operate the electrical equipment for connecting the battery modules 313 and the supercapacitor modules 316 according to the determined electrical configuration.

[0052] In an embodiment, power generation profile of the first power generation source 311 is determined by the historian server based on a first set of measurements from a first set of sensors measuring a plurality of electrical parameters associated with the first power generation source 311, and a second set of measurements from a second set of sensors (317) measuring a plurality of non-electrical parameters associated with the first power generation source 311. For example, the power generation profile includes output power vs time and output power vs. solar light intensity trend information.

[0053] In an embodiment, the central controller 345 is capable of performing power management including power storage to selectively enable power source, load and storage subsystem to optimally utilize the available energy. Here, amongst one or more power storage subsystem 310 and 320, selectively one or more power storage subsystems (310 or 320) can be enabled based on the size of the battery-super \capacitors in the particular subsystem to participate in storing power from the power source or from the grid and supplying power to the grid. This kind of coordination are enabled through the control devices (power conditioning modules or/and controllers) and can be based on available energy, power rating of grid to ensure that no grid components are overloaded and also to support increased life.

[0054] Similarly, within a power storage subsystem (310), the rate of charging and discharging can be dynamically controlled by the corresponding controller 315 for effective utilization of grid infrastructure (no overloading, fast response and lifetime of components/modules) by dynamically changing the ratio/combination of the battery modules 313 and supercapacitor modules 316 connected.

[0055] Similarly, in another embodiment, in case of anticipated power insufficiency, based on the electrical parameters of the electrical bus 350 measured by the sensor 357 or based on the sensor associated with the solar power source or the wind based power source, or the power generation profiles and the power demand profiles, the power conditioning modules (i.e. converters and control logic; also referred to power control module)and the controllers (315, 335) can coordinate amongst themselves along with the central controller (345) to determine the power storage subsystem (310 or 320) from which the additional power has to be supplied to compensate for the anticipated power insufficiency, in order to ensure optimal usage of the power storage subsystems in the micro-grid. [0056] In another embodiment, as shown the figure 3, the control system of the micro- grid is enabled to receive measurement information associated with neighboring micro- grids or nearby locations. In an example, sensors from neighboring micro-grids are connected to the communication bus of the micro-grid via remote network. Based on the measurement information from sensors of neighboring micro-grids or nearby locations, the controller 315 (along the power conditioning module 314) can co-ordinate amongst themselves and the central controller 345, in order to determine possibility of variation in power generation and accordingly determine the combination of battery modules 313 and supercapacitors 316 and their electrical configuration in the power storage subsystem 310 to compensate for such variations. In another example, in such circumstances, control system (controller 315 and central controller 345) would determine that battery modules 313 in the power storage subsystem 310 which are not yet completely charged, are to be charged for the traditional grid in order to compensate for the forecasted variations in power generation, provided that the power tariff rates associated with the power form the traditional grid are acceptable.

[0057] In an embodiment, the components of the micro-grid system are monitored and controlled from remote via a private communication network and/or via internet, by way of wireless or wired communication. In another embodiment, the components of the micro-grid are controlled, monitored and maintained using remote networks via the "Internet of Things" (IOT) technology. For example, the central controller is configured to co-ordinate with meteorological services for receiving meteorological information available on the Internet to determine weather forecast for the location associated with power generation sources and accordingly estimate time periods where large fluctuations in output power of a renewable power source may be seen. Accordingly, the central controller along with the controller 315 associated with the power storage subsystem 310 determine the usage pattern of the power storage subsystem 310 and the configuration and combination of the battery modules 313 and the supercapacitor modules 316 in the power generation subsystem 310. [0058] The central controller is configured to communicate with the traditional grid and central controllers of other neighboring grids. Similarly, in another example, the central controller is configured to communicate with the traditional grid to determine time periods when power from the traditional grid is available at a lesser power tariff rate (as opposed to the normal demand rate) and accordingly coordinate with the controller associated with the power storage subsystem to charge the battery system and the supercapacitor of the power storage subsystem from traditional grid, during unavailability of sufficient power from the local power generation sources.

[0059] While the present invention is described using two power sources, a plurality of power sources may be used including biomass generator and/or a mini-hydro generator (<10 MW) and/or a diesel generator and/or a fuel cell and/or a tide-based turbine and/or a combined heat-power system (CHP).

[0060] In conclusion, with the use of a small percent of supercapacitor energy, it would be feasible to use battery system of lower ratings. In addition a suitably lower charging/discharging current permits to exploit the charge of the battery at the best during working cycles. Additionally, charge and discharge cycles of the battery can be maintained and control for optimal operation to ensure longer battery life. More than doubling battery life would be practically achievable, which in turn would reduce the capex costs over the plant life as well as the maintenance requirements. Additionally, it would be easier to ensure energy balance calculation and exploitation, even in the case of sustained PV/Load power oscillations over time.

