Online checking and early warning method and system for relay protection setting value of power system

Abstract

The invention discloses an electric power system relay protection setting value online checking and early warning method and system, and relates to the technical field of electric power system relay protection and electric power automation, and the method comprises the steps: constructing a relay protection importance index, and sorting each relay protection device; preferentially performing relay protection setting value online checking on the high-importance device according to a sorting result; and if the deviation between the fixed value and the actual operation parameter exceeds a set threshold value in the sensitivity checking process, identifying an influence domain according to the fault quantity change rate, and executing graded early warning in the influence domain. According to the method, the relay protection importance index fusing three risk factors of power supply isolation, load isolation and power grid splitting is constructed, so that quantitative sorting of each relay protection device is realized, and when the constant value deviation exceeds a threshold value in the checking process, the relay protection device is checked. And the fault influence domain is identified based on the fault quantity change rate, and graded early warning is implemented in the influence domain, so that the checking efficiency is improved, the anomaly identification accuracy is enhanced, and the graded response of the risk area is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power system relay protection and power automation, and in particular to a power system relay protection setting value online verification and early warning method and system. Background Art

[0002] In modern power systems, relay protection is one of the core links to ensure the safe, stable, and economical operation of the power grid. The accuracy of its operation is directly related to the speed and scope of system fault isolation. As power systems develop towards scale, interconnection, and intelligence, the grid structure is becoming increasingly complex, the power flow paths are changing, and the system operating mode switches frequently, resulting in higher uncertainty and dynamic requirements for relay protection setting values. Traditional relay protection setting methods often use a setting process based on offline manual calculations and empirical judgment. They rely on simulation analysis of equivalent power grid models under fixed operating modes to complete the initial configuration of protection settings under static conditions. However, such methods often ignore the impact of the system's constantly changing operating state, equipment switching, and changes in generation-side scheduling strategies during actual operation. Relay protection may face insufficient sensitivity, false operation, or failure to operate under dynamic conditions.

[0003] In recent years, the rapid deployment of smart grids and the widespread use of dispatching automation systems have posed new technical requirements for dynamic evaluation and real-time verification of relay protection device settings. Especially in the context of large-scale renewable energy integration, increased regional power flow fluctuations, and intensified load forecasting errors, static settings struggle to cover diverse operating scenarios, easily leading to problems such as inadequate protection, insufficient selectivity, and coordination failures. This can expand the scope of faults, trigger cascading trips, and even system tripping. Consequently, academic and industrial research, both domestically and internationally, has gradually shifted its focus to real-time evaluation and adaptive verification of relay protection settings based on online monitoring data. Some existing efforts have attempted to construct dynamic setting evaluation systems by incorporating methods such as power flow transfer matrices, equivalent short-circuit models, and probabilistic risk assessment. However, these approaches still face numerous challenges, including redundant data extraction across the entire network, heterogeneous response capabilities of relay protection devices, fuzzy risk zone boundaries, and lags in early warning feedback mechanisms. Furthermore, most methods employ a "full coverage" approach, traversing each device individually through verification logic, resulting in an exponential increase in computational complexity and failing to meet the dispatching center's requirements for efficient, accurate, and visual early warnings. Therefore, there is an urgent need for an online verification and early warning strategy system for relay protection settings that integrates dynamic operating condition identification, intelligent prioritization, risk area screening, and multi-level response linkage to meet the protection management needs under complex operating conditions. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: the existing power system relay protection setting value adjustment and risk assessment methods have problems such as response lag, calculation redundancy, and inability to dynamically identify key protection objects, as well as how to achieve real-time verification of relay protection settings and hierarchical warning linkage under complex operating conditions.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: an online calibration and early warning method for relay protection constants in a power system, comprising constructing a relay protection importance index and sorting each relay protection device; based on the sorting results, giving priority to performing online calibration of relay protection constants for high-importance devices; if, during the sensitivity calibration process, the deviation between the constant and the actual operating parameter exceeds a set threshold, the impact domain is identified based on the fault quantity change rate, and a graded early warning is performed within the impact domain.

[0007] As a preferred solution of the online calibration and early warning method of the power system relay protection settings described in the present invention, the relay protection importance index includes a power supply isolation risk index, a load isolation risk index, and a power system decoupling risk index, and the relay protection importance index is constructed by a linear weighted method.

[0008] As a preferred solution of the online calibration and early warning method of the power system relay protection settings described in the present invention, the sorting of each relay protection device includes sorting all relay protection devices based on the relay protection importance index to obtain an importance priority list of the relay protection devices.

