CN114374249B - Energy storage system and arc discharge processing method thereof - Google Patents
Energy storage system and arc discharge processing method thereof Download PDFInfo
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- CN114374249B CN114374249B CN202210059414.6A CN202210059414A CN114374249B CN 114374249 B CN114374249 B CN 114374249B CN 202210059414 A CN202210059414 A CN 202210059414A CN 114374249 B CN114374249 B CN 114374249B
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- 238000004146 energy storage Methods 0.000 title claims abstract description 85
- 238000010891 electric arc Methods 0.000 title claims abstract description 28
- 238000003672 processing method Methods 0.000 title claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 23
- 230000005540 biological transmission Effects 0.000 claims abstract description 18
- 238000001514 detection method Methods 0.000 claims description 12
- 238000007599 discharging Methods 0.000 claims description 5
- 230000002457 bidirectional effect Effects 0.000 claims description 3
- 230000033228 biological regulation Effects 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 3
- 230000006641 stabilisation Effects 0.000 abstract description 3
- 238000011105 stabilization Methods 0.000 abstract description 3
- 230000002159 abnormal effect Effects 0.000 description 17
- 230000001276 controlling effect Effects 0.000 description 12
- 230000008569 process Effects 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000005856 abnormality Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 206010000369 Accident Diseases 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Classifications
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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
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00304—Overcurrent protection
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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
- H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
- H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
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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
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
-
- 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
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
- H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
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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
- Y02E40/10—Flexible AC transmission systems [FACTS]
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The invention provides an energy storage system and an arc discharge processing method thereof, wherein the method firstly judges whether a direct current arc appears in a power transmission branch of each DC/DC converter according to an arc characteristic signal corresponding to each DC/DC converter in the energy storage system; if at least one power transmission branch circuit has a direct current arc, controlling the power of the corresponding DC/DC converter to be reduced to a preset range, and controlling other DC/DC converters to respectively operate with the corresponding preset power; and further, the shutdown of the whole energy storage system when the arc fault is detected is avoided, so that the energy storage system can continuously realize the stabilization effect on the power system.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to an energy storage system and an arc discharge processing method thereof.
Background
The energy storage technology is used as an important component in the power system, so that the running stability of the power system can be effectively improved, the peak valley difference between day and night is eliminated, and the load is smoothed; the method can also stabilize the output fluctuation of the renewable energy sources, eliminate the impact on the power system and promote the development of the renewable energy sources. Compared with other energy storage technologies, the battery energy storage system (Battery Energy Storage System, BESS) has the advantages of high energy density, high response speed, high charge and discharge times, low construction environment requirements and the like, so that more and more large-capacity battery energy storage systems are integrated into a power grid at home and abroad.
As the battery energy storage system is widely used at home and abroad, the safety problem of the battery energy storage system is paid attention to, so that the battery energy storage system is required to have a direct current arc fault detection function, and the fire risk caused by arc faults is reduced. However, in the prior art, when an arc fault is detected, the whole energy storage system is controlled to be stopped, so that the energy storage system is failed to be scheduled, and at the moment, the stabilizing effect of the energy storage system on the whole power system is invalid.
Disclosure of Invention
In view of the above, the present invention provides an energy storage system and an arc discharge processing method thereof, so as to avoid failure of the energy storage system when arc faults are detected.
In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:
The first aspect of the present invention provides an arc discharge processing method of an energy storage system, the energy storage system comprising: at least two DC/DC converters with one side connected in parallel with the DC bus, and a battery unit with the other side connected with the DC/DC converters; the arc discharge processing method comprises the following steps:
judging whether direct current arcs appear in power transmission branches of the DC/DC converters according to arc characteristic signals corresponding to the DC/DC converters;
And if at least one power transmission branch circuit has a direct current arc, controlling the power of the corresponding DC/DC converter to be reduced to a preset range, and controlling other DC/DC converters to operate at corresponding preset powers respectively.
Optionally, the sum of all the preset powers is the scheduling instruction power of the energy storage system.
Optionally, each preset power is the same.
