Fault identification method and device for optical storage direct flexible power supply system, electronic equipment and storage medium

Abstract

The invention discloses a fault identification method and device for an optical storage direct flexible power supply system, electronic equipment and a storage medium, and the method comprises the steps: employing a magnetic ring voltage as an identification basis, carrying out the pole-mode conversion of the magnetic ring voltage, obtaining a line mode voltage and a floor mode voltage, and taking the line mode voltage and the floor mode voltage as the basis of fault type identification and fault section positioning; the electrical quantity of a boundary element magnetic ring of a direct-current system line is adopted as a judgment basis, rapid fault detection is achieved through boundary characteristics of the magnetic ring, as long as a line circuit suddenly changes, the two ends of the magnetic ring can immediately capture an induced voltage peak, and the voltage of the magnetic ring serves as an electrical transient signal and is far faster than a sampling judgment mechanism of a controller; and dead zones and action time limit existing in traditional protection starting do not exist, millisecond-level fault recognition can be achieved, whole line protection is achieved, and the protection sensitivity is higher than that of a traditional mode.

Description

Technical Field

[0001] The present invention belongs to the field of DC fault detection technology, and particularly relates to a fault identification method, device, electronic equipment and storage medium for a photovoltaic-storage DC flexible power supply system. Background Art

[0002] Due to its characteristics such as high efficiency and flexibility, DC distribution systems have received extensive attention in recent years in scenarios such as data centers, rail transit, renewable energy access, and microgrids. DC distribution eliminates the energy conversion link from AC to DC, reduces conversion losses, and has no frequency characteristics, no fundamental wave and harmonic interference. Compared with complex AC distribution systems, the equipment is simpler and the dynamic response is faster.

[0003] Although DC distribution systems have advantages such as low line losses, high power quality, the ability to isolate AC and DC faults, and friendly access for distributed power sources and loads, due to the high peak value of fault current and the fact that the current does not pass through zero, it is difficult for circuit breakers to achieve natural arc extinction and thus difficult to trip. Compared with the drastic changes in current and voltage in AC systems, the voltage drop amplitude in DC systems is limited and the change slope is inconsistent, resulting in low reliability of traditional threshold methods. DC systems have a fast response, and voltage dips and current surges occur within milliseconds. Fault detection and protection actions need to have sub-millisecond identification capabilities, while most existing fault responses are greater than 5 ms, making it difficult to describe high-security scenarios. In addition, the fault characteristics of adjacent lines in the power grid of DC distribution systems are usually similar, making it difficult to distinguish between faults at the end of the protected line and external faults. Summary of the Invention

[0004] Based on this, the present invention aims to propose a fault identification method and related device for a photovoltaic-storage DC flexible power supply system, which uses the electrical quantity characteristics of magnetic rings after system faults for fault identification and fault section location.

[0005] In a first aspect, the present invention provides a fault identification method for a photovoltaic-storage DC flexible power supply system, including:

[0006] Collect the magnetic ring voltage of the DC power supply system line;

[0007] When the magnetic ring voltage meets the protection start condition, perform a polar mode transformation on the magnetic ring voltage to obtain the magnetic ring line mode voltage and the magnetic ring ground mode voltage;

[0008] Determine the fault type and fault section according to the magnetic ring line mode voltage and the magnetic ring ground mode voltage.

[0009] Further, determining the fault type and fault section according to the magnetic ring line mode voltage and the magnetic ring ground mode voltage includes:

[0010] Within a preset time window, perform integral calculations on the magnetic ring line mode voltage and the magnetic ring ground mode voltage respectively to obtain the line mode voltage integral value and the ground mode voltage integral value;

[0011] Determine the fault type based on the integral value of the ground-mode voltage, and determine the fault section based on the integral value of the line-mode voltage.

[0012] Further, the pole-mode transformation of the magnetic-ring voltage to obtain the magnetic-ring line-mode voltage and the magnetic-ring ground-mode voltage includes:

[0013] ,

[0014] Among them, and respectively represent the positive magnetic-ring voltage and the positive magnetic-ring voltage, represents the magnetic-ring line-mode voltage, represents the magnetic-ring ground-mode voltage.