[0009] As a preferred solution of the online calibration and early warning method of the power system relay protection constants described in the present invention, the online calibration of the relay protection constants includes calculating the secondary value, obtaining the sensitivity by the ratio of the secondary value of the minimum two-phase short-circuit current to the protection constant, comparing the sensitivity coefficient with the preset sensitivity threshold, and judging whether the action sensitivity requirements are met.

[0010] Based on the importance priority list, online verification operations are performed on protection devices with higher importance first.

[0011] As a preferred solution of the online calibration and early warning method of the power system relay protection settings described in the present invention, the calculation of the secondary value includes collecting the minimum two-phase short-circuit current value of the line corresponding to the relay protection device under the minimum operating mode, calculating the minimum two-phase short-circuit current under the minimum operating mode based on the system impedance, line impedance and transformer impedance, and converting the short-circuit current into the input current of the relay protection device according to the current transformation ratio of the connected transformer to obtain the secondary value.

[0012] As a preferred solution of the online calibration and early warning method for relay protection settings of a power system described in the present invention, the judgment of whether the action sensitivity requirement is met includes: if the sensitivity coefficient is greater than or equal to the preset sensitivity threshold, it is judged that the action sensitivity requirement is met; if the sensitivity coefficient is less than the preset sensitivity threshold, it is judged that the action sensitivity requirement is not met; if it is judged that the action sensitivity requirement is met, the coordination relationship between the sensitivities of each protection section is checked to judge whether the incremental constraint relationship is met; if it is judged that the action sensitivity requirement is not met, an unsatisfactory prompt is output, it is marked as an abnormal item, and the subsequent coordination verification steps are terminated.

[0013] As a preferred solution of the online calibration and early warning method for relay protection settings of a power system described in the present invention, the method of identifying the impact domain based on the fault quantity change rate includes: when a specific line is detected to be disconnected, obtaining the short-circuit current level change data of the lines adjacent to the line, calculating the fault quantity change rate of the adjacent lines before and after the disconnection, and judging whether the fault quantity change rate exceeds a set threshold. If it exceeds the set threshold, the relay protection device corresponding to the adjacent line is included in the initial impact domain. Based on the bus cascade connection relationship, the impact domain is expanded layer by layer through recursive iteration until all change rates are lower than the set threshold. All relay protection devices in the final determined impact domain are used as the target set for this calibration and early warning.

[0014] As a preferred solution of the online calibration and early warning method for power system relay protection settings described in the present invention, the impact domain includes the area where the setting effects of surrounding relay protection devices change due to changes in short-circuit current levels after the line is disconnected.

[0015] As a preferred solution of the online calibration and early warning method for relay protection settings of the power system described in the present invention, the hierarchical early warning includes, based on the target set of calibration and early warning, calculating the deviation between the operating settings of the relay protection devices in the set and the actual operating parameters, judging whether the deviation exceeds the first-level threshold, if it exceeds, triggering a first-level early warning, marking the protection device as an object requiring attention, if the deviation exceeds the second-level threshold, triggering a second-level early warning, marking it as a high-risk device, triggering a forced calibration process, automatically expanding and identifying the impact domain under the current line break situation according to the topological connection relationship between the lines and the impact of the fault quantity, and triggering the corresponding level of early warning response only for the relay protection devices within the impact domain.

[0016] Another object of the present invention is to provide an online verification and early warning system for relay protection settings in a power system, which can solve the problems of poor real-time performance, inaccurate risk identification, and delayed early warning response in the current static setting technology of relay protection settings through the collaborative operation and information linkage mechanism among various modules.

[0017] As a preferred solution of the power system relay protection constant online verification and early warning system described in the present invention, it includes: a relay protection importance assessment module, a constant sensitivity online verification module, and an impact domain identification and hierarchical early warning module; the relay protection importance assessment module includes an importance index construction unit and a protection device sorting unit, the importance index construction unit is used to integrate three types of risks: power source isolation, load isolation, and power system decoupling, and calculate the importance index of the relay protection device in a weighted manner, and the protection device sorting unit is used to prioritize all protection devices according to the calculated relay protection importance index, so as to provide a basis for subsequent verification decisions; the constant sensitivity online verification module includes a fault current acquisition and conversion unit, a sensitivity judgment and matching unit The fault current acquisition and conversion unit is used to collect the minimum two-phase short-circuit current of the line where the protection device is located under the minimum operating mode, and calculate the corresponding secondary current value. The sensitivity judgment and matching unit is used to obtain the sensitivity coefficient by comparing the secondary value with the protection set value, and judge whether it is greater than the set threshold, and further judge whether the set values of each section meet the matching relationship; the impact domain identification and graded warning module includes an impact domain identification unit and a graded warning response unit. The impact domain identification unit is used to identify the area where the set value may fail based on the fault quantity change rate and the bus topology relationship when the set value deviation is found to exceed the threshold during verification. The graded warning response unit is used to set multi-level warning thresholds according to the degree of deviation, and implement a first-level or second-level warning for the protection device in the impact domain, prompting that attention or forced verification is required.

