Power grid operation monitoring system for terminal current and voltage monitoring

Abstract

The invention relates to the technical field of electric power engineering, and discloses a power grid operation monitoring system for terminal current and voltage monitoring, which comprises a data acquisition unit, a data preprocessing unit, a feature extraction unit, a state analysis unit and a result output unit, according to the method, data collection is comprehensive and orderly, key parameters are covered, operation vectors are formed, and a foundation is laid for subsequent analysis; in data preprocessing, in a cleaning link, an abnormal value is identified and replaced by calculating an average value and a standard deviation, so that interference is avoided; through normalization processing, different parameters can be compared at the same scale, and the data quality is improved; the feature extraction unit can accurately extract voltage fluctuation, current imbalance, power factor and frequency deviation features, and provides a basis for state analysis; and the state analysis unit can timely discover various problems and evaluate the overall health degree of the power grid through single and comprehensive judgment, and classify the operation state, so that the operation and maintenance personnel can conveniently process in a targeted manner.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power engineering, and in particular to a power grid operation monitoring system for terminal current and voltage monitoring. Background Art

[0002] As modern society becomes increasingly dependent on electricity supply, the stable operation of the power grid is of vital importance. The power grid is a complex system, and the operating conditions of its key nodes and equipment are interrelated and directly affect the performance of the entire power grid. During the operation of the power grid, parameters such as voltage, current, power and frequency are key indicators reflecting the operating status of the power grid. Traditional power grid monitoring methods often have many limitations when faced with a large amount of operating data.

[0003] On the one hand, the original operation data collected from many key nodes and devices in the power grid often contain various noises, interferences and outliers. If these data quality issues are not properly handled, they will seriously affect the accuracy of the subsequent analysis of the power grid status. For example, outliers in the data may be caused by sensor failures, transmission interference, etc. If they are used directly for analysis, they may lead to misjudgment of the power grid status. On the other hand, the evaluation of the power grid operation status needs to comprehensively consider the characteristics of multiple parameters. Previous analysis methods may only look at single parameters such as voltage, current, power factor and frequency in isolation, such as a power grid line fault identification method and system disclosed in the application with publication number CN118884117A, which lacks comprehensive consideration of the relationship between them and cannot comprehensively and accurately evaluate the overall operation status of the power grid. This makes it difficult for operation and maintenance personnel to quickly and accurately obtain power grid operation status information, and it is difficult to discover potential problems and hidden dangers in a timely manner, such as voltage fluctuations may cause equipment damage, current imbalance may cause equipment heating and increased loss, too low power factor may cause insufficient reactive power compensation, and abnormal frequency may affect the synchronous operation of the power grid and the normal operation of equipment. Summary of the invention

[0004] The purpose of the present invention is to provide a power grid operation monitoring system for terminal current and voltage monitoring, which solves the technical problems raised in the background technology.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A power grid operation monitoring system for terminal current and voltage monitoring, comprising:

[0007] The data acquisition unit is used to collect operation data from various key nodes and equipment of the power grid. The operation data includes operation parameters corresponding to voltage, current, power and frequency;

[0008] A data preprocessing unit, used for preprocessing the operation data, wherein the preprocessing includes data cleaning and data normalization;

[0009] A feature extraction unit is used to perform feature extraction processing on the preprocessed operation data and extract the operation characteristics of the power grid, which include voltage fluctuation characteristics, current imbalance characteristics, power factor characteristics, and frequency deviation characteristics;

[0010] A state analysis unit is used to analyze the operation state of the power grid according to the extracted features, and determine the voltage state, current state, power factor state, frequency state and comprehensive state in the power grid according to the analysis results;

[0011] The result output unit is used to display the results obtained by the status analysis unit to relevant operation and maintenance personnel.

[0012] As a further solution of the present invention: wherein, after running data collection:

[0013] In the specified period, the voltage parameter in the operating data is marked as U t , the current parameter is marked as L t , the power parameter is marked as P t , the frequency parameter is marked as F t , where t = 1, 2, ... e, and e represents the number of all acquisition time nodes in the specified period;

[0014] At the same time, the operating parameters collected at each time node in the specified period are defined as the operating vector X t , where X t ∈[U t , L t , P t , F t ].

