A single-ended full-line high-speed protection method and system based on an active boundary

Abstract

The present invention discloses a single - ended full - line high - speed protection method and system based on an active boundary. By utilizing the highly controllable nature of power electronic equipment, an active boundary is actively constructed, and the setting value is determined according to the protection sensitivity requirement, the boundary signal injection intensity, and the local protection detection ability. After a fault occurs, the remote active boundary actively injects a preset boundary signal according to the fault situation. After the local protection detects the signal sent by the active boundary, the active boundary signal detected by the local protection is compared with the set setting value. If the action requirement is met, it is an in - zone fault and the protection acts; otherwise, it is an out - of - zone fault and the protection does not act. The method of the present invention has the ability to identify faults within the full - line range and is applicable to transmission and distribution lines with power electronic equipment at the remote end.

Description

Technical Field

[0001] The present invention belongs to the technical field of relay protection, and particularly relates to a single-ended quantity full-line quick-acting protection method and system based on an active boundary. Background Technique

[0002] Single-ended electrical quantity full-line quick-acting protection, also known as boundary protection, refers to a single-ended quantity protection that realizes rapid fault identification within the entire line range through the cooperation of the protection at the local end of the line and the boundary at the opposite end of the line when there is a boundary (response characteristic distortion point) at the opposite end of the line. Because boundary protection has the advantages of fast speed, no need to cooperate with adjacent protection, and no need for communication, it is the goal pursued by relay protection workers.

[0003] The single-ended quantity full-line quick-acting protection cooperates with the boundary element at the opposite end to protect the entire length of the line. The current boundary elements are mainly passive boundaries, that is, they respond to the disturbances of the power grid through the impedance characteristics of the elements themselves, and their key mechanism is the "specific response characteristics" under internal and external faults. According to the topological structure of the boundary element, it can be divided into three categories: parallel access type, series access type, and combined access type. The parallel access type boundary, such as the stray capacitance between the bus and the ground in an AC transmission system and the capacitor used for filtering and clamping the DC voltage in a VSC-type flexible DC system; the series access type boundary, such as the series reactor used to limit the rising speed of the short-circuit current in an MMC-type DC system; the combined access type boundary, such as the boundary formed by the combination of the wave trap used for carrier communication and the stray capacitance of the bus in an AC system, and the boundary formed by the combination of the DC filter and the smoothing reactor in a high-voltage DC LCC-HVDC system.

[0004] The above parameter design of the boundary element only meets the requirements of the primary system and does not consider the cooperation problem with the protection. In most cases, directly borrowing these boundaries, the performance of the protection often fails to meet the requirements. In addition, without an existing boundary, single-ended full-line quick-acting protection cannot be achieved. Therefore, actively constructing a boundary with a deterministic cooperation relationship with the single-ended quantity protection is an effective way to solve the above problems. For this reason, many scholars have proposed the idea of actively constructing the line boundary, such as using a ferrite magnetic ring to construct the boundary of the distribution line to achieve full-line quick-acting protection.

[0005] With the construction of a new power system with new energy as the main body, the proportion of power electronic equipment in the power grid will further increase. If the high controllability characteristics of power electronic equipment are fully utilized, and signals carrying discriminant information of the opposite-end protection are injected into the power grid during a fault, as a kind of boundary information, to cooperate with the local protection, then a single-ended full-line rapid protection based on actively constructing an active boundary by power electronic equipment can be achieved. Currently, domestic and foreign scholars have carried out a large amount of exploratory work in aspects such as detection protection, reclosing, and fault discrimination based on the injection of characteristic signals by power electronic devices. However, the current research still focuses on injecting voltage and current by the local power electronic device to improve the sensitivity and reliability of the local protection, and no research work has been found on constructing an active boundary by cooperating the local protection with the opposite-end power electronic equipment to realize the single-ended full-line rapid protection function in the form of information. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a single-ended full-line rapid protection method and system based on an active boundary in view of the deficiencies in the above-mentioned prior art. During a power grid fault, a boundary signal reflecting the fault information is injected by the opposite-end power electronic equipment, and the local protection discriminates between internal and external faults through the response characteristics it senses, so as to solve the technical problem of not realizing the single-ended full-line rapid protection function in the form of information.