[0018] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a method for online verification and early warning of relay protection settings in a power system.

[0019] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of an online verification and early warning method for relay protection settings of a power system.

[0020] The beneficial effects of the present invention are as follows: by constructing a relay protection importance index that integrates three types of risk factors, namely power supply isolation, load isolation and grid decoupling, quantitative ranking of each relay protection device is achieved, and online sensitivity calibration is performed on high-importance protection devices in priority based on the ranking results. In the calibration process, when the fixed value deviation exceeds the threshold, the fault impact domain is identified based on the fault quantity change rate and graded warning is implemented within the impact domain, thereby establishing a "risk priority assessment-fixed value dynamic calibration-regional precise warning" linkage mechanism, improving calibration efficiency, enhancing anomaly identification accuracy, and achieving graded response to risk areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is an overall flow chart of an online verification and early warning method for relay protection settings in a power system provided by the first embodiment of the present invention.

[0023] Figure 2 This is a circuit diagram for determining the influence domain of an online verification and early warning method for relay protection settings in a power system provided by the first embodiment of the present invention.

[0024] Figure 3 A fault quantity determination circuit diagram of an online calibration and early warning method for relay protection settings in a power system provided by the first embodiment of the present invention.

[0025] Figure 4 This is an overall flow chart of an online verification and early warning system for relay protection settings in a power system provided by the third embodiment of the present invention. DETAILED DESCRIPTION

[0026] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0027] Example 1, with reference to Figure 1-Figure 3 , as one embodiment of the present invention, provides a method for online verification and early warning of relay protection settings in a power system, comprising:

[0028] S1: Construct a relay protection importance index and rank each relay protection device.

[0029] Furthermore, the relay protection importance index includes a power supply isolation risk index, a load isolation risk index, and a power system decoupling risk index, and the relay protection importance index is constructed by a linear weighted method.

[0030] It should be noted that power isolation refers to a short circuit fault on a line, which triggers the incorrect operation of the relay protection and causes the generator to be disconnected from the system. The probability of its occurrence is expressed as:

[0031]

[0032] Among them, η BI represents the probability of power isolation risk, M represents the total number of faults, i represents the index of the power isolation path, and B(i) represents the unit power loss or impact measurement value caused by the misoperation of the relay protection device in the i-th power isolation path.

[0033] When power supply isolation occurs in the power system, B(i)=1, otherwise B(i)=0.

[0034] Power isolation will cause a certain amount of power loss in the power system. The unitized power loss result is expressed as:

[0035]

[0036] Among them, H BI Indicates the unitized processing result of power loss, P G (i) represents the output power of the cut-off power unit in the i-th isolated scenario, P S Indicates the total power supply capacity of the entire power system under this operating mode.

[0037] In a power system consisting of J lines, the power isolation risk caused by incorrect operation of the k-th relay protection is expressed as:

[0038]

[0039] Among them, S BI (k) represents the power isolation risk index of the kth relay protection device, j represents the number of the power node, J represents the total number of power nodes in the system, η(j) represents the weight factor of the jth power node, η BI (j,k) represents the probability or trigger factor of the kth relay protection device being isolated due to misoperation in the jth power node scenario, H BI (j,k) represents the power loss impact metric caused by the kth protection device when it is isolated at power node j.

[0040] Load isolation refers to a situation where a short circuit fault occurs on a line, triggering the incorrect action of the relay protection, causing the load to be disconnected from the system. The probability of its occurrence is expressed as:

[0041]

[0042] Among them, η LI It represents the probability of load isolation risk, and L(i) represents the occurrence identification quantity of the load disconnecting from the power supply system due to the malfunction of the relay protection device in the i-th operating scenario.

[0043] When load isolation occurs in the power system, L(i) = 1; otherwise, L(i) = 0.

[0044] Load isolation will cause the power system to lose a certain amount of load. The unitized processing result of the lost load is expressed as:

[0045]

[0046] Among them, H LI Indicates the load isolation impact index, P L (i) represents the total load power loss caused by the misoperation of a protection device in the i-th operating scenario.

[0047] The load isolation risk caused by the incorrect operation of the relay protection at the kth position is expressed as:

[0048]

[0049] Among them, S LI (k) represents the load isolation risk index, η LI (j,k) represents the probability of load isolation caused by malfunction of protection device k in scenario j, H LI (j,k) represents the power lost by the kth protection device in the scenario of isolated load at node j.

