Active power distribution network protection method and device based on state quantity information and electronic equipment

Abstract

The application discloses an active power distribution network protection method and device based on state quantity information and electronic equipment, in the background of 5G communication, a distributed communication mode is adopted, that is, each regional protection can communicate with each other by means of 5G. When one or more protections in the active power distribution network judge and generate overcurrent protection action information, the protection actively shares the information with adjacent protections, head-end protections and end protections in the same region, and as long as the overcurrent protection action information of the short-circuit current flowing through the protection appears, the action information is shared at certain time intervals. If the protection is a double-end power supply regional head-end protection or an end protection, the head-end protection and the end protection of the double-end power supply region and the head-end protection of the radial region exchange and share the compensation impedance polarity information with the end protection or the head-end protection in the same region respectively, then the head-end protection and the end protection of the double-end power supply region and the head-end protection of the radial region respectively analyze the information and take corresponding protection action logic.

Description

Technical Field

[0001] This invention relates to the fields of power communication technology and power system distribution network relay protection, and more specifically, to an active distribution network protection method, device, and electronic equipment based on state quantity information. Background Technology

[0002] Traditional single-ended power supply radial distribution networks mainly employ a three-stage current protection principle, with selectivity ensured through the coordination of setting values ​​and time limits between each protection level. However, three-stage current protection suffers from drawbacks such as complex settings, large outage range, and poor selectivity. With the increasing integration of distributed generation (DG) into distribution networks, traditional single-source distribution networks are gradually transforming into active distribution networks containing multiple sources. Active distribution networks are characterized by bidirectional flow of power and fault current, and the fault output characteristics of inverter-type DGs (such as photovoltaics) differ significantly from those of synchronous generators. The fault currents provided by inverter-type DGs exhibit amplitude limitations and phase lag, making traditional three-stage current protection unsuitable for active distribution networks. To address these issues, the applicant has proposed a protection method for DG-containing distribution networks based on multi-point state information. This method combines overcurrent protection action information and compensation impedance polarity information to locate fault sections upstream of the DG, and utilizes overcurrent protection action information to locate fault sections downstream of the DG and along radial feeders.

[0003] However, for new loads such as electric vehicles connected to long-distance radial lines, the overcurrent protection setting value is relatively large, while the two-phase short-circuit fault current is relatively small. Furthermore, when current transformers (CTs) break at some protection installation points, current information at those points is lost. Therefore, for radial feeders without DG (distributed generation) access and radial lines downstream of DG, relying solely on overcurrent protection operation information cannot guarantee the reliability of fault location. Moreover, in the proposed scheme, to locate fault sections upstream of DG, a setting impedance equal to the number of lines in that area is set only at the first-end protection of the upstream area. The protection range corresponding to the maximum setting impedance exceeds the entire length of the upstream DG line, meaning the protection range includes the DG grid connection point. Therefore, coverage of the DG grid connection point will affect the supplementary impedance polarity information corresponding to this setting impedance, potentially impacting the accuracy of fault location.

[0004] In active distribution networks, differential protection has absolute selectivity. Fiber optic communication can meet the requirements of current differential protection channels. However, factors such as the large number of fiber optic cables to be laid, the difficulty of laying them, the long construction period, and the high infrastructure costs limit the popularization rate of fiber optic channels in distribution networks. Summary of the Invention

[0005] In the context of 5G communication, this invention provides an active distribution network protection method, device, and electronic equipment based on state quantity information. This mitigates the impact of distributed power source integration on traditional relay protection schemes, achieving rapid and accurate fault location of line sections and fast, selective protection of the entire line length. Simultaneously, it fully utilizes existing current and voltage information in the active distribution network, eliminating the need for additional potential transformers (PTs) and reducing retrofit costs. A compensation impedance relationship is constructed based on the directional impedance amplitude-ratio action equation. By utilizing voltage and current information at the feeder head and the distributed power source grid connection point, the setting method and configuration principle of the protection compensation impedance are improved. This ensures that the protection range of the set impedance is smaller than the entire line length and does not include the distributed power source grid connection point. This makes the protection method unaffected by factors such as the type, quantity, capacity, and output of the distributed power source, resulting in more accurate fault location. Simultaneously, by comparing the polarity information of the compensation impedance and the overcurrent protection action information, fault location and protection action logic was designed. This enabled the location of faulty line sections in the dual-end power supply area between the system and the distributed power source grid connection point, the area from the distributed power source grid connection point furthest from the system to the end of the feeder, and the radial area without distributed power source feeders. For radial areas, the compensation impedance information of the protection can be redundant with the overcurrent protection action information, thereby ensuring the accuracy of the fault location results.

[0006] According to one aspect of the present invention, an active distribution network protection method based on state quantity information is provided, comprising:

[0007] Using the voltage and current information at the feeder head and the grid connection point of the distributed power source, a criterion for the polarity of the compensation impedance is constructed.

[0008] In an active distribution network, each protection in each double-ended power supply area and radial area collects current information and determines whether there is overcurrent protection action information. Each first-end protection and last-end protection in each double-ended power supply area and radial area combines their respective setting impedance and compensation impedance polarity criteria to determine the compensation impedance polarity information.

[0009] Within the radial area, if the line protection has overcurrent protection action information or the polarity information of the compensation impedance of the head protection is negative, it is determined whether there is a CT disconnection within the radial area. Based on the presence of the CT disconnection, the line protection or the head protection uses 5G communication to send a blocking signal or tripping command to the corresponding target protection.

[0010] In a dual-power supply area, if the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative, the first-end protection and the last-end protection will determine whether there is only one line in the dual-power supply area, and determine the specific location of the fault based on the number of lines in the dual-power supply area. Based on the specific location of the fault, a trip command will be sent to the corresponding target protection using 5G communication.

[0011] Alternatively, the expression for the compensation impedance polarity criterion is as follows:

[0012]

[0013] In the formula: Z dir To compensate for the impedance polarity, Z mea For measuring impedance values; Z set This is the set impedance value.

