A multi-level protection collaborative configuration system for a high-proportion distributed photovoltaic power distribution network

Abstract

This invention relates to the field of distribution network protection technology and discloses a multi-level protection collaborative configuration system for high-proportion distributed photovoltaic distribution networks. The invention constructs a distribution network topology model and candidate fault scenarios, extracts the fault current amplitude, current direction, and electrical response distance of each protection device under different fault scenarios, and calculates the protection responsibility coefficient based on the above information to achieve dynamic division of the main protection, backup protection, and constraint protection of the protection devices. On this basis, it generates the action priority, timing coordination, and interlocking relationships between multi-level protections, and outputs the final configuration scheme through selectivity, sensitivity, and coordination checks. This invention can adapt to the operating characteristics of multiple power sources and uncertain current direction under high-proportion distributed photovoltaic access conditions, improving the selectivity, sensitivity, and coordination of distribution network protection.

Description

Technical Field

[0001] This invention relates to the field of power distribution network protection technology, and in particular to a multi-level protection collaborative configuration system for a high-proportion distributed photovoltaic power distribution network. Background Technology

[0002] With the large-scale integration of distributed photovoltaic power into the distribution network, the distribution network is gradually changing from the traditional single-source, unidirectional power supply structure to a multi-source, multi-path power supply structure. In this type of system, when a fault occurs, the current may be supplied to the fault point by multiple sources at the same time, resulting in a more dispersed distribution of the fault current amplitude and uncertainty in the current direction, which in turn changes the response characteristics of protection devices at all levels to the fault.

[0003] Existing distribution network protection configuration methods are usually based on fixed topology and preset master-slave relationships, and the coordination between protections is achieved by setting current settings and time differences. However, under the condition of high proportion of distributed photovoltaic access, the fault current amplitude, current direction and electrical position relationship with the fault point detected by different protection devices under the same fault scenario are different. The fixed master-slave configuration is difficult to accurately reflect the role of each protection device in the actual fault, thus affecting the coordination and adaptability between multi-level protections.

[0004] Therefore, in high-proportion distributed photovoltaic distribution networks, how to comprehensively consider the fault current response intensity, current direction characteristics, and electrical proximity of each protection device in different fault scenarios, reasonably evaluate the role of each protection device in faults, and realize the role division and coordinated configuration of multi-level protection devices accordingly, so as to improve the selectivity, sensitivity, and coordination of the protection system, has become an urgent technical problem to be solved. Summary of the Invention

[0005] The present invention aims to solve the technical problem of difficult multi-level protection coordination in high-proportion distributed photovoltaic distribution networks due to the complex fault current characteristics.

[0006] To achieve the above objectives, this application adopts the following technical solution: a multi-level protection and collaborative configuration system for a high-proportion distributed photovoltaic distribution network, comprising:

[0007] The operation information acquisition module is used to acquire the network structure, line parameters, distributed photovoltaic access information, protection device information, and real-time operation status of the distribution network;

[0008] The network topology and protection object modeling module is used to establish the topology model of the distribution network and the relationship model between multi-level protection objects based on network structure information, line parameter information, distributed photovoltaic access information and protection device information.

[0009] The fault scenario generation module is used to construct a set of candidate fault scenarios containing different fault locations based on the topology model;

[0010] The response quantity extraction module is used to extract the fault current amplitude, current direction angle, and electrical distance relative to the fault point of each protection device under each candidate fault scenario.

[0011] The protection role classification module is used to classify each protection device into main protection, backup protection or constraint protection based on the protection responsibility coefficient of each protection device in each fault scenario.

[0012] The collaborative configuration generation module is used to generate the action priority, timing coordination, setting coordination and interlocking relationship between protection devices based on the role division results;

[0013] The configuration verification and output module is used to selectively, sensitively, and coordinately verify the collaborative configuration results and output the final configuration scheme.

[0014] Preferably, the protection device information acquired by the operation information acquisition module includes: the installation location of each protection device, the range of primary equipment it protects, the protection type, and a unique number; the total number of protection devices participating in the collaborative configuration is at least two, and each candidate fault scenario has a unique number.

[0015] Preferably, the candidate fault scenarios constructed by the fault scenario generation module include at least: main line faults, branch line faults, and faults near distributed photovoltaic access points; for any fault scenario, the response quantity extraction module detects the fault current amplitude of each protection device, and the amplitude is recorded as zero when the protection device does not detect a valid fault current.

