Line fault identification method, device and electronic equipment based on mutation impedance sum

Abstract

The present invention discloses a line fault identification method based on mutation impedance sum, including: obtaining synchronous voltage and synchronous current on both sides of the line; calculating sequence mutation impedance on both sides based on the synchronous voltage and synchronous current on both sides and obtaining sequence mutation impedance sum; judging whether the fault occurs inside or outside the area according to the amplitude of sequence mutation impedance sum and / or the resistance component of sequence mutation impedance sum and / or the fluctuation degree of sequence mutation impedance sum. The scheme of the present invention has a good fault identification effect on the transmission and distribution lines with high penetration power electronic power supply access.

Description

Technical Field

[0001] The present invention relates to the field of relay protection of electric power systems, and in particular to a method, a device and an electronic device for identifying line faults based on a sudden change impedance sum. Background Art

[0002] With the rapid development and engineering construction of technologies such as renewable energy power generation and flexible direct current transmission, the structure of traditional power systems has gradually changed. The proportion of traditional synchronous generators has continued to decline, while the proportion of power electronic power supplies has gradually increased. Since the fault characteristics of power electronic power supplies are quite different from those of synchronous generators, traditional power system relay protection designed based on synchronous generators is also facing unprecedented challenges.

[0003] In traditional power systems, differential protection is the most commonly used line main protection, which has absolute selectivity and very high sensitivity. Most of the faults in the area are removed by differential protection, which effectively ensures the safe and stable operation of the power grid. However, in the power grid with high penetration of power electronic power sources, due to the strong controllability of the fault characteristics of power electronic equipment, the sensitivity of traditional differential protection is seriously affected, and the failure of the area may refuse to operate under extreme conditions. Therefore, it is necessary to study new line fault identification methods that can be applied to high penetration of power electronic power sources. Summary of the invention

[0004] In order to solve the shortcomings of the prior art, the present invention discloses a line fault identification method, device and electronic equipment based on mutation impedance and, which utilizes the mutation impedance and different characteristics on both sides of the fault line inside and outside the area to identify the fault location, thereby realizing the rapid identification of line faults with high penetration power electronic power supply access.

[0005] In order to achieve the above object, the solution of the present invention is:

[0006] As a first aspect of the present invention, a line fault identification method based on a sudden change impedance sum is proposed, comprising:

[0007] Step 10: Obtain the synchronous voltage and synchronous current on both sides of the line;

[0008] Step 20: Calculate the sequence mutation impedance on both sides based on the synchronous voltage and synchronous current on both sides and obtain the sequence mutation impedance sum;

[0009] Step 30: Determine whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum and / or the resistance component of the sequence mutation impedance sum and / or the degree of fluctuation of the sequence mutation impedance sum.

[0010] Further, the step 20 comprises:

[0011] Step 21: Calculate the positive sequence component and negative sequence component of the synchronous voltage and the synchronous current on both sides according to the symmetrical component method based on the synchronous voltage and the synchronous current on both sides;

[0012] Step 22: calculating the sequence mutation impedance on both sides based on the positive sequence components and negative sequence components of the synchronous voltage and synchronous current on both sides;

[0013] Step 23: Calculate the sum of sequence mutation impedances based on the sequence mutation impedances on both sides.

[0014] Furthermore, the calculation formula of the impedance of the two-side sequence mutation is:

[0015]

[0016]

[0017] Wherein, k is the sampling number; T is the power frequency cycle; b is the number of power frequency cycles for the calculation of mutation amount to fall back, b≥1; Represents different sequence components, + is positive sequence, - is negative sequence; are the synchronous voltage and synchronous current sequence components on this side; is the impedance of the mutation quantity of this side sequence; are the sequence components of the synchronous voltage and current on the opposite side; is the impedance of the lateral sequence mutation.

[0018] Furthermore, the sequence mutation impedance and calculation formula are as follows:

[0019]

[0020] in, They are the sudden change impedance on this side and the sudden change impedance on the opposite side at sampling number k respectively; is the impedance sum of the sequence mutation at sampling number k, Represents different sequence components, + is positive sequence and - is negative sequence.

[0021] Furthermore, the amplitude criterion of the sequence mutation impedance sum is specifically: when the positive sequence mutation impedance sum amplitude is greater than the positive sequence amplitude threshold or the negative sequence mutation impedance amplitude is greater than the negative sequence amplitude threshold, it is considered that the amplitude criterion of the sequence mutation impedance sum meets the fault action condition.