[0015] Further, determining the fault type based on the integral value of the ground-mode voltage includes:

[0016] Compare the integral value of the ground-mode voltage with the fault-polarity selection threshold as follows:

[0017] ,

[0018] Among them, represents the fault type, and a, b, and c respectively represent positive-pole fault, bipolar fault, and negative-pole fault, represents the integral value of the ground-mode voltage, represents the fault-polarity selection threshold.

[0019] Further, determining the fault section based on the integral value of the line-mode voltage includes:

[0020] When the integral value of the line-mode voltage satisfies , determine that the fault section is within the zone and trigger the protection action, represents the zone-identification threshold.

[0021] Further, the protection startup condition includes:

[0022] The magnetic-ring voltage exceeds the preset action threshold.

[0023] Further, the magnetic-ring voltage exceeding the preset action threshold for the protection startup condition includes:

[0024] The magnetic-ring voltage exceeds the preset action threshold for N consecutive sampling values, N≥1.

[0025] In a second aspect, the present invention proposes a fault identification device for an optical storage DC flexible power supply system, including:

[0026] A magnetic-ring voltage acquisition module for acquiring the magnetic-ring voltage of the DC power supply system line;

[0027] A magnetic ring voltage conversion module is used to perform a polar-mode conversion on the magnetic ring voltage to obtain a magnetic ring line-mode voltage and a magnetic ring ground-mode voltage when the magnetic ring voltage meets the protection startup condition.

[0028] A fault identification module is used to determine the fault type and fault section according to the magnetic ring line-mode voltage and the magnetic ring ground-mode voltage.

[0029] In a third aspect, the present invention provides an electronic device, including a memory storing computer-executable instructions and a processor. When the computer-executable instructions are executed by the processor, the device executes each step of the fault identification method for a photovoltaic-storage-direct-current flexible power supply system provided in the first aspect.

[0030] In a fourth aspect, the present invention provides a readable storage medium storing a computer-executable program. When the program is executed, each step of the fault identification method for a photovoltaic-storage-direct-current flexible power supply system provided in the first aspect can be implemented.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention proposes a fault identification method for a photovoltaic-storage-direct-current flexible power supply system, using the magnetic ring voltage as the identification basis. By performing a polar-mode conversion on the magnetic ring voltage, the line-mode voltage and the ground-mode voltage are obtained as the basis for fault type identification and fault section location. The present invention uses the electrical quantity of the magnetic ring at the boundary element of the DC system line as the judgment basis, and utilizes the boundary characteristics of the magnetic ring to achieve rapid detection of faults. As long as there is a sudden change in the line circuit, the induced voltage spike can be immediately captured at both ends of the magnetic ring. The magnetic ring voltage, as an electrical transient signal, is much faster than the sampling judgment mechanism of the controller, and there is no dead zone and action time limit existing in the traditional protection startup, which can achieve millisecond-level fault identification and realize the full-line protection of the line, and the protection sensitivity is higher than the traditional method. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0034] Figure 1 It is a flowchart for implementing the fault identification method for a photovoltaic-storage-direct-current flexible power supply system provided in an embodiment of the present invention;

[0035] Figure 2 It is a schematic diagram of the simulation model of the photovoltaic-storage-direct-current flexible power supply system provided in an embodiment of the present invention;

[0036] Figure 3For a fault in an embodiment of the present invention The line voltages obtained by simulation and the line at both ends of the magnetic core;

[0037] Figure 4 For a fault in an embodiment of the present invention The line voltages obtained by simulation and the line at both ends of the magnetic core;

[0038] Figure 5 For a fault in an embodiment of the present invention The line voltages obtained by simulation and the line at both ends of the magnetic core;

[0039] Figure 6 Schematic diagram of the structure of a fault identification device for an optical storage direct current flexible power supply system provided by an embodiment of the present invention;

[0040] Figure 7 Architecture diagram of an electronic device provided by an embodiment of the present invention. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] Refer to Figure 1 , an embodiment of the present invention provides a fault identification method for an optical storage direct current flexible power supply system, including the following steps:

[0043] Step S110. Collect the magnetic core voltage of the direct current power supply system line.