[0016] Preferably, the response quantity extraction module is also used to: for any fault scenario, add up the fault current amplitude of all protection devices in that scenario to obtain the total fault current level of that scenario, and use the sum to measure the overall response strength of all protection devices to the fault.

[0017] Preferably, the response quantity extraction module extracts the fault current direction angle of each protection device under each fault scenario; the network topology and protected object modeling module or the response quantity extraction module simultaneously determines the dominant fault current direction angle of each fault scenario, which represents the main flow direction of the fault current; the above two angles adopt the same angle measurement system.

[0018] Preferably, the response quantity extraction module determines the electrical response distance of each protection device relative to the fault point in each fault scenario; the electrical response distance is obtained by any of the following methods: based on the equivalent impedance value between the protection device and the fault point, based on the cumulative value of the line impedance, or based on the electrical path length in the network; the smaller the distance value, the closer the protection device is to the fault point electrically.

[0019] Preferably, the protection role division module divides roles in the following way: For each fault scenario, the protection responsibility coefficient of each protection device is calculated, and then all protection devices are sorted from largest to smallest according to the coefficient value; the protection devices ranked first are classified as the main protection for the scenario, those ranked in the middle are classified as backup protection, and those ranked last are classified as constraint protection.

[0020] Preferably, the collaborative configuration generation module generates the following configuration strategies based on the role division results: configuring the primary protection with the highest priority action permissions and the shortest action delay; configuring the backup protection with sequentially increasing delay action relationships; and configuring the constraint protection with blocking conditions, additional start criteria, or suppression action conditions.

[0021] Preferably, the configuration verification and output module performs the following verifications: checks whether the main protection meets the selectivity requirements, that is, the fault should be preferentially cleared by the protection device with the closest electrical response distance; checks whether the sensitivity coefficient of each protection device meets the setting requirements; checks whether the action delay and setting value of each level of protection are coordinated; and outputs an executable multi-level protection collaborative configuration table after the verification is passed.

[0022] Preferably, the protection liability coefficient is calculated in the following way:

[0023] The current ratio factor is obtained by dividing the fault current amplitude detected by the protection device by the sum of the current amplitudes of all protection devices. The value of this factor is greater than or equal to zero and less than or equal to one.

[0024] Based on the degree of deviation between the current direction angle of the protection device and the dominant direction angle of the fault scenario, the direction consistency factor is calculated. When the two directions are exactly the same, the factor takes a value of one; when the two directions are completely opposite, the factor takes a value of zero; otherwise, the factor takes a value between greater than zero and less than one.

[0025] The distance attenuation factor is calculated based on the electrical response distance between the protection device and the fault point. When the electrical response distance is zero, the factor takes the value of one. As the electrical response distance increases, the factor gradually decreases and approaches zero. The value range of the factor is greater than zero and less than or equal to one.

[0026] Multiplying the current proportion factor, the direction consistency factor, and the distance attenuation factor together yields the protection primary responsibility coefficient. The value of this coefficient is greater than or equal to zero and less than or equal to one. The larger the value, the more suitable the protection device is to assume the primary protection responsibility in this fault scenario.

[0027] The technical effects and advantages of this invention are as follows:

[0028] This invention quantifies the role of each protection device in a fault by comprehensively considering the fault current response intensity, current direction characteristics, and electrical proximity to the fault point of each protection device under different fault scenarios. This allows for a more accurate reflection of the responsibility of each protection device in actual faults, improving the rationality and objectivity of protection role classification. Simultaneously, based on the protection responsibility coefficient, the invention classifies protection devices into primary protection, backup protection, and constraint protection, and establishes priority relationships, timing coordination relationships, and interlocking relationships among multi-level protection. This enables differentiated adjustments to protection configurations for different fault scenarios, thereby improving the coordination among multi-level protection, avoiding false tripping or failure to trip due to fixed primary / backup relationships, and enhancing the reliability of the protection system under complex operating conditions. Attached Figure Description

[0029] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0030] Figure 1 This is a flowchart of the process steps of the present invention;

[0031] Figure 2 This is a timing diagram of the process of the present invention. Detailed Implementation

[0032] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0033] Example 1: Refer to Figures 1-2 As shown, this invention provides a multi-level protection collaborative configuration system for a high-proportion distributed photovoltaic distribution network, comprising: an operation information acquisition module, a network topology and protected object modeling module, a fault scenario generation module, a response quantity extraction module, a protection role division module, a collaborative configuration generation module, and a configuration verification and output module. These modules are connected sequentially to collaboratively complete the collaborative configuration of multi-level protection devices.