[0022] Furthermore, the resistance component criterion of the sequence mutation impedance sum is specifically: when the resistance component of the positive sequence mutation impedance sum is greater than the positive sequence resistance threshold or the resistance component of the negative sequence mutation impedance sum is greater than the negative sequence resistance threshold, it is considered that the resistance component criterion of the sequence mutation impedance sum meets the fault action condition.

[0023] Furthermore, the fluctuation degree criterion of the sequence mutation quantity impedance sum is specifically: when the fluctuation degree of the positive sequence mutation quantity impedance sum is greater than the positive sequence fluctuation threshold or the fluctuation degree of the negative sequence mutation quantity impedance sum is greater than the negative sequence fluctuation threshold, it is considered that the fluctuation degree criterion of the sequence mutation quantity impedance sum meets the fault action condition.

[0024] Furthermore, the step 30 includes a single criterion type, that is, judging whether the fault occurs inside or outside the zone only based on the amplitude of the impedance sum of the mutation quantity, when the amplitude of the impedance sum of the sequence mutation quantity meets the fault action condition, it is judged that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone;

[0025] Alternatively, it is determined whether the fault occurs inside or outside the zone only based on the resistance component of the sequence mutation impedance sum. When the resistance component of the sequence mutation impedance sum meets the fault action condition, it is determined that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone.

[0026] Alternatively, it is determined whether the fault occurs inside or outside the zone only based on the fluctuation degree of the sequence mutation impedance sum. When the fluctuation degree of the sequence mutation impedance sum meets the fault action condition, it is determined that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone.

[0027] Furthermore, the step 30 includes a dual criterion type, that is, judging whether the fault occurs inside or outside the zone according to any two criteria of the amplitude of the sequence mutation impedance sum, the resistance component of the sequence mutation impedance sum and the degree of fluctuation of the sequence mutation impedance sum. If any one of the two criteria meets the fault action condition, it is determined that the fault occurs inside the zone; when both criteria do not meet the fault action condition, it is determined that the fault occurs outside the zone.

[0028] Furthermore, step 30 includes three criterion types, namely, judging whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum, the resistance component of the sequence mutation impedance sum, and the degree of fluctuation of the sequence mutation impedance sum. If any one of the three criteria meets the fault action condition, it is determined that the fault occurs inside the zone. When all three criteria do not meet the fault action condition, it is determined that the fault occurs outside the zone.

[0029] As a second aspect of the present invention, a line fault identification device based on a sudden change impedance sum is proposed, comprising a data acquisition unit, a calculation unit and a fault identification unit, wherein:

[0030] The data acquisition unit is used to obtain the synchronous voltage and synchronous current on both sides of the line;

[0031] The calculation unit is used to calculate the sequence mutation impedance on both sides based on the synchronous voltage and the synchronous current on both sides and obtain the sequence mutation impedance sum;

[0032] The fault identification unit is used to determine whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum and / or the resistance component of the sequence mutation impedance sum and / or the fluctuation degree of the sequence mutation impedance sum.

[0033] As a third aspect of the present invention, an electronic device is provided, including a processor and a storage medium;

[0034] The storage medium is used to store instructions;

[0035] The processor is used to operate according to the instructions to execute the steps of any of the above methods.

[0036] The beneficial effect of the present invention is that, compared with the prior art, the system and method of the present invention fully utilize one or more of the new characteristics of the power electronic power supply, namely, large amplitude of sudden impedance, phase angle offset, and obvious fluctuation, which are different from the traditional synchronous machine power supply. When an out-of-zone fault occurs, the sum of the sudden impedances on both sides of the line is the line impedance. When an in-zone fault occurs, the sum of the sudden impedances on both sides of the line is the sum of the sudden impedances of the power supplies on both sides. A corresponding fault identification criterion is designed according to the sudden impedance characteristics of the power electronic power supply, which significantly improves the adaptability of the protection to the fault characteristics of the power electronic power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of a two-node system according to an exemplary embodiment

[0038] Figure 2 It is a flow chart of the line fault identification method based on the sudden change impedance sum of the present invention;

[0039] Figure 3 This is a flow chart of the present invention for calculating the impedance sum of sequential mutation quantities;

[0040] Figure 4 It is a single criterion logic diagram of the amplitude of the sequence mutation quantity impedance and ...