[0044] In this step, the electrical quantity of the magnetic core of the boundary element of the line is used as the collection object. The "magnetic core voltage" usually refers to the voltage signal induced by the magnetic core (or fluxgate sensor) surrounding the wire, and its magnitude is proportional to the difference between the positive and negative currents (or unbalanced current) in the direct current loop. Under normal circumstances, the magnitudes of the positive and negative currents in the direct current system are equal and the directions are opposite, and the magnetic flux (or voltage) output by the magnetic core surrounding the two poles is zero; when a single-pole grounding fault occurs, an unbalanced current generates magnetic flux, and the sensor outputs a non-zero voltage, and its positive and negative polarities reflect the fault polarity.

[0045] Specifically, when collecting data, the magnetic ring sensor can be installed on the power supply wire of the DC transmission line. Generally, an open or closed magnetic ring structure can be adopted, so that the positive and negative wires each pass through the magnetic ring once and are located on the same magnetic path. The output signal of the sensor is led out and sent to the data acquisition device after circuit conditioning (such as differential amplification and filtering) to collect the output voltage of the magnetic ring.

[0046] Step S120. When the magnetic ring voltage meets the protection startup condition, perform a polar mode transformation on the magnetic ring voltage to obtain the magnetic ring line mode voltage and the magnetic ring ground mode voltage.

[0047] In this step, the magnetic ring voltages of the positive and negative poles collected are converted into line mode components and ground mode components through polar mode transformation. Among them, the line mode component is the differential mode component of the magnetic ring voltage, which refers to the voltage difference between the two wires, and the ground mode voltage is the common mode component of the magnetic ring voltage, which refers to the average value of the voltages of the two wires to the ground. When the sampled magnetic ring voltage meets the protection startup condition, the protection logic is triggered, and thus the polar mode transformation operation starts. At this time, the magnetic ring voltage values of the positive and negative poles are read out from the ADC, and the line mode voltage and the ground mode voltage signals are calculated according to the differential and common mode formulas.

[0048] The protection startup condition is usually judged by a software interrupt or a hardware comparator: for example, if the sampled value continuously exceeds a certain set jump threshold, it is determined that the fault analysis is entered. The mode transformation can be implemented according to mathematical formulas in the MCU or FPGA: for example, a digital multiplication and addition circuit is used to directly calculate the difference between the line modes and their average value; an operational amplifier can also be used to build a differential / common mode transformation circuit. The transformation operation is completed in the triggered interrupt or timed polling to ensure that the transformation result is sent to the subsequent fault discrimination process in a timely manner.

[0049] Furthermore, the protection startup condition includes that the magnetic ring voltage exceeds a preset action threshold. A more preferred implementation mode is to improve the reliability of the protection device for anti-interference. The startup condition is that the protection logic is triggered when N consecutive sampled values exceed the preset action threshold.

[0050] Exemplarily, assuming that the protection startup condition is that three consecutive sampled values all exceed the preset action threshold, the protection startup condition can be expressed as follows:

[0051]

[0052] In the formula, 、 、 represent three consecutive sampled values of the magnetic ring voltage, and the preset action threshold is set according to the maximum fluctuation amplitude of the voltage across the magnetic ring during normal operation. When the protection startup condition is met, the time corresponding to the first sampling point that satisfies the protection startup criterion is set as the fault initial moment.

[0053] Further, the pole-mode transformation of the magnetic-ring voltage to obtain the magnetic-ring line-mode voltage and magnetic-ring ground-mode voltage includes:

[0054]

[0055] Among them, and represent the positive magnetic-ring voltage and the positive magnetic-ring voltage respectively, represents the magnetic-ring line-mode voltage, represents the magnetic-ring ground-mode voltage.