[0034] The operation information acquisition module acquires various information about the high-proportion distributed photovoltaic distribution network in real time or near real time through the data interface of the distribution automation system, such as IEC61850, IEC104, or Modbus protocol. Specifically, this includes:

[0035] Network structure information: node-branch relationships in the distribution network, current open / closed status of each switch, connection relationships between each line, and topological connections between busbars and lines, etc.

[0036] Line parameter information: resistance per unit length, reactance per unit length, line length, current carrying capacity, positive sequence impedance, and zero sequence impedance parameters for each line.

[0037] Distributed photovoltaic access information: the location of each distributed photovoltaic power source's access node, rated capacity, inverter type (such as voltage source or current source), control strategy (such as constant power control, constant voltage and constant frequency control), low voltage ride-through parameters, anti-islanding protection configuration, etc.

[0038] Protection device information: The installation location of each protection device (specifically, at which node or branch endpoint), protection range (the primary equipment protected, such as a line, transformer, or busbar section), protection type (e.g., definite-time overcurrent protection, inverse-time overcurrent protection, directional overcurrent protection, distance protection, etc.), and corresponding protection number. The total number of protection devices participating in the coordinated configuration is recorded as follows: ,and The number is a positive integer greater than or equal to 2, and each protection device has a unique number. ( ).

[0039] Operating status information: voltage amplitude and phase angle of each node, active and reactive power of each branch, current amplitude and phase angle of each branch, system frequency, real-time output of distributed photovoltaic, etc.

[0040] The runtime information acquisition module packages the above information into a unified internal data format and sends it to the network topology and protection object modeling module.

[0041] After receiving the data from the operation information acquisition module, the network topology and protected object modeling module performs the following operations:

[0042] (i) Establishing a distribution network topology model: This module constructs a distribution network topology model using graph theory based on network structure information and switch status. Specifically, it abstracts devices such as buses, switches, transformers, and distributed photovoltaic grid connection points in the distribution network as nodes, and lines and cables as edges, forming an undirected graph. Then, based on the location of the power source and the switch status under the current operating mode, it determines the power flow direction and generates a directed graph. This directed graph can reflect the power supply path from the system power source and distributed photovoltaic power source to each load node, providing a basis for subsequent analysis of fault current direction.

[0043] (II) Establishing a Multi-Level Protection Object Model: This module establishes a multi-level protection object model based on the protection device information and the voltage level and power supply zone of the distribution network. Specifically, the protection devices are organized into a tree-like hierarchical structure from the power source side to the load side. For example, the protection device at the incoming circuit breaker is defined as the first-level protection, the protection device at the feeder trunk section switch is defined as the second-level protection, the protection device at the beginning of the branch line is defined as the third-level protection, and so on. For each protection device, this module also determines its upstream protection device (i.e., protection closer to the power source along the power direction) and downstream protection device (i.e., protection further away from the power source along the load direction), as well as the line segment or equipment corresponding to the protection range of each protection device. This multi-level protection object model provides a hierarchical basis for subsequent role division and collaborative configuration.

[0044] The fault scenario generation module constructs a set of candidate fault scenarios based on the distribution network topology model. This module generates candidate fault scenarios according to the following steps:

[0045] (a) Determining the fault location: Candidate fault scenarios must include at least the fault scenarios corresponding to different fault locations; specifically, candidate fault scenarios must include at least one or more of the following types:

[0046] Main line fault scenarios: Set fault points at different locations on each main line (e.g., the beginning, middle, and end of the line);

[0047] Branch line fault scenarios: Set fault points at the entrance, middle point and end of each branch line;

[0048] Distributed photovoltaic access point proximity fault scenario: Fault points are directly set up on the upstream and downstream lines and grid connection points of each distributed photovoltaic access point.