[0041] Figure 5 It is a single criterion logic diagram of the resistance component of the sequential mutation quantity impedance and the resistance component proposed in the embodiment of the present invention;

[0042] Figure 6 It is a single criterion logic diagram of the fluctuation degree of the sequence mutation quantity impedance and the sequence mutation quantity impedance and the fluctuation degree of ...

[0043] Figure 7 It is a dual criterion logic diagram of the amplitude of the sequence mutation impedance sum and the resistance component of the sequence mutation impedance sum proposed in the embodiment of the present invention;

[0044] Figure 8 It is a dual criterion logic diagram of the amplitude of the sequence mutation impedance sum and the fluctuation degree of the sequence mutation impedance sum proposed in an embodiment of the present invention;

[0045] Fig. 9 It is a dual criterion logic diagram of the resistance component of the sequence mutation impedance sum and the fluctuation degree of the sequence mutation impedance sum proposed in an embodiment of the present invention;

[0046] Fig.10 It is a three-criteria logic diagram proposed in an embodiment of the present invention;

[0047] Fig.11 is a schematic diagram of a line fault identification device based on a sudden change impedance sum according to an exemplary embodiment of the present invention;

[0048] Fig.12 is a block diagram of an electronic device illustrating an example embodiment of the present invention. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0050] Figure 1 A schematic diagram of a two-node system according to an exemplary embodiment is shown. Figure 1 As shown, it is a schematic diagram of a two-node system. For the convenience of description, the M side is called the local side and the N side is called the opposite side. The protection devices M and N are used to receive current and voltage electrical quantity data to identify line faults.

[0051] like Figure 2 As shown, a line fault identification method based on mutation impedance and includes:

[0052] S10: Acquire synchronous voltage and synchronous current on both sides of the line;

[0053] The protection devices installed on both sides of the line obtain the synchronous voltage and synchronous current at the protection installation through voltage transformers and current transformers. The synchronous voltage and synchronous current on this side are recorded as and The synchronous voltage and current on the opposite side are recorded as and

[0054] S20: Calculate the sequence mutation impedance on both sides based on the synchronous voltage and synchronous current on both sides and obtain the sequence mutation impedance sum. Figure 3 Shown include:

[0055] S21: Calculate the positive sequence component and negative sequence component of the synchronous voltage and synchronous current on both sides according to the symmetrical component method based on the synchronous voltage and synchronous current on both sides.

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] in, are the positive and negative sequence components of the synchronous voltage on this side, respectively. are respectively the positive sequence component and negative sequence component of the synchronous current on this side, are the positive and negative sequence components of the synchronous voltage on the opposite side, are the positive sequence component and negative sequence component of the synchronous current on the opposite side, respectively. α represents the operator of the phasor phase relationship. The calculation formula is as follows:

[0065]

[0066] S22: Calculate the sequence mutation impedance on both sides based on the positive sequence components and negative sequence components of the synchronous voltage and synchronous current on both sides. The sequence mutation impedance includes the positive sequence mutation impedance and the negative sequence mutation impedance.

[0067]

[0068]

[0069] Wherein, k is the sampling number; T is the power frequency cycle; b is the number of power frequency cycles for the calculation of mutation amount to fall back, b≥1; Represents different sequence components, + is positive sequence, - is negative sequence; are the synchronous voltage and synchronous current sequence components on this side; is the impedance of the mutation quantity of this side sequence; are the sequence components of the synchronous voltage and current on the opposite side; is the impedance of the lateral sequence mutation.

[0070] S23: Calculate the sum of sequence mutation impedances based on the sequence mutation impedances on both sides.

[0071]

[0072] in, They are the sudden change impedance on this side and the sudden change impedance on the opposite side at sampling number k respectively; is the impedance sum of the sequence mutation at sampling number k, Represents different sequence components, + is positive sequence and - is negative sequence.

[0073] S30: judging whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum and / or the resistance component of the sequence mutation impedance sum and / or the fluctuation degree of the sequence mutation impedance sum.

