CN112769161A - Multi-mode energy storage micro-grid system - Google Patents
Multi-mode energy storage micro-grid system Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/01—Arrangements for reducing harmonics or ripples
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/28—The renewable source being wind energy
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/40—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E70/00—Other energy conversion or management systems reducing GHG emissions
- Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
Abstract
The invention discloses a multi-mode energy storage micro-grid system, and relates to the technical field of new energy power generation, wherein a first branch, a second branch, a third branch and a fourth branch of the system are connected to a primary bus of a micro-grid in parallel; the first branch is formed by sequentially connecting a first photovoltaic module, a photovoltaic inverter and a first controllable switch in series; the second branch is formed by sequentially connecting a second photovoltaic module, the light storage integrated machine and a second control switch in series; the third branch is formed by sequentially connecting an energy type battery, a light storage all-in-one machine and a second controllable switch in series; the fourth branch is formed by sequentially connecting a power battery, an energy storage converter and a third controllable switch in series. The invention can reduce the harmonic influence and achieve the purpose of stable and reliable operation.
Description
Technical Field
The invention relates to the technical field of new energy power generation, in particular to a micro-grid system with multi-mode energy storage.
Background
With the rapid development of new energy, a micro-grid system is developed, the micro-grid system is a core framework of an energy internet, is an important support for the transformation development of future energy, and particularly under the dual pressure of environmental protection and energy structure adjustment, the micro-grid technology containing clean energy is widely researched and applied.
The micro-grid system is a set of system constructed on the basis of distributed photovoltaic, wind power generation systems, energy storage systems, various loads and other electrical units. The photovoltaic module is greatly influenced by environmental factors, so that the energy storage device is an indispensable component for maintaining the power balance of the system, can be used as a key link in a micro-grid system, can store intermittent renewable energy sources such as solar energy and wind energy, and meanwhile, the access of the energy storage device provides possibility for the flexible switching operation of the photovoltaic power generation system between an off-grid mode and a grid-connected mode.
With the increasing of electric equipment such as nonlinear load and the like, the micro-grid system correspondingly has the defects of lower power factor, serious harmonic pollution and the like, so that the electric energy utilization efficiency in the micro-grid system is reduced, the electric equipment is overheated, and the service life of electric elements is shortened. And because the output power of the photovoltaic electric field can change the power flow distribution, the line transmission power and the inertia of the whole system of the original electric power system to a certain extent, the voltage stability of the micro-grid system is influenced.
The energy storage technology solves the problems of fluctuation and randomness of new energy power generation to a great extent, and effectively improves the predictability, the certainty and the economy of the intermittent micro source. In addition, the energy storage technology can adjust frequency and voltage, improve the active and reactive power balance level of the system and improve the stable operation capability of the micro-grid system. In an electric power system with high wind and light power generation permeability, when the electric power system has frequency change and voltage change and the wind and light storage cluster is required to have strong real-time performance on the stability and the electric energy quality of the electric power system, the reliable operation of the electric power system can be ensured only by fully considering the adjusting capacity of the wind and light storage cluster according to the real-time state of the electric power system.
Traditional photovoltaic energy storage power generation system mainly comprises a plurality of converters, and the many converters can not avoid receiving the harmonic influence after connecting in parallel, bring a great deal of disadvantages for exchanging parallel system, and converter, dc-to-ac converter can't support little electric wire netting voltage, frequency when little electric wire netting isolated island operation.
Disclosure of Invention
The invention aims to provide a multi-mode energy storage micro-grid system which can reduce harmonic influence and achieve the purpose of stable and reliable operation.
In order to achieve the purpose, the invention provides the following scheme:
a multi-mode energy storage microgrid system comprises a distributed power generation power supply, a distributed hybrid energy storage unit, a distributed inversion energy storage unit and a distributed controllable switch;
the first branch circuit, the second branch circuit, the third branch circuit and the fourth branch circuit are connected to a primary bus of the microgrid in parallel;
the distributed power generation power supply comprises a first photovoltaic assembly and a second photovoltaic assembly, and the distributed hybrid energy storage comprises a power type battery and an energy type battery; the distributed inversion energy storage unit comprises a photovoltaic inverter, a light storage integrated machine and an energy storage converter; the distributed controllable switches comprise a first controllable switch, a second controllable switch and a third controllable switch; the first branch is formed by sequentially connecting the first photovoltaic module, the photovoltaic inverter and the first controllable switch in series; the second branch is formed by sequentially connecting the second photovoltaic module, the light storage all-in-one machine and the second control switch in series; the third branch is formed by sequentially connecting the energy-type battery, the light storage all-in-one machine and the second controllable switch in series; the fourth branch is formed by sequentially connecting the power type battery, the energy storage converter and the third controllable switch in series.