[0049] (II) Determining Fault Types and Transition Resistances: For each fault location, multiple fault types (e.g., single-phase ground fault, two-phase short circuit, two-phase ground fault, three-phase short circuit) and multiple transition resistance values ​​(e.g., 0Ω, 10Ω, 50Ω, 100Ω) are set to cover different fault conditions. The fault scenario generation module outputs a set of candidate fault scenarios, each with a unique number. ( ),in The total number of candidate fault scenarios is a positive integer greater than or equal to 1.

[0050] The response extraction module is designed for each candidate fault scenario. Through fault analysis calculations (such as short-circuit calculations based on the symmetrical component method or electromagnetic transient simulations), the fault response quantities of each protection device under this scenario are extracted. Specifically, the following three quantities are extracted:

[0051] (a) Fault response current amplitude For each protection device In fault scenarios Below, the fundamental effective value (amplitude) of the fault current detected by the protection device is extracted and recorded as follows: ; It is a non-negative real number; when the protection device fails to detect a valid fault response, for example, if the fault current is less than the protection device's activation threshold, or if the protection device is located on the reverse path of the fault current and the directional element is blocked, making it impossible to measure the forward fault current, then The value is zero; for each candidate fault scenario The response quantity extraction module also sums the fault response current amplitudes of all protection devices participating in the coordinated configuration to obtain the total protection response current under the candidate fault scenario. ,in This is an index variable for the protection device, and its value range is... The sum of the protection response currents is used to characterize the overall fault response level of each protection device under the same candidate fault scenario.

[0052] (ii) Fault current direction angle and dominant fault response direction angle Response quantity extraction module extraction protection device In candidate fault scenarios The direction angle of the detected fault current is denoted as . This direction angle is usually referenced to the positive sequence voltage phasor, and the phase angle of the current phasor relative to this reference is measured. The range of values ​​is or The specific format used can be preset by the system.

[0053] Meanwhile, the network topology and protected object modeling module or the response quantity extraction module determines candidate fault scenarios. The dominant fault response direction angle, denoted as The method for determining the dominant fault response direction angle is as follows: based on the fault component network, the fault point is equivalent to an injected current source, the fault current flowing through each branch is calculated, and the direction of the fault current with the largest amplitude flowing through the adjacent branch of the fault point is taken as the dominant direction; or it can be obtained by calculating the direction angle from the fault point to the equivalent electromotive force of the system power supply. and Using the same angle system and with the same value range; dominant fault response direction angle Used to characterize the dominant direction of the fault response current under the candidate fault scenario.

[0054] (iii) Electrical response distance The response extraction module also identifies the protection device. Relative candidate fault scenarios The electrical response distance of the fault point is denoted as Electrical response distance Used to characterize protective devices The electrical proximity of the fault point; the methods for obtaining this information include one or more of the following:

[0055] Based on the equivalent impedance between the protection device and the fault point: calculate the equivalent positive sequence impedance (including line impedance, transformer impedance, etc.) from the installation point of the protection device to the fault point, and use the magnitude or per-unit value of the equivalent impedance as the electrical response distance.

[0056] Based on the cumulative line impedance between the protection device and the fault point: The impedance amplitudes of each section of the line from the protection device to the fault point are summed to obtain the cumulative impedance value as the electrical response distance.

[0057] Obtaining the network electrical path length between the protection device and the fault point: In the topology graph, the length or impedance of each branch is used as the weight of the edge, and the weight of the shortest path from the protection device node to the fault point node is calculated as the electrical response distance.

[0058] It is a non-negative real number, and The smaller the value, the more protective the device. The greater the electrical proximity to the fault point.

[0059] The protection role classification module classifies each protection device into primary protection, backup protection, and constraint protection roles based on the protection responsibility coefficient of each device under each candidate fault scenario. This module first calculates the protection responsibility coefficient of each protection device under each candidate fault scenario, and then classifies roles according to the magnitude of the coefficient.

[0060] (I) System preset parameters: Before calculating the protection primary responsibility coefficient, the system presets two parameters:

[0061] Distance correction factor : is a positive real number used to adjust the degree of influence of electrical response distance on the protection responsibility coefficient; The range of values ​​is ; The larger the value, the stronger the attenuation effect of the electrical response distance on the protection responsibility coefficient; The smaller the value, the weaker the attenuation effect. In this specific implementation, an appropriate value can be selected within the specified range based on the scale of the distribution network and the protection configuration requirements. Value, for example, taking .