Optionally, each preset power is related to at least one of the following parameters respectively:
SOC of the corresponding battery cell;
The temperature of the corresponding battery cell; the method comprises the steps of,
And corresponding to the voltage of the battery cell.
Optionally, if the energy storage system is in a discharging state, each preset power is positively related to the SOC and/or voltage of the corresponding battery unit, or is negatively related to the temperature of the corresponding battery unit, respectively;
And if the energy storage system is in a charging state, each preset power is respectively and inversely related to at least one of the SOC, the voltage and the temperature of the corresponding battery unit.
Optionally, before controlling the power of the corresponding DC/DC converter to fall within the preset range and controlling the other DC/DC converters to operate with the corresponding preset powers, the method further includes:
recording the power of the DC/DC converter with the occurrence of a direct current arc as a first power;
after controlling the power of the corresponding DC/DC converter to fall within a preset range and controlling other DC/DC converters to respectively operate with the corresponding preset power, the method further comprises the following steps:
after a first preset time, controlling all the DC/DC converters to be restored to the state before power regulation is carried out on the DC/DC converters;
After a second preset time, recording the power of the DC/DC converter with the DC arc again as a second power;
judging whether the difference between the absolute values of the first power and the second power is larger than a preset threshold value or not;
And if the difference between the absolute values is larger than the preset threshold value, judging that the DC/DC converter with the direct current arc has an arc-drawing fault.
Optionally, determining whether a DC arc occurs in a power transmission branch of each DC/DC converter according to an arc characteristic signal corresponding to each DC/DC converter includes:
analyzing each arc characteristic signal to obtain each corresponding frequency domain signal;
Judging whether each frequency domain signal exceeds a preset value;
and if the frequency domain signal exceeds the preset value, judging that the corresponding power transmission branch circuit has a direct current arc.
The second aspect of the present invention also provides an energy storage system comprising: the device comprises a controller, at least one detection device, at least two DC/DC converters and battery units respectively connected with the DC/DC converters; wherein,
The DC/DC converter is a bidirectional converter;
The other side of the DC/DC converter is connected in parallel with a direct current bus;
The detection device is used for detecting arc characteristic signals corresponding to the DC/DC converters and sending the arc characteristic signals to the controller;
the controller is configured to perform the arc discharge processing method of the energy storage system according to any one of the preceding paragraphs.
Optionally, the detection device is a sensor for detecting leakage current.
Optionally, the number of the sensors is the same as that of the DC/DC converters, and the sensors are in one-to-one correspondence with the DC/DC converters.
Optionally, the battery unit is a battery cluster.
Optionally, the method further comprises: a DC/AC converter;
The alternating current side of the DC/AC converter is connected with a power grid and/or a load;
And a bus capacitor is arranged between the anode and the cathode of the direct current bus.
The invention provides an arc discharge processing method of an energy storage system, which comprises the steps of firstly judging whether a direct current arc appears in a power transmission branch of each DC/DC converter according to arc characteristic signals corresponding to each DC/DC converter in the energy storage system; if at least one power transmission branch circuit has a direct current arc, controlling the power of the corresponding DC/DC converter to be reduced to a preset range, and controlling other DC/DC converters to respectively operate with the corresponding preset power; and further, the shutdown of the whole energy storage system when the arc fault is detected is avoided, so that the energy storage system can continuously realize the stabilization effect on the power system.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will briefly explain the embodiments or the drawings to be used in the description of the prior art, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an energy storage system according to the prior art;
FIG. 2 is a flowchart of an arc discharge processing method of an energy storage system according to an embodiment of the present invention;
FIG. 3 is a partial flow chart of an arc discharge processing method of an energy storage system according to an embodiment of the present invention;
FIG. 4 is another flowchart of an arc discharge processing method of an energy storage system according to an embodiment of the present invention;
fig. 5 is a schematic diagram of an application of a sensor in an energy storage system according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the present disclosure, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The invention provides an arc discharge processing method of an energy storage system, which is used for avoiding the failure of the energy storage system when arc faults are detected.