[0050] When a cascading fault occurs in the power system, the line cascading tripping phenomenon may cause the power system to be disconnected. The probability of occurrence is expressed as:

[0051]

[0052] Among them, η NB represents the probability of power system disconnection risk, and N(i) represents the occurrence flag of the system disconnection event caused by improper operation of the protection device in the i-th operation scenario.

[0053] When power system decoupling occurs in the power system, N(i)=1, otherwise N(i)=0.

[0054] The power system decoupling will result in a certain amount of system capacity loss. The unitized processing result of the lost capacity is expressed as:

[0055]

[0056] Among them, H NB Indicates the system decoupling capacity impact index, P N (i) represents the total capacity loss value caused by structural splitting after the system is disconnected in the i-th scenario.

[0057] The risk of power system disconnection caused by incorrect operation of the k-th relay protection is expressed as:

[0058]

[0059] Among them, S NB (k) represents the risk index value of power system disconnection caused by incorrect operation of the k-th relay protection, η NB (j, k) represents the probability of a power system disconnection event caused by the misoperation of the kth relay protection device in the jth line or topological path, H NB (j,k) represents the normalized impact value of capacity loss caused by system disconnection due to malfunction of the kth relay protection device in the jth line.

[0060] The weighted combined power source isolation risk, load isolation risk, and power system decoupling risk are used to establish the relay protection importance index, which is expressed as:

[0061] G(k)=w B S BI (k)+w L S LI (k)+w N S NB (k)

[0062] Among them, G(k) represents the comprehensive importance index value corresponding to the k-th relay protection device, w B represents the weighted coefficient of the power isolation risk term, w L Weighted coefficient of load isolation risk term, w N It represents the weighting coefficient of the system decoupling risk item.

[0063] Furthermore, sorting the relay protection devices includes sorting all the relay protection devices based on the relay protection importance index to obtain an importance priority list of the relay protection devices.

[0064] It should also be noted that the comprehensive importance index values corresponding to all relay protection devices are sorted from high to low to obtain a priority list of protection device importance. This ranking result is used to guide the execution priority of the subsequent online setting value verification process, prioritizing operations such as sensitivity calculation, setting value coordination check, and influence domain identification for high-risk devices, thereby achieving precise scheduling of protection resources and forward-looking control of system risks.

[0065] S2: Based on the sorting results, prioritize online verification of relay protection settings for devices with high importance.

[0066] Furthermore, the online verification of relay protection settings includes calculating the secondary value, obtaining the sensitivity by the ratio of the secondary value of the minimum two-phase short-circuit current to the protection setting, and comparing the sensitivity coefficient with the preset sensitivity threshold to determine whether the action sensitivity requirements are met;

[0067] Based on the importance priority list, online verification operations are performed on protection devices with higher importance first.

[0068] It should be noted that under the current operating mode, the primary value of the minimum two-phase short-circuit current in the fault scenario is obtained and converted into a secondary value based on the current transformer ratio. This secondary value is then compared with the operating current setting set by the protection device to obtain the operating sensitivity coefficient. This sensitivity coefficient is compared with the preset operating sensitivity threshold to determine whether it meets the minimum sensitivity requirement of the protection device in this operating scenario, thereby verifying the reliability and effectiveness of the setting. When performing actual online verification, priority is given to high-importance relay protection devices with a high ranking for setting analysis. This improves the safety verification coverage of key equipment, balances system resource efficiency with verification task scheduling accuracy, and achieves risk-driven optimization of online verification execution.

[0069] Furthermore, calculating the secondary value includes collecting the minimum two-phase short-circuit current value of the line corresponding to the relay protection device under the minimum operating mode, calculating the minimum two-phase short-circuit current under the minimum operating mode based on the system impedance, line impedance and transformer impedance, and converting the short-circuit current into the input current of the relay protection device according to the current transformation ratio of the connected transformer to obtain the secondary value.

[0070] It should also be noted that to obtain the minimum short-circuit current, the relationship between line impedance, transformer impedance, and busbar connection is constructed based on the system's electrical parameters. The short-circuit current amplitude at different nodes under the minimum operating mode is calculated according to the fault location and system topology. The resulting short-circuit current is the primary current value, i.e., the physical current occurring at the actual device end. This primary short-circuit current is converted based on the current transformer ratio connected to the protection device to obtain the corresponding secondary current value, i.e., the input current signal received by the relay protection device under actual operating conditions. The secondary value is the core basis for calculating relay protection sensitivity and can achieve real-time quantitative assessment of operating capacity under fault conditions without changing the on-site wiring and setting parameters. The calculation of the secondary value is applicable not only to conventional busbar single-input scenarios, but also to multi-power dual-side power supply structures. In such structures, the fault equivalent path should be automatically adjusted based on the power flow distribution to ensure the accuracy of the short-circuit current simulation and the representativeness of the secondary value.

