A multi-level cooperative-based voltage excursion diagnosis and treatment method and system

Abstract

The present application relates to the field of power management, in particular to a voltage out-of-limit diagnosis and treatment method and system based on multi-level cooperation; the multi-source heterogeneous voltage data from multiple metering points in the power grid are standardized to obtain standardized voltage data; based on the standardized voltage data, the power supply path along the transformer substation, feeder, distribution transformer and user is judged step by step, and the voltage out-of-limit cause is output; based on the voltage out-of-limit cause, an optimized treatment scheme is generated; the optimized treatment scheme includes constructing a three-level problem list covering the bus, feeder and transformer area, and verifying at least one of the distribution transformer gear adjustment and bus voltage target value optimization based on the graphical simulation environment to output the optimized treatment scheme; the present application solves the problems of high misjudgment rate, low multi-level traceability efficiency, lack of cooperative optimization of treatment strategy and insufficient system compatibility caused by data heterogeneity in the prior art.

Description

Technical Field

[0001] This invention relates to the field of power management, specifically to a method and system for diagnosing and managing voltage over-limit based on multi-level collaboration. Background Technology

[0002] In modern power systems, voltage is a crucial indicator of power quality, and its stability and reliability play a vital role in the safe operation of the power system and the normal operation of various electrical equipment. Voltage exceeding limits refers to a voltage amplitude at a node in the power system exceeding the prescribed normal operating range, including both overvoltage and undervoltage situations.

[0003] Overvoltage can damage the insulation of electrical equipment, shorten its lifespan, and even cause serious accidents such as electrical fires, threatening the safe and stable operation of the power system. Undervoltage, on the other hand, reduces the output power and operating efficiency of electrical equipment such as motors, affecting normal industrial production and lowering the quality of life for residents. Furthermore, voltage exceeding limits also increases power losses in the power grid, reducing the economic efficiency of the power system.

[0004] With rapid economic development and continuous social progress, electricity demand continues to grow, the scale of the power system is expanding, and its structure is becoming more complex. The large-scale integration of distributed energy resources, the emergence of new loads such as electric vehicle charging stations, and the diversification of power grid operation modes have all brought new challenges to voltage control in the power system, making voltage limit violations increasingly prominent. On the one hand, existing analytical methods and models are not yet perfect for voltage limit violations caused by the interaction of multiple factors in complex power systems, making it difficult to accurately and comprehensively reveal their underlying mechanisms. On the other hand, a mature and effective system for the coordinated optimization of voltage control measures has not yet been formed, and the coordination between different control devices and strategies is not close enough, affecting the further improvement of control effectiveness. Summary of the Invention

[0005] To address the problems mentioned in the prior art, this invention proposes a multi-level collaborative method and system for voltage over-limit diagnosis and mitigation. This system enables real-time monitoring and analysis of voltage data from all users, timely and accurately identifying voltage over-limit problems, taking targeted mitigation measures, effectively solving voltage over-limit issues, improving power quality, ensuring the safe and stable operation of the power system, and providing a reliable power supply for the normal operation of various electrical equipment.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention discloses a multi-level collaborative method for diagnosing and mitigating voltage over-limit conditions, comprising the following steps: S1. Standardize the multi-source heterogeneous voltage data from multiple metering points in the power grid to obtain standardized voltage data; S2. Based on standardized voltage data, the cause of voltage exceeding the limit is determined step by step along the power supply path of substation, feeder, distribution transformer and user. S3. Based on the causes of voltage exceeding limits, generate an optimized governance plan; the optimized governance plan includes constructing a three-level problem list covering the busbar, feeder and transformer area, and verifying at least one measure in the adjustment of distribution transformer tap and optimization of busbar voltage target value based on a graphical simulation environment, so as to output the optimized governance plan.

[0007] As a further improvement of the present invention, the standardization process in S1 includes at least one of voltage level correction, primary value correction, and sampling frequency correction.

