CN213185533U

CN213185533U - Multi-mode energy storage microgrid

Info

Publication number: CN213185533U
Application number: CN202021546910.7U
Authority: CN
Inventors: 徐杰彦; 王鹤; 柴宝双; 洪瑞新; 刘晓琳; 褚渊; 许雯旸
Original assignee: State Grid Beijing Comprehensive Energy Planning And Design Institute Co ltd
Current assignee: State Grid Beijing Comprehensive Energy Planning And Design Institute Co ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2021-05-11
Anticipated expiration: 2030-07-30

Abstract

The utility model discloses a multi-mode energy storage microgrid, which comprises m groups of photovoltaic components, fans and energy storage units which are connected in parallel to a primary bus of the microgrid, and a control system which is respectively electrically connected with the photovoltaic components, the fans and the energy storage units, wherein the control system comprises n light and energy storage integrated machines, a fan control cabinet, a photovoltaic inverter and an energy storage converter; the n light storage integrated machines are connected to a primary bus of the microgrid through a controllable switch, and m is more than n and is more than or equal to 1; the energy storage system is provided with a lead-carbon battery/lithium iron phosphate battery and a super capacitor; the n groups of photovoltaic components and the lead carbon battery/lithium iron phosphate battery are connected in parallel to the light storage integrated machine, and the super capacitor is connected to the primary bus through the energy storage converter. The utility model discloses a little grid system adopts photovoltaic, energy storage converter integrated design, and the operation is stable, the dependable performance, and the battery performance of mixing the energy storage is respectively different, and the advantage is complementary, and the battery of energy type provides voltage support, the battery of power type provides the power fluctuation and supports.

Description

Multi-mode energy storage microgrid

Technical Field

The utility model belongs to the technical field of new forms of energy electricity generation, concretely relates to utilize mode energy storage such as light-storage all-in-one, super capacitor little grid system.

Background

With the rapid development of new energy, a micro-grid system is developed, the micro-grid is a core framework of an energy internet and 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 units, 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, and the photovoltaic module is used as a key link in a micro-grid system and can store intermittent renewable energy sources such as solar energy, wind energy and the like. Meanwhile, the access of the energy storage equipment provides possibility for the flexible switching operation of the photovoltaic power generation system between the off-grid mode and the grid-connected mode.

With the increasing number of electric equipment such as nonlinear loads and the like, the micro-grid system has the problems of low power factor, serious harmonic pollution and the like, so that the utilization efficiency of electric energy in the micro-grid system is reduced, the electric equipment is overheated, and the service life of an electric element 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 power grid 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. In a power system with high wind and light power generation permeability, when the frequency and voltage of the power system change, the wind and light storage cluster is required to have high real-time performance on the stability and the power quality of the power system, and the reliable and economic operation of the 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 power system. The traditional photovoltaic energy storage power generation system is mainly composed of a plurality of converters, the inevitable harmonic influence after the multiple converters are connected in parallel brings a lot of disadvantages to an alternating current parallel system, and the converters and the inverters cannot support the voltage and the frequency of a microgrid when the microgrid is in isolated island operation.

Disclosure of Invention

In order to solve the problems of the prior art, the utility model provides a micro-grid of multi-mode energy storage, which comprises m groups of photovoltaic assemblies, fans and energy storage units which are connected in parallel to a primary bus of the micro-grid, and a control system which is respectively electrically connected with the photovoltaic assemblies, the fans and the energy storage units, and is characterized in that the control system comprises n light-storage integrated machines, a fan control cabinet, a photovoltaic inverter and an energy storage converter; wherein the content of the first and second substances,

the n light storage integrated machines are connected to the primary bus of the micro-grid through controllable switches, and m is more than n and is more than or equal to 1;

the energy storage unit is provided with a lead-carbon battery/lithium iron phosphate battery and a super capacitor; the photovoltaic modules and the lead carbon batteries/lithium iron phosphate batteries are connected in parallel to the light storage all-in-one machine, and the super capacitor is connected to the primary bus through an energy storage converter.

Further, at least one light stores up all-in-one and is connected with photovoltaic module with the lead carbon battery respectively.

Further, at least one light stores up all-in-one with photovoltaic module with lithium iron phosphate battery is connected respectively.

