A method and system for evaluating the status of AC sampling in substation protection and control

Abstract

The present invention provides a substation protection measurement and control AC sampling state evaluation method and evaluation system, which relates to the field of electric power technology, and the specific steps include: S1. Collecting static state parameters and dynamic state parameters of substation protection measurement and control equipment, the static state parameters include current dispersion, power factor and voltage amplitude, and the dynamic state parameters include voltage frequency and phase angle; S2. Non-dimensionalizing the current dispersion, power factor and voltage amplitude, and performing correlation analysis to generate the static state coefficient of the substation protection measurement and control equipment, non-dimensionalizing the voltage frequency and phase angle, and performing correlation analysis to generate the dynamic state coefficient of the substation protection measurement and control equipment. The present invention evaluates the substation protection measurement and control AC sampling state by collecting current dispersion, power factor, voltage amplitude, voltage frequency and phase angle, thereby improving the evaluation accuracy and evaluation range of the protection measurement and control AC sampling state.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a transformer substation protection measurement and control alternating current sampling state evaluation method and evaluation system. Background Art

[0002] With the further acceleration of the construction of smart substations in my country, the scale of intelligent secondary equipment in substations will also grow rapidly. The number and importance of relay protection and measurement and control devices in substations are constantly increasing. As the first line of defense for power grid security protection, the safe operation of relay protection equipment in substations is particularly important for protecting the safe and stable operation of the power grid. Relay protection measurement and control AC sampling is a key link in relay protection equipment, which directly affects whether the protection and measurement and control devices can work normally and operate correctly. The conventional periodic inspection of relay protection is a preventive maintenance method. The equipment maintenance cycle is determined based on experience without considering the actual operation of the equipment. For the status assessment of the AC sampling module of relay protection measurement and control equipment, the method of regular maintenance test is often used. This inspection mode consumes a lot of manpower, the labor intensity of the operation and inspection personnel is high, the efficiency is low, the power outage time is long, there are many repetitive tasks, the maintenance cost is high, and the maintenance and safety measures work still has risks and hidden dangers, which can easily cause abnormal or malfunction of protection. Therefore, the development trend of status maintenance work based on online operation data has received more and more attention.

[0003] In the prior art, a method for evaluating the status of AC sampling of protection and control of intelligent substations is provided with publication number CN108335036B. The method realizes online evaluation of the status of AC sampling of protection and control of intelligent substations through online analysis based on the discreteness of homologous data of AC sampling. The method solves the problem of lack of effective online evaluation method for the operation status of AC sampling of relay protection and control equipment for a long time through online patrol monitoring of AC sampling and realizing status evaluation of AC sampling of protection and control of intelligent substations based on the discreteness of homologous data, thereby avoiding the waste of resources caused by regular maintenance and the impact on the reliable operation of the power grid. At the same time, the advantages of digitization and online monitoring of sampling of intelligent substations are utilized. Through online status evaluation, the hidden dangers of AC sampling can be discovered in time, and a new idea is explored for realizing the status maintenance of relay protection of intelligent substations.

[0004] However, there are still the following shortcomings. It can be seen from the above statements that the above only collects discreteness, and through online analysis of the discreteness of the AC sampling homologous data, online evaluation of the AC sampling status of the intelligent substation protection and control is achieved. Compared with collecting multiple parameters and comprehensively analyzing parameters such as discreteness, power factor and voltage amplitude, the evaluation accuracy and evaluation range of the protection and control AC sampling status are limited.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0006] The object of the present invention is to provide a method and system for evaluating the status of AC sampling in substation protection and control, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for evaluating the status of AC sampling of a substation protection and control, comprising the following specific steps:

[0009] S1. Collect static state parameters and dynamic state parameters of substation protection and control equipment, the static state parameters include current dispersion, power factor and voltage amplitude, the dynamic state parameters include voltage frequency and phase angle;