[0008] As a further improvement of the present invention, the voltage level correction includes: When the user's voltage level is inconsistent with the metering point's voltage level, the average value of all voltage samples taken at the metering point on that day is calculated, and the voltage level is automatically corrected based on the preset range in which the average value falls. The sampling frequency correction includes: taking a natural month as the cycle, calculating the maximum number of daily voltage sampling points within the previous 30 days, and correcting the actual sampling frequency based on the interval in which the maximum value falls. As a further improvement of the present invention, the primary value correction includes: If the secondary sample value is within the first preset voltage range, it is determined to be a line voltage sample, and the primary value = secondary value × turns ratio; If the secondary sampled value is within the second preset voltage range and the wiring method is three-phase four-wire system, it is determined to be phase voltage sampling, and the primary value = secondary value × transformation ratio × 1.732.

[0009] As a further improvement to the present invention, the step-by-step analysis along the power supply path of the substation, feeder, distribution transformer, and user in step S2 includes: For same-direction over-limit, a bottom-up tracing path is used for analysis. Same-direction over-limit refers to the voltage deviation direction of adjacent levels on the power supply path being the same. For reverse over-limits, the analysis is performed using a horizontal comparison path of the same or related levels. The reverse over-limits refer to the voltage deviation directions of adjacent levels on the power supply path being opposite.

[0010] As a further improvement of the present invention, the step-by-step judgment includes at least one level of analysis: Substation-level analysis: Analyze at least one of the following: bus voltage exceeding limits, main transformer tap position rationality, and reactive power compensation operation status; Feeder-level analysis: Analyze at least one of the following problems: excessively long power supply radius, excessively thin wire diameter, high load rate, and low power factor; Transformer-level analysis: Analyze at least one of the following issues: three-phase imbalance of the transformer, unreasonable tap position, abnormal load rate, and impact of photovoltaic distribution area. User-level analysis: Analyze at least one of the following issues: start-up and shutdown of high-power user equipment, abnormal internal wiring, and fluctuating load.

[0011] As a further improvement of the present invention, the three-level problem list in S3, which covers the bus, feeder and transformer area, includes the collection of voltage maximum and minimum values, over-limit duration and over-limit situation of each level.

[0012] As a further improvement to the present invention, the graphical simulation environment in S3 includes: In the simulation environment, the adjustment of the tap changer position of the distribution transformer is simulated, and its impact on the voltage of related users is predicted. And / or, simulate and modify the voltage target value of the automatic voltage control system for the power station bus, and predict its global impact on the voltage distribution of the downstream power grid.

[0013] As a further improvement of the present invention, the optimization of the target value of the bus voltage in S3 is a time-sharing and segmented optimization of the target value of the bus AVC voltage, specifically including: Determine the target value range margin based on the voltage change caused by capacitor switching and main transformer tap adjustment; Time segmentation is performed based on the peak-valley-flat characteristics of the load curve; The optimal median voltage is obtained by simulating a typical day, and the upper and lower limits of the target voltage range for each bus segment are generated.

[0014] This invention proposes a voltage over-limit diagnosis and mitigation system based on multi-level collaboration, including the above-mentioned method, comprising: The processing module is used to standardize multi-source heterogeneous voltage data from multiple metering points in the power grid to obtain standardized voltage data. The judgment module is used to make judgments step by step along the power supply path of substation, feeder, distribution transformer and user based on standardized voltage data, and output the cause of voltage exceeding the limit. The generation module is used to generate an optimized mitigation plan based on the causes of voltage exceeding limits. The optimized mitigation plan includes constructing a three-level problem list covering the busbar, feeder and transformer substation, and verifying at least one measure in transformer tap adjustment and busbar voltage target value optimization based on a graphical simulation environment, so as to output the optimized mitigation plan.

[0015] Compared with the prior art, the present invention achieves the following technical effects: Regarding the accuracy of problem identification, the method of this invention effectively overcomes the data heterogeneity problem caused by the diverse types of sensors, complex voltage levels, and inconsistent data formats in the power grid through dynamic data correction, transforming raw data into standardized data. This lays a data foundation for subsequent diagnostic processes, ensuring that voltage limit violations are not misjudged due to data quality issues. Secondly, this invention employs a four-level judgment rule to analyze the entire path from "station-line-transformer-customer." This method changes the time-consuming traditional model of relying on manual step-by-step investigation, enabling the identification of the transmission direction of voltage deviations and pinpointing the specific cause of limit violations in a very short time. It represents a fundamental shift from passive response and experience-based judgment to proactive early warning and diagnosis, significantly improving speed.