Furthermore, the control system comprises a distributed power generation control unit, the distributed power generation control unit comprises 2 light storage all-in-one machines, one of the light storage all-in-one machines is respectively connected with the photovoltaic module and the lead-carbon battery, and the other light storage all-in-one machine is respectively connected with the photovoltaic module and the lithium iron phosphate battery.

Furthermore, the control system of the microgrid also comprises a transformer, and the light storage all-in-one machine is connected to the primary bus of the microgrid through a controllable switch and the transformer.

Further, the m-n groups of photovoltaic assemblies are connected to the primary bus through the photovoltaic inverter.

The utility model has the advantages that:

the micro-grid system is designed in a photovoltaic and energy storage and conversion integrated mode, 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 on-grid and off-grid operation modes, has active and reactive real-time scheduling and low-voltage ride-through functions (during grid-connected operation), and has short-circuit supporting and self-recovery functions (during off-grid operation). The hybrid energy storage batteries have different performances and complementary advantages, and the energy type batteries provide voltage support and the power type batteries provide power fluctuation support.

Drawings

Fig. 1 is a schematic structural diagram of the multi-mode energy storage microgrid of the present invention.

Fig. 2 is a basic schematic block diagram of the light storage integrated converter of the present invention.

Fig. 3 is a schematic diagram of the photovoltaic power generation access microgrid of the utility model.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention.

As shown in fig. 1, the utility model discloses a microgrid of multi-mode energy storage, including distributed generation power, for example m group photovoltaic module 1, fan 2 etc. they and energy storage unit connect in parallel extremely microgrid's primary bus, distributed generation power and energy storage unit, respectively through control system, controllable switch with microgrid's primary bus connects. 10kV/380V in FIG. 1 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 intelligent control switches. Workflow of lines 1, 2: lines 1 and 2 are mains power supplies and are spare to each other. Under the condition that the microgrid is not used, S1-S3 are respectively connected with a mains supply line L1-1, L1-2 and L1-3, and mains supply supplies power to an electric load; under the condition that the microgrid is put into use, the S1-S3 is automatically switched to be connected with the L2-1, the L2-2 and the L2-3, the microgrid supplies power to the load, and the normal and stable operation of the microgrid system is maintained according to a grid-connected and off-grid operation strategy of the microgrid.

The Control System comprises distributed generation Control units, such as n light storage integrated machines, a fan Control cabinet, a photovoltaic inverter and an energy storage converter (Power Control System, PCS), wherein a controllable switch is arranged in front of a primary bus connected to the microgrid for grid connection and grid disconnection Control.

The light-storage integrated machine 3, namely the light-storage integrated converter, integrates the functions of an inverter and an energy storage PCS into a whole, 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. 2. The light-storage integrated machine 3 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 converter converts the voltage generated by the photovoltaic module into the voltage required by the direct current bus; the energy storage side converter enables energy to flow in two directions, and charges the storage battery in a grid-connected mode; in the off-grid mode, the energy storage side converter is used as a storage battery to charge a direct current bus, and the voltage of the bus is kept constant; the DC/AC converter adopts a T-shaped three-level topology, and can respectively operate in a grid-connected mode and an off-grid mode according to the working state of the power grid. The n groups of photovoltaic assemblies 1 are connected with the energy storage battery in parallel on the direct current side, inverted and boosted through the light storage integrated machine, and then connected into the microgrid through the controllable switch 4 and the transformer 5 to realize grid-connected power generation, and the transformer 5 can adopt a double-winding transformer. Its access to the microgrid is shown in fig. 3.

The quantity and the capacity of the light storage integrated machine 3 are determined according to the quantity and the power generation quantity of the photovoltaic modules 1 which need to be connected.

In order to ensure that the micro-grid can continuously meet the power supply requirement of each load under the condition that the large power grid loses power, the micro-grid system is also provided with an energy storage unit consisting of a lead-carbon battery 5, a lithium iron phosphate battery 6 and a super capacitor 7. The energy storage unit has the functions of smoothing the power generated by the photovoltaic fan, absorbing the photovoltaic surplus electric energy, participating in peak clipping and valley filling of the power grid and the like. The energy storage unit is provided with a lead-carbon battery/lithium iron phosphate battery and a super capacitor; the photovoltaic modules and the lead carbon batteries/lithium iron phosphate batteries are connected in parallel to the light storage integrated machine, and the super capacitor 7 is connected to the primary bus through an energy storage converter. 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, the stored energy mainly plays the roles of smoothing distributed generation output and peak clipping and valley filling when the stored energy is normally connected to the grid, and plays the role of a standby power supply under emergency and some specific control conditions.