[0071] Furthermore, judging whether the action sensitivity requirement is met includes: if the sensitivity coefficient is greater than or equal to the preset sensitivity threshold, it is judged that the action sensitivity requirement is met; if the sensitivity coefficient is less than the preset sensitivity threshold, it is judged that the action sensitivity requirement is not met; if it is judged that the action sensitivity requirement is met, the coordination relationship between the sensitivities of each protection segment is checked to judge whether the incremental constraint relationship is met; if it is judged that the action sensitivity requirement is not met, an unsatisfactory prompt is output, it is marked as an abnormal item, and the subsequent coordination verification steps are terminated.

[0072] It should also be noted that the sensitivity threshold is the preset minimum allowable action sensitivity value, which is set based on the minimum action coefficient requirements of the relevant relay protection regulations for the regional power system. Among the three-stage setting of overcurrent protection, the action sensitivity required for overcurrent stage I, stage II and stage III should be in a strictly increasing relationship, and their sensitivity should satisfy the following formula:

[0073] K <K I <K II <K III

[0074] Among them, K represents the minimum allowed motion sensitivity threshold, K I Indicates the sensitivity coefficient of overcurrent protection stage I, K II Indicates the sensitivity coefficient of overcurrent protection stage II, K III Indicates the sensitivity coefficient of overcurrent protection stage III.

[0075] The sensitivity coefficients of each segment must meet the specified minimum sensitivity threshold, K, to ensure adequate protection operation even under the system's most adverse operating conditions. The thresholds used in our invention are based on this industry standard and are statistically optimized using extensive simulation data to arrive at recommended values. While ensuring protection reliability, they offer a certain tolerance, balancing selectivity and sensitivity, resulting in an optimal threshold that balances accuracy and engineering feasibility.

[0076] S3: If the deviation between the set value and the actual operating parameter exceeds the set threshold during the sensitivity calibration process, the impact domain is identified based on the fault quantity change rate, and a graded warning is performed within the impact domain.

[0077] Furthermore, identifying the impact domain based on the fault quantity change rate includes, when a specific line is detected to be disconnected, obtaining the short-circuit current level change data of the adjacent lines of the line, calculating the fault quantity change rate of the adjacent lines before and after the disconnection, and judging whether the fault quantity change rate exceeds the set threshold. If it exceeds the set threshold, the relay protection device corresponding to the adjacent line is included in the initial impact domain. Based on the busbar cascade connection relationship, the impact domain is expanded layer by layer through recursive iteration until all change rates are lower than the set threshold. All relay protection devices in the final determined impact domain are used as the target set for this verification and early warning.

[0078] It should be noted that after the main line is disconnected, by comparing the short-circuit current change rate before and after the disconnection, the impact domain can be dynamically identified and expanded to achieve the boundary identification of the fault response area, such as Figure 2 As shown, Figure 2 L0 indicates the target line disconnected by the fault, and the affected range needs to be identified. L1 to L 14Represents all lines directly or indirectly connected to L0. In our invention, preferably, the threshold value of the fault quantity change rate is set to 10%, that is, when the short-circuit current change rate of the line where a certain protection device is located is greater than 10%, it can be regarded that the device may be affected by the propagation of the previous fault. This threshold is derived from the statistical mean of the multi-region power grid simulation results. While ensuring the recognition coverage, it can avoid mistakenly including non-associated devices in the analysis scope, thereby improving the recognition efficiency and accuracy. After being included in the initial impact domain, the system adopts a breadth-first traversal method based on the busbar topology connection relationship to determine step by step whether the next-level line connected to it also has a fault quantity change rate exceeding the limit. If the conditions are met, it will continue to expand until the change rate of all lines is lower than the preset threshold, that is, the recursion is terminated to form the final impact domain. All relay protection devices within the final confirmed impact domain will be used as the fixed value verification and graded warning targets of the current batch.

[0079] Furthermore, the impact domain includes the area where the setting effects of surrounding relay protection devices change due to changes in short-circuit current levels after the line is disconnected.