[0062] tiny positive numbers To prevent the division of tiny positive numbers with a denominator of zero; The range of values ​​is When the sum of the fault response current amplitudes of all protection devices under a certain fault scenario is zero (theoretically possible in the case of no fault or extremely small fault current), this This can prevent calculation errors caused by a denominator of zero.

[0063] (II) Calculation formula for the protection primary responsibility coefficient: Protection Primary Responsibility Coefficient The following formula is used for calculation: ;

[0064] The meanings of the symbols in the formula are as follows:

[0065] Protective devices In candidate fault scenarios The protection responsibility coefficient is used to characterize the degree to which the protection device assumes the responsibility of prioritizing fault clearing in the corresponding candidate fault scenario; the larger the coefficient, the more likely the protection device should take priority in clearing the fault.

[0066] Protective devices In candidate fault scenarios The amplitude of the fault response current detected below.

[0067] All protection devices participating in the collaborative configuration in candidate fault scenarios The sum of the fault response current amplitudes.

[0068] : A small positive number, used to prevent the denominator from being zero.

[0069] Protective devices In candidate fault scenarios The direction angle of the detected fault current.

[0070] Candidate Fault Scenario The dominant fault response direction angle.

[0071] Protective devices Relative candidate fault scenarios Electrical response distance at the fault point.

[0072] Distance correction factor.

[0073] (III) Range of values ​​for the protection liability coefficient: The three factors in the formula have the following ranges of values:

[0074] Current ratio factor Since the numerator is a non-negative real number, the denominator is a positive real number, and the numerator does not exceed the denominator (when... When the value is very small, the numerator is closest to the denominator, therefore the range of values ​​for this factor is... .

[0075] Directional consistency factor Since the range of the cosine function is ,therefore The range of values ​​is After dividing by 2, the range is When the directions are completely the same (angle difference is 0), the factor takes a value of 1; when the directions are completely opposite (angle difference is 0), the factor takes a value of 1. or When ), the factor takes the value of 0.

[0076] Distance decay factor :because , denominator Therefore, the range of values ​​for this factor is... When the electrical response distance When the factor is at its maximum value, it takes the value of 1; as the time elapses... As the factor increases, it gradually decreases and approaches 0, but remains greater than 0.

[0077] Multiplying the three factors together yields the protection liability coefficient. The range of values ​​for is: .

[0078] (iv) The physical meaning of the protection responsibility coefficient: The larger the value, the more protective the device. In candidate fault scenarios The larger the detected fault current amplitude, the more consistent the current direction with the dominant direction, and the closer the electrical distance to the fault point, the more suitable this protection device is to be configured as the main protection; conversely, The smaller the value, the stronger the protection device. In this scenario, the detected fault current is very small, or in the opposite direction, or the electrical distance is very far, making it more suitable for configuration as backup protection or constraint protection.

[0079] (v) Specific methods for role division: The protection role division module divides the protection devices according to the candidate fault scenarios. The corresponding protection responsibility coefficient is used to rank each protection device; specifically, for each candidate fault scenario... Calculate all Value, then according to The protection devices are sorted in descending order of size.

[0080] After sorting, the protection is divided into primary protection, backup protection, and constraint protection according to the sorting results:

[0081] The top-ranked protection devices are designated as primary protections; the number of primary protections can be a pre-set fixed number (e.g., taking the first two from the ranking result), or it can be based on... The value is determined dynamically, for example, selecting all The protection device serves as the main protection.

[0082] Several protection devices that are in the middle of the sequence are designated as backup protection; the number of backup protection devices can be fixed or selected to meet a certain coefficient threshold range, for example... The protective device.

[0083] The remaining protection devices that are ranked lower are classified as constraint protections, i.e., selected... A protection device for values ​​below a certain lower threshold.

[0084] Based on the above classification, each protection device has obtained a clear role label in each candidate fault scenario: main protection, backup protection, or constraint protection.

[0085] Based on the protection role classification results, the collaborative configuration generation module generates action priorities, action timing relationships, protection setting activation relationships, and interlocking relationships among multi-level protection devices. This module addresses each candidate fault scenario. Based on the role classification results, a corresponding collaborative configuration strategy is generated.