[0015] As a further solution of the present invention: the data cleaning method is as follows:

[0016] StepQ1, through Calculate X t The average value P X ;

[0017] That is, P X ∈[P U , P L , P P , P F ];

[0018] in,

[0019] P L Indicates all L t The average value of

[0020] P P Indicates that all P t The average value of

[0021] P F Indicates all F t The average value of

[0022] P U Indicates all U t The average value of

[0023] Step Q2, pass Calculate the standard deviation B of Xt X ;

[0024] That is to get B X ∈[B U , B L , B P , B F ];

[0025] in,

[0026] B L Indicates all L t The standard deviation of

[0027] B P Indicates that all P t The standard deviation of

[0028] B F Indicates all F t The standard deviation of

[0029] B U Indicates all U t The standard deviation of

[0030] StepQ3, run vector X t Combined with P X and B X , analyze the running vector X t Outliers in ;

[0031] Specifically:

[0032] If X t -P X >α×B X , then the corresponding running vector X t Mark as outlier;

[0033] Wherein, α is a preset multiple value, and the value of α is 3;

[0034] Step Q4, extract all running vectors except the outliers, calculate their average values, and then use the average values ​​as replacement values ​​for the outliers;

[0035] After replacing the corresponding abnormal value with the replacement value, the new running vector data is obtained;

[0036] That is, new voltage data, current data, power data and frequency data are obtained.

[0037] As a further solution of the present invention: the data normalization process is as follows:

[0038] StepG1, extract all new running vectors X t , then extract the running vector with the largest value and the running vector with the smallest value and mark them as X max and X min ;

[0039] StepG2, then pass Calculate the normalized value Y of each running vector t ;

[0040] That is, we get Y t ∈[YU t , YL t , Y.P. t , YF t ];

[0041] in,

[0042] YL t Indicates the corresponding L t The normalized value of

[0043] YP t Indicates the corresponding P t The normalized value of

[0044] YF t Indicates the corresponding F t The normalized value of

[0045] YU t Indicates the corresponding U t The normalized value of .

[0046] As a further solution of the present invention: the feature extraction unit is as follows:

[0047] Step T1. Voltage fluctuation characteristics

[0048] Extract all YU from the preprocessed voltage data t , followed by Calculate all YU t The average value P YU ;

[0049] Afterwards through Calculate the voltage fluctuation rate BDL YU ;

[0050] Step T2, current imbalance characteristics

[0051] Extract the three-phase current from the preprocessed current data and mark them as Y, La t , YLb t , YLc t ;

[0052] Then through Calculate the average value P of the three-phase current at the acquisition time node YL，t ;

[0053] Afterwards through Calculate the unbalance degree BPH of the three-phase current YL ;

[0054] Step T3, power factor characteristics:

[0055] In a three-phase circuit, extract the instantaneous values ​​of the three-phase voltages and mark them as ua t ,ub t and uc t , and extract the instantaneous values ​​of the three-phase currents and mark them as da t ,db t and dc t ;

[0056] Then through: Calculate the three-phase active power P SX ;

[0057] Then pass:

[0058] Last passed Calculate the power factor cosθ;

[0059] Step T4, frequency deviation characteristics

[0060] Get the rated frequency of the power grid and record it as FE;

[0061] Then Calculate the frequency deviation PC F .

