Evaluation Method and Monitoring Device for Verifying the Differentiated Configuration Effect of Distribution Network Lightning Arresters

Abstract

The present invention relates to an evaluation method and a monitoring device for verifying the differential configuration effect of distribution network lightning arresters. The present invention collects the installation quantity and configuration position of lightning arresters in the distribution network and installs lightning arrester monitoring devices; determines evaluation indexes for judging the effectiveness of the differential lightning protection scheme; the evaluation indexes are the annual average discharge operation times, the mean value of annual lightning current amplitudes, and the ratios of the total leakage current and resistive leakage current under normal operation; establishes an evaluation model for the effectiveness of distribution network lightning arresters according to the evaluation indexes and defines a utilization rate index; according to the evaluation model for the effectiveness of distribution network lightning arresters, divides the effectiveness levels of lightning arresters according to the range of the utilization rate index, and formulates subsequent operation and maintenance and transformation schemes for the distribution network or the same type of distribution network. The present invention can establish an evaluation model for the effectiveness of distribution network lightning arresters and define a utilization rate index, so as to evaluate the effectiveness of lightning arresters.

Description

Technical Field

[0001] The present invention belongs to the technical field of lightning protection for distribution networks, and in particular to an evaluation method and a monitoring device for verifying the effects of differentiated configurations of lightning arresters in distribution networks. Background Art

[0002] Lightning is the main cause of 10 kV distribution line failures. In order to reduce the impact of lightning on the distribution network, lightning arresters are often installed on the lines. However, if lightning arresters are installed on the entire distribution network, the investment cost will be large, which is not conducive to economic efficiency. In order to improve the safety, reliability and economy of the power supply system, differentiated lightning protection configurations are often performed on towers based on the actual lightning disaster situation of the distribution network. At present, many methods have been proposed for differentiated lightning protection configuration strategies for transmission and distribution networks. The configuration is usually based on the evaluation of the lightning damage risk level of the towers based on topographic information, lightning activity density distribution and historical tripping data, so as to achieve differentiated lightning protection. However, most of the current studies have only developed differentiated lightning protection strategies for lightning arresters for distribution networks, and have not verified the effectiveness of differentiated lightning protection schemes for lightning arresters. Summary of the invention

[0003] In order to solve the above problems, the present invention proposes an evaluation method and monitoring device for verifying the effect of differentiated configuration of lightning arresters in distribution networks. The present invention installs a monitoring device on the lightning arresters after differentiated lightning protection configuration, records the number of discharge actions, the average lightning current amplitude, the total leakage current and the resistive leakage current of each lightning arrester within a period of time, establishes a lightning arrester effectiveness evaluation model for distribution networks and defines a utilization index, thereby evaluating the effectiveness of the lightning arrester.

[0004] The technical solution adopted by the present invention is:

[0005] An evaluation method for verifying the effect of differentiated configuration of lightning arresters in a distribution network comprises the following steps:

[0006] Step 1: According to the evaluation requirements of the differentiated configuration effects of lightning arresters in distribution networks, a lightning arrester monitoring device for collecting lightning parameters and electrical parameters of lightning arresters is designed;

[0007] Step 2: Select the distribution network that needs to be evaluated for the effect of differentiated lightning protection configuration, collect the number and configuration location of lightning arresters installed in the distribution network, and install a lightning arrester monitoring device;

[0008] Step 3: Count the lightning parameters and electrical parameters of each lightning arrester in the distribution network that has experienced thunderstorm weather for at least one year; the parameters include the number of discharge actions, the amplitude of lightning current, and the proportion of total leakage current and resistive leakage current under normal operation;

[0009] Step 4: Determine the evaluation indicators for judging the effectiveness of the differential lightning protection scheme; the evaluation indicators are the annual average number of discharge operations, the average value of annual lightning current amplitude, and the proportion of total leakage current and resistive leakage current under normal operation;

[0010] Step 5: Establish an evaluation model for the effectiveness of distribution network lightning arresters based on the evaluation indicators and define the utilization rate index;

[0011] Step 6: According to the evaluation model for the effectiveness of distribution network lightning arresters, divide the effectiveness levels of lightning arresters based on the range of the utilization rate index, and formulate subsequent operation and maintenance and transformation plans for the distribution network or the same type of distribution network.

[0012] Further preferably, in step 2, it is necessary to determine the lightning damage risk evaluation indicators and the grading criteria for lightning damage risk levels adopted when formulating the differential lightning protection scheme for this distribution network.

[0013] Further preferably, in step 3, monitor the number of discharge operations, lightning current amplitude, and the proportion of total leakage current and resistive leakage current under normal operation of the lightning arrester through the lightning arrester counter. Determine that the time period to be counted is from Y1 to Y after the differential lightning protection layout of the distribution network n years. The number of discharge operations and the average value of lightning current amplitude are taken as the annual average values, and the proportion of total leakage current and resistive leakage current is taken as the current measured value.

[0014] Step 5 includes the following sub-steps:

[0015] Step 5.1: Collect the annual average number of discharge operations m a of the lightning arrester to be evaluated, the average value of annual lightning current amplitude n a , and the total leakage current I a under normal operation and the proportion of resistive leakage current d a .

[0016] Step 5.2: First, judge the aging status of the lightning arrester through the proportion of total leakage current and resistive leakage current;

[0017] Step 5.3: Use the annual average number of discharge operations, the average value of lightning current amplitude, the total leakage current, and the proportion of resistive leakage current of the lightning arrester to judge the effectiveness of the distribution network lightning arrester;

[0018] Step 5.4: For the lightning arresters evaluated as ineffective by step 5.3, define the utilization rate index S to quantify its effectiveness degree. The utilization rate index S is composed of the utilization rate index S1 of the annual average number of discharge operations of the lightning arrester, the utilization rate index S2 of the average value of lightning current amplitude, the utilization rate index S3 of the total leakage current value, and the utilization rate index S4 of the proportion of resistive leakage current.