[0014] Optionally, the setting impedance for the first-end protection of the radial region and the first-end and last-end protection of the dual-ended power supply region are set as follows:

[0015] For radial regions, the nearest head protection within the radial region to the system is according to Z. set =K rel_d Z L The magnitude of the setting impedance is calculated, and its setting impedance Z is set. set The number of elements is equal to the number of lines n within the radial region plus 1; for n set impedances, the reliability coefficient K is used in the setting calculation process. rel_d Z takes values ​​from 1.1 to 1.2. L The value is the impedance value from the first end of the radial region to the end of each line within the radial region that is furthest from the system; for the remaining setting impedance, the reliability coefficient K is used in the setting calculation process. rel_d The value ranges from 0.8 to 0.9, Z L The value is the total length of the line where the first-end protection is located;

[0016] For the dual-ended power supply region, both the first-end protection and the last-end protection within the radial region are implemented according to Z. set =K rel_u Z L The magnitude of the setting impedance is calculated, and its setting impedance Z is set. set The number of [something] is equal to the number of lines n in the region; where the reliability coefficient K [is...]. rel_u Take a value of 0.8 to 0.9; for head-end protection, Z L The value is the impedance value from the first end protection of the radial region to the end of each line within the radial region that is furthest from the system; for the end protection, Z... LThe value is the impedance value from the end of the radial region protection to the end of each line in the radial region that is farther from the distributed power source.

[0017] Optionally, based on the presence of a CT disconnection, the line protection or head-end protection uses 5G communication to send a blocking signal or tripping command to the corresponding target protection, including:

[0018] If there is no CT disconnection, the protection that generates overcurrent protection action information will send a blocking signal to the adjacent protection that is closer to the system side via 5G communication. When the protection that generates overcurrent protection action information but has not received a blocking signal trips its circuit breaker, the fault location is determined to be on the line between two protections with inconsistent overcurrent protection action information in the radial area.

[0019] If a CT (Cable Transmitter) disconnection occurs, the faulty line is located by combining the polarity information of the compensation impedance corresponding to each set impedance within the radial area's head-end protection. If only the compensation impedance corresponding to the set impedance with the largest protection range in the head-end protection has a negative polarity, the fault location is determined to be on the line farthest from the head-end protection, and a trip command is sent to the protection on the line farthest from the head-end protection using 5G communication. If the compensation impedance polarity information corresponding to each set impedance in the head-end protection is negative, the fault location is determined to be on the line where the head-end protection is located, and a trip command is sent to the line protection closest to the system using 5G communication. If the polarity of the compensation impedance corresponding to the largest setting impedance in the first-end protection is positive, and the polarity information of the compensation impedances corresponding to other setting impedances is negative or both positive and negative, then the fault location is determined to be in the non-overlapping area of ​​the protection ranges corresponding to two adjacent setting impedances with opposite compensation impedance polarity information, excluding the setting impedance corresponding to the largest protection range. Then, a trip command is sent to the protection in the non-overlapping area using 5G communication. If the aforementioned situation of opposite compensation impedance polarity information still exists, then a trip command is sent to the protection adjacent to the aforementioned tripped protection and closer to the system using 5G communication.

[0020] Optionally, determining the specific location of the fault based on the number of lines contained in the dual-end power supply area, and sending a tripping command to the corresponding target protection using 5G communication based on the specific location of the fault, includes:

[0021] When there is only one line in the dual-end power supply area, it is determined that the fault point is located on the line. The first-end protection and the last-end protection of the dual-end power supply area respectively trip their circuit breakers and send a trip command to the other-end protection with the help of 5G communication to reliably disconnect the faulty line.

[0022] When a dual-end power supply area contains more than one line, if the dual-end power supply area contains multiple lines and the polarity of all compensation impedances of the first-end protection or the last-end protection is negative, then the fault point is determined to be on the line where the first-end protection or the last-end protection is located. The first-end protection or the last-end protection trips the circuit breaker at that point and sends a trip command to the protection at the opposite end of the line where this protection is located via 5G communication. If the dual-end power supply area contains multiple lines and the polarity of the compensation impedances corresponding to each setting impedance with the same relative size of the protection range in the first-end protection and the last-end protection is negative, then the fault is determined to be on the line with the smallest overlap range. Both the first-end protection and the last-end protection send trip information to the protections at both ends of that line via 5G communication.

[0023] If a dual-power supply area contains multiple lines and the compensation impedance polarity information corresponding to two adjacent setting impedances in the head-end or tail-end protection is opposite, then the fault location is determined to be in the non-overlapping area of ​​the protection range corresponding to the two adjacent setting impedances in the head-end or tail-end protection. The head-end or tail-end protection sends a trip command to the protection in this non-overlapping area via 5G communication, and then combines the overcurrent protection action information or compensation impedance polarity information to determine the specific location of the fault. If the head-end protection has supplementary impedance polarity information that is opposite, has sent a trip command to the protection in the non-overlapping area, and is close to the system at this time... If the protection on the side still has overcurrent protection action information or the corresponding compensation impedance polarity in the head protection is still negative, then the head protection continues to send trip commands to the protection adjacent to the tripped protection and closer to the system side via 5G communication; if the end protection has supplementary impedance polarity information that is opposite, has sent trip commands to the protection in the non-overlapping area, and at this time the protection near the distributed power source side still has overcurrent protection action information or the corresponding compensation impedance polarity in the end protection is still negative, then the end protection continues to send trip commands to the protection adjacent to the tripped protection and closer to the distributed power source side via 5G communication.

[0024] Optionally, the area between the feeder head and the distributed power grid connection point is defined as the dual-end power area, and the area between the distributed power grid connection point farthest from the system and the feeder end, as well as feeders without distributed power access, are defined as radial areas.

[0025] Optionally, within a dual-end power supply area, the protection closest to the system is defined as the first-end protection of the dual-end power supply area, and the protection closest to the distributed power supply grid connection point is defined as the last-end protection of the dual-end power supply area; within a radial area, the protection closest to the system is defined as the first-end protection of the radial area; within a radial area, for two adjacent protections, the protection closer to the system side is defined as the upstream protection of the other adjacent protection.

[0026] According to another aspect of the present invention, an active distribution network protection device based on state quantity information is provided, comprising:

[0027] The criterion construction module is used to construct the compensation impedance polarity criterion using the voltage and current information at the feeder head and the grid connection point of the distributed power source;

[0028] The first judgment module is used to collect current information and determine whether there is overcurrent protection action information in each protection in each double-ended power supply area and radial area in the active distribution network. Each first-end protection and end protection in each double-ended power supply area and radial area combines their respective setting impedance and compensation impedance polarity criteria to determine the compensation impedance polarity information.