Optionally, the microgrid system further comprises a fifth branch; the first branch, the second branch, the third branch, the fourth branch and the fifth branch are connected to a primary bus of the microgrid in parallel; the distributed power generation power supply further comprises a fan, and the distributed inversion energy storage unit further comprises a fan control cabinet; the distributed controllable switches further comprise a fourth controllable switch; the fifth branch is formed by connecting the fan, the fan control cabinet and the fourth controllable switch in series in sequence.
Optionally, the microgrid system further comprises a transformer; the first branch circuit, the second branch circuit, the third branch circuit, the fourth branch circuit and the fifth branch circuit are connected to one end of the transformer in parallel, and the other end of the transformer is connected to a primary bus of the microgrid.
Optionally, the microgrid system further comprises a grid-connected point fast switch; the first branch circuit, the second branch circuit, the third branch circuit, the fourth branch circuit and the fifth branch circuit are connected in parallel to one end of the grid-connected point quick switch, and the other end of the grid-connected point quick switch is connected with one end of the transformer.
Optionally, the microgrid system further comprises a control unit; the control unit is respectively connected with the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch, and is configured to control the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch to be turned on and off.
Optionally, the number of the first branch, the second branch, the third branch and the fourth branch is one or more, and the number of the second branch is the same as the number of the third branch.
Optionally, the energy-type battery includes a lead-carbon battery and/or a lithium iron phosphate battery; the third branch is a branch formed by sequentially connecting the lead carbon battery, the light storage all-in-one machine and the second controllable switch in series, and/or the third branch is a branch formed by sequentially connecting the lithium iron phosphate battery, the light storage all-in-one machine and the second controllable switch in series.
Optionally, the power type battery is a super capacitor.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the multi-mode energy storage micro-grid system provided by the invention adopts a photovoltaic, energy storage and current transformation integrated design, reduces the harmonic influence of the micro-grid system after multiple current transformers are connected in parallel, and achieves the purposes of stable operation and reliable performance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a block diagram of a multi-mode energy storage microgrid system according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a micro-grid system for multi-mode energy storage according to a second embodiment of the present invention;
FIG. 3 is a schematic block diagram of a second optical storage integrated machine according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a process of accessing a photovoltaic module to a microgrid according to a second embodiment of the present invention;
fig. 5 is a schematic structural diagram of a three-multimode energy storage microgrid system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a multi-mode energy storage micro-grid system which can reduce harmonic influence and achieve the purpose of stable and reliable operation.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Example one
As shown in fig. 1, the multi-mode energy storage microgrid system provided in this embodiment includes a distributed power generation source, a distributed hybrid energy storage unit, a distributed inverter energy storage unit, and a distributed controllable switch.
The first branch circuit, the second branch circuit, the third branch circuit and the fourth branch circuit are connected to a primary bus of the microgrid in parallel.
The distributed power generation power supply comprises a first photovoltaic assembly and a second photovoltaic assembly, and the distributed hybrid energy storage comprises a power type battery and an energy type battery; the distributed inversion energy storage unit comprises a photovoltaic inverter, a light storage integrated machine and an energy storage converter; the distributed controllable switches comprise a first controllable switch, a second controllable switch and a third controllable switch; the first branch is formed by sequentially connecting the first photovoltaic module, the photovoltaic inverter and the first controllable switch in series; the second branch is formed by sequentially connecting the second photovoltaic module, the light storage all-in-one machine and the second control switch in series; the third branch is formed by sequentially connecting the energy-type battery, the light storage all-in-one machine and the second controllable switch in series; the fourth branch is formed by sequentially connecting the power type battery, the energy storage converter and the third controllable switch in series.
As a preferred specific implementation manner, the microgrid system provided in this embodiment further includes a fifth branch; the first branch, the second branch, the third branch, the fourth branch and the fifth branch are connected to a primary bus of the microgrid in parallel; the distributed power generation power supply further comprises a fan, and the distributed inversion energy storage unit further comprises a fan control cabinet; the distributed controllable switches further comprise a fourth controllable switch; the fifth branch is formed by connecting the fan, the fan control cabinet and the fourth controllable switch in series in sequence. The number of the fifth branches is set to be one or more according to the requirement.