As shown in fig. 1, the energy storage system includes: at least two DC/DC converters (DC/DC 1, DC/DC 2 … DC/DC n as shown in the figure) with one side connected in parallel to the DC bus, and a Battery unit (Battery 1, battery 2 … Batteryn as shown in the figure) connected with the other side of the DC/DC converters; in practical application, each DC/DC converter may be connected to one battery unit, or may be connected to at least two battery units in parallel; the battery unit may refer to a battery cluster, a battery pack, a battery box and the like, and is within the scope of the present application according to the specific application environment.
As shown in fig. 2, the arc discharge processing method of the energy storage system includes:
s101, judging whether direct current arcs appear in power transmission branches of the DC/DC converters according to arc characteristic signals corresponding to the DC/DC converters.
Energy storage direct current arc faults are divided into a series type and a parallel type, wherein the series arc faults are more common and are generally caused by bad contact among electric cells in a battery pack, between battery packs, between a wiring and a junction box, between broken connection lines and the like. The energy of the series arc is large, the damage to the circuit and the equipment is extremely large, and the fire accident is easy to cause. The prior art generally judges series arc faults according to some abrupt change characteristics of direct current in a time domain or a frequency domain.
In this embodiment, the detection and judgment process for the dc arc may be the same as the prior art, for example, the judgment is also performed by using some abrupt change features in the frequency domain, and the specific process is as shown in fig. 3, and includes:
S201, analyzing each arc characteristic signal to obtain each corresponding frequency domain signal.
The arc characteristic signal may refer to a voltage signal detected by a sensor for detecting leakage current. The process of analyzing the signal to obtain the frequency domain signal thereof is only needed by referring to the prior art, and will not be described in detail.
S202, judging whether each frequency domain signal exceeds a preset value.
And S203, if the frequency domain signal exceeds a preset value, judging that the corresponding power transmission branch circuit has a direct current arc.
If there is at least one power transmission branch, a dc arc occurs, step S102 is performed.
S102, controlling the power of the corresponding DC/DC converter to be reduced to be within a preset range, and controlling other DC/DC converters to respectively operate at the corresponding preset power.
The preset range may be a small value close to zero, so that the corresponding DC/DC converter enters a standby state, thereby ensuring that the power transmission branch having the DC arc is disconnected, and no more serious faults and safety problems occur.
In practical application, the preset power corresponding to each other DC/DC converter can be set in real time according to the practical situation, can be set in advance, and can also keep the original power, so long as the other DC/DC converters are still in an operating state, the energy storage system can keep the function of externally charging and discharging.
According to the arc discharge processing method of the energy storage system, through the principle, the whole energy storage system can be prevented from being stopped when an arc fault is detected, and the energy storage system can continue to achieve the stabilizing effect on the power system.
It is worth to say that, as the energy storage system is commonly used, power abnormality of the power system is easily caused under the abnormal condition, and further output power fluctuation is caused, namely, the energy storage system fails to schedule. Therefore, based on the above embodiment, preferably, in step S102, the sum of all the preset powers may be set as the scheduling instruction power of the energy storage system.
That is, when the direct current arc occurs in the power transmission branch of any DC/DC converter, even if the operation of the power transmission branch is stopped, the power of other DC/DC converters can be regulated, so that the whole power of the whole energy storage system cannot fluctuate, the whole energy storage system can be ensured to realize the dispatching instruction power, the dispatching function of the whole energy storage system is further normally realized, and the stabilization effect on the power system can be ensured; if the direct current bus is connected to the grid through a corresponding DC/AC converter, it is also possible to reduce its impact on the grid.
In practical application, the operation of the energy storage system is divided into a charging state and a discharging state, and the discharging state is taken as an example for explanation:
If the occurrence of direct current arc in the Kth path is detected, the current I SK1 and the power P SK1 of the abnormal branch K are recorded, then the corresponding DC/DC converter, namely the DC/DC K, is controlled to be reduced to a certain threshold value, the DC/DC converters in other paths are controlled to continuously work, the power of the other paths is increased, and energy is supplemented, so that the external overall power of the energy storage system is kept unchanged, namely power fluctuation does not occur, and the normal scheduling of the energy storage system is further ensured.