[0007] The present invention adopts the following technical solutions:

[0008] A single-ended full-line rapid protection method based on an active boundary actively constructs an active boundary by using the controllability of the opposite-end power electronic equipment, and determines the setting value according to the protection sensitivity requirement, the injection intensity of the boundary signal, and the detection ability of the local protection. After a fault occurs, the opposite-end active boundary actively injects a preset boundary signal according to the fault situation. After the local protection detects the signal sent by the active boundary, it compares the active boundary signal detected by the local protection with the setting value. If the action requirement is met, it is an internal fault and the protection acts; otherwise, it is an external fault and the protection does not act.

[0009] Specifically, constructing the opposite-end active boundary specifically includes:

[0010] Determine the equipment for injecting the active boundary signal according to the primary topological structure of the power system and the power electronic equipment contained in the primary topological structure; divide the power electronic equipment into parallel-type active boundaries and series-type active boundaries according to the connection method to the power grid; select the boundary information injection circuit in combination with the characteristics of the equipment for injecting the active boundary signal and the fault type; select the boundary signal characteristics reflecting faults at different positions according to the primary topological structure of the power system and the opposite-end direction criterion, and complete the construction of the opposite-end active boundary.

[0011] Furthermore, the active boundary utilizes the specific response characteristics of the power electronic equipment under internal and external faults in the active simulation area, including waveform, amplitude, or frequency parameters of the signal.

[0012] Specifically, the startup criterion is as follows:

[0013] When the opposite end determines a forward fault, the active boundary starts to inject the preset boundary signal representing the forward fault at the opposite end. Conversely, the active boundary injects the preset boundary signal representing the reverse fault at the opposite end.

[0014] Specifically, judging whether the protection action is satisfied according to the response characteristics of the local protection is as follows:

[0015] When the local protection determines that a forward fault has occurred, continue with the protection judgment; when the local protection determines that a reverse fault has occurred at the local protection, it is directly judged as an external fault.

[0016] Furthermore, continuing with the protection judgment is specifically as follows:

[0017] Compare the active boundary signal extracted at the local protection with its setting value to determine whether it is an internal fault or an external fault.

[0018] Furthermore, when the local protection satisfies a forward fault, the active boundary signal representing the forward fault at the opposite end extracted by the local protection meets the setting value condition, while the active boundary signal representing the reverse fault at the opposite end extracted by the local protection does not meet the setting value condition, that is, it is judged as an internal fault and the protection operates.

[0019] Furthermore, when the local protection satisfies a forward fault, the active boundary signal representing the reverse fault at the opposite end extracted by the local protection meets the setting condition, that is, it is judged as an external fault and the protection does not operate.

[0020] In a second aspect, an embodiment of the present invention provides a single - end quantity full - line fast - acting protection system based on an active boundary, including:

[0021] An additional control module for actively constructing an active boundary by utilizing the controllability of the opposite - end power electronic equipment;

[0022] A setting module for determining the setting value according to the protection sensitivity requirement, the boundary signal injection intensity, and the local protection detection ability,

[0023] An injection module. After a fault occurs, the active boundary at the opposite end actively injects the preset boundary signal according to the fault situation, and the local protection detects the signal sent by the active boundary;

[0024] The protection module is used to compare the active boundary signal detected by the local protection with the setting value. If the action requirement is met, it is a fault within the zone, and the protection acts; otherwise, it is a fault outside the zone, and the protection does not act.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] A single - ended quantity full - line quick - acting protection method based on an active boundary according to the present invention. In the case where the parameters of traditional boundary elements serve the requirements of the primary system, it is often difficult to meet the protection performance requirements, and with the improvement of the performance of power electronic devices leading to the weakening of traditional boundary elements, an active boundary with a deterministic cooperation relationship with single - ended quantity protection is actively constructed. The invention can have the fault recognition ability within the full - line range without cooperation with other protections and is applicable to the grid protection of power - electronic power systems.

[0027] Furthermore, the remote active boundary utilizes the flexible controllability and fast adjustment speed of power electronic equipment, which has the ability to simulate traditional boundary elements, and actively generates different responses according to different faults, which ensures and improves the boundary characteristics and the performance of boundary protection.

[0028] Furthermore, the remote start - up criterion needs to cooperate with the direction element to obtain the states of all outgoing lines, select the active boundary signal characteristics according to the positive - direction or reverse - direction fault results obtained by discrimination, and inject the active boundary signal through the active boundary.