[0086] (i) Regarding the priority action relationship for primary protection: For protection devices designated as primary protection, the collaborative configuration generation module configures them with the highest action priority; in specific implementation, a priority level can be generated for each protection device in each scenario. The primary protection has the lowest priority level, for example... This indicates that the protection should be the first to act when a fault occurs; at the same time, the shortest possible action delay should be configured for the main protection, such as setting it to instantaneous action or a very small fixed delay, such as 0.1 seconds, to ensure that the fault can be quickly cleared.

[0087] (ii) Configuring delayed action relationships for backup protection: For protection devices classified as backup protection, the collaborative configuration generation module configures delayed action relationships for them; specifically, based on the backup protection's position in the sequence (i.e., its... The operating delay of each backup protection is determined by the value relative to the main protection and other backup protections, or their electrical response distance; typically, the delay of backup protection is set according to a stepped time coordination principle: the closer to the fault point (i.e., the greater the distance from the fault point, the lower the operating delay). The larger the backup protection value, the shorter its action delay; the farther the backup protection is from the fault point, the longer its action delay; delay value It can be represented as , The duration of the primary protective action, For time intervals, This is the level number for backup protection.

[0088] (III) Configuring Lockout Conditions, Additional Criteria, or Suppression Conditions for Constraint Protection: For protection devices classified as constraint protection, the collaborative configuration generation module configures one or more of the following: lockout conditions, additional criteria, or suppression conditions. Specifically:

[0089] Blocking condition: Generate a logic blocking signal so that the protection device is prohibited from tripping in the fault scenario, that is, it will not operate regardless of whether its electrical quantity meets the operating conditions.

[0090] Additional criteria: Configure additional operating conditions for the protection device, such as requiring that it only operates when the direction is pointing towards the line and the current exceeds a higher set value, otherwise it will not operate.

[0091] Suppression of operation conditions: When certain characteristic quantities, such as harmonic content and voltage drop depth, meet specific conditions, the operation of the protection device is suppressed.

[0092] (iv) Generation of protection setting activation relationships: Since the same protection device may play different roles in different candidate fault scenarios (e.g., it is the main protection in one scenario and the backup protection or constraint protection in another scenario), the collaborative configuration generation module generates multiple sets of setting groups for the protection device; each set of setting groups includes operating current setting, operating time setting, directional element engagement / disengagement flag, and blocking logic enable, etc.; the protection setting activation relationship is defined as follows: for the protection device and candidate fault scenarios Which set of settings should be used; when the system detects the characteristics of a certain fault scenario, it automatically switches to the corresponding set of settings.

[0093] Based on the above configuration strategy, the collaborative configuration generation module outputs multi-level protection collaborative configuration results applicable to different candidate fault scenarios. These results can be organized in the form of a data table, for example:

[0094] Action Priority Table: Records the priority level of each protection device under each fault scenario.

[0095] Action timing table: Records the action delay settings of each protection device under each fault scenario.

[0096] Lockout Relationship Table: Records the locking conditions or additional criteria for each constraint protection under each fault scenario.

[0097] Setting group activation relationship table: records the setting group number that should be activated for each protection device in each fault scenario.

[0098] The configuration verification and output module performs selective, sensitive, and coordination verification on the collaborative configuration results output by the collaborative configuration generation module to ensure that the configuration scheme meets the basic requirements of distribution network protection. After the verification is passed, the final multi-level protection collaborative configuration result is output.

[0099] (i) Selective Verification: Selective verification is used to check that for each fault scenario, the fault should be preferentially cleared by its main protection, and the time difference between the main protection and backup protection, and between adjacent backup protections, meets the selectivity requirement. Specifically, for each fault scenario... Consider any two protection devices and ,in Configured as primary protection or backup protection closer to the fault point. If configured as a backup protection point further from the fault, then the following must be met: ,in The minimum time difference is set (usually 0.2 to 0.3 seconds). If a pair of protections does not meet this condition, the verification fails, and the system needs to adjust the delay setting or re-assign roles.

[0100] (II) Sensitivity Verification: Sensitivity verification is used to check whether the sensitivity of each protection device meets the preset requirements when a metallic fault occurs at the furthest point within its protection range; for each protection device... Calculate its sensitivity coefficient , ,in To protect the device by detecting the minimum fault current under the most unfavorable operating conditions, The operating current setting for this protection device must be specified; the sensitivity coefficient must not be less than the specified lower limit of the sensitivity coefficient, for example, for overcurrent protection, it must be specified that... For distance protection, the requirements are as follows: If the conditions are not met, the verification will fail, and the system will prompt that the protection settings need to be adjusted or the protection configuration scheme needs to be changed.