[0010] S2. The current dispersion, power factor and voltage amplitude are dimensionless processed, and correlation analysis is performed to generate the static state coefficient of the substation protection and control equipment, and the voltage frequency and phase angle are dimensionless processed, and correlation analysis is performed to generate the dynamic state coefficient of the substation protection and control equipment;

[0011] S3. The static state coefficient of the substation protection and control equipment and the dynamic state coefficient of the substation protection and control equipment are dimensionless processed, and correlation analysis is performed to generate a comprehensive index for evaluating the substation protection and control AC sampling state, and the comprehensive index is compared with a preset comprehensive index threshold to determine the level of the substation protection and control AC sampling state;

[0012] S4. Execute different strategies according to the different levels.

[0013] Furthermore, the current dispersion, power factor and voltage amplitude are dimensionless processed and correlation analysis is performed to generate the static state coefficient XS of the substation protection and control equipment. JT , the calculation formula is as follows:

[0014]

[0015] Among them, the parameters mean: LD is the current dispersion, GS is the power factor, DZ is the voltage amplitude, α is the factor coefficient of current dispersion, β is the factor coefficient of power factor, γ is the factor coefficient of voltage amplitude, 0.2≤α≤0.4, 0.2≤β≤0.4, 0.2≤γ≤0.4, C1 is the constant correction coefficient.

[0016] Further, the voltage frequency and phase angle are made dimensionless and correlation analysis is performed to generate the dynamic state coefficient XS of the substation protection and measurement and control equipment DT , and the calculation formula is as follows:

[0017]

[0018] Among them, the parameter meanings are: DP is the voltage frequency, XJ is the phase angle, μ is the factor coefficient of the voltage frequency, is the factor coefficient of the phase angle, 0.2 ≤ μ ≤ 0.4, C2 is the constant correction coefficient.

[0019] Further, the static state coefficient XS of the substation protection and measurement and control equipment JT and the dynamic state coefficient XS of the substation protection and measurement and control equipment DT are made dimensionless and correlation analysis is performed to generate the comprehensive index ZS for evaluating the AC sampling state of the substation protection and measurement and control. The calculation formula is as follows:

[0020] ZS = δXS JT + σXS DT + C3

[0021] Among them, the parameter meanings are: δ is the factor coefficient of the static state coefficient, σ is the factor coefficient of the dynamic state coefficient, 0.2 ≤ δ ≤ 0.4, 0.2 ≤ σ ≤ 0.4, and C3 is the constant correction coefficient.

[0022] Further, the process of comparing the comprehensive coefficient ZS with the preset comprehensive coefficient threshold YZ to judge the level of the AC sampling state of the substation protection and measurement and control is as follows:

[0023] When ZS > YZ, the AC sampling state of the substation protection and measurement and control is at a high level;

[0024] When 0.5YZ < ZS ≤ YZ, the AC sampling state of the substation protection and measurement and control is at a medium level;

[0025] When 0 < ZS ≤ 0.5YZ, the AC sampling state of the substation protection and measurement and control is at a low level.

[0026] Further, according to the different levels, the process of executing different strategies is as follows:

[0027] When the AC sampling state of the substation protection and measurement and control is at a high level, no operation is required and the system operates normally;

[0028] When the AC sampling state of the substation protection and measurement and control is at a medium level, a warning notice is issued to remind the operation and maintenance personnel to pay attention, and further inspection and maintenance may be required;

[0029] When the AC sampling status of the substation protection and control is at a low level, automatic or manual protection measures are triggered, which may include removing the faulty equipment or switching to backup equipment.