[0056] Step S130. Determine the fault type and fault section according to the magnetic-ring line-mode voltage and magnetic-ring ground-mode voltage.

[0057] Specifically, the DC fault types mainly include single-pole grounding faults (positive or negative pole grounding) and bipolar faults (both poles grounded or short-circuited) etc. In the line-mode / ground-mode analysis, the single-pole fault shows a significant common-mode voltage signal, and the symbol indicates the fault polarity; in the case of a bipolar fault, the common-mode component is close to zero but the differential-mode component increases abnormally. This step identifies the fault type and fault section according to the calculated line-mode voltage and ground-mode voltage.

[0058] Further, step S130 includes the following steps:

[0059] Step S131. Integrate and calculate the magnetic-ring line-mode voltage and magnetic-ring ground-mode voltage respectively within a preset time window to obtain the line-mode voltage integral value and the ground-mode voltage integral value.

[0060] After the protection logic is triggered, the line-mode voltage and the ground-mode voltage are integrated within a short time window. The integral value is essentially used to suppress the instantaneous noise and extract the stable energy / trend information. When a fault occurs, the magnetic-ring voltage instantaneously rises at the millisecond level, and its integral value is significantly greater than the normal disturbance, and it can distinguish the magnetic flux changes of different polarities.

[0061] The line-mode voltage integral value and the ground-mode voltage integral value can be expressed as follows respectively:

[0062]

[0063] In the formula, represents the line-mode voltage integral value, represents the ground-mode voltage integral value, represents the integral time window.

[0064] Step S132. Determine the fault type according to the ground-mode voltage integral value, and determine the fault section according to the line-mode voltage integral value.

[0065] When identifying the fault type in this step, compare the ground-mode voltage integral value with the fault selection pole threshold as follows:

[0066]

[0067] Among them, represents the fault type, where a, b, and c represent positive pole fault, bipolar fault, and negative pole fault respectively, represents the integral value of the ground mode voltage, represents the fault pole selection threshold.

[0068] When identifying the fault section, the integral value of the line mode voltage is compared with the area identification threshold. When is satisfied, it is considered an in-zone fault and the protection action is triggered; otherwise, the protection does not act. represents the area identification threshold.

[0069] The following further illustrates the fault identification method proposed by the present invention through a simulation example.

[0070] Figure 2 Schematically shows a simulation model of a photovoltaic-storage-direct-current-flexible power supply system provided by an embodiment of the present invention. The "photovoltaic-storage-direct-current-flexible" power supply system is connected to the urban distribution network through a converter VSC and a step-up transformer. The VSC adopts a double closed-loop control strategy of constant DC voltage and reactive power, which can be used to regulate the voltage level of the DC system. The rated voltage of the system is ±375V. A load cable and a distributed photovoltaic-storage cable are connected to the DC bus at the outlet of the VSC, with lengths of 500m and 300m respectively. The photovoltaic-storage power supply model contains distributed photovoltaic power sources and battery energy storage.

[0071] Figure 2 When the system shown is operating normally, the AC system and the photovoltaic-storage system supply power to loads such as charging piles together. Therefore, when the system is operating normally, the positive pole current of the protection measuring point on line is to the right, and the positive pole current of the protection measuring point on line is to the left. Among them, , represent DC distribution line faults, represents a converter VSC bridge arm short circuit fault, represents an AC transmission line fault. As shown in Figure 2 , for line , belongs to an in-zone fault, , , belong to out-of-zone faults; for line , belongs to an in-zone fault, , , belong to out-of-zone faults. This embodiment aims to distinguish in-zone faults and out-of-zone faults for the protected line and identify their fault types.

[0072] Under the steady-state operating conditions of the system, the line current exhibits quasi-static characteristics and changes very little. Therefore, the voltage across the magnetic ring hardly fluctuates. However, during the fault transient process, the current rises rapidly, resulting in a large voltage fluctuation across the magnetic ring. Therefore, the above characteristics of the voltage across the magnetic ring can be used as the basis for protection.