[0062] As a further solution of the present invention: the mode of the state analysis unit is as follows:

[0063] Step Z1: Voltage status judgment

[0064] The voltage fluctuation rate BDL YU Compare with the preset voltage fluctuation rate threshold BDL1:

[0065] When BDL YU >BDL1, it is judged that the voltage is in an unstable state and there is a voltage fluctuation problem;

[0066] Step Z2: Current status judgment

[0067] The unbalance degree of three-phase current BPH YL Compare with the preset imbalance threshold BPH1:

[0068] When BPH YL >BPH1, it is judged that there is a current imbalance problem, which may cause the equipment to heat up and increase losses;

[0069] Step Z3: Power factor status judgment

[0070] Compare the power factor cosθ with the preset power factor threshold cosθ1:

[0071] When cosθ>cosθ1, it is judged that the power factor is too low, and there is a hidden danger of insufficient reactive power compensation of the power grid;

[0072] Step Z4: Frequency status judgment

[0073] Set the frequency deviation PC F The absolute value of is compared with the preset frequency deviation threshold PC1:

[0074] When PC F > PC1, it is judged that the grid frequency is abnormal, and there is a problem that affects the synchronous operation of the grid and the normal operation of the equipment;

[0075] Step Z5: Comprehensive status judgment

[0076] Extraction voltage fluctuation rate BDL YU , three-phase current imbalance BPH YL , power factor cosθ and frequency deviation PC F ;

[0077] Then through Calculate the comprehensive evaluation index ZPG;

[0078] Wherein, λ1, λ2, λ3, λ4 are corresponding preset weight coefficients;

[0079] Then the comprehensive evaluation index ZPG is compared with the preset comprehensive evaluation threshold ZPG1:

[0080] When ZPG<ZPG1, it is judged that all characteristic parameters of the power grid operation are within the normal range, the power grid is currently in a normal state of stable operation, and no abnormal signal is generated;

[0081] When ZPG1≤ZPG<1.4×ZPG1, it is determined that the power grid is currently in a slightly abnormal state, and a slightly abnormal signal is generated;

[0082] When 1.4×ZPG1≤ZPG<1.8×ZPG1, it is judged that the power grid is currently in a moderate abnormal state and a slight abnormal signal is generated;

[0083] When ZPG≥1.8×ZPG1, the grid operation is judged to be in a serious unstable state and a mild abnormal signal is generated.

[0084] As a further solution of the present invention: wherein, the display content includes the judgment results of various states of the power grid and related data characteristic values; it is displayed to the power grid operation and maintenance personnel through a visual interface.

[0085] Beneficial effects of the present invention:

[0086] The present invention collects multiple operating parameters such as voltage, current, power, frequency, etc. from various key nodes and devices of the power grid through a data acquisition unit, comprehensively covering the key information reflecting the operating status of the power grid, and providing a rich data basis for subsequent accurate analysis. During the acquisition process, each parameter is marked and defined within a specified period to form an operating vector, making the organization and management of data more orderly, which is conducive to improving the accuracy of the entire system's evaluation of the power grid operating status.

[0087] In the present invention, the data cleaning process in the data preprocessing unit can accurately identify and mark outliers by calculating the mean value and standard deviation of the running vector through rigorous steps. The data points that may interfere with the analysis results are reasonably screened out. Subsequently, the outliers are replaced by calculating the mean value of the running vector other than the outliers to obtain more reliable new running vector data, which effectively avoids the adverse effects of the abnormal data on subsequent analysis and improves the data quality and the credibility of the analysis results.

[0088] In the present invention, data normalization processing calculates the normalized value of each operation vector by extracting the maximum value in the new operation vector. This enables voltage, current, power, and frequency data of different magnitudes and ranges to be compared and analyzed on the same scale, further optimizing the data quality, providing standardized data support for subsequent links such as feature extraction and state analysis, and enhancing the scientific nature of the system's evaluation of the power grid operation status.

[0089] In the present invention, the feature extraction unit can accurately extract key grid operation features such as voltage fluctuation features, current imbalance features, power factor features and frequency deviation features for the pre-processed operation data. These features are quantitatively analyzed through specially designed calculation formulas, such as the formulas for calculating voltage fluctuation rate, three-phase current imbalance, power factor and frequency deviation. These accurately extracted features can deeply reflect the inherent state of grid operation, provide a highly targeted and representative basis for subsequent state analysis, and help to more accurately grasp the actual situation of grid operation.