[0080] It should also be noted that, in the present invention, the influence domain refers to a set of relay protection devices whose relay protection setting effect changes significantly after a topological disturbance (such as line disconnection). Its essence is that the parameters such as the power distribution, short-circuit current level, and equivalent impedance of the power grid are changed due to line break faults, which causes the original setting strategy to lose its applicability or lack sensitivity in the new electrical environment. The identification of the influence domain is not only based on the fixed value deviation judgment of a single node, but also comprehensively considers the short-circuit current change rate of each branch adjacent to the fault line before and after the fault occurs. When the short-circuit current change of a branch exceeds the preset sensitivity tolerance threshold, indicating that the relay protection setting effect it relies on has deviated significantly, it is considered to have entered the influence domain. In the case of multiple line breaks, by analyzing the degree of influence of different branch disconnections on the short-circuit current response of the fault point, the influence ranking of the fault propagation path is realized, thereby improving the accuracy of the influence domain generation and the efficiency of priority control, such as Figure 3 As shown, Figure 3 In the figure, F1 is the fault point, indicating that a short circuit fault occurs here. R1 represents the relay protection device installed on busbars L2~L3. L1~L6 represent multiple busbar sections and their connecting lines. The fault current propagation path is simulated and determined under different disconnection conditions.

[0081] Furthermore, the graded warning includes, based on the target set of verification and warning, calculating the deviation between the operating set value and the actual operating parameter of the relay protection device in the set, judging whether the deviation exceeds the first-level threshold. If it exceeds, the first-level warning is triggered, and the protection device is marked as an object requiring attention. If the deviation exceeds the second-level threshold, the second-level warning is triggered, and it is marked as a high-risk device, triggering the forced verification process. According to the topological connection relationship between the lines and the impact of the fault volume, the impact domain under the current line break situation is automatically expanded and identified, and the corresponding level of warning response is triggered only for the relay protection devices within the impact domain.

[0082] It should also be noted that based on the target set of verification and early warning, a comparison analysis is performed on the operating set values and actual operating parameters of each relay protection device in the set, and the deviation value is calculated. If the deviation value exceeds the first-level warning threshold, a first-level warning is triggered, and the protection device is marked as an object requiring attention, prompting the user or dispatch end to conduct a review and evaluation; if the deviation value further exceeds the second-level warning threshold, a second-level warning is triggered, and it is marked as a high-risk device, and the mandatory verification process is automatically started to ensure its effectiveness and response accuracy under the current operating mode.

[0083] A preferred option for the first-level warning threshold is 10%, indicating that there is a significant deviation between the set value and the actual value, which may be caused by changes in system flow, power supply access, or load structure, and requires manual review by the dispatching end. A preferred option for the second-level warning threshold is 20%, indicating that the set value may seriously deviate from the system fault characteristics, and there is a risk of refusal to operate or false operation, and mandatory verification is required.

[0084] Example 2 is an embodiment of the present invention, which provides an online calibration and early warning method for relay protection settings in a power system. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0085] Relay protection devices were deployed in a 220kV regional power grid, and quantitative analysis of importance, setting value verification, and graded warning tests were performed to verify the effectiveness of the technical approach based on "importance ranking + sensitivity verification + impact domain identification + graded warning" proposed in this paper.

[0086] First, a "relay protection importance index" model was constructed. Quantitative indicators were extracted from three aspects: source isolation risk, load isolation risk, and power system decoupling risk. After normalization and weighting, a unified importance value was generated. Seven protection devices were prioritized based on the obtained importance indicators to determine the priority treatment targets.

[0087] Next, sensitivity checks are prioritized for high-priority devices (such as A, D, and F). During the test, the minimum two-phase short-circuit current is collected from each device. The secondary current value is calculated using a proportional calculation, and the sensitivity coefficient is calculated based on this constant. If the sensitivity coefficient deviation exceeds the set threshold (between 0.10 and 0.15), the system initiates the next stage of processing.

[0088] Finally, for devices with abnormal sensitivity, the system identifies their impact domain based on the rate of change in the fault load and triggers a Level 1 or Level 2 alert for each device within that domain. The alert level is determined by the magnitude of the deviation, with a Level 1 threshold of 10% and a Level 2 threshold of 20%. The impact domain is tracked using the line topology and short-circuit current propagation path, and all devices in the anomaly propagation chain are identified, achieving a comprehensive analysis loop from single-point anomaly to coordinated protection. The experimental data is shown in Table 1.

[0089] Table 1 Relay protection setting value verification and early warning experiment data table

[0090]

[0091]

[0092] As can be seen from the table above, by ranking protection devices based on importance, devices such as A, D, and F are given higher priority due to their critical locations or high-risk connections. This "target set prioritization" mechanism avoids the problem of delayed detection of important nodes caused by the even distribution of resources in traditional fixed-value inspections, thereby improving verification efficiency.

[0093] During the sensitivity verification phase, devices A, D, and F all exhibited significant deviations (sensitivity coefficients S of 1.02, 1.12, and 0.94, respectively), exceeding the set thresholds and successfully triggering either the first or second level warning process. Device D, in particular, had the highest importance and deviation coefficient, leading the model to accurately identify it as a "high-risk device" and promptly initiate the second level warning mechanism. This demonstrates the system's acumen in identifying anomalies and its flexibility in responding to tiered responses.