[0029] The second judgment module is used to determine whether there is a CT disconnection in the radial area if the line protection has overcurrent protection action information or the compensation impedance polarity information of the head protection is negative. Based on the existence of the CT disconnection, the line protection or the head protection uses 5G communication to send a blocking signal or tripping command to the corresponding target protection.

[0030] The third judgment module is used to determine whether there is only one line in the dual-end power supply area if the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative. Based on the number of lines in the dual-end power supply area, the module determines the specific location of the fault and sends a trip command to the corresponding target protection using 5G communication based on the specific location of the fault.

[0031] According to another aspect of the present invention, a computer-readable storage medium is provided, the storage medium storing a computer program for performing the methods described in any of the above aspects of the present invention.

[0032] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method described in any of the preceding aspects of the present invention.

[0033] Compared with the prior art, the positive effects of this invention include the following:

[0034] (1) The present invention adopts a distributed communication method, which only needs to transmit status information (i.e., the polarity of the compensation impedance of the protection or the overcurrent protection action information). The 5G communication data volume is small, the data synchronization requirement is low, it is easy to implement in engineering, and it can cope with multi-point faults.

[0035] (2) This invention only needs to utilize the voltage and current information at the feeder head and the grid connection point of the distributed power source, without the need to install new voltage transformers, and the modification cost is low.

[0036] (3) This invention does not have a protection dead zone. When a fault occurs at the protection output, the compensation impedance is zero because the voltage is zero. Since the polarity of the compensation impedance being zero has been classified as negative, it does not affect the protection judgment, and there is no dead zone.

[0037] (4) This invention is not affected by distributed power sources. Since the range of the set impedance does not include the grid connection point of the distributed power source, the calculation of the polarity information of the compensation impedance is not affected by factors such as the type, quantity, capacity and output of the distributed power source.

[0038] (5) This invention is not affected by the type of fault. In order to ensure that the effectiveness of the protection scheme is not affected by the type of fault, six sets of measurement impedances are calculated by three sets of phase-to-phase voltages and corresponding phase-to-phase currents, and three sets of phase voltages and corresponding phase currents. As long as there is any set of measurement impedances that can make the polarity of the corresponding compensation impedance negative, it indicates that the fault location is within the protection range corresponding to the protection setting impedance.

[0039] (6) This invention is not affected by factors such as CT disconnection at some protection installation points causing current information loss, or long lines connected to large loads. The proposed solution only requires voltage and current information from the first and last protection points of the dual-end power supply area and the first protection point of the radial area to realize backup protection or fault section location of the active distribution network, and is not affected by the integrity of current information of other lines.

[0040] (7) 5G communication systems will be a powerful alternative to fiber optic communication. Their low latency characteristics can provide transmission delays as low as 10ms, effectively improving relay protection speed. They are also suitable for wide-area distributed feeder systems, especially in areas where fiber optic cables cannot be laid or are extremely expensive to lay. Compared to protection based on local information, communication-based protection schemes can fully utilize multi-point electrical or status information, enabling rapid and accurate location of fault sections along the entire line. Therefore, they can serve as a backup protection scheme for protection based on local information. Attached Figure Description

[0041] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0042] Figure 1 This is a flowchart illustrating an active distribution network protection method based on state quantity information provided in an exemplary embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram of an active power distribution network topology and the setting impedance range of the first-end protection and the last-end protection of each region, provided by an exemplary embodiment of the present invention.

[0044] Figure 3This is a flowchart of an active power distribution network protection scheme based on state quantity information under an exemplary embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram of the structure of an active power distribution network protection device based on state quantity information provided in an exemplary embodiment of the present invention;

[0046] Figure 5 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0047] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0048] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0049] Figure 1 A flowchart illustrating the active distribution network protection method based on state quantity information provided by this invention is shown. Figure 1 As shown, the active distribution network protection method based on state quantity information includes: constructing a compensation impedance polarity criterion using voltage and current information at the feeder head and distributed power source grid connection point; in the active distribution network, each protection in each double-ended power source area and radial area collects current information and determines whether there is overcurrent protection action information; each head protection and end protection in each double-ended power source area and radial area combines its own setting impedance and compensation impedance polarity criterion to determine the compensation impedance polarity information; in the radial area, if the line protection has overcurrent protection action information or the head protection compensation impedance polarity is determined... If the polarity information is negative, it is determined whether there is a CT disconnection within the radial area. Based on the presence of the CT disconnection, the line protection or the first-end protection uses 5G communication to send a blocking signal or trip command to the corresponding target protection. In a dual-end power supply area, if the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative, the first-end protection and the last-end protection determine whether there is only one line in the dual-end power supply area. Based on the number of lines in the dual-end power supply area, the specific location of the fault is determined. Based on the specific location of the fault, a trip command is sent to the corresponding target protection using 5G communication.

[0050] In this embodiment of the invention, under the background of 5G communication, an active distribution network protection method based on state quantity information is proposed, which specifically includes the following aspects:

[0051] (1) Typically, voltage transformers are installed on the low-voltage side busbar of the transformer in the substation and at the distributed power source grid connection point. Therefore, the voltage and current information at the feeder head and the distributed power source grid connection point can be fully utilized to construct a compensation impedance polarity criterion, and combined with the overcurrent protection action information to achieve accurate location of the line fault. In addition, the area between the feeder head and the distributed power source grid connection point is defined as the dual-end power source area, and the area between the distributed power source grid connection point farthest from the system and the feeder end, as well as feeders without distributed power source access, are defined as radial areas. At the same time, within the dual-end power source area, the protection closest to the system is defined as the dual-end power source area head protection, and the protection closest to the distributed power source grid connection point is defined as the dual-end power source area end protection; within the radial area, the protection closest to the system is defined as the radial area head protection. Within the radial area, for two adjacent protections, the protection closer to the system side is defined as the upstream protection of the other adjacent protection.

[0052] (2) Referring to the amplitude-based operating equation of the directional impedance relay, the expression for the directional compensation impedance Zdir is constructed as follows:

[0053]

[0054] In the formula: Z dir To compensate for the impedance polarity, Z mea For measuring impedance values; Z set This is the set impedance value.