[0073] For the fault a simulation is carried out, with two-pole grounding set and the transition resistance taken as 0.1 Ω. The voltage data across the magnetic rings of line and line are obtained respectively, and the results are as shown in Figure 3 .

[0074] For the protection device of line , an internal fault of line belongs to a forward fault. As can be seen from 3(a), the polarity of the voltage across the positive-pole magnetic ring of line is positive; for the protection device of line , an internal fault of line belongs to a reverse fault. As can be seen from Figure 3 (b), the polarity of the voltage across the positive-pole magnetic ring of line is negative.

[0075] For the fault a simulation is carried out, with positive-pole grounding set and the transition resistance taken as 0.1 Ω. The voltage data across the magnetic rings of line and line are obtained respectively, and the results are as shown in Figure 4 .

[0076] For the protection device of line , an internal fault of line belongs to a reverse fault. As can be seen from Figure 4 (a), the polarity of the voltage across the positive-pole magnetic ring of line is negative; for the protection device of line , an internal fault of line belongs to a forward fault. As can be seen from Figure 4 (b), the polarity of the voltage across the positive-pole magnetic ring of line is positive.

[0077] For the fault a simulation is carried out, with negative-pole grounding set and the transition resistance taken as 0.1 Ω. The voltage data across the magnetic rings of line and line are obtained respectively, and the results are as shown in Figure 5 .

[0078] For the protection device of line and line protection device, the short-circuit faults of the VSC bridge arms of the converter all belong to reverse faults, and are caused by Figure 5 It can be seen that for line and line the polarities of the voltages at both ends of the negative magnetic ring are both positive.

[0079] Taking the TT grounding mode of the system as an example, simulations are carried out for different types of faults occurring at different positions, and the voltage across the magnetic ring on line is measured to determine whether the protection can identify the fault type and act correctly. The faults verified by simulation and their calculation and judgment results are listed in Table 1 below.

[0080] Table 1

[0081]

[0082] The voltage across the magnetic ring on line is measured to determine whether the protection device can identify the fault type and act correctly. The faults verified by simulation and their calculation and judgment results are listed in Table 2 below.

[0083] Table 2

[0084]

[0085] Taking Table 2 as an example, for line , the fault occurring belongs to an in-zone fault, that is, the third row of Table 2, and the protection device should act. Other faults all belong to out-of-zone faults, and the protection should not act. As can be seen from Table 2, the protection device can act correctly, verifying the correctness of the fault identification method proposed in this paper when executed on line . In addition, the value of the ground mode voltage corresponds to the fault type, and the scheme of the present invention can correctly judge the fault type.

[0086] The above-mentioned embodiments propose a fault identification method for a photovoltaic-storage-direct-soft power supply system, which uses the magnetic ring voltage as the identification basis, and obtains the line mode voltage and the ground mode voltage through the polar mode transformation of the magnetic ring voltage as the basis for fault type identification and fault section location; the present invention uses the electrical quantity of the magnetic ring of the boundary element of the DC system line as the judgment basis, and utilizes the boundary characteristics of the magnetic ring to realize the rapid detection of faults. As long as there is a mutation in the line circuit, the induction voltage spike can be immediately captured at both ends of the magnetic ring. The magnetic ring voltage, as an electrical transient signal, is much faster than the sampling judgment mechanism of the controller, and there is no dead zone and action time limit existing in the traditional protection startup, and it can realize fault identification in milliseconds and achieve full-line protection of the line, and the protection sensitivity is higher than the traditional method.

[0087] The above - disclosed method can be implemented by devices in various forms. Therefore, the present invention also discloses a device corresponding to the above - mentioned method, and specific embodiments are given below for detailed description.