[0016] This invention, through main and distribution network coordinated simulation and multi-scheme comparison and optimization, can combine and simulate various measures such as voltage regulation, voltage adjustment, and reactive power compensation, evaluate their synergistic impact on the overall voltage distribution, and generate the most technically and economically optimal governance scheme, significantly improving the overall qualification level of the power grid voltage. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall process of the present invention; Figure 2 This is a flowchart of the voltage level correction rule for this invention; Figure 3 This is a flowchart of the first correction rule for the voltage operating curve; Figure 4 This is a flowchart of the sampling frequency correction rules; Figure 5 This is a substation-level analysis diagram; Figure 6 Main and distribution network coordinated simulated voltage regulation; Figure 7 Time-sharing and segmented voltage target value diagram; Figure 8 This is a map for identifying weak points in the power grid. Detailed Implementation

[0018] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0024] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0025] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0026] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] See Figure 1 This embodiment proposes a voltage over-limit diagnosis and mitigation method based on multi-level collaboration, including the following steps: S1. Standardize the multi-source heterogeneous voltage data from multiple metering points in the power grid to obtain standardized voltage data; S2. Based on standardized voltage data, the cause of voltage exceeding the limit is determined step by step along the power supply path of substation, feeder, distribution transformer and user. S3. Based on the causes of voltage exceeding limits, generate an optimized governance plan; the optimized governance plan includes constructing a three-level problem list covering the busbar, feeder and transformer area, and verifying at least one measure in the adjustment of distribution transformer tap and optimization of busbar voltage target value based on a graphical simulation environment, so as to output the optimized governance plan.

[0029] Step 1: During online monitoring of voltage limits, there is a discrepancy between the voltage levels recorded in the full user metering point ledger and the actual sampled voltage levels in the metering point's operating data. This discrepancy affects the accuracy of voltage limit judgment. Therefore, this embodiment proposes rules for correcting the metering point voltage levels. The specific process is as follows: Figure 2 As shown.

[0030] When the user's voltage level differs from the metering point's voltage level, the average value of all single-sample voltage values ​​taken at the metering point that day is calculated, and the voltage level is automatically corrected based on the preset range into which this average value falls. For example, when the average value falls within the range [0.154, 0.286] kV, the corrected voltage level is 0.22 kV.

[0031] Because the sampling devices at user metering points cannot be completely consistent in practical applications, the uploaded metering point data contains a large number of heterogeneous values. For example, some sampling devices upload secondary voltage values ​​as line voltages, while others upload secondary voltage values ​​as phase voltages.

[0032] Therefore, as Figure 3 As shown, this embodiment proposes a correction rule for the voltage upload data at the metering point. The specific values ​​of N1, N2, N3, and N4 are related to the sensor and sampling conditioning circuit, and are set according to specific circumstances. Primary value correction unit: Based on the range of secondary sampling values ​​and the wiring method, it converts the secondary values ​​into primary values. Specifically: (1) If the quadratic value is within [N1, N2]V, then the linear value = quadratic value × ratio; (2) If the secondary value is within [N3, N4]V and it is a three-phase four-wire system, then the primary value = secondary value × transformation ratio × 1.732.

[0033] When conducting online monitoring of voltage limits, there is a discrepancy between the voltage levels recorded in the full user metering log and the actual sampled voltage levels in the metering data, which affects the accuracy of voltage limit judgment. To address this, this paper proposes rules for correcting the voltage levels of metering points. The specific correction process is as follows: Figure 4 As shown, the maximum number of voltage sampling points per day within the first 30 days is calculated using a natural month as the cycle, and the actual sampling frequency is corrected based on the interval in which the maximum value falls.