As a preferred specific implementation manner, the present embodiment further provides a transformer; the first branch circuit, the second branch circuit, the third branch circuit, the fourth branch circuit and the fifth branch circuit are connected to one end of the transformer in parallel, and the other end of the transformer is connected to a primary bus of the microgrid.
As a preferred specific implementation manner, the microgrid system provided by the present embodiment further includes a grid-connected point fast switch; the first branch circuit, the second branch circuit, the third branch circuit, the fourth branch circuit and the fifth branch circuit are connected in parallel to one end of the grid-connected point quick switch, and the other end of the grid-connected point quick switch is connected with one end of the transformer.
As a preferred specific implementation manner, the microgrid system provided by the present embodiment further includes a control unit; the control unit is respectively connected with the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch, and is configured to control the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch to be turned on and off.
As a preferred specific implementation manner, in this embodiment, the number of the first branch, the second branch, the third branch, and the fourth branch is one or more, and the number of the second branch is the same as the number of the third branch.
As a preferred specific implementation manner, the energy-type battery provided in this embodiment includes a lead-carbon battery and/or a lithium iron phosphate battery; the third branch circuit is the lead carbon battery, the light stores up the all-in-one and the branch circuit that the controllable switch of second establishes ties in proper order, and/or the third branch circuit is the lithium iron phosphate battery, the light stores up the all-in-one with the branch circuit that the controllable switch of second establishes ties in proper order, and this embodiment has at least one promptly the light stores up the all-in-one respectively with the second photovoltaic module with the lithium iron phosphate battery is connected, perhaps has at least one the light stores up the all-in-one respectively with the second photovoltaic module with the lead carbon battery is connected to when the number of light storing up the all-in-one is two, one of them the light stores up the all-in-one respectively with the second photovoltaic module with the lead carbon battery is connected, another the light stores up the all-in-one respectively with. Here, the number of the second photovoltaic modules is the same as the number of the light storage integrated machines.
As a preferred specific implementation manner, the power type battery provided in this embodiment is a super capacitor.
As a preferred specific implementation manner, the number of the photovoltaic modules provided in this embodiment is greater than the number of the light storage integrated machines.
The multi-mode energy storage micro-grid system provided by the embodiment adopts a photovoltaic, energy storage and current transformation integrated design, reduces the harmonic influence of the micro-grid system after the multi-current transformers are connected in parallel, and achieves the purposes of stable operation and reliable performance.
Example two
As shown in fig. 2, the multi-mode energy storage microgrid system provided in this embodiment includes a distributed power generation source, for example, m groups of photovoltaic modules, a group of fans, and the like, which are connected in parallel to a primary bus of a microgrid through a distributed inversion energy storage unit, specifically, the distributed power generation source is connected to the primary bus of the microgrid through the distributed inversion energy storage unit and a controllable switch. The micro-grid system further comprises a control unit, and the control unit controls the on and off of the controllable switch according to a grid-connected and off-grid operation strategy of the micro-grid.
10kV/380V in FIG. 2 is a transformer, AC380V is a low-voltage AC bus, L1-L5 represents a branch line on the side of a micro-grid power supply, L1-1, L1-2 and L1-3 represent commercial power supply lines, L2-1, L2-2 and L2-3 represent micro-grid power supply lines, S1-S3 represent double-power-supply circuit breakers, and K1-K5 represent controllable switches.
The working process of the line 1 and the line 2 is as follows: line 1 and line 2 are mains supply, and are mutually standby. Under the condition that the micro-grid system is not put into use, the double-power-supply circuit breakers S1-S3 are respectively connected with the commercial power supply lines L1-1, L1-2 and L1-3, and commercial power supplies power to the electric loads; under the condition that the microgrid system is put into service, the double-power-supply circuit breakers S1-S3 are automatically switched to be connected with the microgrid power supply circuits L2-1, L2-2 and L2-3, the microgrid system supplies power to loads, and normal and stable operation of the microgrid system is maintained according to a microgrid grid-connected and off-grid operation strategy.