[0061] In conclusion, with the use of a small percent of supercapacitor energy the following advantages can be achieved reduced power rating of the battery storage system, even more than 50% is possible; easier energy balance calculation and exploitation, even in the case of sustained PV/Load power oscillations over time and daily single charge/discharge cycles of the battery within the charge/discharge times specified by the manufacturer which multiply the battery life expectancy. More than double battery life would be practically achievable, which in turn would reduce the capex costs over the plant life as well as the maintenance requirements

[0062] This written description uses examples to describe the subject matter herein, including the best mode, and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

What is claimed is:

1) A method (400) for controlling and operating a power storage subsystem (310) in a section (100) of the micro grid, by a controller (115), the micro grid comprising one or more electrical loads (130) electrically connectable to the power storage subsystem (310), and one or more power generation sources (111), wherein the power storage subsystem (110) comprises one of more battery modules (113) and one or more super-capacitor modules (116) electrically connectable to the one or more battery modules (113) via one or more electrical equipment, the method (400) comprising: a. receiving at least one of power generation profile of a first power generation source and power demand profiles of the one or more electrical loads (130) connected to the first power generation source (111), from a historian server; b. determining a first combination of battery modules (116) and supercapacitor modules (116) in a first ratio for supporting a first power generation source (111) based on at least one of a power generation profile of the first power generation source (111) and power demand profiles of one or more electrical loads (130) connected to the first power generation source (111); and c. operating the power storage subsystem (110) based on first combination of battery modules (113) and supercapacitor modules (116) in a first ratio for supporting a first power generation source (111), wherein operating the power storage subsystem (110) includes one of receiving power from the first power generation source (111) and supplying power to the one or more electrical loads (130) connected to the first power generation source (111).

2) The method (400) as claimed in claim 1, wherein the power generation profile of the first power generation source ( 111 ) is determined by the historian server based on a first set of measurements from a first set of sensors measuring a plurality of electrical parameters associated with the first power generation source (111), and a second set of measurements from a second set of sensors measuring a plurality of non-electrical parameters associated with the first power generation source (111).

3) The method 400 as claimed in claim 1, the controller (115) of the power storage subsystem (110) is configured to coordinate with a central controller (145) for determining the first combination of battery modules (113) and supercapacitor modules (116) in the first ratio, based on meteorological information associated with a location of the first power generation source (111).

4) The method (400) as claimed in claim 1, the controller (115) of the power storage subsystem (110) is configured to coordinate with a central controller (145) for determining the first combination of battery modules (113) and supercapacitor modules (116) in the first ratio, based on one of power tariff information of a traditional power grid and electrical information of section of a second micro-grid, wherein an electrical bus of the section of the second micro-grid is electrically connectable to the one or more electrical loads (130) of the micro-grid for supplying power.

5) The method (400) as claimed in claim 2, wherein the plurality of non-electrical parameters associated with the first power generation source (111) includes at least one of solar light intensity, temperature of the power generation source (111), and wind velocity.

6) A control system for controlling one or more power storage subsystems (310, 320) in a section (300) of the micro grid, the micro grid comprising one or more electrical loads (330) electrically connectable to the one or more power storage subsystems (310, 320), and one or more power generation sources (311, 312), a first set of sensors for measuring a plurality of electrical parameters associated with the power generation sources (311, 312) and the electrical loads, and a second set of sensors (317, 327) for measuring a plurality of non-electrical parameters associated with the one or more power generation sources (311, 312), the control system comprising; a. one or more controllers (315, 345) for controlling the one or more power storage subsystems (310, 320); b. a historian server connectively coupled to the one or more controllers(315, 345), wherein the historian server comprising one or more power generation profiles of the power generation sources (311, 312) and one or more power demand profiles of the electrical loads (330);

Wherein at least one power storage subsystem (310) comprises one of more battery modules (313) and one or more super-capacitor modules (316) electrically connectable to the one or more battery modules (313) via one or more electrical equipment, and wherein a controller (315) of the at least one power storage subsystem (310) determines a first combination of battery modules (313) and supercapacitor modules (316) in a first ratio based on at least one of a power generation profile of a first power generation source (311) and power demand profiles of one or more electrical loads (330) connected to the first power generation source (311), for operating the at least one power storage subsystem (310) for supporting the first power generation source (311).

7) The control system as claimed in claim 3, wherein at least one controller (315) from the one or more controllers (315, 345), associated with the control of the at least one power storage subsystem (310) is configured to a. determine an electrical configuration for connecting the one or more battery modules (313) and the one or more super-capacitor modules (316) based on the determined combination of battery modules (313) and supercapacitor modules (316) in a first ratio, and operate the electrical equipment for connecting the battery modules (313) and the supercapacitor modules (316) according to the determined electrical configuration.