CN114374249A - 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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- 238000004146 energy storage Methods 0.000 title claims abstract description 86
- 238000010891 electric arc Methods 0.000 title claims abstract description 33
- 238000003672 processing method Methods 0.000 title claims abstract description 28
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- 230000002159 abnormal effect Effects 0.000 description 20
- 230000001276 controlling effect Effects 0.000 description 17
- 238000007599 discharging Methods 0.000 description 5
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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
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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
- 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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- 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 comprises the steps of firstly judging whether a power transmission branch of each DC/DC converter has a direct current arc or not 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 at corresponding preset power; and then 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 stabilizing 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 operation stability of the power system can be effectively improved, the day and night peak-valley difference is eliminated, and the load is smoothed; the output fluctuation of the renewable energy can be stabilized, the impact of the renewable energy on a power system is eliminated, and the development of the renewable energy is promoted. Compared with other Energy Storage technologies, a Battery Energy Storage System (BESS) has the advantages of high Energy density, high response speed, high charge-discharge multiple, low construction environment requirement and the like, so that more and more high-capacity Battery Energy Storage systems are incorporated into a power grid at home and abroad.
With the widespread application of battery energy storage systems at home and abroad, the safety problem of the battery energy storage systems is concerned, so that the battery energy storage systems are required to have a direct-current arc fault detection function so as to reduce the fire risk caused by arc faults. However, in the prior art, when an arc fault is detected, the entire energy storage system is controlled to be stopped, so that the energy storage system is failed to schedule, and at this time, the stabilizing effect of the energy storage system on the entire power system is failed.
Disclosure of Invention
In view of this, the present invention provides an energy storage system and an arc discharge processing method thereof to avoid failure of the energy storage system when an arc fault is detected.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the invention provides an arc discharge processing method of an energy storage system in a first aspect, wherein the energy storage system comprises: at least two DC/DC converters with one side connected in parallel to the DC bus, and a battery unit connected to the other side of the DC/DC converters; the arc discharge processing method comprises the following steps:
judging whether a power transmission branch of each DC/DC converter has a direct current arc or not according to the arc characteristic signal corresponding to each DC/DC converter;
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 respectively operate at corresponding preset power.
Optionally, the sum of all the preset powers is a scheduling command power of the energy storage system.
Optionally, each of the preset powers is the same.
Optionally, each of the preset powers is respectively associated with at least one of the following parameters:
the SOC of the respective battery cell;
the temperature of the respective battery cells; and a process for the preparation of a coating,
corresponding to the voltage of the battery cell.
Optionally, if the energy storage system is in a discharging state, each of the preset powers is positively related to the SOC and/or the voltage of the corresponding battery unit, or 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 negatively related to at least one of the SOC, the voltage and the temperature of the corresponding battery unit.
Optionally, before controlling the power corresponding to the DC/DC converter to decrease to a preset range and controlling the other DC/DC converters to operate at corresponding preset powers, the method further includes:
recording the power of the DC/DC converter at which the direct current arc occurs as a first power;
after controlling the power corresponding to the DC/DC converter to be reduced to a preset range and controlling the other DC/DC converters to operate at corresponding preset powers, the method further includes:
after the first preset time, controlling all the DC/DC converters to recover 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 as a second power again;
judging whether the difference between the absolute values of the first power and the second power is greater than a preset threshold value or not;
and if the difference of the absolute values is larger than the preset threshold value, judging that the DC/DC converter with the DC arc has an arc discharge fault.
Optionally, determining whether a DC arc occurs in the power transmission branch of each DC/DC converter according to the arc characteristic signal corresponding to each DC/DC converter includes:
analyzing each arc characteristic signal to obtain respective corresponding frequency domain signals;
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, including: the device comprises a controller, at least one detection device, at least two DC/DC converters and battery units connected with the DC/DC converters respectively; 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 corresponding DC/DC converters and sending the arc characteristic signals to the controller;
the controller is configured to execute the arc discharge processing method of the energy storage system according to any of the paragraphs above.
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 correspond to the DC/DC converters one to one.
Optionally, the battery unit is a battery cluster.
Optionally, the method further includes: 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 positive electrode and the negative electrode 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 power transmission branch of each DC/DC converter has a direct current arc or not 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 at corresponding preset power; and then 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 stabilizing 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 drawings to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an energy storage system provided in 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 flowchart 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 view of an application of a sensor in an energy storage 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.
In this application, 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 an … …" does not exclude the presence of other identical 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 an arc fault is detected.