[0074] The fault characteristics of power electronic power supply are different from those of traditional synchronous generator power supply. The short-circuit current output by power electronic power supply is limited, the phase angle is controlled, and the amplitude is unstable, which causes the positive and negative sequence sudden impedance of power electronic power supply to have the characteristics of large amplitude, phase angle deviation from 90°, and unstable amplitude. When an out-of-zone fault occurs, the sum of sudden impedance is equal to the impedance of the protected line, the line impedance amplitude is small, the phase angle is close to 90°, and the amplitude is stable; when an in-zone fault occurs, the sum of sudden impedance is the sum of sudden impedance of the power supplies on both sides. Due to the above characteristics of the sudden impedance of the power electronic power supply, the sum of sudden impedance at this time is significantly different from that of the out-of-zone fault. Different protection criteria can be formed according to the amplitude of the sudden impedance, the resistance component reflecting the phase angle, and the degree of fluctuation reflecting the instability of the amplitude.

[0075] like Figure 4 As shown, in some embodiments, a single criterion type is used to judge whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum. Specifically, when the amplitude of the positive sequence mutation impedance sum is greater than the positive sequence amplitude threshold or the amplitude of the negative sequence mutation impedance sum is greater than the negative sequence amplitude threshold, it is considered that the amplitude criterion of the sequence mutation impedance sum meets the fault action condition. When the fault action condition is met, it is determined that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone.

[0076] The formula is as follows:

[0077]

[0078] in, is the sequence amplitude threshold, when Take +, Represents the positive sequence amplitude threshold. Pick-, Indicates the negative sequence amplitude threshold.

[0079] like Figure 5As shown, in some embodiments, a single criterion type is used to determine whether the fault occurs inside or outside the zone according to the resistance component of the sequence mutation impedance sum. Specifically, when the resistance component of the positive sequence mutation impedance sum is greater than the positive sequence resistance threshold or the resistance component of the negative sequence mutation impedance sum is greater than the negative sequence resistance threshold, it is considered that the resistance component criterion of the sequence mutation impedance sum meets the fault action condition. When the fault action condition is met, it is determined that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone.

[0080] The formula is as follows:

[0081]

[0082] in, is the sequence resistance threshold, when Take +, Indicates the positive sequence resistance threshold. Pick-, Indicates the negative sequence resistance threshold.

[0083] like Figure 6 As shown, in some embodiments, a single criterion type is used to judge whether the fault occurs inside or outside the zone according to the fluctuation degree of the sequence mutation impedance sum. Specifically, when the fluctuation degree of the positive sequence mutation impedance sum is greater than the positive sequence fluctuation threshold or the fluctuation degree of the negative sequence mutation impedance sum is greater than the negative sequence fluctuation threshold, it is considered that the fluctuation degree criterion of the sequence mutation impedance sum meets the fault action condition. When the fault action condition is met, it is determined that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone.

[0084] The formula is as follows:

[0085] The method for determining the fluctuation degree of the mutation impedance and is as follows:

[0086]

[0087] Wherein, L is the calculation window length, and L is greater than or equal to 2; is the impedance and mean of the L point sequence mutation, and the calculation formula is is the sequence fluctuation threshold, when Take +, Represents the positive sequence fluctuation threshold, when Pick-, Indicates the negative sequence fluctuation threshold.

[0088] like Figure 7 , 8As shown in Figure 9, some embodiments adopt a dual criterion type, and judge whether the fault occurs inside or outside the zone according to any two criteria of the amplitude of the sequence mutation impedance sum, the resistance component of the sequence mutation impedance sum, and the fluctuation degree of the sequence mutation impedance sum. If any one of the two criteria meets the fault action condition, the fault is judged to occur inside the zone. When both criteria do not meet the fault action condition, the fault is judged to occur outside the zone. How to judge whether the amplitude of the sequence mutation impedance sum meets the fault action condition, whether the resistance component criterion of the sequence mutation impedance sum meets the fault action condition, and whether the fluctuation degree criterion of the sequence mutation impedance sum meets the fault action condition will not be repeated here.

[0089] like Fig.10 As shown, in some embodiments, three types of criteria are used: judging whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum, the resistance component of the sequence mutation impedance sum, and the fluctuation degree of the sequence mutation impedance sum, if any one of the three criteria meets the fault action condition, the fault is judged to occur inside the zone, and if none of the three criteria meets the fault action condition, the fault is judged to occur outside the zone. How to judge whether the amplitude of the sequence mutation impedance sum meets the fault action condition, whether the resistance component criterion of the sequence mutation impedance sum meets the fault action condition, and whether the fluctuation degree criterion of the sequence mutation impedance sum meets the fault action condition will not be repeated here.