[0034] Based on the type of overrun, analyze the causes of problems in the upstream substation, feeders, and distribution areas, and provide the reasons and remedial measures. For cases where there are no problems with the upstream power supply, low-voltage users can be categorized as having other issues, while medium- and high-voltage users can be categorized as having their own issues. The judgment rules and logic for each type of problem are explained.

[0035] Step Two: This embodiment uses a step-by-step approach to pinpoint the cause of voltage exceedances along the "station-line-transformer-customer" path. Following the principle of "for voltage exceedances in the same direction, look to the higher level; for voltage exceedances in the opposite direction, look to the same level," for voltage exceedances in the same direction, a bottom-up analysis is performed from "customer-distribution transformer-busbar"; for voltage exceedances in the opposite direction, a point-to-area analysis is performed from "customer-transformer area," analyzing each transformer individually. This allows for a systematic analysis of the causes of voltage exceedance problems, providing assessment suggestions to improve the voltage quality of the power grid and users. Figure 5 The following is an analysis at the substation level: (1) Substation-level analysis: Analyze problems such as bus voltage exceeding limits, unreasonable main transformer tap positions, and insufficient reactive power compensation.

[0036] (2) Feeder-level analysis: Analyze problems such as excessively long power supply radius, excessively thin wire diameter, high load rate, and low power factor.

[0037] (3) Transformer level assessment: Analyze issues such as three-phase imbalance, unreasonable tap position, high / low load rate, and the impact of photovoltaic areas on the transformer. For example, when the maximum daily three-phase imbalance of the transformer is greater than 25% (Dyn11 connection) and the load rate is higher than 30%, it is judged as three-phase imbalance exceeding the limit.

[0038] (4) User-level analysis: Analyze problems such as the start-up and shutdown of high-power equipment, abnormal internal wiring, and fluctuating loads.

[0039] Step 3: This embodiment is used to generate and optimize the governance plan.

[0040] (1) Three-level control list generation unit: Construct a three-level problem list of "bus-feeder-transformer area", collect the maximum and minimum voltage values, over-limit duration, and over-limit situation of each level, and realize the optimal allocation of problem resources.

[0041] (2) Main and distribution network coordinated analog voltage regulation unit: such as Figure 6 It is a main and distribution network coordinated voltage regulation simulation, providing a graphical simulation environment to support transformer tap adjustment simulation and bus-transformer coordinated voltage regulation simulation.

[0042] (3) Implement time-sharing and segmented optimization of the target value of bus AVC voltage: Figure 7 It is a time-segmented voltage target value map. The target value range margin is determined based on the voltage change caused by capacitor switching and main transformer tap adjustment. The time segmentation is combined with the peak-valley-flat characteristics of the load curve. The optimal voltage median is obtained by simulating a typical day, and the upper and lower limits of the target value range of the bus voltage for each segment are generated.

[0043] (4) Governance scheme generation and comparison unit: Figure 8 It is a power grid weak point identification map. The system locates and displays the weak points in the power grid on a single-line map, automatically generates governance / renovation solutions in different dimensions, and compares the effectiveness of different solutions in terms of indicator improvement and technical and economic indicators.

[0044] The method in this embodiment is applied to the system platform to support the operation and integration of various modules. The system platform is developed based on the SpringBoot + SpringCloud microservice architecture and adopts a front-end and back-end separation mode (Java for the back-end and Vue for the front-end). In addition, it is integrated with the data platform, power grid resource business platform, BPM process platform and power grid map system through RESTful services to realize multi-source data fusion and business process driving. Data storage adopts PostgreSQL relational database and Redis cache database and is deployed on the State Grid Cloud Platform.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for voltage over-limit diagnosis and mitigation based on multi-level collaboration, characterized in that, Includes the following steps: S1. Standardize the multi-source heterogeneous voltage data from multiple metering points in the power grid to obtain standardized voltage data; S2. Based on standardized voltage data, the cause of voltage exceeding the limit is determined step by step along the power supply path of substation, feeder, distribution transformer and user. S3. Based on the causes of voltage exceeding limits, generate an optimized governance plan; the optimized governance plan includes constructing a three-level problem list covering the busbar, feeder and transformer area, and verifying at least one measure in the adjustment of distribution transformer tap and optimization of busbar voltage target value based on a graphical simulation environment, so as to output the optimized governance plan.

2. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 1, characterized in that, The standardization process in S1 includes at least one of voltage level correction, primary value correction, and sampling frequency correction.

3. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 2, characterized in that, The voltage level correction includes: When the user's voltage level is inconsistent with the metering point's voltage level, the average value of all voltage samples taken at the metering point on that day is calculated, and the voltage level is automatically corrected based on the preset range in which the average value falls. The sampling frequency correction includes: taking a natural month as the cycle, calculating the maximum number of daily voltage sampling points within the previous 30 days, and correcting the actual sampling frequency based on the interval in which the maximum value falls.

4. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 2, characterized in that, The primary value correction includes: If the secondary sample value is within the first preset voltage range, it is determined to be a line voltage sample, and the primary value = secondary value × turns ratio; If the secondary sampled value is within the second preset voltage range and the wiring method is three-phase four-wire system, it is determined to be phase voltage sampling, and the primary value = secondary value × transformation ratio × 1.

732.

5. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 1, characterized in that, The S2 process involves a step-by-step analysis along the power supply path from substation, feeder, distribution transformer, to user, including: For same-direction over-limit, a bottom-up tracing path is used for analysis. Same-direction over-limit refers to the voltage deviation direction of adjacent levels on the power supply path being the same. For reverse over-limits, the analysis is performed using a horizontal comparison path of the same or related levels. The reverse over-limits refer to the voltage deviation directions of adjacent levels on the power supply path being opposite.

6. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 5, characterized in that, The step-by-step judgment includes at least one level of analysis: Substation-level analysis: Analyze at least one of the following: bus voltage exceeding limits, main transformer tap position rationality, and reactive power compensation operation status; Feeder-level analysis: Analyze at least one of the following problems: excessively long power supply radius, excessively thin wire diameter, high load rate, and low power factor; Transformer-level analysis: Analyze at least one of the following issues: three-phase imbalance of the transformer, unreasonable tap position, abnormal load rate, and impact of photovoltaic distribution area. User-level analysis: Analyze at least one of the following issues: start-up and shutdown of high-power user equipment, abnormal internal wiring, and fluctuating load.

7. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 1, characterized in that, The S3 section constructs a three-level problem list covering buses, feeders, and transformer substations, including the collection of maximum and minimum voltage values, over-limit durations, and area-wide over-limit situations at each level.

8. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 1, characterized in that, The graphical simulation environment in S3 includes: In the simulation environment, the adjustment of the tap changer position of the distribution transformer is simulated, and its impact on the voltage of related users is predicted. And / or, simulate and modify the voltage target value of the automatic voltage control system for the power station bus, and predict its global impact on the voltage distribution of the downstream power grid.

9. The voltage over-limit diagnosis and mitigation method based on multi-level collaboration according to claim 8, characterized in that, The optimization of the target value of the bus voltage in S3 is a time-sharing and segmented optimization of the target value of the bus AVC voltage, specifically including: Determine the target value range margin based on the voltage change caused by capacitor switching and main transformer tap adjustment; Time segmentation is performed based on the peak-valley-flat characteristics of the load curve; The optimal median voltage is obtained by simulating a typical day, and the upper and lower limits of the target voltage range for each bus segment are generated.

10. A voltage over-limit diagnosis and mitigation system based on multi-level collaboration, comprising the method described in any one of claims 1 to 9, characterized in that, include: The processing module is used to standardize multi-source heterogeneous voltage data from multiple metering points in the power grid to obtain standardized voltage data. The judgment module is used to make judgments step by step along the power supply path of substation, feeder, distribution transformer and user based on standardized voltage data, and output the cause of voltage exceeding the limit. The generation module is used to generate an optimized mitigation plan based on the causes of voltage exceeding limits. The optimized mitigation plan includes constructing a three-level problem list covering the busbar, feeder and transformer substation, and verifying at least one measure in transformer tap adjustment and busbar voltage target value optimization based on a graphical simulation environment, so as to output the optimized mitigation plan.

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