[0030] A substation protection measurement and control AC sampling state assessment system, comprising:

[0031] A data acquisition module is used to collect static state parameters and dynamic state parameters of the substation protection and control equipment, wherein the static state parameters include current dispersion, power factor and voltage amplitude, and the dynamic state parameters include voltage frequency and phase angle;

[0032] A data processing module is used to perform dimensionless processing on the current dispersion, power factor and voltage amplitude, and perform correlation analysis to generate a static state coefficient of the substation protection and measurement equipment, and to perform dimensionless processing on the voltage frequency and phase angle, and perform correlation analysis to generate a dynamic state coefficient of the substation protection and measurement equipment;

[0033] A data analysis module, used to perform dimensionless processing on the static state coefficient of the substation protection and measurement equipment and the dynamic state coefficient of the substation protection and measurement equipment, and perform correlation analysis, to generate a comprehensive index for evaluating the substation protection and measurement AC sampling state, and to compare the comprehensive index with a preset comprehensive index threshold to determine the level of the substation protection and measurement AC sampling state;

[0034] The execution module executes different strategies according to the different levels.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention collects parameters related to the evaluation of the AC sampling state of the protection and measurement control of the substation, such as current dispersion, power factor, voltage amplitude, voltage frequency and phase angle, performs correlation analysis on the current dispersion, power factor and voltage amplitude, generates the static state coefficient of the protection and measurement control equipment of the substation, performs correlation analysis on the voltage frequency and phase angle, generates the dynamic state coefficient of the protection and measurement control equipment of the substation, performs correlation analysis on the static state coefficient of the protection and measurement control equipment of the substation and the dynamic state coefficient of the protection and measurement control equipment of the substation, generates a comprehensive index for evaluating the AC sampling state of the protection and measurement control of the substation, and compares the comprehensive index with a preset comprehensive index threshold value to judge the level of the AC sampling state of the protection and measurement control of the substation. Therefore, by collecting the current dispersion, power factor, voltage amplitude, voltage frequency and phase angle, the AC sampling state of the protection and measurement control of the substation is evaluated, and the evaluation accuracy and evaluation range of the AC sampling state of the protection and measurement control are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of the method of the present invention;

[0038] Figure 2 It is a block diagram of the module composition of the present invention. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0040] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0041] Embodiment:

[0042] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0043] A method for evaluating the status of AC sampling in substation protection and control, such as Figure 1 As shown, the specific steps include:

[0044] S1. Collect static state parameters and dynamic state parameters of substation protection and control equipment, the static state parameters include current dispersion, power factor and voltage amplitude, the dynamic state parameters include voltage frequency and phase angle;

[0045] S2. Non-dimensionalize the current dispersion, power factor and voltage amplitude, and perform correlation analysis to generate the static state coefficient of the substation protection and control equipment; non-dimensionalize the voltage frequency and phase angle, and perform correlation analysis to generate the dynamic state coefficient of the substation protection and control equipment;

[0046] S3. The static state coefficient of the substation protection and control equipment and the dynamic state coefficient of the substation protection and control equipment are dimensionless processed, and correlation analysis is performed to generate a comprehensive index for evaluating the substation protection and control AC sampling state, and the comprehensive index is compared with a preset comprehensive index threshold to determine the level of the substation protection and control AC sampling state;

[0047] S4. Execute different strategies according to the different levels.

[0048] When the current dispersion changes, it will cause the state of the AC sampling of the substation protection and control equipment to change. The following are the specific reasons:

[0049] Protection system sensitivity adjustment: Changes in current dispersion may indicate an increase or decrease in the volatility of current in the system;

[0050] Fault detection and location: Changes in current dispersion may indicate a line or equipment fault;

[0051] Overcurrent protection response: An increase in current dispersion may be caused by load or fault in the system;

[0052] Dynamic stability assessment: Changes in current dispersion may reflect system oscillations or instability.

[0053] Therefore, it is particularly important to measure the current dispersion through the current sensor. If this can be done, the following effects will occur:

[0054] Fault detection and diagnosis: An increase in current dispersion may be an indication of a fault in the power system. By monitoring changes in dispersion, abnormal conditions in the system, such as short circuits, breaks or other faults, can be detected more quickly and diagnosed quickly.