[0090] In the present invention, the voltage, current, power factor and frequency state judgment steps in the state analysis unit respectively compare the corresponding characteristic values ​​with the preset thresholds. In this way, single-type problems such as voltage fluctuations, current imbalance, too low power factor and frequency anomalies can be discovered in a timely and accurate manner. This is conducive to quickly locating potential risks in the operation of the power grid, such as voltage flicker problems that may be caused by voltage fluctuations, equipment heating and increased losses caused by current imbalance, insufficient reactive power compensation caused by low power factor, and the impact of frequency anomalies on the synchronous operation of the power grid and the normal operation of equipment, thereby providing powerful guidance for targeted maintenance and adjustment measures.

[0091] In the present invention, the comprehensive status judgment is to calculate the comprehensive evaluation index by comprehensively considering the voltage fluctuation rate, three-phase current imbalance, power factor and frequency deviation, and compare it with the preset comprehensive evaluation threshold. This comprehensive evaluation method can judge the health of the power grid operation as a whole, and subdivide the power grid operation status into different levels such as normal, slightly abnormal, moderately abnormal and severely unstable. Different levels correspond to different signal generation mechanisms, so that operation and maintenance personnel can clearly understand the overall status of the power grid operation, and take appropriate measures in time according to different abnormal levels, effectively ensuring the safe and stable operation of the power grid.

[0092] In the present invention, the result output unit displays the judgment results of each state of the power grid and the relevant data characteristic values ​​to the operation and maintenance personnel through a visual interface. This intuitive display method enables the operation and maintenance personnel to quickly and clearly obtain the power grid operation status information without the need for a complicated data interpretation process. The visual interface facilitates the operation and maintenance personnel to find problems and take corresponding measures at the first time, greatly improving the operation and maintenance efficiency and reducing the risk of power grid failures that may be caused by untimely or inaccurate information acquisition. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] The present invention will be further described below in conjunction with the accompanying drawings.

[0094] Figure 1 The system block diagram of a power grid operation monitoring system for terminal current and voltage monitoring of the present invention. DETAILED DESCRIPTION

[0095] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0096] Embodiment 1

[0097] See also Figure 1 As shown, the present invention is a power grid operation monitoring system for terminal current and voltage monitoring, comprising:

[0098] The data acquisition unit is used to collect operation data from various key nodes and equipment of the power grid. The operation data includes operation parameters corresponding to voltage, current, power and frequency;

[0099] In the specified period, the voltage parameter in the operating data is marked as U t , the current parameter is marked as L t , the power parameter is marked as P t , the frequency parameter is marked as F t , where t = 1, 2, ... e, and e represents the number of all acquisition time nodes in the specified period;

[0100] At the same time, the operating parameters collected at each time node in the specified period are defined as the operating vector X t , where X t ∈[U t , L t , P t , F t ];

[0101] A data preprocessing unit, used for preprocessing the running data, wherein the preprocessing includes data normalization processing;

[0102] The data normalization process is as follows:

[0103] StepG1, extract all running vectors X t , then extract the running vector with the largest value and the running vector with the smallest value and mark them as X max and X min ;

[0104] StepG2, then pass Calculate the normalized value Y of each running vector t ;

[0105] That is, we get Y t ∈[YU t, YL t , Y.P. t , YF t ];

[0106] in,

[0107] YL t Indicates the corresponding L t The normalized value of

[0108] YP t Indicates the corresponding P t The normalized value of

[0109] YF t Indicates the corresponding F t The normalized value of

[0110] YU t Indicates the corresponding U t The normalized value of

[0111] A feature extraction unit is used to perform feature extraction processing on the pre-processed operation data, and extract features that can reflect the operation status of the power grid, including voltage fluctuation features, current imbalance features, power factor features, and frequency deviation features;

[0112] The specific method is as follows:

[0113] Step T1. Voltage fluctuation characteristics

[0114] Extract all YU from the preprocessed voltage data t , followed by Calculate all YU t The average value P YU ;

[0115] Afterwards through Calculate the voltage fluctuation rate BDL YU ;

[0116] Step T2, current imbalance characteristics

[0117] Extract the three-phase current from the preprocessed current data and mark them as Y, La t , YLb t , YLc t ;