[0055] From equation (1), it can be seen that when a fault occurs within the protection range, there is Therefore, we can know Z dir The value of Z is less than zero or equal to zero. dir When Z equals zero, it is defined as negative polarity. Therefore, when the fault occurs inside the protection range, Z... dir The polarity is negative; however, when a fault occurs outside the protection range, there is... Therefore, we can know Z dir The value of Z is greater than zero, meaning that when the fault occurs outside the protection range, dir The polarity is positive. Through Z dir The polarity information can be used to determine whether a positive fault has occurred and whether the fault is within the protection range.

[0056] (3) To fully leverage the advantages of 5G communication and make full use of the voltage information at the feeder head and distributed power grid connection point, while accurately locating the fault section, backup protection for the protected area should be formed. For radial area lines and dual-ended power supply area lines, different compensation impedance setting methods need to be implemented, which will benefit the Z-axis protection in multiple protection points within the protected area. dirThe coordination between polarity information and overcurrent protection action information, and the identification of fault sections.

[0057] (i) For radial regions, only the head protection closest to the system within this region can be implemented according to Z. set =K rel_d Z L The magnitude of the compensation impedance is calculated, and Z is set. set The number of [something] equals the number of lines in the area plus one. The reliability coefficient K [is also mentioned]. rel_d Take 1.1 to 1.2, Z L This refers to the impedance value from the first end of the area protection to the end of each line within the area that is furthest from the system. For the remaining Z... set Its reliability coefficient ranges from 0.8 to 0.9, Z L The value is taken as the total length of the line where the first-end protection is located.

[0058] (ii) For dual-ended power supply areas, both the first-end protection (the protection closest to the system) and the last-end protection (the protection closest to the DG grid connection point) within this area shall comply with Z set =K rel_u Z L The magnitude of the compensation impedance is calculated, and Z set The number of [something] is equal to the number of lines in the area. The reliability coefficient K [is also included]. rel_u Take a value of 0.8 to 0.9; for head-end protection, Z L For the first-end protection of the area, Z represents the impedance value from the end of each line within the area that is furthest from the system; for the last-end protection, Z... L The impedance value of the line at the end of the region that is far from the distributed power source is used for regional end protection.

[0059] (4) For lines within a radial area, the fault section can be located using overcurrent protection action information. That is, when there is overcurrent protection action information for the line protection within the radial area, the protection uses 5G communication to send a blocking signal to the upstream protection that is close to the system. In the end, only the system-side protection closest to the fault point has both overcurrent protection action and will not receive a blocking signal. This protection action can determine that the fault is located between two protections with inconsistent overcurrent protection action information.

[0060] However, when new loads such as electric vehicles are connected to long-distance radial lines, or when current information is lost due to CT failure at some protection installation points on radial lines, relying solely on overcurrent protection operation information cannot guarantee the reliability of fault location. In such cases, fault location needs to be achieved based on the polarity of the compensation impedance of the first-end protection within the radial area. The basic principle is as follows: When the polarity of all compensation impedances of the first-end protection is negative, the fault point can be determined to be on the line covered by the first-end protection, and the first-end protection will trip the circuit breaker at that location to disconnect the faulty line. When only the compensation impedance corresponding to the largest setting impedance in the first-end protection has a negative polarity, the fault point can be determined to be on the line farthest from the first-end protection. In this case, the first-end protection sends a trip command to the protection of the faulty line via 5G communication to disconnect the faulty line. Furthermore, it can be determined that the fault point is located in the non-overlapping area corresponding to two adjacent setting impedances of opposite polarities, excluding the setting impedance corresponding to the largest setting impedance in the protection range. In this scenario, the first-end protection first sends a trip command to the protection within the non-overlapping area via 5G communication. Then, it combines the overcurrent protection action information or the compensation impedance polarity information to determine the specific location of the fault. If the aforementioned situation of reversed compensation impedance polarity still exists, the first-end protection sends a trip command to the protection adjacent to the aforementioned tripped protection and closer to the system side via 5G communication.

[0061] (5) For lines in a dual-power supply area, the fault section is located based on the polarity information of the compensation impedance of the first-end protection and the last-end protection in the area. The basic principle is as follows: When the dual-power supply area contains only one line, as long as the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative, it can be determined that the fault point is located on the line. The first-end protection and the last-end protection trip their respective circuit breakers and send trip information to the protection at the other end through 5G communication. When the dual-power supply area contains multiple lines and the polarity of all compensation impedances of the first-end protection or the last-end protection is negative, it can be determined that the fault point is located on the line where the first-end protection or the last-end protection is located. The first-end protection or the last-end protection trips its respective circuit breaker and sends a trip command to the protection at the other end of the line where this protection is located through 5G communication. When the dual-power supply area contains multiple lines and the polarity of the compensation impedances corresponding to the setting impedances of the first-end protection and the last-end protection with the same protection range is negative, it can be determined that the fault is located on the line with the smallest overlap range. The first-end protection and the last-end protection send trip information to the protection at both ends of the line through 5G communication. In addition, when a fault occurs in a dual-end power supply area containing multiple lines, there may be a situation where the polarity information of the compensation impedance corresponding to two adjacent setting impedances in the first-end protection or the last-end protection is opposite. In this case, the fault location is on the non-overlapping area of ​​the protection range corresponding to the two adjacent setting impedances in the first-end protection or the last-end protection. First, the first-end protection or the last-end protection sends a trip command to the protection in the non-overlapping area through 5G communication, and then combines the overcurrent protection action information or the compensation impedance polarity information to determine the specific location of the fault. If the first-end protection has reversed supplementary impedance polarity information, has sent a trip command to the protection in the non-overlapping area, and the protection closer to the system side still has overcurrent protection action information or the corresponding compensation impedance polarity in the first-end protection is still negative, then the first-end protection continues to send a trip command to the protection adjacent to the already tripped protection and closer to the system side via 5G communication; if the last-end protection has reversed supplementary impedance polarity information, has sent a trip command to the protection in the non-overlapping area, and the protection closer to the distributed power source side still has overcurrent protection action information or the corresponding compensation impedance polarity in the last-end protection is still negative, then the last-end protection continues to send a trip command to the protection adjacent to the already tripped protection and closer to the distributed power source side via 5G communication.