[0055] Improve the sensitivity of the protection system: Changes in current dispersion can be used to adjust the sensitivity of the protection system. Increasing sensitivity can more accurately detect small changes in the system, thereby improving the timely response to potential problems.

[0056] Accurate load management: Monitoring of current dispersion helps to understand current fluctuations more accurately, which is very important for achieving accurate load management and power system planning. Load distribution and system operation strategies can be adjusted according to changes in dispersion to improve energy efficiency.

[0057] Prevent equipment damage: Abnormal current fluctuations may cause damage to equipment. By monitoring current dispersion, potential problems can be predicted and preventive measures can be taken to reduce equipment damage and maintenance costs.

[0058] Optimizing the operation and stability of power systems: Monitoring of current dispersion can be used to assess the stability of power systems. Based on changes in dispersion, measures can be taken to optimize system operation and improve system stability and reliability.

[0059] Improve system safety: By monitoring current dispersion in real time, potential problems can be discovered earlier, thereby improving the safety of the power system. This is crucial to prevent dangerous situations such as system overload and short circuit.

[0060] When the power factor changes, the state of the AC sampling of the substation protection and control equipment will change. The following are the specific reasons:

[0061] Adjustment of protection sensitivity: Changes in power factor may be used as an input to the protection system to adjust the protection sensitivity of the system. For example, a more sensitive protection action may be required for certain types of faults.

[0062] Changes in the operating range of protection devices: The operating range of some protection devices may be related to the power factor. Changes in the power factor may cause the state of the device to change to adapt to the new operating conditions of the system.

[0063] Fault detection and location: Abnormal changes in power factor may be associated with faults, so protection devices may trigger fault detection and location mechanisms based on changes in power factor.

[0064] Therefore, it is particularly important to measure the power factor through a power factor meter. If this can be done, the following effects will occur:

[0065] Optimizing energy utilization: Accurately measuring the power factor can help evaluate the energy utilization efficiency of the power system. Maintaining a good power factor helps reduce power loss and improve the overall efficiency of the power system.

[0066] Reduced energy costs: By monitoring the power factor, it is possible to identify low power factor conditions in the system. Taking steps to improve the power factor, such as using compensation devices or optimizing load sharing, can help reduce energy costs and avoid additional expenses due to low power factor.

[0067] Extended Equipment Life: Low power factor can cause overheating and extra losses in equipment, which can reduce the life of the equipment. By maintaining a proper power factor, this extra load can be reduced and the life of the equipment can be extended.

[0068] Improve power system stability: A good power factor helps improve the stability and reliability of the power system. By maintaining a suitable power factor, the frequency of voltage drops, current fluctuations and other problems in the system can be reduced.

[0069] Reducing the reactive load on the system: Optimizing the power factor can reduce the reactive power in the system, which helps to reduce the load on the power system and improve the efficient use of energy.

[0070] When the voltage amplitude changes, the state of the AC sampling of the substation protection and control equipment will change. The following are the specific reasons:

[0071] Overvoltage protection triggering: When the voltage amplitude exceeds the set upper limit, the overvoltage protection may be triggered. In this case, the protection measurement and control equipment may change its state and take corresponding measures to protect the system equipment from overvoltage.

[0072] Undervoltage protection triggering: When the voltage amplitude is lower than the set lower limit, the undervoltage protection may be triggered. This may cause the protection and control equipment to change its state to perform the necessary measures to deal with the undervoltage situation.

[0073] Changes in voltage closing conditions: Some protection devices may adjust their closing conditions based on changes in voltage amplitude. For example, a drop in voltage amplitude may cause the protection system to adopt a more conservative strategy and delay the closing operation.

[0074] System stability detection: The change in voltage amplitude may be used as an indicator of system stability detection. If the voltage change causes system instability, the protection and control equipment may take corresponding measures, such as opening the circuit breaker or reducing the load.