[0118] Then through Calculate the average value P of the three-phase current at the acquisition time node YL，t ;

[0119] Afterwards through Calculate the unbalance degree BPH of the three-phase current YL ;

[0120] Step T3, power factor characteristics:

[0121] In a three-phase circuit, extract the instantaneous values ​​of the three-phase voltages and mark them as ua t ,ub t and uc t , and extract the instantaneous values ​​of the three-phase currents and mark them as da t ,db t and dc t ;

[0122] Then through: Calculate the three-phase active power P SX ;

[0123] Then pass:

[0124] Last passed Calculate the power factor cosθ;

[0125] Step T4, frequency deviation characteristics

[0126] Get the rated frequency of the power grid and record it as FE;

[0127] Then Calculate the frequency deviation PC F ;

[0128] A state analysis unit, used for analyzing the operation state of the power grid according to the extracted features;

[0129] The specific method is as follows:

[0130] Step Z1: Voltage status judgment

[0131] The voltage fluctuation rate BDL YU Compare with the preset voltage fluctuation rate threshold BDL1:

[0132] When BDL YU >BDL1, it is judged that the voltage is in an unstable state and there is a voltage fluctuation problem;

[0133] Step Z2: Current status judgment

[0134] The unbalance degree of three-phase current BPH YL Compare with the preset imbalance threshold BPH1:

[0135] When BPH YL >BPH1, it is judged that there is a current imbalance problem, which may cause the equipment to heat up and increase losses;

[0136] Step Z3: Power factor status judgment

[0137] Compare the power factor cosθ with the preset power factor threshold cosθ1:

[0138] When cosθ>cosθ1, it is judged that the power factor is too low, and there is a hidden danger of insufficient reactive power compensation of the power grid;

[0139] Step Z4: Frequency status judgment

[0140] Set the frequency deviation PC F The absolute value of is compared with the preset frequency deviation threshold PC1:

[0141] When PC F > PC1, it is judged that the grid frequency is abnormal, and there is a problem that affects the synchronous operation of the grid and the normal operation of the equipment;

[0142] Step Z5: Comprehensive status judgment

[0143] Extraction voltage fluctuation rate BDL YU , three-phase current imbalance BPH YL , power factor cosθ and frequency deviation PC F ;

[0144] Then through Calculate the comprehensive evaluation index ZPG;

[0145] Wherein, λ1, λ2, λ3, λ4 are corresponding preset weight coefficients;

[0146] Then the comprehensive evaluation index ZPG is compared with the preset comprehensive evaluation threshold ZPG1:

[0147] When ZPG<ZPG1, it is judged that all characteristic parameters of the power grid operation are within the normal range, the power grid is currently in a normal state of stable operation, no abnormal signals are generated, the equipment is working normally, and there is almost no potential risk;

[0148] That is, the voltage fluctuation rate is far lower than its corresponding threshold, the current imbalance is also smaller than its corresponding threshold, the power factor meets the requirements, and the frequency deviation is within the allowable deviation;

[0149] When ZPG1≤ZPG<1.4×ZPG1, it is judged that some parameters are close to or slightly exceed their thresholds, the power grid is currently in a slightly abnormal state, and a slightly abnormal signal is generated, which means that the power grid can continue to operate, but attention needs to be paid to related parameters, and some preventive maintenance measures may need to be arranged;

[0150] That is, the voltage fluctuation rate may increase slightly, but it has not yet had a significant impact on the operation of the power grid; or the power factor is slightly lower than the ideal value, but still within an acceptable range;

[0151] Maintenance measures include checking whether the reactive power compensation device is working properly;

[0152] When 1.4×ZPG1≤ZPG<1.8×ZPG1, it is judged that there are obvious problems in the operation of the power grid, the power grid is currently in a moderate abnormal state, and a slight abnormal signal is generated, which means that timely measures need to be taken for adjustment and repair;

[0153] For example: there may be frequent voltage fluctuations, affecting the operation of some sensitive equipment; high current imbalance, causing heating of some lines or equipment; low power factor, increasing reactive power loss of the power grid; or a certain degree of increase in frequency deviation, affecting the synchronization performance of the power grid;