[0062] The following will combine Figure 2 and Figure 3 , to attach Figure 2 Taking faults occurring at different locations within dual-ended power supply zones 1 and 2 as examples, this paper specifically describes the fault location and protection action logic within the dual-ended power supply zones. Specifically, protection 1 and protection 4 are the initial protections for dual-ended power supply zones 1 and 2, respectively, while protection 8 and protection 9 are the final protections for dual-ended power supply zones 1 and 2, respectively.

[0063] When a fault occurs at point f1, all compensation impedances Z of the end protection 8 of the dual-ended power supply region 1 will be affected. dir_DC Z dir_DB and Z dir_DA Since the polarity of all values ​​is negative, it can be directly determined that the fault occurs on the DC line. Therefore, the end protection 8 trips its circuit breaker and sends a trip command to protection 3 via 5G communication.

[0064] When a fault occurs at point f2, the setting impedance Z, which is adjacent to the protection range size in the first-end protection 1 of the double-ended power supply region 1, is... set_AC and Z set_AD The corresponding compensation impedances have different polarities, and the non-overlapping region spans lines BC and CD within the double-ended power supply region 1; the setting impedances Z of adjacent protection range sizes in the end protection 8 are... set_DC and Z set_DB The corresponding compensation impedances also have different polarities, and the non-overlapping region spans line DC and line CB. Therefore, with the help of 5G communication, both the first-end protection 1 and the last-end protection 8 send trip commands to protection 3 on line CD. After protection 3 trips its circuit breaker, for the first-end protection 1, the polarity information of the compensation impedance corresponding to its setting impedance is positive, and protection 2 no longer sends overcurrent protection action information, indicating that the fault has been cleared, and no more trip commands are sent. For the last-end protection 8, its compensation impedance Z dir_DB The polarity information is still negative, and the overcurrent protection information of protection 8 still exists, indicating that the fault occurred on line CD, and the end protection 8 tripped the circuit breaker at that location.

[0065] When a fault occurs at point f3, the compensation impedance corresponding to the setting impedance of the first-end protection 1 and the last-end protection 8 of the double-ended power supply region 1, which have the same relative protection range, corresponds to Z. dir_AD With Z dir_AC Z dir_DA With Z dir_DB The polarities of all are negative, and the minimum overlap of the set impedance pairs is located on line BC. Based on this, it can be determined that the fault point is located on line BC. Therefore, both the first-end protection 1 and the last-end protection 8 send trip commands to protection 2 and protection 3 via 5G communication.

[0066] When a fault occurs at point f4, the compensation impedance Z in the first-end protection 4 of the double-ended power supply region 2... dir_DE And the compensation impedance Z in the end protection 9 dir_ED Since all values ​​are negative, the fault point is determined to be on line DE. The first-end protection 4 and the last-end protection 9 trip their respective circuit breakers and send trip commands to the opposite-end protection via 5G communication to ensure reliable disconnection of the faulty line.

[0067] When a fault occurs at point f5, the compensation impedance Z in the first-end protection 4 of the double-ended power supply region 2... dir_DE For negative, end protection 9, the compensation impedance Zdir_ED A positive result indicates that the fault occurred within the protection range corresponding to the setting impedance of protection 4, but not within the protection range corresponding to the setting impedance of protection 9. However, since the dual-end power supply area 2 contains only one line, it can be determined that the fault point is located on line DE. The first-end protection 4 and the last-end protection 9 respectively trip their circuit breakers and send trip commands to the protection at the other end via 5G communication to ensure reliable disconnection of the faulty line.

[0068] With attachment Figure 2 Taking faults occurring at different locations within radial area 1 as an example, this paper describes in detail the fault location and protection action logic of the radial area. Among them, protection 6 is the first-end protection of radial area 1.

[0069] When a fault occurs at point f6, all compensation impedances Z in the first-end protection 6 of the radial area 1 will be affected. dir_AG Z dir_AH1 and Z dir_AH2 Since the polarity of all values ​​is negative, it can be directly determined that the fault location is within the protection range corresponding to the minimum set impedance value. That is, the line AG where the first-end protection 6 is located is the fault line, so protection 6 directly trips the circuit breaker at that location.

[0070] When a fault occurs at point f7, the compensation impedance Z in the first-end protection 6 of the radial area 1... dir_AG Polarity is positive, Z dir_AH1 and Z dir_AH2 Since the polarity is negative, it can be determined that the fault point is located in the non-overlapping area of ​​the protection range corresponding to two other setting impedances besides the maximum setting impedance of the protection range. Therefore, the first-end protection 6 first sends a trip command to protection 7 via 5G communication. After protection 7 trips, the Z-axis in the first-end protection 6... dir_AH1 The polarity information is still negative, and the overcurrent protection information of the first-end protection 6 is still active. Therefore, it can be determined that the fault point is on line AG, and the first-end protection 6 trips the circuit breaker at that point.

[0071] When a fault occurs at point f8, the compensation impedance Z in the first-end protection 6 of the radial area 1... dir_AG Polarity is positive, Z dir_AH1 and Z dir_AH2 Since the polarity is negative, it can be determined that the fault point is located in the non-overlapping area of ​​the protection range corresponding to two other setting impedances besides the maximum setting impedance of the protection range. Therefore, the first-end protection 6 first sends a trip command to protection 7 via 5G communication. After protection 7 trips, the Z-axis in the first-end protection 6... dir_AH1 and Z dir_AH2 The polarity information is all positive, and the first-end protection 6 no longer has overcurrent protection action information, so it can be determined that the fault point is on line GH.

[0072] When a fault occurs at point f9, the first-end protection 6 in Z... dir_AG and Zdir_AH1 The polarity of Z is positive, while Z is positive. dir_AH2 Since the polarity is negative, it is directly determined that the fault point is located on the line GH, which is farthest from the first-end protection. The first-end protection 6 sends a trip command to the protection 7 via 5G communication to disconnect the faulty line.