[0029] Furthermore, for the local protection start - up identification, the direction of the fault is judged. In particular, for the reverse fault at the local protection, it is directly judged as an external - zone fault without waiting for the remote active boundary signal.

[0030] Furthermore, after the local protection meets the condition of a positive - direction fault, it is necessary to further judge whether the fault occurs in the line or outside the line. At this time, the active boundary signal is required to provide information, and the active boundary signal at the local protection is compared with the setting value to realize single - ended quantity full - line quick - acting protection in the form of information.

[0031] Furthermore, according to the information provided by the active boundary signal for analysis and processing, if the extracted information meets the condition of a remote positive - direction fault, it meets the action requirement for an internal - zone fault, and the protection acts.

[0032] Furthermore, according to the information provided by the active boundary signal for analysis and processing, if the extracted information meets the condition of a remote reverse - direction fault, it meets the condition of an external - zone fault and does not act.

[0033] It can be understood that the beneficial effects of the second aspect can refer to the relevant descriptions in the first aspect above and will not be elaborated here.

[0034] In summary, the present invention makes full use of the high controllability of power electronic devices in an electrified power system, actively simulates the characteristics of traditional boundary elements in the primary system, generates different specific responses according to different faults, further improves the sensitivity and reliability of boundary protection, and realizes the research work of single-ended full-line fast protection function in the form of information.

[0035] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the specific flowchart of active boundary protection;

[0037] Figure 2 is the diagram of a two-terminal MMC DC power transmission system;

[0038] Figure 3 is the diagram of a DC power grid model built using PSCAD / EMTDC;

[0039] Figure 4 is the waveform diagram of the sinusoidal active boundary signal injected by the opposite-end MMC2;

[0040] Figure 5 is the waveform diagram of the active boundary signal of the local protection under a monopole ground fault. Among them, (a) is the waveform diagram of the positive pole reception of the local protection under a positive pole ground fault, and (b) is the active boundary signal received by the positive pole of the local protection extracted by the matrix pencil algorithm;

[0041] Figure 6 is the waveform diagram of the active boundary signal of the local protection under an external fault. Among them, (a) is the waveform diagram of the positive pole reception of the local protection under an external fault, and (b) is the active boundary signal received by the positive pole of the local protection extracted by the matrix pencil algorithm. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0043] In the description of the present invention, it should be understood that the terms "including" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0044] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0045] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0046] It should be understood that although terms such as first, second, and third may be used in the embodiments of the present invention to describe preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range. Similarly, the second preset range may also be referred to as the first preset range.

[0047] Depending on the context, the word "if" as used herein can be interpreted as "when", "while", "in response to determining", or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (stated condition or event)" can be interpreted as "when determined", "in response to determining", "when detecting (stated condition or event)", or "in response to detecting (stated condition or event)".

[0048] Schematic diagrams of various structures according to the disclosed embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are only exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0049] The present invention provides a single-ended full-line fast protection method based on an active boundary, which actively constructs an active boundary by using power electronic equipment and involves two parts: the construction of the active boundary and the implementation of the single-ended full-line fast protection criterion.

[0050] Please refer to Figure 1 , the specific steps of a single-ended full-line fast protection method based on an active boundary of the present invention are as follows:

[0051] S1. Construct an active boundary at the opposite end;

[0052] S101. Determine the equipment for injecting the active boundary signal according to the primary topological structure of the power system and the power electronic equipment contained therein; classify the power electronic equipment into a parallel active boundary and a series active boundary according to the way of connecting to the power grid.

[0053] The parallel boundary means that there are multiple lines on the bus at the outlet of the power electronic equipment. For example, in a radial or looped flexible DC power grid, the MMC can be considered as a parallel boundary;

[0054] The series boundary means that there is only one line on the bus at the outlet of the power electronic equipment, such as a high-voltage DC circuit breaker DCCB and an intelligent soft switch SOP.

[0055] S102. Select the boundary information injection loop in combination with the equipment characteristics of the injected active boundary signal and the fault type;

[0056] S103. Select the boundary signal characteristics reflecting faults at different positions according to the primary topological structure of the power system and the opposite-end protection criterion, that is, use the power electronic equipment to actively simulate the "specific response characteristics" under internal and external faults. The boundary signal characteristics are the waveform, amplitude or frequency parameters of the signal, or a combination of the above parameters;

[0057] S104. Design an additional control strategy for the active boundary signal of the power electronic equipment according to different injection equipment, injection loops and characteristic signals.