[0088] As Figure 6 shown, an embodiment of the present invention provides a fault identification device for a photovoltaic - energy - storage - direct - current - flexible power supply system, including:

[0089] A magnetic - ring voltage acquisition module 602, configured to acquire the magnetic - ring voltage of the direct - current power - supply system line;

[0090] A magnetic - ring voltage transformation module 604, configured to perform a polar - mode transformation on the magnetic - ring voltage to obtain a magnetic - ring line - mode voltage and a magnetic - ring ground - mode voltage when the magnetic - ring voltage meets the protection start condition;

[0091] A fault identification module 606, configured to determine the fault type and the fault section according to the magnetic - ring line - mode voltage and the magnetic - ring ground - mode voltage.

[0092] For the device provided in the embodiments of the present application, its implementation principle and the technical effects produced are the same as those of the foregoing method embodiments. For the sake of brief description, for the parts not mentioned in the device embodiments, reference may be made to the corresponding content in the foregoing method embodiments.

[0093] The methods and related devices mentioned in the above embodiments are described with reference to the method flowcharts and / or structural schematic diagrams provided in the embodiments of the present application. Specifically, they can be implemented by computer program instructions for each process and / or block in the method flowchart and / or structural schematic diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram. These computer program instructions can be provided to the processor of a general - purpose computer, a special - purpose computer, an embedded processor, or other programmable data - processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data - processing devices generate a device for implementing the functions specified in one process Figure 1 one process or multiple processes and / or structural schematic Figure 1 one block or multiple blocks. These computer program instructions can also be stored in a computer - readable memory that can direct the computer or other programmable data - processing devices to work in a specific manner, so that the instructions stored in the computer - readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in one process Figure 1 one process or multiple processes and / or structural schematic Figure 1 one block or multiple blocks. These computer program instructions can also be loaded onto the computer or other programmable data - processing devices, so that a series of operation steps are executed on the computer or other programmable devices to generate a computer - implemented process. Thus, the instructions executed on the computer or other programmable devices provide for implementing the functions specified in one process Figure 1One or more processes and / or structures illustrate the steps of the functions specified in one or more boxes.

[0094] In the following embodiments, the method is illustrated by taking its application to a computer device as an example. It can be understood that the computer device can be any device with computing and processing functions, and can be, but is not limited to, a server, a personal laptop computer, etc. In one of the embodiments, the computer device can be an application server, which can be a server for running the application under test.

[0095] Refer to Figure 7 , which shows a hardware block diagram of an electronic device. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present application described herein and / or claimed.

[0096] As Figure 7 shown, the electronic device includes: at least one processor 1, at least one communication interface 2, at least one memory 3, and at least one communication bus 4;

[0097] In the embodiments of the present application, the number of the processor 1, the communication interface 2, the memory 3, and the communication bus 4 is at least one, and the processor 1, the communication interface 2, and the memory 3 complete mutual communication through the communication bus 4;

[0098] The processor 1 may be a central processing unit CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention, etc.;

[0099] The memory 3 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk memory;

[0100] Among them, the memory stores a program, and the processor can call the program stored in the memory. The program is used to: implement each processing flow of the aforementioned fault identification method for the optical storage direct current flexible power supply system.

[0101] An embodiment of the present invention further provides a readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, each processing flow of the fault identification method for an optical storage direct-current flexible power supply system provided by any possible implementation manner of the above embodiment and / or the combined embodiment is implemented.

[0102] The above embodiments have described the present invention in particular detail with respect to possible scenarios. Those skilled in the art will recognize that the present invention can be practiced through other embodiments. The specific naming of components, the case of terms, attributes, data structures, or any other programming or structural aspects are not mandatory or important. The mechanism or its features for implementing the present invention can have different names, forms, or procedures. The system can be implemented through a combination of hardware and software (as described), entirely through hardware elements, or entirely through software elements. The specific division of functions between various system components described in the text is merely exemplary and not mandatory; on the contrary, the functions performed by a single system component can be performed by multiple components, or the functions performed by multiple components can be performed by a single component.

[0103] Those skilled in the art should understand that each step of the above-disclosed method can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Optionally, they can be implemented with program code executable by the computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to implement. Thus, the disclosure of the embodiments of the present invention is not limited to any specific combination of hardware and software.