[0073] In the context of 5G communication, this solution employs a distributed communication approach, requiring protection zones to communicate with each other via 5G. When one or more protections in an active distribution network detect and generate overcurrent protection action information, the protection actively shares this information with adjacent protections, the first-end protection, and the last-end protection in the same area. Furthermore, whenever an overcurrent protection action occurs due to a short-circuit current flowing through the protection, this action information is shared at regular time intervals (e.g., 5ms). If the protection is the first-end or last-end protection in a dual-power supply area, it will exchange and share compensation impedance polarity information with the last-end or first-end protection in the same area. Then, the first-end and last-end protections in the dual-power supply area, as well as the first-end protection in the radial area, will perform information analysis and take corresponding protection action logic. The above-mentioned active distribution network protection method based on state quantity information in the context of 5G communication includes the following steps:

[0074] Step 1: In the active power distribution network, each protection device in each dual-ended power supply area and radial area collects current information and determines whether overcurrent protection operation information exists. Each first-end protection device and each last-end protection device in each dual-ended power supply area and radial area determines the polarity information of the compensation impedance based on its respective setting impedance. If overcurrent protection operation information exists in the radial area or the polarity information of the compensation impedance of the first-end protection is negative, proceed to Step 2. If the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative in the dual-ended power supply area, proceed to Step 5.

[0075] Step 2: Within the radial area, if there is no CT disconnection, the protection that generated overcurrent protection action information sends blocking signals to the adjacent protection that is closer to the system side. The protection that generated overcurrent protection action information but did not receive a blocking signal will trip its circuit breaker. The fault location is determined to be on the line between the two protections with inconsistent overcurrent protection action information within the radial area. If there is a CT disconnection, proceed to Step 3.

[0076] Step 3: Locate the faulty line by combining the polarity information of the compensation impedances corresponding to the setting impedances within the head-end protection of the radial area. If the polarity information of the compensation impedances corresponding to the setting impedances in the head-end protection is all negative, a trip command is sent to the line protection furthest from the system to determine that the fault location is on the line furthest from the head-end protection. If the polarity information of the compensation impedances corresponding to the setting impedances in the head-end protection is not all negative, proceed to Step 4.

[0077] Step 4: Determine the fault location as being within the non-overlapping area of ​​the protection ranges corresponding to two adjacent setting impedances with opposite polarity information, excluding the maximum setting impedance of the protection range. Send a trip command to the protection in the non-overlapping area. If the aforementioned situation of opposite polarity information of the compensation impedance still exists, continue to send trip commands to the protection adjacent to the previously tripped protection and closer to the system.

[0078] Step 5: Determine if the dual-power supply area contains only one line. If so, determine that the fault point is located on that line. The first-end and last-end protections of this area will trip their respective circuit breakers and send a trip command to the opposite-end protection to reliably disconnect the faulty line. If not, proceed to Step 6.

[0079] Step 6: If the dual-end power supply area contains multiple lines and the polarity of all compensation impedances of the first-end protection or the last-end protection is negative, then the fault point can be determined to be located on the line where the first-end protection or the last-end protection is located. The first-end protection or the last-end protection trips the circuit breaker at that location and sends a trip command to the protection at the opposite end of the line using 5G communication. Otherwise, proceed to step 7.

[0080] Step 7: If the dual-end power supply area contains multiple lines and the polarity of the compensation impedances corresponding to the setting impedances of the first-end protection and the last-end protection, which have the same relative protection range, is negative, then it can be determined that the fault is located on the line with the smallest overlap range. Both the first-end protection and the last-end protection send trip information to the protections at both ends of this line via 5G communication. Otherwise, proceed to step 8.

[0081] Step 8: If the dual-end power supply area contains multiple lines and the compensation impedance polarity information corresponding to two adjacent setting impedances in the first-end protection or the last-end protection is opposite, then the fault location can be determined to be in the non-overlapping area of ​​the protection range corresponding to the two adjacent setting impedances in the first-end protection or the last-end protection. At this time, the first-end protection or the last-end protection first sends a trip command to the protection in this non-overlapping area via 5G communication, and then combines the overcurrent protection action information or compensation impedance polarity information to determine the specific location of the fault. If the first-end protection has reversed supplementary impedance polarity information, has sent a trip command to the protection in the non-overlapping area, and the protection closer to the system side still has overcurrent protection action information or the corresponding compensation impedance polarity in the first-end protection is still negative, then the first-end protection continues to send a trip command to the protection adjacent to the already tripped protection and closer to the system side via 5G communication; if the last-end protection has reversed supplementary impedance polarity information, has sent a trip command to the protection in the non-overlapping area, and the protection closer to the distributed power source side still has overcurrent protection action information or the corresponding compensation impedance polarity in the last-end protection is still negative, then the last-end protection continues to send a trip command to the protection adjacent to the already tripped protection and closer to the distributed power source side via 5G communication.

[0082] in, Figure 3 A flowchart of an active power distribution network protection scheme based on state quantity information in the context of 5G communication is shown.

[0083] Therefore, the active distribution network protection method based on state quantity information proposed in this invention has the following positive effects compared with the prior art:

[0084] (1) The present invention adopts a distributed communication method, which only needs to transmit status information (i.e., the polarity of the compensation impedance of the protection or the overcurrent protection action information). The 5G communication data volume is small, the data synchronization requirement is low, it is easy to implement in engineering, and it can cope with multi-point faults.

[0085] (2) This invention only needs to utilize the voltage and current information at the feeder head and the grid connection point of the distributed power source, without the need to install new voltage transformers, and the modification cost is low.

[0086] (3) This invention does not have a protection dead zone. When a fault occurs at the protection output, the compensation impedance is zero because the voltage is zero. Since the polarity of the compensation impedance being zero has been classified as negative, it does not affect the protection judgment, and there is no dead zone.

[0087] (4) This invention is not affected by distributed power sources. Since the range of the set impedance does not include the grid connection point of the distributed power source, the calculation of the polarity information of the compensation impedance is not affected by factors such as the type, quantity, capacity and output of the distributed power source.

[0088] (5) This invention is not affected by the type of fault. In order to ensure that the effectiveness of the protection scheme is not affected by the type of fault, six sets of measurement impedances are calculated by three sets of phase-to-phase voltages and corresponding phase-to-phase currents, and three sets of phase voltages and corresponding phase currents. As long as there is any set of measurement impedances that can make the polarity of the corresponding compensation impedance negative, it indicates that the fault location is within the protection range corresponding to the protection setting impedance.

[0089] (6) This invention is not affected by factors such as CT disconnection at some protection installation points causing current information loss, or long lines connected to large loads. The proposed solution only requires voltage and current information from the first and last protection points of the dual-end power supply area and the first protection point of the radial area to realize backup protection or fault section location of the active distribution network, and is not affected by the integrity of current information of other lines.