[0075] Abnormal voltage monitoring: Abnormal changes in voltage amplitude may be an indication of problems in the power system. Protection and measurement equipment may take preventive measures based on such abnormal changes to prevent potential failures or problems.

[0076] Therefore, it is particularly important to measure the voltage amplitude through a voltmeter. If this can be done, the following effects will occur:

[0077] Power system operation monitoring: Regularly measuring voltage amplitude helps monitor the operating status of the power system. Abnormal voltage fluctuations may indicate potential problems such as grid problems, equipment failures, or power instability.

[0078] Equipment status assessment: Voltage amplitude measurement can be used to assess the status of power equipment. Stable voltage amplitude helps ensure the normal operation of the equipment, while abnormal fluctuations may indicate a problem with the equipment.

[0079] Power quality analysis: Voltage amplitude is one of the important parameters for power quality analysis. Measuring voltage amplitude can help analyze problems such as waveform distortion and harmonics in the power system, thereby improving power quality.

[0080] Equipment protection: Voltage amplitude monitoring can be used for equipment protection. For example, in the event of excessively high or low voltage, the protection device can take measures, such as cutting off the power supply, to prevent equipment damage.

[0081] When the voltage frequency changes, the state of the AC sampling of the substation protection and control equipment will change. The following are the specific reasons:

[0082] Frequency protection triggering: Some protection devices may trigger corresponding frequency protection according to the change of voltage frequency. If the frequency deviates from the normal range, the protection system may think that there is a system problem and change its state to take necessary protection measures.

[0083] Frequency-sensitive equipment adjustment: Some equipment and protection systems may be very sensitive to voltage frequency changes. Abnormal frequency fluctuations may cause equipment parameters to need adjustment, or trigger over-frequency or under-frequency protection of some equipment.

[0084] System stability detection: Frequency changes may be used as an indicator for system stability detection. If the frequency change causes system instability, the protection and control equipment may take corresponding measures, such as cutting off the power supply or reducing the load.

[0085] Power system dispatch adjustment: The frequency change of the power system may lead to the adjustment of the power system dispatch. The protection and measurement and control equipment may respond to the changes in the system dispatch to maintain the balance and stability of the system.

[0086] Therefore, it is particularly important to measure the voltage frequency change through a frequency meter. If this can be done, the following effects will occur:

[0087] Protection triggering judgment: Substation protection and control equipment usually needs to sample the signals in the power system and trigger the corresponding protection action according to certain logic and algorithms. Changes in voltage frequency may trigger certain protection devices. Therefore, measuring frequency changes through a frequency meter helps to evaluate whether the protection device should trigger the protection action.

[0088] Protection sensitivity adjustment: For some protection devices, changes in frequency may require adjustments to their sensitivity and thresholds. By measuring frequency changes with a frequency meter, it is possible to assess whether the settings of the protection device need to be adjusted to better accommodate the effects of system frequency changes.

[0089] System stability detection: Changes in voltage frequency may be an indicator of power system stability problems. Monitoring the frequency and analyzing its changes can help assess the stability of the system so that timely measures can be taken to prevent problems caused by system instability.

[0090] When the phase angle changes, the state of the AC sampling of the substation protection and control equipment will change. The following are the specific reasons:

[0091] Phase angle jump causes protection triggering: In the power system, a sudden jump of the phase angle may trigger certain protection devices. For example, if there is a phase angle jump in the system, it may cause the triggering of overcurrent protection or differential protection, because this jump may be related to current abnormality.

[0092] Differential protection failure: Differential protection usually compares the current waveforms at both ends and performs differential comparison when the phase angle changes. If the phase angle changes greatly, it may cause differential protection failure or malfunction, thus affecting the stability of the system.

[0093] Therefore, it is particularly important to measure the phase angle change through an oscilloscope. If this can be done, the following effects will occur:

[0094] Triggering protection devices: Changes in phase angle may affect the triggering conditions of protection devices. Some protection devices may trigger protection actions based on changes in phase difference, so accurately measuring phase angle changes is very important to correctly determine when to activate the protection device.