When the microgrid runs off the grid, the stored energy is used as a main power supply to provide reference frequency for the microgrid. 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.

Examples

As shown in fig. 1, the utility model discloses be applied to certain university, insert the utility model discloses a photovoltaic module 1 of little electric wire netting mainly is the roof photovoltaic of six buildings such as 1, 2, 3 teaching buildings, picture and text information synthesis building, academic exchange and affairs center, ability machine college. The method is characterized in that 2 light storage integrated machines are used in the microgrid, the capacities of the light storage integrated machines are 150kW and 100kW respectively, roof photovoltaics of a teaching building No. 1 and a teaching building No. 2 and a graphic and text information comprehensive building are connected into the microgrid through the light storage integrated machines, and roof photovoltaics of other buildings are connected into a microgrid bus through a photovoltaic inverter. The system also comprises 1 fan 2 and an energy storage unit which are connected to the microgrid bus through a fan control cabinet and an energy storage PCS.

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 inserts the photovoltaic capacity of light storage all-in-one machine and be 235.2kW, then the energy storage unit capacity of configuration is: the lead-carbon battery 5/lithium iron phosphate battery 6 with the power of 250kW multiplied by 2h is additionally provided with a super capacitor 7 with the power of 100kW multiplied by 10s for energy storage, so that the requirement of rapid power regulation is met. 150kW light stores up all-in-one with photovoltaic module with lead carbon battery 5 connects respectively, 100kW light stores up all-in-one with photovoltaic module with lithium iron phosphate battery 6 connects 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 7 is charged and discharged rapidly to deal with the short-term 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 a 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 micro-grid is also provided with a plurality of series-connected 48V165F super capacitors, and PCS used by the super capacitors is a single screen cabinet.

In the daytime, the photovoltaic power generation energy supplies power to the user load, and the redundant electric energy is stored in the energy storage unit; and the energy storage unit is arranged to release a part of electric energy at night in a proper amount, so that a proper space is provided for storing energy again in the next day.

The utility model discloses a light stores up all-in-one and the scheme of mixing the energy storage, including the battery of plumbous charcoal battery and lithium iron phosphate energy type and super capacitor power type. The light stores up the all-in-one and adopts photovoltaic and energy storage to gather the mode through DC/DC common direct current generating line respectively, and control is nimble, and stability is high, not only can realize photovoltaic MPPT (maximum power point tracking) control, can also adapt to the energy storage of different grade type, and the control range of full play energy storage optimizes the charge-discharge control of energy storage, improves the utilization ratio of energy. 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.

Claims

1. A multi-mode energy storage microgrid comprises m groups of photovoltaic assemblies, fans and energy storage units which are connected to a primary bus of the microgrid in parallel, and a control system which is electrically connected with the photovoltaic assemblies, the fans and the energy storage units respectively, and is characterized in that the control system comprises n light storage integrated machines, a fan control cabinet, a photovoltaic inverter and an energy storage converter; wherein the content of the first and second substances,

2. The microgrid of claim 1, wherein at least one of the light-storage all-in-one machines is connected with the photovoltaic module and the lead-carbon battery respectively.

3. The microgrid of claim 1, wherein at least one of the light-storage all-in-one machines is connected with the photovoltaic module and the lithium iron phosphate battery respectively.

4. The microgrid of claim 1, wherein the control system comprises a distributed power generation control unit, the distributed power generation control unit comprises 2 light storage all-in-one machines, one of the light storage all-in-one machines is respectively connected with the photovoltaic module and the lead-carbon battery, and the other light storage all-in-one machine is respectively connected with the photovoltaic module and the lithium iron phosphate battery.

5. The microgrid of claim 1, wherein the control system of the microgrid further comprises a transformer, and the light storage all-in-one machine is connected to the primary busbar of the microgrid through a controllable switch and the transformer.

6. The microgrid of claim 1, wherein the m-n groups of photovoltaic modules are connected to the primary bus through the photovoltaic inverter.