[0090] Exemplary device

[0091] Figure 4 This is a schematic diagram of the structure of an active power distribution network protection device based on state quantity information provided in an exemplary embodiment of the present invention. Figure 4 As shown, the device 400 includes:

[0092] The criterion construction module 410 is used to construct the compensation impedance polarity criterion using the voltage and current information at the feeder head and the grid connection point of the distributed power source.

[0093] The first judgment module 420 is used to collect current information and determine whether there is overcurrent protection action information in each protection in each double-ended power supply area and radial area in the active power distribution network. Each first-end protection and end protection in each double-ended power supply area and radial area determines the polarity information of the compensation impedance by combining their respective setting impedance and compensation impedance polarity criteria.

[0094] The second judgment module 430 is used to determine whether there is a CT disconnection in the radial area if the line protection has overcurrent protection action information or the polarity information of the compensation impedance of the head protection is negative. Based on the existence of the CT disconnection, the line protection or the head protection uses 5G communication to send a blocking signal or tripping command to the corresponding target protection.

[0095] The third judgment module 440 is used to determine whether there is only one line in the dual-end power supply area if the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative. Based on the number of lines in the dual-end power supply area, the module determines the specific location of the fault and sends a trip command to the corresponding target protection using 5G communication based on the specific location of the fault.

[0096] The active distribution network protection device based on state quantity information in the embodiments of the present invention corresponds to the active distribution network protection method based on state quantity information in another embodiment of the present invention, and will not be described again here.

[0097] Exemplary electronic devices

[0098] Figure 5 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. For example... Figure 5 As shown, the electronic device 50 includes one or more processors 51 and memory 52.

[0099] The processor 51 may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0100] The memory 52 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 51 may execute the program instructions to implement the methods for information mining of historical change records and / or other desired functions of the software programs of the various embodiments of the present invention described above. In one example, the electronic device may also include an input device 53 and an output device 54, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0101] In addition, the input device 53 may also include, for example, a keyboard, a mouse, etc.

[0102] The output device 54 can output various information to the outside. The output device 54 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0103] Of course, for the sake of simplicity, Figure 5 Only some of the components of the electronic device relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device may include any other suitable components depending on the specific application.

[0104] Exemplary computer program products and computer-readable storage media

[0105] In addition to the methods and apparatus described above, embodiments of the present invention may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0106] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of the present invention. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0107] Furthermore, embodiments of the present invention may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps of the methods for information mining of historical change records according to various embodiments of the present invention as described in the "Exemplary Methods" section above.

[0108] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0109] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0110] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0111] The block diagrams of devices, systems, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, systems, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0112] The methods and systems of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0113] It should also be noted that in the systems, apparatus, and methods of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered equivalents of the present invention. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0114] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. An active distribution network protection method based on state quantity information, characterized in that, include: Using the voltage and current information at the feeder head and the grid connection point of the distributed power source, a criterion for the polarity of the compensation impedance is constructed. In an active power distribution network, each protection device in each dual-ended power supply area and radial area collects current information and determines whether overcurrent protection operation information exists. Each first-end and last-end protection device in each dual-ended power supply area and radial area determines the polarity information of the compensation impedance based on its respective setting impedance and compensation impedance polarity criteria. The setting impedance settings for the first-end protection in the radial area and the first-end and last-end protection in the dual-ended power supply area are as follows: For radial regions, the nearest head protection within the radial region to the system is as follows: The magnitude of the setting impedance is calculated, and its setting impedance is set. Z set The number of [number] is equal to the number of lines within the radial region. n Add 1; for one of them n For each set impedance, during the setting calculation process, the reliability coefficient... K rel_d The value ranges from 1.1 to 1.

2. Z L The value is the impedance value from the first end of the radial region to the end of each line within the radial region that is furthest from the system; for the remaining set impedance, the reliability coefficient is used in the setting calculation process. K rel_d The value ranges from 0.8 to 0.

9. Z L The value is the total length of the line where the first-end protection is located; For the dual-ended power supply region, both the first-end protection and the last-end protection within the dual-ended power supply region shall be in accordance with The magnitude of the setting impedance is calculated, and its setting impedance is set. Z set The number of [items] and the number of lines within the region n Equal; where the reliability coefficient is... K rel_u Take a value of 0.8~0.9; for head-end protection, Z L The value is the impedance value from the first-end protection of the dual-ended power supply area to the end of each line in the dual-ended power supply area that is farther from the system; for the end protection, Z L The value is the impedance value from the end protection of the dual-ended power supply area to the end of each line in the dual-ended power supply area that is farther away from the distributed power source. Within the radial area, if the line protection has overcurrent protection action information or the polarity information of the compensation impedance of the head protection is negative, it is determined whether there is a CT disconnection within the radial area. Based on the presence of the CT disconnection, the line protection or the head protection uses 5G communication to send a blocking signal or tripping command to the corresponding target protection. In a dual-power supply area, if the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative, the first-end protection and the last-end protection will determine whether there is only one line in the dual-power supply area, and determine the specific location of the fault based on the number of lines in the dual-power supply area. Based on the specific location of the fault, a trip command will be sent to the corresponding target protection using 5G communication.

2. The method according to claim 1, characterized in that, The expression for the polarity criterion of the compensation impedance is as follows: ； In the formula: To compensate for impedance polarity, To measure impedance value; This is the set impedance value.

3. The method according to claim 1, characterized in that, Based on the presence of a CT disconnection, the line protection or head-end protection uses 5G communication to send a blocking signal or tripping command to the corresponding target protection, including: If there is no CT disconnection, the protection that generates overcurrent protection action information will send a blocking signal to the adjacent protection that is closer to the system side via 5G communication. When the protection that generates overcurrent protection action information but has not received a blocking signal trips its circuit breaker, the fault location is determined to be on the line between two protections with inconsistent overcurrent protection action information in the radial area. If a CT (Cable Transmitter) disconnection occurs, the faulty line is located by combining the polarity information of the compensation impedance corresponding to each set impedance within the radial area's head-end protection. If only the compensation impedance corresponding to the set impedance with the largest protection range in the head-end protection has a negative polarity, the fault location is determined to be on the line farthest from the head-end protection, and a trip command is sent to the protection on the line farthest from the head-end protection using 5G communication. If the compensation impedance polarity information corresponding to each set impedance in the head-end protection is negative, the fault location is determined to be on the line where the head-end protection is located, and a trip command is sent to the line protection closest to the system using 5G communication. If the polarity of the compensation impedance corresponding to the largest setting impedance in the first-end protection is positive, and the polarity information of the compensation impedances corresponding to other setting impedances is negative or both positive and negative, then the fault location is determined to be in the non-overlapping area of ​​the protection ranges corresponding to two adjacent setting impedances with opposite compensation impedance polarity information, excluding the setting impedance corresponding to the largest protection range. Then, a trip command is sent to the protection in the non-overlapping area using 5G communication. If the aforementioned situation of opposite compensation impedance polarity information still exists, then a trip command is sent to the protection adjacent to the aforementioned tripped protection and closer to the system using 5G communication.