[0090] like Fig.11 The line fault identification device 400 based on the sudden change impedance and includes a data acquisition unit 410, a calculation unit 420 and a fault identification unit 430, wherein:

[0091] The data acquisition unit 410 is used to obtain the synchronous voltage and synchronous current on both sides of the line.

[0092] The calculation unit 420 is used to calculate the sequence mutation impedances on both sides based on the synchronous voltages and synchronous currents on both sides and obtain the sequence mutation impedance sum.

[0093] The fault identification unit 430 is used to determine whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum and / or the resistance component of the sequence mutation impedance sum and / or the fluctuation degree of the sequence mutation impedance sum.

[0094] The device performs the same functions as the method provided above. For other functions, please refer to the previous description and will not be repeated here.

[0095] Fig.12 A block diagram of an electronic device according to an exemplary embodiment is shown.

[0096] Refer to the following Fig.12 The electronic device 500 according to this embodiment of the present application is described. Fig.12The electronic device 500 shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0097] like Fig.12 As shown, the electronic device 500 is in the form of a general computing device. The components of the electronic device 500 may include, but are not limited to: at least one processing unit 510, at least one storage unit 520, a bus 530 connecting different system components (including the storage unit 520 and the processing unit 510), a display unit 540, etc.

[0098] The storage unit stores program codes, and the program codes can be executed by the processing unit 510, so that the processing unit 510 executes the methods described in this specification according to various exemplary embodiments of the present application.

[0099] The storage unit 520 may include a readable medium in the form of a volatile storage unit, such as a random access storage unit (RAM) 5201 and / or a cache storage unit 5202 , and may further include a read-only storage unit (ROM) 5203 .

[0100] The storage unit 520 may also include a program / utility 5204 having a set (at least one) of program modules 5205, such program modules 5205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0101] Bus 530 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0102] The electronic device 500 may also communicate with one or more external devices 500' (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 500, and / or communicate with any device that enables the electronic device 500 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 550. Furthermore, the electronic device 500 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 560. The network adapter 560 may communicate with other modules of the electronic device 500 via a bus 530. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 500, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0103] Through the description of the above implementation methods, it is easy for those skilled in the art to understand that the example implementation methods described here can be implemented by software or by combining software with necessary hardware. The technical solution according to the implementation method of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, or a network device, etc.) to execute the above method according to the implementation method of the present application.

[0104] The software product may use any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination thereof. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0105] Computer readable storage media may include data signals propagated in baseband or as part of a carrier wave, wherein readable program codes are carried. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program codes contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0106] Program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0107] Those skilled in the art will appreciate that the above modules can be distributed in the device according to the description of the embodiment, or can be changed accordingly and only used in one or more devices different from the embodiment. The units of the above embodiments can be combined into one unit, or further divided into multiple sub-units.

[0108] The present invention is not limited to the above-mentioned embodiments. The description in the above-mentioned embodiments is only used to help understand the core idea of ​​the present invention. Any modification or equivalent replacement of the present invention based on the idea of ​​the present invention, and any changes made in the specific implementation mode and application scope should fall within the protection scope of the present invention.

Claims

1. A line fault identification method for high penetration power electronic power supply access based on mutation impedance and, characterized in that: include: Step 10: Obtain the synchronous voltage and synchronous current on both sides of the line; Step 20: Calculate the sequence mutation impedance on both sides based on the synchronous voltage and synchronous current on both sides and obtain the sequence mutation impedance sum; Step 30: judging whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum and / or the resistance component of the sequence mutation impedance sum and / or the fluctuation degree of the sequence mutation impedance sum; The amplitude criterion of the sequence mutation impedance sum is specifically: when the positive sequence mutation impedance sum amplitude is greater than the positive sequence amplitude threshold or the negative sequence mutation impedance amplitude is greater than the negative sequence amplitude threshold, it is considered that the amplitude criterion of the sequence mutation impedance sum meets the fault action condition; The resistance component criterion of the sequence mutation impedance sum is specifically: when the resistance component of the positive sequence mutation impedance sum is greater than the positive sequence resistance threshold or the resistance component of the negative sequence mutation impedance sum is greater than the negative sequence resistance threshold, it is considered that the resistance component criterion of the sequence mutation impedance sum meets the fault action condition; The fluctuation degree criterion of the sequence mutation impedance sum is specifically: when the fluctuation degree of the positive sequence mutation impedance sum is greater than the positive sequence fluctuation threshold or the fluctuation degree of the negative sequence mutation impedance sum is greater than the negative sequence fluctuation threshold, it is considered that the fluctuation degree criterion of the sequence mutation impedance sum meets the fault action condition.