[0101] (III) Coordination Verification: Coordination verification checks whether the current-time operating characteristic curves of adjacent protections do not intersect, ensuring proper coordination between upstream and downstream protections. For definite-time protection, the verification checks that the operating current setting of the upstream protection should be greater than that of the downstream protection (when both can detect the fault), and that the operating time meets the differential requirement. For inverse-time protection, the verification checks that within the possible fault current range, the operating time of the upstream protection is always greater than that of the downstream protection. If there is any intersection or coordination failure, the verification fails, and the system settings need to be adjusted or reconfigured.

[0102] (iv) Output the final configuration result: After verification, the configuration verification and output module outputs the multi-level protection collaborative configuration result; the output format includes:

[0103] Structured data files, such as XML, JSON, or binary files, are directly downloaded to various protection devices or power distribution terminals via communication protocols, enabling automatic deployment of configurations.

[0104] A readable report, in PDF or HTML format, is provided for maintenance personnel to review, archive, and print. The report includes information such as the role of each protection device in different fault scenarios, action delay, setting group activation relationship, and interlocking logic.

[0105] Example 2: In actual operation, the above seven modules work together according to the following process:

[0106] Data acquisition and modeling phase: The operation information acquisition module periodically collects various information from the distribution network, or triggers reconfiguration when there are significant changes in network structure, distributed photovoltaic output, switch status, etc. The network topology and protection object modeling module constructs a distribution network topology model and a multi-level protection object model based on the latest information.

[0107] Fault scenario generation stage: Based on the current topology model, the fault scenario generation module generates a set of candidate fault scenarios, including trunk line faults, branch line faults, and faults near distributed photovoltaic access points.

[0108] Response quantity extraction stage: For each candidate fault scenario, the response quantity extraction module extracts the fault response current amplitude, current direction angle and electrical response distance of each protection device through short-circuit calculation.

[0109] Role segmentation phase: The protected role segmentation module adjusts the distance based on a preset coefficient. and tiny positive numbers Calculate the protection responsibility coefficient for each protection device under each candidate fault scenario according to the protection responsibility coefficient calculation formula. Value, then according to Based on size, the protection devices are divided into main protection, backup protection, and constraint protection.

[0110] Collaborative configuration generation phase: Based on the role division results, the collaborative configuration generation module generates action priority, action timing relationship, protection setting activation relationship and interlocking relationship, and outputs multi-level protection collaborative configuration results.

[0111] Verification and Output Phase: The configuration verification and output module performs selective, sensitivity, and coordination verification on the generated collaborative configuration results. If the verification passes, the final configuration result is output and sent to the protection device; if the verification fails, feedback information is sent to the protection role allocation module or the collaborative configuration generation module to adjust relevant parameters (such as the distance correction coefficient). After considering factors such as role classification thresholds, role classification and configuration are re-generated until the verification is passed.

[0112] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A multi-level protection collaborative configuration system for a high-proportion distributed photovoltaic distribution network, characterized in that, include: The operation information acquisition module is used to acquire the network structure, line parameters, distributed photovoltaic access information, protection device information, and real-time operation status of the distribution network; The network topology and protection object modeling module is used to establish a topology model of the distribution network and an association model between multi-level protection objects based on the network structure information, line parameter information, distributed photovoltaic access information and protection device information. The fault scenario generation module is used to construct a set of candidate fault scenarios containing different fault locations based on the topology model. The response quantity extraction module is used to extract the fault current amplitude, current direction angle, and electrical distance relative to the fault point of each protection device under each candidate fault scenario. The protection role classification module is used to classify each protection device into main protection, backup protection or constraint protection based on the protection responsibility coefficient of each protection device in each fault scenario. The collaborative configuration generation module is used to generate the action priority, timing coordination, setting coordination and interlocking relationship between protection devices based on the role division results; The configuration verification and output module is used to selectively, sensitively, and coordinately verify the collaborative configuration results and output the final configuration scheme.

2. The high-proportion distributed photovoltaic distribution network multi-level protection collaborative configuration system according to claim 1, characterized in that: The protection device information acquired by the operation information acquisition module includes: the installation location of each protection device, the range of primary equipment it protects, the protection type, and a unique number; the total number of protection devices participating in the collaborative configuration is at least two, and each candidate fault scenario has a unique number.