[0154] Adjustment and repair measures include the need to adjust voltage regulation equipment, check the cause of current imbalance and make three-phase balance adjustments, increase reactive power compensation capacity, etc.;

[0155] When ZPG≥1.8×ZPG1, the grid operation is judged to be in a serious unstable state and a mild abnormal signal is generated, which indicates that emergency measures need to be taken immediately;

[0156] For example: the voltage may fluctuate greatly, which may cause the risk of voltage collapse; serious current imbalance may cause equipment damage; a power factor that is too low will seriously affect the economy and stability of the power grid; a large frequency deviation may cause the power grid to lose synchronization, leading to serious consequences such as large-scale power outages.

[0157] Emergency measures include cutting off some loads and adjusting power generation to restore normal operation of the power grid;

[0158] The result output unit is used to display the results obtained by the status analysis unit to relevant operation and maintenance personnel;

[0159] The display content includes the judgment results of various power grid states, relevant data characteristic values ​​and possible problem prompts; it is displayed to power grid operation and maintenance personnel through a visual interface, and can also generate report files for further analysis and archiving.

[0160] This embodiment collects multi-dimensional operating parameters including voltage, current, power, frequency, etc. from key nodes and equipment of the power grid through the data acquisition unit, so as to fully understand the operation of the power grid. Data normalization makes parameters of different magnitudes comparable, which is convenient for subsequent analysis. The feature extraction unit accurately extracts key features such as voltage fluctuation features, current imbalance features, power factor features, frequency deviation features, etc., and provides specific indicators for the analysis of the power grid operation status. The state analysis unit makes detailed state judgments based on different features, and can accurately identify problems such as unstable voltage, unbalanced current, low power factor, and abnormal frequency of the power grid. At the same time, the overall operation status of the power grid is evaluated through comprehensive evaluation indicators, which provides a clear basis for judgment for operation and maintenance personnel, helps to take corresponding maintenance, adjustment and emergency measures in time, and ensures the stable operation of the power grid. The result output unit displays the analysis results to the operation and maintenance personnel through a visual interface, and can generate a report file, which is convenient for further analysis and archiving, and improves the efficiency and traceability of power grid operation and maintenance.

[0161] Embodiment 2

[0162] As the second embodiment of the present invention, when the present application is specifically implemented, compared with the first embodiment, the technical solution of the present embodiment is different from the first embodiment only in that in the present embodiment, the preprocessing also includes data cleaning processing, and the data cleaning method is as follows:

[0163] StepQ1, through Calculate the average value P of Xt X ;

[0164] That is, P X ∈[P U , P L , P P , P F ];

[0165] in,

[0166] P L Indicates all L t The average value of

[0167] P P Indicates that all P t The average value of

[0168] P F Indicates all F t The average value of

[0169] P U Indicates all U t The average value of

[0170] Step Q2, pass Calculate X tThe standard deviation of B X ;

[0171] That is to get B X ∈[B U , B L , B P , B F ];

[0172] in,

[0173] B L Indicates all L t The standard deviation of

[0174] B P Indicates that all P t The standard deviation of

[0175] B F Indicates all F t The standard deviation of

[0176] B U Indicates all U t The standard deviation of

[0177] StepQ3, run vector X t Combined with P X and B X , analyze the running vector X t Outliers in ;

[0178] Specifically:

[0179] If X t -P X >α×B X , then the corresponding running vector X t Mark as outlier;

[0180] Wherein, α is a preset multiple value, and the value of α is 3;

[0181] Step Q4, extract all running vectors except the outliers, calculate their average values, and then use the average values ​​as replacement values ​​for the outliers;

[0182] After replacing the corresponding abnormal value with the replacement value, the new running vector data is obtained;

[0183] That is, new voltage data, current data, power data and frequency data are obtained.

[0184] This embodiment can accurately identify outliers by calculating the mean value and standard deviation of the running vector, replace the outliers, and obtain new running vector data, which improves the accuracy and reliability of the data and provides a better data basis for subsequent analysis and judgment.