[0104] These programs executable by the computing devices (also referred to as programs, software, software applications, or code) include machine instructions of a programmable processor, and these computing programs can be implemented using high-level procedures and / or object-oriented programming languages, and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, device, and / or apparatus (e.g., a disk, an optical disc, a memory, a programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0105] Certain aspects of the present invention include the process steps and instructions described herein in the form of algorithms. It should be noted that the process steps and instructions of the present invention can be implemented in software, firmware, and / or hardware. When implemented by software, it can be downloaded and saved on different platforms used by various operating systems and operated from these platforms.

[0106] Those skilled in the art can understand that the structures shown in the respective drawings are only block diagrams of some of the structures related to the solution of the present application, and do not constitute a limitation on the terminal devices to which the solution of the present application is applied. The specific terminal devices may include more or fewer components than those shown in the figures, or combine some components, or have different component arrangements.

[0107] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "possible design", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0108] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fault identification method for a photovoltaic-storage-direct-current-soft power supply system, characterized in that Including: Collecting the magnetic ring voltage of the DC power supply system line; When the magnetic ring voltage meets the protection start condition, performing a polar-mode transformation on the magnetic ring voltage to obtain a magnetic ring line-mode voltage and a magnetic ring ground-mode voltage; Determining the fault type and fault section according to the magnetic ring line-mode voltage and the magnetic ring ground-mode voltage.

2. The method according to claim 1, wherein The determining the fault type and fault section according to the magnetic ring line-mode voltage and the magnetic ring ground-mode voltage includes: Within a preset time window, respectively performing integral calculations on the magnetic ring line-mode voltage and the magnetic ring ground-mode voltage to obtain a line-mode voltage integral value and a ground-mode voltage integral value; Determining the fault type according to the ground-mode voltage integral value and determining the fault section according to the line-mode voltage integral value.

3. The method according to claim 2, wherein The determining the fault type according to the ground-mode voltage integral value includes: Comparing the ground-mode voltage integral value with a fault selection pole threshold as follows: ， Among them, represents the fault type, where a, b, and c represent positive pole fault, bipolar fault, and negative pole fault respectively, represents the integral value of the ground mode voltage, represents the fault pole selection threshold.

4. The method according to claim 2, wherein The determining the fault section according to the line-mode voltage integral value includes: When the line-mode voltage integral value satisfies it is determined that the fault section is within the zone and the protection action is triggered, indicating the regional recognition threshold value.

5. The method according to claim 1, wherein The performing a polar-mode transformation on the magnetic ring voltage to obtain a magnetic ring line-mode voltage and a magnetic ring ground-mode voltage includes: ， Among them, and represent the positive magnetic ring voltage and the positive magnetic ring voltage respectively, represents the magnetic ring line mode voltage, represents the magnetic ring ground mode voltage.

6. The method according to claim 1, wherein The protection start condition includes: The magnetic ring voltage exceeds a preset action threshold.

7. The method according to claim 6, wherein The magnetic ring voltage exceeding the preset action threshold includes: The magnetic ring voltage exceeds the preset action threshold for N consecutive sampling values, where N≥1.

8. A fault identification device for a photovoltaic-storage-direct-current flexible power supply system, characterized in that, Including: A magnetic ring voltage acquisition module for collecting the magnetic ring voltage of the DC power supply system line; A magnetic ring voltage transformation module for performing a polar-mode transformation on the magnetic ring voltage to obtain a magnetic ring line-mode voltage and a magnetic ring ground-mode voltage when the magnetic ring voltage meets the protection start condition; A fault identification module for determining the fault type and fault section according to the magnetic ring line-mode voltage and the magnetic ring ground-mode voltage.

9. An electronic device, characterized in that, Including a memory storing computer-executable instructions and a processor, and when the computer-executable instructions are executed by the processor, the device executes the fault identification method for the optical storage DC flexible power supply system according to any one of claims 1 to 7.

10. A readable storage medium, characterized in that, Storing a computer-executable program, and when the program is executed, the fault identification method for the optical storage DC flexible power supply system according to any one of claims 1 to 7 can be realized.

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