The distributed inversion energy storage unit comprises n light storage integrated machines, a fan Control cabinet, a photovoltaic inverter and an energy storage converter (Power Control System, PCS), wherein the light storage integrated machines, the fan Control cabinet, the photovoltaic inverter and the energy storage converter are connected with a controllable switch in advance before being connected to a primary bus of a microgrid and used for grid-connection and grid-disconnection Control.
The light-storage integrated machine, namely the light-storage integrated converter, integrates the functions of an inverter and an energy storage PCS (Power conversion System), is a link between a power grid and photovoltaic power generation and electric energy storage equipment, and has the functions of charging and electric energy feedback. The basic schematic block diagram of the light storage integrated current transformer is shown in fig. 3. The light-storage integrated machine mainly comprises two DC/DC converters on a photovoltaic side and an energy storage side and a DC/AC converter on a load side. The photovoltaic side DC/DC converter converts the voltage generated by the photovoltaic module into the voltage required by the direct current bus; the energy storage side DC/DC converter enables energy to flow in two directions, the energy storage side DC/DC converter charges a storage battery in a grid-connected mode, and the energy storage side DC/DC converter charges a direct-current bus as the storage battery in an off-grid mode to maintain the voltage of the bus constant; the DC/AC converter adopts a T-shaped three-level topological structure and can respectively operate in a grid-connected mode and an off-grid mode according to the working state of a power grid.
The n groups of photovoltaic components are connected with an energy storage device (storage battery) in parallel at a direct current side, inverted and boosted by the light storage integrated machine, and then connected into a microgrid through a controllable switch and a transformer to realize grid-connected power generation, wherein the transformer can adopt a double-winding transformer. The process of accessing the microgrid is shown in fig. 4.
The quantity and the capacity of the light storage integrated machine are determined according to the quantity and the power generation quantity of the photovoltaic modules which need to be connected.
In order to ensure that the micro-grid system can continuously meet the power supply requirement of each load under the condition that a large power grid loses power, the micro-grid system is also provided with a distributed hybrid energy storage unit comprising a lead-carbon battery, a lithium iron phosphate battery and a super capacitor. The distributed hybrid energy storage unit has the functions of smoothing the power generation output of the photovoltaic fan, absorbing the photovoltaic surplus electric energy, participating in peak clipping and valley filling of the power grid and the like. The photovoltaic modules and the lead-carbon batteries/lithium iron phosphate batteries are connected in parallel to the light storage all-in-one machine, then the light storage all-in-one machine is connected to a primary bus of the microgrid through a controllable switch, and the super capacitor is connected to the primary bus of the microgrid through an energy storage converter and the controllable switch; the photovoltaic module is connected to a primary bus of the microgrid through the photovoltaic inverter and the controllable switch, and the fan is connected to the primary bus of the microgrid through the fan control cabinet and the controllable switch.
The distributed generation power supply in the micro-grid is used by self, when the generation power is greater than the load power consumption power, the redundant part preferentially charges the stored energy, and the rest power is on line; when the power generation power is smaller than the power consumption power of the load, the stored energy is discharged to supplement the power shortage, and if the stored energy is not enough to supplement the power shortage, the power is taken from the power grid for supplement.
In a micro-grid system, distributed hybrid energy storage units mainly play roles of smoothing distributed generation output and performing peak clipping and valley filling when the distributed hybrid energy storage units are normally connected to a grid, and play roles of a standby power supply in emergency and some specific control conditions.
When the microgrid runs off the grid, the distributed hybrid energy storage unit serves as a main power supply to provide reference frequency for the microgrid system. In order to ensure the off-grid stable operation of the micro-grid, the off-grid stable operation of the micro-grid is realized by coordinating the distribution among the distributed power supply, the load and the energy storage, and the reliable operation of important loads is supported for a certain time.
The microgrid system provided by the embodiment adopts a photovoltaic module and energy storage and current transformation integrated design, is stable in operation and reliable in performance, has an autonomous energy management function, supports intelligent charging and discharging, supports three-phase 100% unbalanced on-load operation, realizes online seamless switching of grid-connected and off-grid operation modes, has active and reactive real-time scheduling and low-voltage ride-through functions (grid-connected operation), and has short-circuit supporting and self-recovery functions (off-grid operation). In addition, the hybrid energy storage batteries have different performances and complementary advantages, the energy type batteries provide voltage support, and the power type batteries provide power fluctuation support.