2. The line fault identification method according to claim 1, characterized in that: The step 20 comprises: Step 21: Calculate the positive sequence component and negative sequence component of the synchronous voltage and the synchronous current on both sides according to the symmetrical component method based on the synchronous voltage and the synchronous current on both sides; Step 22: calculating the sequence mutation impedance on both sides based on the positive sequence components and negative sequence components of the synchronous voltage and synchronous current on both sides; Step 23: Calculate the sum of sequence mutation impedances based on the sequence mutation impedances on both sides.

3. The line fault identification method according to claim 2, characterized in that: The calculation formula of the impedance of the two-side sequence mutation is: Wherein, k is the sampling number; T is the power frequency cycle; b is the number of power frequency cycles for the calculation of mutation amount to fall back, b≥1; - represents different sequence components, + is positive sequence, - is negative sequence; are the synchronous voltage and synchronous current sequence components on this side; is the impedance of the mutation quantity of this side sequence; are the sequence components of the synchronous voltage and current on the opposite side; is the impedance of the lateral sequence mutation.

4. The line fault identification method according to claim 2, characterized in that: The calculation formula of the sequence mutation impedance is: in, They are the sudden change impedance on this side and the sudden change impedance on the opposite side at sampling number k respectively; is the impedance sum of the sequence mutation at sampling number k, - represents different sequence components, + is positive sequence and - is negative sequence.

5. The line fault identification method according to claim 1, characterized in that: The step 30 includes a single criterion type, that is, judging whether the fault occurs inside or outside the zone only based on the amplitude of the impedance sum of the mutation quantity. When the amplitude of the impedance sum of the sequence mutation quantity meets the fault action condition, it is judged that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone. Alternatively, it is determined whether the fault occurs inside or outside the zone only based on the resistance component of the sequence mutation impedance sum. When the resistance component of the sequence mutation impedance sum meets the fault action condition, it is determined that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone. Alternatively, it is determined whether the fault occurs inside or outside the zone only based on the fluctuation degree of the sequence mutation impedance sum. When the fluctuation degree of the sequence mutation impedance sum meets the fault action condition, it is determined that the fault occurs inside the zone, otherwise it is considered that the fault occurs outside the zone.

6. The line fault identification method according to claim 1, characterized in that: The step 30 includes a dual criterion type, that is, judging whether the fault occurs inside or outside the zone according to any two criteria of the amplitude of the sequence mutation impedance sum, the resistance component of the sequence mutation impedance sum and the fluctuation degree of the sequence mutation impedance sum. If any one of the two criteria meets the fault action condition, it is determined that the fault occurs inside the zone. When both criteria do not meet the fault action condition, it is determined that the fault occurs outside the zone.

7. The line fault identification method according to claim 1, characterized in that: The step 30 includes three types of criteria, namely, judging whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum, the resistance component of the sequence mutation impedance sum and the degree of fluctuation of the sequence mutation impedance sum. If any one of the three criteria meets the fault action condition, it is determined that the fault occurs inside the zone. When all three criteria do not meet the fault action condition, it is determined that the fault occurs outside the zone.

8. A line fault identification device for high penetration power electronic power supply access based on sudden change impedance and, used to implement the line fault identification method according to any one of claims 1 to 7, characterized in that: It includes a data acquisition unit, a calculation unit and a fault identification unit, wherein: The data acquisition unit is used to obtain the synchronous voltage and synchronous current on both sides of the line; The calculation unit is used to calculate the sequence mutation impedance on both sides based on the synchronous voltage and the synchronous current on both sides and obtain the sequence mutation impedance sum; The fault identification unit is used to determine whether the fault occurs inside or outside the zone according to the amplitude of the sequence mutation impedance sum and / or the resistance component of the sequence mutation impedance sum and / or the fluctuation degree of the sequence mutation impedance sum.

9. An electronic device, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 7.

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