3. The high-proportion distributed photovoltaic distribution network multi-level protection collaborative configuration system according to claim 1, characterized in that: The candidate fault scenarios constructed by the fault scenario generation module include at least: main line faults, branch line faults, and faults near distributed photovoltaic access points; for any fault scenario, the response quantity extraction module detects the fault current amplitude of each protection device, and the amplitude is recorded as zero when the protection device does not detect a valid fault current.

4. The high-proportion distributed photovoltaic distribution network multi-level protection collaborative configuration system according to claim 3, characterized in that: The response quantity extraction module is also used to: for any fault scenario, add up the fault current amplitude of all protection devices in that scenario to obtain the total fault current level of that scenario, and use the sum to measure the overall response strength of all protection devices to the fault.

5. A multi-level protection and collaborative configuration system for a high-proportion distributed photovoltaic distribution network according to claim 1, characterized in that: The response quantity extraction module extracts the fault current direction angle of each protection device under various fault scenarios; The network topology and protected object modeling module or the response quantity extraction module simultaneously determines the dominant fault current direction angle for each fault scenario. This dominant direction angle represents the main flow direction of the fault current. The two angles mentioned above use the same angle measurement system.

6. The high-proportion distributed photovoltaic distribution network multi-level protection collaborative configuration system according to claim 1, characterized in that: The response quantity extraction module determines the electrical response distance of each protection device relative to the fault point in each fault scenario; the electrical response distance is obtained by any of the following methods: based on the equivalent impedance value between the protection device and the fault point, based on the cumulative value of the line impedance, or based on the electrical path length in the network; the smaller the distance value, the closer the protection device is to the fault point electrically.

7. A multi-level protection and collaborative configuration system for a high-proportion distributed photovoltaic distribution network according to claim 1, characterized in that: The protection role division module divides roles in the following way: For each fault scenario, the protection responsibility coefficient of each protection device is calculated, and then all protection devices are sorted from largest to smallest according to the coefficient value; The protection devices ranked first are designated as the primary protection for this scenario, those ranked in the middle are designated as backup protection, and those ranked last are designated as constraint protection.

8. A multi-level protection collaborative configuration system for a high-proportion distributed photovoltaic distribution network according to claim 7, characterized in that: The collaborative configuration generation module generates the following configuration strategies based on the role division results: for primary protection, it configures the highest priority action permissions and the shortest action delay; for backup protection, it configures sequentially increasing delay action relationships; and for constraint protection, it configures blocking conditions, additional start criteria, or suppression action conditions.

9. A multi-level protection and collaborative configuration system for a high-proportion distributed photovoltaic distribution network according to claim 1, characterized in that: The configuration verification and output module performs the following verifications: checks whether the main protection meets the selectivity requirements, that is, the fault should be preferentially cleared by the protection device with the closest electrical response distance; checks whether the sensitivity coefficient of each protection device meets the setting requirements; checks whether the action delay and setting value of each level of protection are coordinated; and outputs an executable multi-level protection collaborative configuration table after the verification is passed.

10. A multi-level protection and collaborative configuration system for a high-proportion distributed photovoltaic distribution network according to claim 9, characterized in that: The protection responsibility coefficient is calculated in the following way: The current ratio factor is obtained by dividing the fault current amplitude detected by the protection device by the sum of the current amplitudes of all protection devices. The value of this factor is greater than or equal to zero and less than or equal to one. Based on the degree of deviation between the current direction angle of the protection device and the dominant direction angle of the fault scenario, the direction consistency factor is calculated. When the two directions are exactly the same, the factor takes a value of one; when the two directions are completely opposite, the factor takes a value of zero; otherwise, the factor takes a value between greater than zero and less than one. The distance attenuation factor is calculated based on the electrical response distance between the protection device and the fault point. When the electrical response distance is zero, the factor takes the value of one. As the electrical response distance increases, the factor gradually decreases and approaches zero. The value range of the factor is greater than zero and less than or equal to one. Multiplying the current proportion factor, the direction consistency factor, and the distance attenuation factor together yields the protection primary responsibility coefficient. The value of this coefficient is greater than or equal to zero and less than or equal to one. The larger the value, the more suitable the protection device is to assume the primary protection responsibility in this fault scenario.

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