For example, when 10 DC/DC converters work, each 100KW is operated for a total of 1MW, a controller of the energy storage system, such as a total power scheduling unit, turns off the DC/DC 1 and the DC/DC 2 after detecting that the DC/DC 1 and the DC/DC 2 are abnormal, and distributes the power of the DC/DC 1 and the DC/DC 2 to other DC/DC converters.
In practical application, when power distribution is carried out on other DC/DC converters, one scheme is to carry out average distribution on the DC/DC converters, and at the moment, all preset powers are the same, namely, the power of other 8 paths of DC/DC converters is regulated to 125KW for operation, so that the output power of an energy storage system is ensured to be 1MW, the output is unchanged, and the influence on normal scheduling of energy storage is avoided. Another solution is to distribute these DC/DC converters unevenly, for example, it may be to distribute at least one of SOC (State of charge), temperature, voltage, etc. of the corresponding battery cells; taking the SOC as an example, the distribution can be carried out according to the SOC of the battery unit connected with other 8 paths of DC/DC converters, the larger the SOC is, the larger the distribution power is, and the lower the SOC is, the lower the distribution power is; alternatively, the SOC of the other 8-way battery unit may be obtained, and the average value soc_ave is obtained, so that SOC is greater than soc_ave and outputs more energy to be distributed, and SOC is less than soc_ave and outputs less energy to be distributed.
That is, when the energy storage system is in a discharge state, each preset power is positively related to the SOC and/or voltage of the corresponding battery cell, and the larger the SOC and/or voltage is, the larger the allocated power is; alternatively, the respective preset powers may be inversely related to the temperatures of the respective battery cells, i.e., the higher the temperature, the lower the power allocated thereto.
The energy storage system can be pushed in this way, except that the higher the temperature of the battery unit is, the more power should be reduced, so that each preset power in the charging state is inversely related to at least one of the SOC, voltage and temperature of the corresponding battery unit.
According to the embodiment, the DC/DC of the abnormal branch and the DC/DC of the non-abnormal branch are controlled, so that fluctuation of the overall power of the energy storage system is greatly reduced, impact on the power grid voltage is reduced, normal dispatching of the energy storage system is guaranteed, economic losses caused by unnecessary shutdown are avoided, and reliable operation of an applied power system such as a photovoltaic system is effectively guaranteed.
It should be noted that, in the above embodiment, after the step S101 is performed for one time, it is determined that the power conversion branch having the DC arc is an abnormal branch, and the DC/DC converter in the abnormal branch is controlled not to be started any more, and only the DC/DC in the non-abnormal branch continues to operate according to the above scheme; however, in the energy storage system, particularly in the energy storage converter, due to the fact that the energy storage system comprises a large number of power electronic switching devices, noise generated during normal operation of the system can cause great interference to most of the existing arc detection technologies; therefore, the accuracy of the detection result cannot be completely ensured by detecting only the single characteristic of the arc; in order to avoid false detection caused by the energy storage system being susceptible to interference of environmental noise and other system actions, the arc discharge processing method provided in this embodiment is preferably based on the above embodiment, as shown in fig. 4:
it further includes, before step S102:
s301, the power of the DC/DC converter in which the direct current arc occurs is recorded as the first power.
And, after step S102, further includes:
S302, after a first preset time, all the DC/DC converters are controlled to be restored to the state before power regulation is carried out on the converters.
And S303, after a second preset time, recording the power of the DC/DC converter with the direct current arc again as a second power.
S304, judging whether the difference between the absolute values of the first power and the second power is larger than a preset threshold value.
If the difference between the absolute values is greater than the preset threshold, step S305 is performed.
S305, judging that the DC/DC converter with the direct current arc generates arc discharge faults.