[0095] Sensitivity of protection devices: Phase angle changes may affect the sensitivity and triggering threshold of protection devices. Too large or too small a phase change may make the protection device oversensitive or insensitive, thus affecting its response to system faults or abnormalities.

[0096] System stability assessment: Phase angle change is one of the important indicators of system stability. Accurately measuring the change in phase angle helps to assess system stability and promptly identify problems that may cause system instability.

[0097] Impact assessment on equipment operating status: Phase angle changes may affect the operating status of equipment (such as generators, transformers, etc.). Measuring phase angle changes helps to evaluate the operating status of these devices under different phase conditions and predict possible problems.

[0098] In summary, collecting current dispersion, power factor, voltage amplitude, voltage frequency and phase angle plays an extremely important role in evaluating the AC sampling status of substation protection and control. The following is a specific implementation method for collecting current dispersion, power factor, voltage amplitude, voltage frequency and phase angle data in this implementation method.

[0099] Among them, the current dispersion, power factor and voltage amplitude are dimensionless, and correlation analysis is performed to generate the static state coefficient XS of the substation protection and control equipment. JT , the calculation formula is as follows:

[0100]

[0101] Among them, the meanings of the parameters are: LD is the current dispersion, GS is the power factor, DZ is the voltage amplitude, α is the factor coefficient of current dispersion, β is the factor coefficient of power factor, γ is the factor coefficient of voltage amplitude, 0.2≤α≤0.4, 0.2≤β≤0.4, 0.2≤y≤0.4, and C1 is the constant correction coefficient.

[0102] From the above formula, we can see that when LD is higher, the static state coefficient XS JT The lower the GS, the higher the efficiency factor XS. XL The higher the DZ, the higher the efficiency coefficient XS XL The higher the value, the higher the LD and XS JT Negatively correlated, GS, DZ and XS JT There is a positive correlation, and the factor coefficient is used to balance the proportion of each data in the formula, thereby promoting the accuracy of the calculation results.

[0103] The voltage frequency and phase angle are dimensionless and the correlation analysis is performed to generate the dynamic state coefficient XS of the substation protection and control equipment. DT , the calculation formula is as follows:

[0104]

[0105] Among them, the parameters mean: DP is the voltage frequency, XJ is the phase angle, μ is the factor coefficient of the voltage frequency, is the factor coefficient of the phase angle, 0.2≤μ≤0.4, C2 is the constant correction coefficient.

[0106] From the above formula, we can see that when DP is higher, the dynamic state coefficient XS DT The lower the XJ, the higher the dynamic state coefficient XS DT The lower the value, the higher the DP and XS DT Negatively correlated, XJ and XS DT There is a negative correlation, and the factor coefficient is used to balance the proportion of each data in the formula, thereby promoting the accuracy of the calculation results.

[0107] Among them, the static state coefficient XS of the substation protection and control equipment JT and the dynamic state coefficient XS of the substation protection and control equipment DT Dimensionless processing and correlation analysis are performed to generate a comprehensive index ZS for evaluating the AC sampling status of substation protection and control. The calculation formula is as follows:

[0108] ZS=δXS JT +σXS DT +C3

[0109] Among them, the parameter meanings are as follows: δ is the factor coefficient of the static state coefficient, σ is the factor coefficient of the dynamic state coefficient, 0.2 ≤ δ ≤ 0.4, 0.2 ≤ σ ≤ 0.4, and C3 is the constant correction coefficient.

[0110] The process of comparing the comprehensive index ZX with the preset comprehensive index threshold YZ to judge the level of the AC sampling state of substation protection and measurement and control is as follows:

[0111] When ZS > YZ, the AC sampling state of substation protection and measurement and control is at a high level;

[0112] When 0.5YZ < ZS ≤ YZ, the AC sampling state of substation protection and measurement and control is at a medium level;

[0113] When 0 < ZS ≤ 0.5YZ, the AC sampling state of substation protection and measurement and control is at a low level.