EXAMPLE III
As shown in fig. 5, the microgrid system provided in this embodiment is applied to a university, and the photovoltaic components connected to the microgrid system are mainly rooftop photovoltaics of six buildings, such as a 1, 2, and 3 teaching building, a graphic and text information integrated building, an academic exchange and business center, and an energy-machine college. The method is characterized in that 2 light storage integrated machines are used in a microgrid system, the capacities of the light storage integrated machines are 150kW and 100kW respectively, roof photovoltaics of a teaching building 1 and a teaching building 2 and a graphic and text information comprehensive building are connected to a primary bus of the microgrid through the light storage integrated machines, and roof photovoltaics of other buildings are connected to the primary bus of the microgrid through photovoltaic inverters. The micro-grid system further comprises 1 wind power system and a super capacitor, wherein the wind power system and the super capacitor are connected to a primary bus of the micro-grid through a fan control cabinet and an energy storage converter.
School district photovoltaic capacity is 478KW, and school district's important load includes data center and data center air conditioner, need ensure 2 h's reliable power supply under the off-grid condition, and the photovoltaic capacity of inserting light and storing up the all-in-one is 235.2kW, and then the distributed mixed energy storage unit capacity of configuration is: the lead-carbon battery/lithium iron phosphate battery with the power consumption of 250kW multiplied by 2h is additionally provided with a super capacitor for storing energy of 100kW multiplied by 10s so as to meet the demand of rapid power regulation.
The 150kW light storage integrated machine is connected with the photovoltaic module and the lead-carbon battery respectively, and the 100kW light storage integrated machine is connected with the photovoltaic module and the lithium iron phosphate battery respectively. And in the case of off-grid or main network failure, power is preferentially supplied to important loads such as a data center and the like. At the moment, the 150kW light storage integrated machine provides reference voltage and frequency for the alternating current bus, the 100kW light storage integrated machine works in a P/Q mode (namely an output power control mode), and reliable power supply of a data center is preferentially ensured. In addition, the super capacitor is charged and discharged rapidly to deal with the short-time power fluctuation of the air conditioning load of the data center.
The charge-discharge multiplying power of the lead-carbon battery is not greatly different from that of the lithium iron phosphate battery, the normal discharge multiplying power of the lead-carbon battery is 0.5C, and the charge-discharge multiplying power of the lithium iron phosphate battery is about 1C, so that the capacity of the lead-carbon battery and the capacity configuration of the lithium iron phosphate battery are close to each other as much as possible under the condition of hybrid energy storage. The capacity of the lead carbon battery is configured to be 150kW/300kWh, the capacity of a single battery is 2V/1000Ah, and the lead carbon battery is connected to the battery side input end of the 150kW light storage integrated machine; the capacity of the lithium iron phosphate battery is configured to be 100kW/200kWh, the capacity of a single battery is 3.2V/200Ah, the single battery is connected to the battery side input end of the 100kW light storage integrated machine, and the input voltage of the two types of batteries is 250V-520V.
The discharge depth of the lead carbon battery is 80%, the actual discharge capacity of the 300kWh lead carbon battery is 240kWh, so that the voltage range of the plurality of lead carbon batteries connected in series is 263V-352V, the rated voltage is 300V, and the input voltage range of the energy storage side of the light and energy storage integrated machine is met.
The discharge depth of the lithium iron phosphate battery is 90%, the actual discharge capacity of the 200kWh lithium iron phosphate battery is 180kWh, so that the voltage range of the multiple lithium iron phosphate batteries connected in series and in parallel is 281V-380V, the rated voltage is 332V, and the input voltage range of the energy storage side of the light storage integrated machine is met.
The microgrid system is also provided with a plurality of series-connected 48V165F super capacitors, and energy storage converters used by the super capacitors are arranged in a single screen cabinet.
In the daytime, the photovoltaic power generation energy supplies power to the user load, and the redundant power is stored in the distributed hybrid energy storage unit; and the distributed hybrid energy storage units are arranged to release a part of electric energy at night in a proper amount, so that a proper space is available for storing energy again in the next day.