[0094] In addition, compared with traditional methods that do not adopt this system, the latter relies on manual investigation and periodic inspection, and cannot achieve online update and dynamic response of fixed parameters. The present invention significantly improves the response rate and warning accuracy through real-time data collection and model-driven mechanism.

[0095] In summary, this embodiment verifies the comprehensive advantages of the present invention in the three aspects of "abnormal recognition rate, response efficiency, and resource scheduling efficiency", provides a practical technical path for the regional power grid to achieve "intelligent protection + lean operation and maintenance", and has significant practical value and engineering promotion prospects.

[0096] Example 3, reference Figure 4, which is an embodiment of the present invention, provides an online calibration and early warning system for relay protection settings in a power system, including a relay protection importance assessment module 100, an online calibration module for setting sensitivity 200, and an impact domain identification and graded early warning module 300.

[0097] Among them, S4: the relay protection importance assessment module 100 includes an importance index construction unit 101 and a protection device sorting unit 102. The importance index construction unit 101 is used to integrate three types of risks: power supply isolation, load isolation, and power system decoupling, and calculate the importance index of the relay protection device in a weighted manner. The protection device sorting unit 102 is used to prioritize all protection devices according to the calculated relay protection importance index, providing a basis for subsequent verification decisions.

[0098] It should also be noted that the importance index construction unit 101 calculates the risk level index of each protection device, and the protection device sorting unit 102 prioritizes the devices according to the index results of the importance index construction unit 101 to form a priority checklist.

[0099] S5: The constant value sensitivity online verification module 200 includes a fault current acquisition and conversion unit 201 and a sensitivity judgment and matching unit 202. The fault current acquisition and conversion unit 201 is used to acquire the minimum two-phase short-circuit current of the line where the protection device is located under the minimum operating mode, and calculate the corresponding secondary current value. The sensitivity judgment and matching unit 202 is used to obtain the sensitivity coefficient by comparing the secondary value with the protection constant value, determine whether it is greater than the set threshold, and further determine whether the constant values of each section meet the matching relationship.

[0100] It should also be noted that the fault current collection and conversion unit 201 collects the short-circuit current of the top-ranked device under the minimum operating mode and converts it into a secondary value. The sensitivity judgment and matching unit 202 compares the secondary current with the fixed value to obtain the sensitivity coefficient and compares it with the threshold to determine whether the action requirements are met.

[0101] S6: The impact domain identification and graded warning module 300 includes an impact domain identification unit 301 and a graded warning response unit 302. The impact domain identification unit 301 is used to identify the area where the fixed value may fail based on the fault quantity change rate and the bus topology relationship when the fixed value deviation is found to exceed the threshold during verification. The graded warning response unit 302 is used to set multi-level warning thresholds according to the degree of deviation, and implement a first-level or second-level warning for the protection device in the impact domain, prompting that attention or mandatory verification is required.

[0102] It should also be noted that if the action sensitivity or coordination relationship is not met, the impact domain identification unit 301 expands the impact domain based on the fault quantity change rate and the topological relationship, and the graded warning response unit 302 sets multi-level warning thresholds according to the deviation size, triggers the corresponding level of warning for the abnormal device in the impact domain and decides whether to perform forced verification.

[0103] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0104] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0105] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0106] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having logic gate circuits for implementing logical functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc. It should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to be limiting. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications should be encompassed by the claims of the present invention.

Claims

1. A method for online verification and early warning of relay protection settings in a power system, characterized in that: include: Construct a relay protection importance index and rank each relay protection device; Based on the ranking results, priority is given to online verification of relay protection settings for devices with high importance; If the deviation between the set value and the actual operating parameter exceeds the set threshold during the sensitivity calibration process, the impact domain is identified based on the fault quantity change rate, and a graded warning is performed within the impact domain.

2. The method for online verification and early warning of relay protection settings in a power system according to claim 1, characterized in that: The relay protection importance index includes a power supply isolation risk index, a load isolation risk index, and a power system decoupling risk index, and the relay protection importance index is constructed by a linear weighting method.

3. The method for online verification and early warning of relay protection settings in a power system according to claim 1 or 2, characterized in that: The ranking of the relay protection devices includes ranking all the relay protection devices based on the relay protection importance index to obtain an importance priority list of the relay protection devices.

4. The method for online verification and early warning of relay protection settings in a power system according to claim 3, characterized in that: The online verification of the relay protection setting includes calculating the secondary value, obtaining the sensitivity by the ratio of the secondary value of the minimum two-phase short-circuit current to the protection setting, and comparing the sensitivity coefficient with a preset sensitivity threshold to determine whether the action sensitivity requirement is met; Based on the importance priority list, online verification operations are performed on protection devices with higher importance first.