As shown in fig. 1, the energy storage system includes: at least two DC/DC converters (such as DC/DC 1 and DC/DC 2 … DC/DC n shown in the figure) with one side connected in parallel with the direct current bus, and Battery units (such as Battery 1 and Battery2 … Battery yn 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 in parallel to at least two battery units; moreover, the battery unit may refer to a battery cluster, a battery pack, a battery box, and the like, depending on the specific application environment, and is within the protection scope of the present application.
As shown in fig. 2, the arc discharge processing method of the energy storage system includes:
s101, judging whether the power transmission branch of each DC/DC converter has a direct current arc or not according to the arc characteristic signal corresponding to each DC/DC converter.
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 poor contact among battery cells in a battery pack, between the battery pack and the battery pack, between a wiring and a junction box, between broken connecting wires and the like. The series arc has large energy, great harm to lines and equipment and easy fire accident. The prior art generally judges the series type arc fault according to some sudden change characteristics of direct current in a time domain or a frequency domain.
In this embodiment, the detection and determination process for the dc arc may be the same as that in the prior art, for example, the determination is performed by also performing some abrupt change characteristics on the frequency domain, and a specific process thereof is shown in fig. 3, and includes:
s201, analyzing the arc characteristic signals to obtain corresponding frequency domain signals.
The arc signature may be a voltage signal detected by a sensor for detecting the leakage current. The process of analyzing the signal to obtain the frequency domain signal thereof may be referred to in the prior art, and is not described in detail.
S202, judging whether the frequency domain signals exceed preset values.
And S203, if the frequency domain signal exceeds the preset value, judging that the corresponding power transmission branch circuit has the direct current arc.
If at least one power transmission branch circuit has a direct current arc, step S102 is executed.
And S102, 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 at corresponding preset power.
The preset range can be a small value close to zero, so that the corresponding DC/DC converter enters a standby state, and further the power transmission branch with the direct current arc is ensured to be disconnected, and further more serious faults and safety problems can not occur.
In practical application, the preset power corresponding to each of the other DC/DC converters may be set in real time according to actual conditions, may also be set in advance, and may also maintain its original power, all within the protection scope of the present application, as long as it is ensured that each of the other DC/DC converters is still in an operating state, the energy storage system may be enabled to retain the function of externally performing charging and discharging.
According to the arc discharge processing method of the energy storage system, the shutdown of the whole energy storage system can be avoided when the arc fault is detected through the principle, so that the energy storage system can continuously realize the stabilizing effect on the power system.
It is worth explaining that, as the energy storage system is generally applied, power abnormality of the power system is easily caused under the abnormal condition, and further output power fluctuation is caused, that is, the energy storage system fails to be scheduled. Therefore, on the basis of the above embodiment, preferably, in step S102, the sum of all preset powers may be set as the scheduling command power of the energy storage system.
That is, when a power transmission branch of any DC/DC converter generates a direct current arc, even if the power transmission branch stops operating, the power of other DC/DC converters can be regulated, so that the overall power of the DC/DC converters cannot fluctuate, the whole energy storage system can realize the dispatching instruction power, the dispatching function of the energy storage system can be normally realized, and the power transmission branch can realize the stable action on the power system; if the direct current buses are connected with the power grid through the corresponding DC/AC converters, the impact of the direct current buses on the power grid can be reduced.
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 direct current arc is detected to appear in the Kth path, recording the current I of the abnormal branch K at the momentSK1And power PSK1And then controlling the corresponding DC/DC converter, namely DC/DC K, so that the power of the DC/DC converter is reduced to a certain threshold value, controlling the DC/DC converters of other paths to continuously work, increasing the power of other paths, and performing energy supplement, so that the external overall power of the energy storage system is kept unchanged, namely no power fluctuation occurs, and further ensuring the normal scheduling of the energy storage system.
For example, when 10 DC/DC converters work, each of 100KW runs at 1MW, and a controller of the energy storage system, such as a total power scheduling unit, detects that DC/DC 1 and DC/DC 2 are abnormal, turns off DC/DC 1 and DC/DC 2, and distributes power of DC/DC 1 and DC/DC 2 to other DC/DC converters.
In practical application, when other DC/DC converters are subjected to power distribution, one scheme is to perform average distribution on the DC/DC converters, and at the moment, all preset powers are the same, namely, the powers of the other 8-path DC/DC converters are regulated to 125KW for operation, so that the output power of the energy storage system is ensured to be unchanged at 1MW, and the influence on normal energy storage scheduling is avoided. Another scheme is to distribute these DC/DC converters unevenly, for example, the distribution may be performed according to at least one of SOC (State of charge), temperature, voltage, and the like of the corresponding battery unit; taking the SOC as an example, the distribution can be performed according to the SOC of the battery unit connected to the other 8-circuit DC/DC converter, 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 cells may be obtained, and the average value SOC _ AVE may be obtained, so that the SOC is greater than the SOC _ AVE and the output thereof is more distributed, and the SOC is less than the SOC _ AVE and the output thereof is less distributed.