[0114] The process of implementing different strategies according to different levels is as follows:

[0115] When the AC sampling state of substation protection and measurement and control is at a high level, no operation is required and the system runs normally;

[0116] When the AC sampling state of substation protection and measurement and control is at a medium level, a warning notice is issued to remind the operation and maintenance personnel to pay attention, and further inspection and maintenance may be required;

[0117] When the AC sampling state of substation protection and measurement and control is at a low level, automatic or manual protection measures are triggered, which may include cutting off the faulty equipment or switching to standby equipment.

[0118] α, β, γ, μ in the formula, The specific values of δ and σ are generally determined by those skilled in the art according to the actual situation. The essence of this formula is weighted summation for comprehensive analysis. Those skilled in the art collect multiple groups of sample data, set corresponding preset proportional coefficients for each group of sample data, substitute the set preset proportional coefficients and the collected sample data into the formula, screen the calculated coefficients and take the average value to obtain the values of α, β, γ, μ, δ, σ.

[0119] In addition, the magnitudes of the preset factor coefficients are specific values obtained by quantifying each parameter. For the convenience of subsequent comparison, the magnitudes of the coefficients depend on the number of sample data and the preset proportional coefficients initially set by those skilled in the art for each group of sample data, and are not unique, as long as they do not affect the proportional relationship between the parameters and the quantified values.

[0120] A substation protection and measurement and control AC sampling state evaluation system, as Figure 2 shown, includes:

[0121] A data acquisition module is used to collect static state parameters and dynamic state parameters of the substation protection and control equipment, wherein the static state parameters include current dispersion, power factor and voltage amplitude, and the dynamic state parameters include voltage frequency and phase angle;

[0122] A data processing module is used to perform dimensionless processing on the current dispersion, power factor and voltage amplitude, and perform correlation analysis to generate a static state coefficient of the substation protection and measurement equipment, and to perform dimensionless processing on the voltage frequency and phase angle, and perform correlation analysis to generate a dynamic state coefficient of the substation protection and measurement equipment;

[0123] A data analysis module, used to perform dimensionless processing on the static state coefficient of the substation protection and measurement equipment and the dynamic state coefficient of the substation protection and measurement equipment, and perform correlation analysis, to generate a comprehensive index for evaluating the substation protection and measurement AC sampling state, and to compare the comprehensive index with a preset comprehensive index threshold to determine the level of the substation protection and measurement AC sampling state;

[0124] The execution module executes different strategies according to the different levels.

[0125] 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 in the formula are set by technicians in this field according to actual conditions.

[0126] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by computer software, electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraints of the technical solution.

[0127] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0128] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the 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.