5. The method for online verification and early warning of relay protection settings in a power system according to claim 4, characterized in that: The calculation of the secondary value includes collecting the minimum two-phase short-circuit current value of the line corresponding to the relay protection device under the minimum operating mode, calculating the minimum two-phase short-circuit current under the minimum operating mode based on the system impedance, line impedance and transformer impedance, and converting the short-circuit current into the input end current of the relay protection device according to the current transformation ratio of the connected transformer to obtain the secondary value.

6. The method for online verification and early warning of relay protection settings in a power system according to claim 5, characterized in that: The determining whether the action sensitivity requirement is met includes determining that the action sensitivity requirement is met if the sensitivity coefficient is greater than or equal to a preset sensitivity threshold; If the sensitivity coefficient is less than the preset sensitivity threshold, it is judged that the action sensitivity requirement is not met; if it is judged that the action sensitivity requirement is met, the coordination relationship between the sensitivities of each protection segment is checked to determine whether the incremental constraint relationship is met; if it is judged that the action sensitivity requirement is not met, an unsatisfactory prompt is output, it is marked as an abnormal item, and the subsequent coordination verification steps are terminated.

7. The method for online verification and early warning of relay protection settings in a power system according to claim 1 or 6, characterized in that: The identification of the impact domain based on the fault quantity change rate includes, when a specific line is detected to be disconnected, obtaining short-circuit current level change data of the lines adjacent to the line, calculating the fault quantity change rate of the adjacent lines before and after the disconnection, and determining whether the fault quantity change rate exceeds a set threshold. If the set threshold is exceeded, the relay protection device corresponding to the adjacent line is included in the initial impact domain. Based on the busbar cascade connection relationship, the impact domain is expanded layer by layer through recursive iteration until all change rates are lower than the set threshold. All relay protection devices in the final determined impact domain are used as the target set for this verification and early warning.

8. The method for online verification and early warning of relay protection settings in a power system according to claim 7, characterized in that: The impact domain includes the area where the setting effects of surrounding relay protection devices change due to changes in short-circuit current levels after the line is disconnected.

9. The method for online verification and early warning of relay protection settings in a power system according to claim 1 or 8, characterized in that: The hierarchical warning includes, based on the target set of verification and warning, calculating the deviation between the operating set value and the actual operating parameter of the relay protection device in the set, judging whether the deviation exceeds the first-level threshold, if so, triggering the first-level warning, marking the protection device as an object requiring attention, if the deviation exceeds the second-level threshold, triggering the second-level warning, marking it as a high-risk device, triggering the forced verification process, and automatically expanding and identifying the impact domain under the current line break situation according to the topological connection relationship between the lines and the impact of the fault volume, and triggering the corresponding level of warning response only for the relay protection devices within the impact domain.

10. An online verification and early warning system for relay protection settings in a power system, characterized by: It includes a relay protection importance evaluation module (100), a fixed value sensitivity online calibration module (200), and an impact domain identification and graded warning module (300); The relay protection importance evaluation module (100) comprises an importance index construction unit (101) and a protection device sorting unit (102). The importance index construction unit (101) is used to integrate three types of risks, namely, power source isolation, load isolation, and power system decoupling, and calculate the importance index of the relay protection device in a weighted manner. The protection device sorting unit (102) is used to prioritize all protection devices according to the calculated relay protection importance index, thereby providing a basis for subsequent verification and decision-making. The fixed value sensitivity online calibration module (200) comprises a fault current acquisition and conversion unit (201) and a sensitivity judgment and matching unit (202), wherein the fault current acquisition and conversion unit (201) is used to acquire the minimum two-phase short-circuit current of the line where the protection device is located in the minimum operating mode and calculate the corresponding secondary current value, and the sensitivity judgment and matching unit (202) is used to obtain a sensitivity coefficient by comparing the secondary value with the protection fixed value, judge whether the sensitivity coefficient is greater than a set threshold, and further judge whether each section fixed value satisfies a matching relationship; The impact domain identification and graded warning module (300) comprises an impact domain identification unit (301) and a graded warning response unit (302). The impact domain identification unit (301) is used to identify areas where the fixed value may fail based on the fault quantity change rate and busbar topology relationship when a fixed value deviation exceeds a threshold value during verification. The graded warning response unit (302) is used to set multi-level warning thresholds according to the degree of deviation, implement a first-level or second-level warning for the protection device in the impact domain, and prompt that attention or mandatory verification is required.

11. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the power system relay protection setting online calibration and early warning method according to any one of claims 1 to 9 are implemented.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for online calibration and early warning of relay protection settings of a power system according to any one of claims 1 to 9 are implemented.

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