That is, when the energy storage system is in a discharging state, each preset power is positively related to the SOC and/or the voltage of the corresponding battery unit, and the larger the SOC and/or the voltage is, the larger the distributed power is; alternatively, each preset power may also be negatively correlated to the temperature of the corresponding battery cell, i.e., the higher the temperature, the lower the distributed power.
The energy storage system may be in a charging state by analogy, except that the higher the temperature of the battery unit is, the more the power of the battery unit should be reduced, and therefore, each preset power in the charging state is negatively related to at least one of the SOC, the voltage and the temperature of the corresponding battery unit.
According to the embodiment, the abnormal branch DC/DC and the non-abnormal branch DC/DC are controlled, so that the fluctuation of the overall power of the energy storage system is greatly reduced, the impact of the abnormal branch DC/DC and the non-abnormal branch DC/DC on the voltage of a power grid is reduced, the energy storage system can be normally scheduled, the economic loss caused by unnecessary shutdown is avoided, and the reliable operation of an electric power system such as a photovoltaic system applied by the energy storage system is effectively guaranteed.
It should be noted that, in the previous embodiment, after the step S101 is performed for one time, it is determined that the power conversion branch in which the DC arc occurs is an abnormal branch, and the DC/DC converter in the abnormal branch is controlled not to be started, and only the DC/DC converter in the non-abnormal branch continues to operate according to the above scheme; however, in the energy storage system, especially in the energy storage converter, because of the 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 guaranteed only by detecting the arc with the single characteristic; in order to avoid false detection caused by the environmental noise and interference of other system actions, the arc discharge processing method provided in this embodiment is preferably based on the previous embodiment, as shown in fig. 4:
before step S102, the method further includes:
s301, recording the power of the DC/DC converter with the DC arc as a first power.
Further, after step S102, the method further includes:
and S302, after the first preset time, controlling all the DC/DC converters to recover to the state before power regulation is carried out on the DC/DC converters.
And S303, after a second preset time, recording the power of the DC/DC converter with the DC arc as a second power again.
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 predetermined threshold, step S305 is executed.
S305, judging that the arc discharge fault occurs in the DC/DC converter with the direct current arc.
The discharge state is still taken as an example for explanation:
if detecting that the K-th path generates arc discharge, recording the power of the abnormal branch K at the moment as the first power PSK1Then, the corresponding DC/DC converter, namely DC/DC K, is controlled to enable the power of the DC/DC converter to be reduced to a certain threshold value, and the DC/DC converters of other paths are controlled to continue working and increase the power of other paths for energy supplement, so that the external overall power of the energy storage system is kept unchanged, namely no power fluctuation occurs, 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, controlling the DC/DC K in the abnormal branch to work quickly and adjusting the power to the first power PSK1And controlling the DC/DC converters in the non-abnormal branches to exit the running state and recover to the respective original power. After delaying for a second preset time H2, detecting the power of DC/DC K in the abnormal branch at the moment as a second power PSK2(ii) a It should be noted that the second power PSK2May be positive or negative. Finally, the difference P Δ (P) between the absolute values of the power of the abnormal branch K before and after the above operation is calculatedSK1|-|PSK2And |) when the value is larger than a preset threshold value Pset, the arc discharge fault is considered to occur. The charging state can be analogized in the same way, and the description is omitted.
The embodiment not only ensures the stability of the overall power of the energy storage system by adjusting the power of the DC/DC converter of the abnormal branch and the power of the DC/DC converter of the non-abnormal branch, but also reduces the possibility of misjudgment of the arcing fault by comparing the powers of the abnormal branch before and after the abnormal branch stops and resumes operation, avoids unnecessary fault judgment and subsequent operation, greatly reduces the false alarm rate of the arc fault, and can reduce the false alarm rate of the arc fault.
Another embodiment of the present invention further provides an energy storage system, as shown in fig. 1, including: a controller (not shown), at least one detection device (such as CT1, CT 2 … CT n shown in the figure), at least two DC/DC converters (such as DC/DC 1, DC/DC 2 … DC/DC n shown in the figure), and Battery units (such as Battery 1, Battery2 … Battery) respectively connected to the DC/DC converters; each DC/DC converter can be respectively connected with one battery unit, and also can be respectively connected with at least two battery units in parallel; moreover, the battery unit may refer to a battery cluster, a battery pack, a battery box, and the like, depending on the specific application environment, and is within the protection scope of the present application.