Claims

1. A method for evaluating the status of AC sampling in substation protection and control, characterized in that: The specific steps include: S1. Collect the static state parameters and dynamic state parameters of the substation protection and measurement and control equipment. The static state parameters include current dispersion, power factor, and voltage amplitude, and the dynamic state parameters include voltage frequency and phase angle; S2. Nondimensionalize the current dispersion, power factor, and voltage amplitude, and perform correlation analysis to generate the static state coefficient of the substation protection and measurement and control equipment. Nondimensionalize the voltage frequency and phase angle, and perform correlation analysis to generate the dynamic state coefficient of the substation protection and measurement and control equipment; S3. Nondimensionalize the static state coefficient and dynamic state coefficient of the substation protection and measurement and control equipment, and perform correlation analysis to generate a comprehensive index for evaluating the AC sampling state of the substation protection and measurement and control. Compare the comprehensive index with a preset comprehensive index threshold to judge the level of the AC sampling state of the substation protection and measurement and control; S4. Execute different strategies according to different levels; The current dispersion, power factor and voltage amplitude are dimensionless processed and correlation analysis is performed to generate the static state coefficient XS of the substation protection and control equipment. JT , the calculation formula is as follows: Among them, the parameter meanings are: LD is the current dispersion, GS is the power factor, DZ is the voltage amplitude, α is the factor coefficient of the current dispersion, β is the factor coefficient of the power factor, γ is the factor coefficient of the voltage amplitude, 0.2 ≤ α ≤ 0.4, 0.2 ≤ β ≤ 0.4, 0.2 ≤ γ ≤ 0.4, and C1 is the constant correction coefficient; The voltage frequency and phase angle are dimensionless processed and correlation analysis is performed to generate the dynamic state coefficient XS of the substation protection and control equipment. DT , the calculation formula is as follows: Among them, the parameters mean: DP is the voltage frequency, XJ is the phase angle, μ is the factor coefficient of the voltage frequency, is the factor coefficient of the phase angle, 0.2≤μ≤0.4, C2 is the constant correction coefficient; The static state coefficient XS of the substation protection and control equipment JT and the dynamic state coefficient XS of the substation protection and control equipment DT Dimensionless processing and correlation analysis are performed to generate a comprehensive index ZS for evaluating the AC sampling status of substation protection and control. The calculation formula is as follows: ZS=δXS JT +σXS DT +C3 Among them, the parameter meanings are: δ is the factor coefficient of the static state coefficient, σ is the factor coefficient of the dynamic state coefficient, 0.2 ≤ δ ≤ 0.4, 0.2 ≤ σ ≤ 0.4, and C3 is the constant correction coefficient.

2. A method for evaluating the status of AC sampling of a substation protection and control according to claim 1, characterized in that: The process of comparing the comprehensive index ZS with a preset comprehensive coefficient threshold YZ to judge the level of the AC sampling state of the substation protection and measurement and control is as follows: When ZS > YZ, the AC sampling state of the substation protection and measurement and control is at a high level; When 0.5YZ < ZS ≤ YZ, the AC sampling state of the substation protection and measurement and control is at a medium level; When 0 < ZS ≤ 0.5YZ, the AC sampling state of the substation protection and measurement and control is at a low level.

3. A method for evaluating the status of AC sampling of a substation protection and control according to claim 2, characterized in that: The process of executing different strategies according to the different levels is as follows: When the AC sampling state of the substation protection and measurement and control is at a high level, no operation is required and the system runs normally; When the AC sampling state of the substation protection and measurement and control is at a medium level, a warning notice is issued to remind the operation and maintenance personnel to pay attention, and further inspection and maintenance may be required; When the AC sampling state of the substation protection and measurement and control is at a low level, automatic or manual protection measures are triggered, which may include cutting off the faulty equipment or switching to standby equipment.

4. A substation protection measurement and control AC sampling state assessment system, the system is used to execute a substation protection measurement and control AC sampling state assessment method according to any one of claims 1 to 3, characterized in that: Include: A data acquisition module for collecting the static state parameters and dynamic state parameters of the substation protection and measurement and control equipment. The static state parameters include current dispersion, power factor, and voltage amplitude, and the dynamic state parameters include voltage frequency and phase angle; A data processing module for nondimensionalizing the current dispersion, power factor, and voltage amplitude, and performing correlation analysis to generate the static state coefficient of the substation protection and measurement and control equipment. Nondimensionalize the voltage frequency and phase angle, and perform correlation analysis to generate the dynamic state coefficient of the substation protection and measurement and control equipment; A data analysis module, used to perform dimensionless processing on the static state coefficient of the substation protection and measurement equipment and the dynamic state coefficient of the substation protection and measurement equipment, and perform correlation analysis, to generate a comprehensive index for evaluating the substation protection and measurement AC sampling state, and to compare the comprehensive index with a preset comprehensive index threshold to determine the level of the substation protection and measurement AC sampling state; The execution module executes different strategies according to different levels.

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