The discharge state will be described as an example:
If the occurrence of arc discharge of the Kth path is detected, the power of the abnormal branch circuit K at the moment is recorded and used as a first power P SK1, then the corresponding DC/DC converter, namely the DC/DC K, is controlled to be reduced to a certain threshold value, the DC/DC converters of other paths are controlled to continuously work, the power of the other paths is increased, and energy is supplemented, so that the external overall power of the energy storage system is kept unchanged, namely power fluctuation does not occur, and the normal scheduling of the energy storage system is further ensured; this process continues for a period of time, i.e., a first preset time H1; after the first preset time H1 is over, the DC/DC K in the abnormal branch is controlled to work quickly, the power is regulated to the first power P SK1, and the DC/DC converter in the non-abnormal branch is controlled to exit the running state and restore to the original power. After delaying for a second preset time H2, detecting the power of the DC/DC K in the abnormal branch circuit at the moment, and taking the power as a second power P SK2; note that the second power P SK2 may be positive or negative. Finally, calculating the difference P delta= (|P SK1|-|PSK2 |) between the absolute values of the power of the abnormal branch circuit K before and after the operation, and considering that the arc discharge fault occurs when the value of the difference P delta= (|P SK1|-|PSK2 |) is larger than a preset threshold value Pset. The state of charge can be similarly calculated and will not be described again.
According to the embodiment, the power adjustment is carried out on the DC/DC converter of the abnormal branch circuit and the DC/DC converter of the non-abnormal branch circuit, so that the overall power stability of the energy storage system is ensured, the possibility of misjudgment of an arc discharge fault is reduced by comparing the power of the abnormal branch circuit before and after stopping and recovering operation, unnecessary fault judgment and subsequent operation are avoided, the false alarm rate of the arc fault is greatly reduced, and the false alarm rate of the arc fault can be reduced.
Another embodiment of the present application also provides an energy storage system, as shown in fig. 1, including: a controller (not shown), at least one detecting device (CT 1, CT 2 … CT n shown in the figure), at least two DC/DC converters (DC/DC 1, DC/DC 2 … DC/DC n shown in the figure), and Battery units (Battery 1, battery2 … Batteryn shown in the figure) to which each DC/DC converter is connected respectively; each DC/DC converter can be respectively connected with one battery unit or at least two battery units in parallel connection; the battery unit may refer to a battery cluster, a battery pack, a battery box and the like, and is within the scope of the present application according to the specific application environment.
Each DC/DC converter is a bidirectional converter; the other side of each DC/DC converter is connected in parallel with a direct current bus, and a bus capacitor is generally arranged between the positive electrode and the negative electrode of the direct current bus. In practical applications, the DC bus is typically connected to a power grid and/or a load through a DC/AC converter, which may be an original device in a power system, such as an inverter in a photovoltaic system; or the DC/AC converter may be a self-contained device in the energy storage system; all are within the protection scope of the application, and are determined according to the specific application environment.
The detection device is used for detecting an arc characteristic signal (V CT1、VCT2…VCTn shown in the figure) corresponding to the corresponding DC/DC converter and sending the arc characteristic signal to the controller.
In practical applications, the detecting device is a sensor for detecting leakage current, and the number of the sensors may be the same as that of the DC/DC converters, and each sensor corresponds to each DC/DC converter one by one, as shown in fig. 1.
In this case, the control DC/DC converter described in the arc discharge processing method performs a certain operation not only for one DC/DC converter but also for the DC/DC converter detected by the corresponding sensor. As shown in fig. 5, the sensor CT1 is provided with cables (pv1_str1 and pv1_str2) for two battery cells of DC/DC 1 and cables (pv2_str1 and pv2_str2) for two battery cells of DC/DC 2; if the sensor CT1 detects an abnormality, controlling the power of the DC/DC 1 and the power of the DC/DC 2 to be reduced to be within a preset range; and by analogy, if the abnormal sensor passes through the cables of the M DC/DC converters, the M DC/DC converters are closed, and the difference value of the power/current of the M DC/DC converters before and after stopping the operation of the recovery is correspondingly detected and compared.
The controller is configured to execute the arc discharge processing method of the energy storage system according to any of the foregoing embodiments, and specific processes and principles of the method may be referred to the foregoing embodiments, which are not described herein in detail. By executing the arc discharge processing method, the whole power stability of the energy storage system can be ensured, the false alarm rate of arc faults can be reduced, and the popularization is facilitated.