In addition, 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 generally connected to the grid and/or the load through a DC/AC converter, which may be a primary device in the power system, such as an inverter in the photovoltaic system; alternatively, the DC/AC converter may be a self-contained device in the energy storage system; all within the scope of protection of the present application, depending on the specific application environment.
The detecting device is used for detecting arc characteristic signals (such as V shown in the figure) corresponding to the corresponding DC/DC convertersCT1、VCT2…VCTn) And sends it 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 may perform an operation not only on one DC/DC converter but also on the DC/DC converter detected by the corresponding sensor. As shown in fig. 5, cables of two battery units of DC/DC 1 (PV1_ str1 and PV1_ str2) and cables of two battery units of DC/DC 2 (PV2_ str1 and PV2_ str2) pass through the sensor CT 1; if the sensor CT1 detects the abnormality, controlling the power of the DC/DC 1 and the DC/DC 2 to fall within a preset range; and in the same way, if the abnormal sensor is detected to pass 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 paths of DC/DC converters before and after the M paths of DC/DC converters stop and resume operation is correspondingly detected and compared.
The controller is configured to execute the arc discharge processing method of the energy storage system according to any embodiment, and the specific process and principle of the method are described in the embodiments, which are not described in detail herein. By executing the arc discharge processing method, the overall power stability of the energy storage system can be ensured, the false alarm rate of the arc fault can be reduced, the missing alarm rate of the arc fault can be reduced, and the method is favorable for popularization.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
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 components and steps have been described above generally in terms of their functionality in order to clearly illustrate this 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 implementation. 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.
In the above description of the disclosed embodiments, the features described in the embodiments in this specification may be replaced or combined with each other 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 (12)
1. An arc discharge processing method of an energy storage system is characterized in that the energy storage system comprises the following steps: at least two DC/DC converters with one side connected in parallel to the DC bus, and a battery unit connected to the other side of the DC/DC converters; the arc discharge processing method comprises the following steps:
judging whether a power transmission branch of each DC/DC converter has a direct current arc or not according to the arc characteristic signal corresponding to each DC/DC converter;
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 respectively operate at corresponding preset power.
2. The arc discharge processing method of the energy storage system according to claim 1, wherein the sum of all the preset powers is a scheduling command power of the energy storage system.
3. The energy storage system arc discharge processing method according to claim 2, wherein each of the preset powers is the same.
4. The arc discharge processing method of the energy storage system according to claim 2, wherein each of the predetermined powers is respectively associated with at least one of the following parameters:
the residual capacity SOC of the corresponding battery unit;
the temperature of the respective battery cells; and a process for the preparation of a coating,
corresponding to the voltage of the battery cell.
5. The arc discharge processing method of the energy storage system according to claim 4, wherein if the energy storage system is in a discharge state, each of the preset powers is positively related to the SOC and/or the voltage of the corresponding battery unit, or 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 negatively related to at least one of the SOC, the voltage and the temperature of the corresponding battery unit.
6. The arc discharge processing method of the energy storage system according to any one of claims 1 to 5, 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 corresponding preset powers, respectively:
recording the power of the DC/DC converter at which the direct current arc occurs as a first power;
after controlling the power corresponding to the DC/DC converter to be reduced to a preset range and controlling the other DC/DC converters to operate at corresponding preset powers, the method further includes:
after the first preset time, controlling all the DC/DC converters to recover 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 as a second power again;
judging whether the difference between the absolute values of the first power and the second power is greater than a preset threshold value or not;
and if the difference of the absolute values is larger than the preset threshold value, judging that the DC/DC converter with the DC arc has an arc discharge fault.
7. The arc discharge processing method of the energy storage system according to any one of claims 1 to 5, wherein judging whether a direct current 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 respective corresponding frequency domain signals;
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.
8. An energy storage system, comprising: the device comprises a controller, at least one detection device, at least two DC/DC converters and battery units connected with the DC/DC converters respectively; 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 corresponding DC/DC converters and sending the arc characteristic signals to the controller;
the controller is used for executing the arc discharge processing method of the energy storage system according to any one of claims 1 to 7.
9. The energy storage system of claim 8, wherein the detection device is a sensor that detects a leakage current.
10. The energy storage system of claim 9, wherein the number of sensors is the same as the number of DC/DC converters, and the sensors are in one-to-one correspondence with the DC/DC converters.
11. The energy storage system of any of claims 8-10, wherein the battery cells are battery clusters.
12. The energy storage system according to any one of claims 8 to 10, 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 positive electrode and the negative electrode of the direct current bus.
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