[0185] Embodiment 3

[0186] As the third embodiment of the present invention, when the present application is implemented, compared with the first and second embodiments, the technical solution of this embodiment is to combine the solutions of the first and second embodiments, and the difference between the technical solution of this embodiment and the first and second embodiments is only in this embodiment;

[0187] The state analysis unit is also used to combine the extracted features with the operation state analysis results for correlation analysis;

[0188] The specific method is as follows:

[0189] Step M1. Voltage-current correlation

[0190] If the voltage fluctuates and the current also has a current imbalance problem, and the two show a trend of increasing and decreasing, such as the current increases when the voltage decreases), it is determined that the power grid has a short circuit fault or a load mutation;

[0191] Step M2: Power factor-voltage-current correlation

[0192] If the power factor is too low, accompanied by a voltage drop and an current increase, it is determined that the power grid has a problem of insufficient reactive power compensation.

[0193] In this embodiment, the voltage-current correlation analysis and power factor-voltage-current correlation analysis performed by the state analysis unit can more accurately determine the cause of the fault when complex problems occur in the power grid, such as short circuit faults, sudden load changes, insufficient reactive power compensation, etc., providing more powerful support for taking targeted measures.

[0194] Embodiment 4

[0195] As the fourth embodiment of the present invention, when the present application is specifically implemented, compared with the first, second and third embodiments, the technical solution of this embodiment is to combine and implement the solutions of the above-mentioned first, second and third embodiments.

[0196] In this embodiment, the comprehensive advantages are more significant: Embodiment 4 combines all the advantages of Embodiments 1, 2, and 3, and realizes comprehensive and accurate monitoring and analysis of the operation status of the power grid. Data collection, preprocessing, feature extraction, state analysis, and result output are coordinated with each other, and the performance of the system is further improved through data cleaning and correlation analysis, providing all-round guarantee for the stable operation of the power grid.

[0197] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters and thresholds in the formula are set by technicians in this field according to actual conditions.

[0198] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A power grid operation monitoring system for terminal current and voltage monitoring, characterized in that: include: The data acquisition unit is used to collect operation data from various key nodes and equipment of the power grid. The operation data includes operation parameters corresponding to voltage, current, power and frequency; A data preprocessing unit, used for preprocessing the operation data, wherein the preprocessing includes data cleaning and data normalization; A feature extraction unit is used to perform feature extraction processing on the preprocessed operation data and extract the operation characteristics of the power grid, which include voltage fluctuation characteristics, current imbalance characteristics, power factor characteristics, and frequency deviation characteristics; A state analysis unit is used to analyze the operation state of the power grid according to the extracted features, and determine the voltage state, current state, power factor state, and frequency state in the power grid according to the analysis results; The result output unit is used to display the results obtained by the status analysis unit to relevant operation and maintenance personnel.

2. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 1, characterized in that: The data cleaning method is as follows: StepQ1. Define the operation parameters collected at each time node in the specified period as the operation vector X t , where X t ∈[U t , L t , P t , F t ],U t is the voltage parameter, L t is the current parameter, P t is the power parameter, F t is the frequency parameter, where t = 1, 2, ..., e, and e represents the number of all acquisition time nodes within the specified period; Calculate a type corresponding to all X t The average value P X ; StepQ2, calculate a type corresponding to all X t The standard deviation of B X ; StepQ3, run vector X t Combined with P X and B X , analyze the running vector X t Outliers in ; Step Q4, extract all running vectors except the outliers, calculate their average values, and then use the average values ​​as replacement values ​​for the outliers; After replacing the corresponding outliers with replacement values, new running vector data is obtained.

3. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 2, characterized in that: In Step Q3, the analysis of outliers is as follows: If X t -P X >α×B X , then the corresponding running vector X t Mark as outlier; Among them, α is a preset multiple value.

4. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 2, characterized in that: The data normalization process is as follows: StepG1, extract all new running vectors X t , then extract the running vector with the largest value and the running vector with the smallest value and mark them as X max and X min ; StepG2, then pass Calculate the normalized value Y of each running vector t .

5. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 4, characterized in that: Currently in StepG2, Y t ∈[YU t , Y.L. t , Y.P. t , Y.F. t ]; Among them, YL t Indicates the corresponding L t Normalized value of YP t Indicates the corresponding P t Normalized value of YF t Indicates the corresponding F t Normalized value of YU t Indicates the corresponding U t The normalized value of .

6. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 5, characterized in that: The feature extraction unit is as follows: Step T1. Voltage fluctuation characteristics Extract all YU from the preprocessed voltage data t , and then calculate all YU t The average value is labeled P YU ; Afterwards through Calculate the voltage fluctuation rate BDL YU ; Step T2, current imbalance characteristics Extract the three-phase current from the preprocessed current data and mark them as Y, La t , YLb t , YLc t ; Then through Calculate the average value P of the three-phase current at the acquisition time node YL，t ; Afterwards through Calculate the unbalance degree BPH of the three-phase current YL ; Step T3, power factor characteristics: In a three-phase circuit, extract the instantaneous values ​​of the three-phase voltages and mark them as ua t ,ub t and uc t , and extract the instantaneous values ​​of the three-phase currents and mark them as da t ,db t and dc t ; Then through: Calculate the three-phase active power P SX ; Then pass: Last passed Calculate the power factor cosθ; Step T4, frequency deviation characteristics Get the rated frequency of the power grid and record it as FE; Then Calculate the frequency deviation PC F .

7. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 6, characterized in that: The state analysis unit is as follows: Step Z1: Voltage status judgment The voltage fluctuation rate BDL YU Compare with the preset voltage fluctuation rate threshold BDL1: When BDL YU >BDL1, the voltage is judged to be in an unstable state; Step Z2: Current status judgment The unbalance degree of three-phase current BPH YL Compare with the preset imbalance threshold BPH1: When BPH YL >BPH1, it is judged that there is a current imbalance problem; Step Z3: Power factor status judgment Compare the power factor cosθ with the preset power factor threshold cosθ1: When cosθ>cosθ1, it is judged that the power factor is too low; Step Z4: Frequency status judgment Set the frequency deviation PC F The absolute value of is compared with the preset frequency deviation threshold PC1: When PC F >PC1, it is judged that the grid frequency is abnormal.

8. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 7, characterized in that: The state analysis unit is also used to analyze the comprehensive state of the power grid according to the voltage state, current state, power factor state, and frequency state in the power grid; the comprehensive state judgment method is as follows: Extraction voltage fluctuation rate BDL YU , three-phase current imbalance BPH YL , power factor cosθ and frequency deviation PC F ; Then through Calculate the comprehensive evaluation index ZPG; Wherein, λ1, λ2, λ3, λ4 are corresponding preset weight coefficients; Then the comprehensive evaluation index ZPG is compared with the preset comprehensive evaluation threshold ZPG1, and the current state of the power grid is determined based on the comparison result, and an abnormal signal is generated according to the abnormal state, and the abnormal degree of the abnormal signal is determined.

9. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 8, characterized in that: The comparison method in comprehensive status judgment is as follows: When ZPG<ZPG1, it is judged that all characteristic parameters of the power grid operation are within the normal range, the power grid is currently in a normal state of stable operation, and no abnormal signal is generated; When ZPG1≤ZPG<1.4×ZPG1, it is determined that the power grid is currently in a slightly abnormal state, and a slightly abnormal signal is generated; When 1.4×ZPG1≤ZPG<1.8×ZPG1, it is judged that the power grid is currently in a moderate abnormal state and a slight abnormal signal is generated; When ZPG≥1.8×ZPG1, the grid operation is judged to be in a serious unstable state and a mild abnormal signal is generated.

10. The power grid operation monitoring system for terminal current and voltage monitoring according to claim 1, characterized in that: in, The display content includes the judgment results of each state of the power grid and the characteristic values ​​of related data; It is displayed to power grid operation and maintenance personnel through a visual interface.

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