[0058] S2. Realize the single-ended quantity full-line quick-acting protection criterion.

[0059] S201. Analyze the response characteristics felt by the local protection after injecting the preset boundary signal in the most severe case of the fault, and set the setting value by comprehensively considering the protection sensitivity requirement, the injection intensity of the boundary signal and the detection ability of the local protection;

[0060] S202. After the fault occurs, the opposite-end active boundary starts to inject the active boundary signal according to the preset starting criterion, the local protection starts to detect the boundary signal, and at the same time judges the fault direction;

[0061] S203. When the opposite end determines that a positive-direction fault has occurred, the active boundary starts to inject the preset boundary signal representing the positive-direction fault at the opposite end. Conversely, the active boundary injects the preset boundary signal representing the reverse fault at the opposite end.

[0062] S204. When the local protection judges that a positive-direction fault has occurred, continue to make a protection judgment; when the local protection judges that a reverse fault has occurred at the local protection, directly judge it as an external fault.

[0063] S205. When the local protection satisfies the condition that a positive-direction fault occurs, the active boundary signal representing a positive-direction fault at the opposite end extracted by the local protection meets the setting condition, while the active boundary signal representing a reverse-direction fault at the opposite end extracted by the local protection does not meet the setting value condition, that is, it is determined as an in-zone fault and the protection operates.

[0064] When the local protection satisfies the condition that a positive-direction fault occurs, the active boundary signal representing a reverse-direction fault at the opposite end extracted by the local protection meets the setting value condition, that is, it is determined as an out-of-zone fault and the protection does not operate.

[0065] In another embodiment of the present invention, a single-ended full-line fast-acting protection system based on an active boundary is provided. This system can be used to implement the above-mentioned single-ended full-line fast-acting protection method based on an active boundary. Specifically, the single-ended full-line fast-acting protection system based on an active boundary includes an additional control module, a setting module, an injection module, and a protection module.

[0066] Among them, the additional control module is used to actively construct an active boundary by using the controllability of the opposite-end power electronic equipment.

[0067] The setting module is used to determine the setting value according to the protection sensitivity requirement, the boundary signal injection intensity, and the local protection detection ability.

[0068] The injection module, when a fault occurs, the opposite-end active boundary actively injects a preset boundary signal for the fault situation, and the local protection detects the signal sent by the active boundary.

[0069] The protection module is used to compare the active boundary signal detected by the local protection with the setting value. If it meets the action requirement, it is an in-zone fault and the protection operates; otherwise, it is an out-of-zone fault and the protection does not operate.

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0071] Please refer to Figure 2 , taking a two-terminal MMC DC transmission system as an example, the specific implementation steps of the active boundary protection are as follows:

[0072] 1. According to the primary topological structure of the power system and the power electronic equipment contained therein, the device for injecting the active boundary signal is determined to be the MMC.

[0073] 2. Under the single-pole grounding fault of the protected line, select the faulty pole as the loop for injecting the active boundary signal; under the inter-pole short-circuit fault, only select one of the poles as the loop for injecting the active boundary signal.

[0074] 3. Select a sine signal to inject the active boundary signal, and the specific frequency is selected as follows:

[0075] For the internal fault of the protected line, the boundary signal is selected as a 2000 Hz sine wave; for the external fault (bus fault or valve-side line fault of the bus), the boundary signal is selected as a 2500 Hz sine wave.

[0076] 4. Based on the additional control strategy for generating sine waves by the MMC, combined with the MMC current-limiting control and the active boundary additional control strategy, realize the active boundary signal voltage command as shown in Equation (1) to construct the active boundary, as Figure 3 shown;

[0077] The active boundary signal voltage command u sig is:

[0078]

[0079] where k sig is the amplitude of the active boundary signal voltage command. In the present invention, an active boundary signal with an amplitude of 0.1 rated voltage is injected into the DC reference voltage, ω sig is the angular frequency of the active boundary signal voltage command. Different angular frequencies are selected according to different active boundary signals, t is time, is the initial phase of the active boundary signal voltage command.