In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for a system or system embodiment, since it is substantially similar to a method embodiment, the description is relatively simple, with reference to the description of the method embodiment being made in part. The systems and system embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative elements and steps are described above generally in terms of functionality in order to clearly illustrate the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The features described in the various embodiments of the present disclosure may be interchanged or combined with one another in the description of the disclosed embodiments to enable those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. An arc discharge processing method of an energy storage system, wherein the energy storage system comprises: at least two DC/DC converters with one side connected in parallel with the DC bus, and a battery unit with the other side connected with the DC/DC converters; the arc discharge processing method comprises the following steps:
judging whether direct current arcs appear in power transmission branches of the DC/DC converters according to arc characteristic signals corresponding to the DC/DC converters;
If at least one power transmission branch circuit has a direct current arc, controlling the power of the corresponding DC/DC converter to be reduced to a preset range, and controlling the power of other DC/DC converters to be increased so that the other DC/DC converters respectively operate with corresponding preset power, so that the overall power of the energy storage system is kept unchanged;
The sum of all the preset powers is the scheduling instruction power of the energy storage system;
each preset power is respectively related to at least one of the following parameters:
The residual electric quantity SOC of the corresponding battery unit;
The temperature of the corresponding battery cell; the method comprises the steps of,
Voltages corresponding to the battery cells;
If the energy storage system is in a discharging state, each preset power is respectively positively related to the SOC and/or the voltage of the corresponding battery unit or respectively negatively related to the temperature of the corresponding battery unit;
And if the energy storage system is in a charging state, each preset power is respectively and inversely related to at least one of the SOC, the voltage and the temperature of the corresponding battery unit.
2. The method of claim 1, wherein each of the predetermined powers is the same.
3. The arc discharge processing method of an energy storage system according to any one of claims 1 to 2, further comprising, before controlling the power of the corresponding DC/DC converter to fall within a preset range and controlling the other DC/DC converters to operate at the corresponding preset powers, respectively:
recording the power of the DC/DC converter with the occurrence of a direct current arc as a first power;
after controlling the power of the corresponding DC/DC converter to fall within a preset range and controlling other DC/DC converters to respectively operate with the corresponding preset power, the method further comprises the following steps:
after a first preset time, controlling all the DC/DC converters to be restored to the state before power regulation is carried out on the DC/DC converters;
After a second preset time, recording the power of the DC/DC converter with the DC arc again as a second power;
judging whether the difference between the absolute values of the first power and the second power is larger than a preset threshold value or not;
And if the difference between the absolute values is larger than the preset threshold value, judging that the DC/DC converter with the direct current arc has an arc-drawing fault.
4. The arc discharge processing method of any one of claims 1 to 2, wherein determining whether a DC arc occurs in a power transmission branch of each DC/DC converter according to an arc characteristic signal corresponding to each DC/DC converter comprises:
analyzing each arc characteristic signal to obtain each corresponding frequency domain signal;
Judging whether each frequency domain signal exceeds a preset value;
and if the frequency domain signal exceeds the preset value, judging that the corresponding power transmission branch circuit has a direct current arc.
5. An energy storage system, comprising: the device comprises a controller, at least one detection device, at least two DC/DC converters and battery units respectively connected with the DC/DC converters; wherein,
The DC/DC converter is a bidirectional converter;
The other side of the DC/DC converter is connected in parallel with a direct current bus;
The detection device is used for detecting arc characteristic signals corresponding to the DC/DC converters and sending the arc characteristic signals to the controller;
the controller is configured to perform the arc discharge processing method of the energy storage system according to any one of claims 1 to 4.
6. The energy storage system of claim 5, wherein said detection means is a sensor for detecting leakage current.
7. The energy storage system of claim 6, wherein the number of sensors is the same as the DC/DC converter and the sensors are in one-to-one correspondence with the DC/DC converter.
8. The energy storage system of any of claims 5 to 7, wherein the battery cells are battery clusters.
9. The energy storage system of any of claims 5 to 7, further comprising: a DC/AC converter;
The alternating current side of the DC/AC converter is connected with a power grid and/or a load;
And a bus capacitor is arranged between the anode and the cathode of the direct current bus.
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