4. The method according to claim 1, characterized in that, The process of determining the specific location of the fault based on the number of lines within the dual-end power supply area, and then sending a tripping command to the corresponding target protection using 5G communication based on the specific location of the fault, includes: When there is only one line in the dual-end power supply area, it is determined that the fault point is located on the line. The first-end protection and the last-end protection of the dual-end power supply area respectively trip their circuit breakers and send a trip command to the other-end protection with the help of 5G communication to reliably disconnect the faulty line. When a dual-end power supply area contains more than one line, if the dual-end power supply area contains multiple lines and the polarity of all compensation impedances of the first-end protection or the last-end protection is negative, then the fault point is determined to be on the line where the first-end protection or the last-end protection is located. The first-end protection or the last-end protection trips the circuit breaker at that point and sends a trip command to the protection at the opposite end of the line where this protection is located via 5G communication. If the dual-end power supply area contains multiple lines and the polarity of the compensation impedances corresponding to each setting impedance with the same relative size of the protection range in the first-end protection and the last-end protection is negative, then the fault is determined to be on the line with the smallest overlap range. Both the first-end protection and the last-end protection send trip information to the protections at both ends of that line via 5G communication. If a dual-power supply area contains multiple lines and the compensation impedance polarity information corresponding to two adjacent setting impedances in the head-end or tail-end protection is opposite, then the fault location is determined to be in the non-overlapping area of ​​the protection range corresponding to the two adjacent setting impedances in the head-end or tail-end protection. The head-end or tail-end protection sends a trip command to the protection in this non-overlapping area via 5G communication, and then combines the overcurrent protection action information or compensation impedance polarity information to determine the specific location of the fault. If the head-end protection has supplementary impedance polarity information that is opposite, has sent a trip command to the protection in the non-overlapping area, and is close to the system at this time... If the protection on the side still has overcurrent protection action information or the corresponding compensation impedance polarity in the head protection is still negative, then the head protection continues to send trip commands to the protection adjacent to the tripped protection and closer to the system side via 5G communication; if the end protection has supplementary impedance polarity information that is opposite, has sent trip commands to the protection in the non-overlapping area, and at this time the protection near the distributed power source side still has overcurrent protection action information or the corresponding compensation impedance polarity in the end protection is still negative, then the end protection continues to send trip commands to the protection adjacent to the tripped protection and closer to the distributed power source side via 5G communication.

5. The method according to claim 1, characterized in that, The area between the feeder head and the distributed power grid connection point is defined as the dual-end power area, and the area between the distributed power grid connection point farthest from the system and the feeder end, as well as feeders without distributed power connection, are defined as radial areas.

6. The method according to claim 4, characterized in that, Within a dual-ended power supply area, the protection closest to the system is defined as the first-end protection of the dual-ended power supply area, and the protection closest to the distributed power supply grid connection point is defined as the last-end protection of the dual-ended power supply area. Within a radial area, the protection closest to the system is defined as the first-end protection of the radial area. Within a radial area, for two adjacent protections, the protection closer to the system side is defined as the upstream protection of the other adjacent protection.

7. An active distribution network protection device based on state quantity information, characterized in that, include: The criterion construction module is used to construct the compensation impedance polarity criterion using the voltage and current information at the feeder head and the grid connection point of the distributed power source; The first judgment module is used to collect current information and determine whether overcurrent protection operation information exists for each protection unit in each dual-ended power supply area and radial area in the active power distribution network. Each first-end protection and last-end protection unit in each dual-ended power supply area and radial area determines the polarity information of the compensation impedance based on its respective setting impedance and compensation impedance polarity criteria. The setting impedance settings for the first-end protection in the radial area and the first-end and last-end protection in the dual-ended power supply area are as follows: For radial regions, the nearest head protection within the radial region to the system is as follows: The magnitude of the setting impedance is calculated, and its setting impedance is set. Z set The number of [number] is equal to the number of lines within the radial region. n Add 1; for one of them n For each set impedance, during the setting calculation process, the reliability coefficient... K rel_d The value ranges from 1.1 to 1.

2. Z L The value is the impedance value from the first end of the radial region to the end of each line within the radial region that is furthest from the system; for the remaining set impedance, the reliability coefficient is used in the setting calculation process. K rel_d The value ranges from 0.8 to 0.

9. Z L The value is the total length of the line where the first-end protection is located; For the dual-ended power supply region, both the first-end protection and the last-end protection within the dual-ended power supply region shall be in accordance with The magnitude of the setting impedance is calculated, and its setting impedance is set. Z set The number of [items] and the number of lines within the region n Equal; where the reliability coefficient is... K rel_u Take a value of 0.8~0.9; for head-end protection, Z L The value is the impedance value from the first-end protection of the dual-ended power supply area to the end of each line in the dual-ended power supply area that is farther from the system; for the end protection, Z L The value is the impedance value from the end protection of the dual-ended power supply area to the end of each line in the dual-ended power supply area that is farther away from the distributed power source. The second judgment module is used to determine whether there is a CT disconnection in the radial area if the line protection has overcurrent protection action information or the compensation impedance polarity information of the head protection is negative. Based on the existence of the CT disconnection, the line protection or the head protection uses 5G communication to send a blocking signal or tripping command to the corresponding target protection. The third judgment module is used to determine whether there is only one line in the dual-end power supply area if the polarity information of the compensation impedance of the first-end protection or the last-end protection is negative. Based on the number of lines in the dual-end power supply area, the module determines the specific location of the fault and sends a trip command to the corresponding target protection using 5G communication based on the specific location of the fault.

8. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for performing the method described in any one of claims 1-6.

9. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1-6.

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