[0080] 5. According to the constructed active boundary, for the local protection device, analyze the response characteristics felt by the local protection after the boundary signal is injected; set the protection setting value U set according to the most severe situation during the fault within the local protection range. After considering the measurement accuracy, the amplitude of the MMC injection component and retaining a certain threshold, the protection setting value is 0.02U dc .

[0081] 6. After the remote active boundary starts to inject the active boundary signal according to the preset starting criterion, the local protection starts to detect the boundary signal, and uses the matrix pencil algorithm to extract the positive and negative voltages U P (ω 2000 )、U P (ω 2500 )、U N (ω2000 )、U N (ω 2500 );

[0082] 7. The local protection judges the fault direction according to Equation (2). If the current mutation rate at the local protection satisfies a positive change and is greater than the threshold of its direction criterion, it is judged that a fault has occurred in the positive direction of the local protection; conversely, if the current mutation rate satisfying the direction criterion is a negative change and is less than the negative value of its criterion threshold, it is judged that a fault has occurred in the reverse direction of the local protection.

[0083]

[0084] where i l is the measured current at the local protection, and Δset i is the threshold of the direction criterion. If the reverse direction criterion is satisfied, it is directly judged as an external fault; if the positive direction fault is satisfied, it is further discriminated by relying on the active boundary signal.

[0085] 8. After the local protection judges that the positive direction fault is satisfied, U P (ω 2000 )、U P (ω 2500 )、U N (ω 2000 )、U N (ω 2500 ) are successively compared with the setting value of the active boundary signal. When any pole at the local protection satisfies Equation (3), it means that the information of the reverse fault at the opposite end is received, and it is judged as an external fault. When any pole at the local protection satisfies Equation (4), it means that the information of the positive direction fault at the opposite end is received, and it is judged as an internal fault.

[0086] U P (ω 2500 )>U set ||U N (ω 2500 )>U set (3)

[0087] U P (ω 2000 )>U set ||U N (ω 2000 )>U set (4)

[0088] Please refer to Figure 2 , a DC power grid model is built using PSCAD / EMTDC, and the simulation results are as follows:

[0089] 1) Injection effect verification

[0090] Taking the injection of a 15 ms, 2500 Hz sinusoidal active boundary signal into MMC2 as an example, the injected time-domain waveform is as follows Figure 4 shown. It can be observed from Figure 4 that after 10 ms of injection, the sinusoidal active boundary signal is basically stably injected.

[0091] 2) Verification of internal faults

[0092] Taking a single-pole grounding fault with a transition resistance R = 100 Ω occurring at the midpoint of the positive pole of the line as an example, the simulation results are as follows Figure 5 shown. First, the local protection of the present invention determines that a forward fault has occurred through the direction element. At the same time, the amplitude of the 2000 Hz information received at the positive pole of the local protection exceeds the setting value, and the internal fault of the line can be reliably identified.

[0093] 3) Verification of external faults

[0094] Taking a single-pole grounding fault of the bus with a transition resistance R = 100 Ω occurring at MMC2 as an example, the simulation results are as follows Figure 6 shown. First, the local protection of the present invention determines that a forward fault has occurred through the direction element. The amplitude of the 2500 Hz information received at the positive pole of the local protection exceeds the setting value. Therefore, it can be determined that an external fault has occurred on the line. The simulation results prove the effectiveness of the present invention. The present invention can reliably identify the faulty line / bus under a 500 Ω transition resistance and has high sensitivity under high-resistance faults.

[0095] In summary, for a single-ended full-line quick-acting protection method and system based on an active boundary according to the present invention, when the performance of traditional boundary element protection is difficult to meet the requirements and the boundary elements are weakened, the flexible and controllable performance and fast adjustment speed of power electronic equipment are utilized to simulate the capabilities of traditional boundary elements, and different preset responses are actively generated according to different faults, ensuring and improving the boundary characteristics and the performance of boundary protection. Based on this, a single-ended full-line quick-acting protection based on active boundary information is constructed. The invention can have the ability to identify faults in the full-line range without cooperation with other protections and has high sensitivity under high-resistance faults.

[0096] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention fall within the protection scope of the claims of the present invention.