The embodiment adopts a light-storage integrated machine and a hybrid energy storage scheme, and comprises a lead-carbon battery/lithium iron phosphate energy type battery and a super-capacitor power type battery. The photovoltaic and the energy storage in the light storage all-in-one machine are respectively collected by the DC/DC converter and the DC bus, the control is flexible, the stability is high, the MPPT (maximum power point tracking) control of the photovoltaic can be realized, the light storage all-in-one machine can adapt to the energy storage of different types, the adjustment range of the energy storage is fully played, the charge and discharge control of the energy storage is optimized, and the utilization rate of the energy is improved. The energy type battery is mainly used for supporting alternating-current bus voltage, and can meet slow power change in the microgrid through a self charging and discharging strategy so as to realize stable operation of the microgrid; the super capacitor can release or absorb relatively large power in a short time to smooth the power fluctuation on the bus.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (8)
1. A multi-mode energy storage micro-grid system is characterized by comprising a distributed power generation power supply, a distributed hybrid energy storage unit, a distributed inversion energy storage unit and a distributed controllable switch;
the first branch circuit, the second branch circuit, the third branch circuit and the fourth branch circuit are connected to a primary bus of the microgrid in parallel;
the distributed power generation power supply comprises a first photovoltaic assembly and a second photovoltaic assembly, and the distributed hybrid energy storage comprises a power type battery and an energy type battery; the distributed inversion energy storage unit comprises a photovoltaic inverter, a light storage integrated machine and an energy storage converter; the distributed controllable switches comprise a first controllable switch, a second controllable switch and a third controllable switch; the first branch is formed by sequentially connecting the first photovoltaic module, the photovoltaic inverter and the first controllable switch in series; the second branch is formed by sequentially connecting the second photovoltaic module, the light storage all-in-one machine and the second control switch in series; the third branch is formed by sequentially connecting the energy-type battery, the light storage all-in-one machine and the second controllable switch in series; the fourth branch is formed by sequentially connecting the power type battery, the energy storage converter and the third controllable switch in series.
2. The microgrid system of claim 1, further comprising a fifth branch; the first branch, the second branch, the third branch, the fourth branch and the fifth branch are connected to a primary bus of the microgrid in parallel; the distributed power generation power supply further comprises a fan, and the distributed inversion energy storage unit further comprises a fan control cabinet; the distributed controllable switches further comprise a fourth controllable switch; the fifth branch is formed by connecting the fan, the fan control cabinet and the fourth controllable switch in series in sequence.
3. The microgrid system of claim 2, further comprising a transformer; the first branch circuit, the second branch circuit, the third branch circuit, the fourth branch circuit and the fifth branch circuit are connected to one end of the transformer in parallel, and the other end of the transformer is connected to a primary bus of the microgrid.
4. A multi-mode energy storage microgrid system according to claim 3, characterized in that the microgrid system further comprises point-of-grid fast switches; the first branch circuit, the second branch circuit, the third branch circuit, the fourth branch circuit and the fifth branch circuit are connected in parallel to one end of the grid-connected point quick switch, and the other end of the grid-connected point quick switch is connected with one end of the transformer.
5. The microgrid system of claim 2, further comprising a control unit; the control unit is respectively connected with the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch, and is configured to control the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch to be turned on and off.
6. The multi-mode energy storage microgrid system of claim 1, characterized in that the number of the first branches, the second branches, the third branches and the fourth branches is one or more, and the number of the second branches is the same as the number of the third branches.
7. The multi-mode energy storage microgrid system of claim 6, wherein the energy-type batteries comprise lead-carbon batteries and/or lithium iron phosphate batteries; the third branch is a branch formed by sequentially connecting the lead carbon battery, the light storage all-in-one machine and the second controllable switch in series, and/or the third branch is a branch formed by sequentially connecting the lithium iron phosphate battery, the light storage all-in-one machine and the second controllable switch in series.
8. The multi-mode energy-storing microgrid system of claim 1, wherein the power-type battery is a supercapacitor.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113472009A (en) * | 2021-07-01 | 2021-10-01 | 北京机械设备研究所 | Multi-working-condition parallel light storage integrated machine system and configuration method thereof |
| CN116581812A (en) * | 2023-04-12 | 2023-08-11 | 长园深瑞能源技术有限公司 | Hybrid light storage inverter, control method and photovoltaic energy storage system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113472009A (en) * | 2021-07-01 | 2021-10-01 | 北京机械设备研究所 | Multi-working-condition parallel light storage integrated machine system and configuration method thereof |
| CN116581812A (en) * | 2023-04-12 | 2023-08-11 | 长园深瑞能源技术有限公司 | Hybrid light storage inverter, control method and photovoltaic energy storage system |
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