Claims

1. A single-ended full-line quick-acting protection method based on an active boundary, characterized in that The active boundary is actively constructed by leveraging the controllability of the peer power electronic equipment, and the setting value is determined according to the protection sensitivity requirement, the boundary signal injection intensity, and the local protection detection ability. After a fault occurs, the peer active boundary actively injects the preset boundary signal according to the fault situation. When the peer determines that a forward fault has occurred, the active boundary starts to inject the preset boundary signal representing the peer forward fault. Conversely, the active boundary injects the preset boundary signal representing the peer reverse fault. After the local protection detects the signal sent by the active boundary, it compares the active boundary signal detected by the local protection with the setting value. If the action requirement is met, it is an in-zone fault, and the protection operates; otherwise, it is an out-of-zone fault, and the protection does not operate. Specifically, constructing the peer active boundary is as follows: Based on the primary topology of the power system and the power electronic equipment contained in the primary topology, determine the equipment for injecting the active boundary signal; according to the way of connecting to the power grid, the power electronic equipment is divided into a parallel-type active boundary and a series-type active boundary. The parallel-type boundary means that there are multiple lines on the bus at the outlet of the power electronic equipment, and the series-type boundary means that there is only one line on the bus at the outlet of the power electronic equipment; combined with the characteristics of the equipment for injecting the active boundary signal and the fault type, select the boundary information injection loop; according to the primary topology of the power system and the peer direction criterion, select the boundary signal characteristics reflecting faults at different positions to complete the construction of the peer active boundary.

2. The single - ended full - line rapid protection method based on the active boundary according to claim 1, characterized in that The active boundary actively simulates the specific response characteristics under in-zone and out-of-zone faults by using power electronic equipment, including signal waveform, amplitude, or frequency parameters.

3. The single - ended full - line - speed protection method based on an active boundary according to claim 1, characterized in that, Specifically, judging whether the protection action is satisfied according to the response characteristics of the local protection is as follows: When the local protection determines that a forward fault has occurred, continue with the protection judgment; when the local protection determines that a reverse fault has occurred at the local protection, it is directly judged as an out-of-zone fault.

4. The single-ended full-line rapid protection method based on an active boundary according to claim 3, characterized in that Continuing with the protection judgment is specifically as follows: Compare the active boundary signal extracted at the local protection with its setting value to determine an in-zone fault or an out-of-zone fault.

5. The single - ended full - line high - speed protection method based on an active boundary according to claim 4, wherein, After the local protection satisfies the condition of a forward fault, if the active boundary signal representing the peer forward fault extracted by the local protection meets the setting value condition, and the active boundary signal representing the peer reverse fault extracted by the local protection does not meet the setting value condition, it is judged as an in-zone fault, and the protection operates.

6. The single - ended full - line rapid protection method based on the active boundary according to claim 4, characterized in that, After the local protection satisfies the condition of a forward fault, if the active boundary signal representing the peer reverse fault extracted by the local protection meets the setting condition, it is judged as an out-of-zone fault, and the protection does not operate.

7. A single - ended full - line rapid protection system based on an active boundary, characterized in that, It includes: An additional control module for actively constructing the active boundary by leveraging the controllability of the peer power electronic equipment; Specifically, constructing the peer active boundary is as follows: Determine the equipment for injecting active boundary signals according to the primary topology of the power system and the power electronic equipment contained in the primary topology; classify the power electronic equipment into parallel active boundaries and series active boundaries according to the connection mode to the power grid. The parallel boundary means that there are multiple lines on the bus at the outlet of the power electronic equipment, and the series boundary means that there is only one line on the bus at the outlet of the power electronic equipment; select the boundary information injection loop in combination with the characteristics of the equipment for injecting active boundary signals and the fault type; select the boundary signal characteristics reflecting faults at different positions according to the primary topology of the power system and the remote direction criterion, and construct the remote active boundary. The setting module is used to determine the setting value according to the protection sensitivity requirement, the boundary signal injection intensity, and the local protection detection ability. The injection module, after a fault occurs, the remote active boundary actively injects the preset boundary signal according to the fault situation. When the remote end determines that a forward fault has occurred, the active boundary starts to inject the preset boundary signal representing the forward fault at the remote end. Otherwise, the active boundary injects the preset boundary signal representing the reverse fault at the remote end. The local protection detects the signal sent by the active boundary. The protection module is used to compare the active boundary signal detected by the local protection with the setting value. If the action requirement is met, it is an in-zone fault and the protection acts; otherwise, it is an out-of-zone fault and the protection does not act.

Images