[0019] Further preferably, the evaluation criteria in step 5.2 are as shown in formulas (1) and (2):

[0020] (1);

[0021] (2);

[0022] When and only when the total leakage current is less than or equal to the total leakage current threshold I and the proportion of resistive leakage current is less than the resistive leakage current proportion threshold d, the arrester is considered to have good performance.

[0023] Further preferably, in step 5.3, for the poles and towers in different lightning damage risk levels, the evaluation criteria are as shown in formulas (3) and (4). When the annual average discharge operation times, the mean value of lightning current amplitude, the total leakage current and the proportion of resistive leakage current of the arrester satisfy formula (3) or formula (4), the distribution network arrester is considered to be effective:

[0024] , , , (3);

[0025] Or:

[0026] , , , (4);

[0027] In formulas (3) and (4), m x and m y are respectively the lower limit value and the upper limit value of the annual average discharge operation times interval of the arrester corresponding to the lightning damage risk level of the pole and tower; n x and n y are respectively the lower limit value and the upper limit value of the mean value interval of the lightning current amplitude corresponding to the lightning damage risk level of the pole and tower.

[0028] Further preferably, in step 5.4, the analytic hierarchy process is used to determine the weight ratio of each utilization rate index. Before using the analytic hierarchy process, it is necessary to sort the importance of the four indicators; according to the determined importance ranking, define the scale difference between adjacent important indicators as p, and construct an n*n order judgment matrix; the elements in the judgment matrix satisfy: a ij >0; a ij =1 / a ji ; a ii =1; a ij is the importance ratio of index i to index j, i, j ∈ {1, 2, 3,..., n}, a ji is the importance ratio of index j to index i, a iiis the importance ratio of index i itself, and the value is determined according to the scaling method;

[0029] According to the constructed judgment matrix, the square root method is used to solve the weights of each index; according to the consistency index CI and the random consistency index RI value, the consistency ratio CR value is solved to judge whether the consistency of the judgment matrix passes; thereby determining the weights of the annual average discharge operation times utilization index S1, the mean value utilization index S2 of lightning current amplitude, the full leakage current value utilization index S3 and the resistive leakage current ratio utilization index S4 of the arrester.

[0030] Further preferably, S1, S2, S3 and S4 are calculated according to different situations.

[0031] The present invention also provides a monitoring device for verifying the differential configuration effect of distribution network arresters, including an arrester counter and a handheld terminal. The handheld terminal wirelessly and remotely collects the lightning parameters and electrical parameters recorded by the arrester counter. The handheld terminal is built-in with an evaluation system for the differential configuration effect of distribution network arresters, and the evaluation system executes each step of an evaluation method for verifying the differential configuration effect of distribution network arresters.

[0032] Further preferably, the arrester monitoring device uses a LORA wireless remote transmission arrester counter, and the handheld terminal uses a handheld meter plastic shell. Through button settings, the operation times, product address, and clock information of the corresponding arrester counter can be queried. At the same time, according to requirements, the operation times, product address, and clock information of the arrester counter can be set.

[0033] The present invention designs an arrester monitoring device for collecting lightning parameters and electrical parameters of arresters; determines evaluation indexes for judging the effectiveness of differential lightning protection schemes; establishes an effectiveness evaluation model for distribution network arresters according to the evaluation indexes and defines utilization indexes; according to the effectiveness evaluation model of distribution network arresters, divides the effectiveness levels of arresters according to the range of utilization indexes, and formulates subsequent operation and maintenance and transformation schemes for distribution networks or the same type of distribution networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described in detail below with reference to the drawings and specific implementation examples:

[0035] Figure 1 is the external shape diagram of the wireless remote transmission arrester counter;

[0036] Figure 2 is the front view of the handheld terminal product.

[0037] Figure 3 is the installation schematic diagram of the arrester. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention will be further clarified in detail below with reference to the embodiments.

[0039] Example 1

[0040] An evaluation method for verifying the differential configuration effect of distribution network lightning arresters, comprising the following steps:

[0041] Step 1: Design a lightning arrester monitoring device for collecting lightning parameters and electrical parameters of lightning arresters according to the evaluation requirements for the differential configuration effect of distribution network lightning arresters;

[0042] Step 2: Select a distribution network that needs to evaluate the differential lightning protection configuration effect, collect the installation quantity and configuration locations of lightning arresters in the distribution network, and install the lightning arrester monitoring device;

[0043] Step 3: Statistically analyze the lightning parameters and electrical parameters of each lightning arrester in the distribution network that has experienced at least one year of thunderstorm weather; the parameters include the number of discharge operation times, the lightning current amplitude, and the proportion of the total leakage current and resistive leakage current under normal operation;

[0044] Step 4: Determine the evaluation indexes for judging the effectiveness of the differential lightning protection scheme; the evaluation indexes are the annual average number of discharge operation times, the average value of the annual lightning current amplitude, and the proportion of the total leakage current and resistive leakage current under normal operation;

[0045] Step 5: Establish an effectiveness evaluation model for distribution network lightning arresters according to the evaluation indexes and define the utilization rate index;

[0046] Step 6: According to the effectiveness evaluation model of distribution network lightning arresters, divide the effectiveness levels of lightning arresters according to the range of the utilization rate index, and formulate subsequent operation and maintenance and transformation schemes for the distribution network or the same type of distribution network.

[0047] During operation, the lightning arrester gradually deteriorates, its insulation performance decreases, which will lead to an increase in leakage current. A severely deteriorated lightning arrester may experience an internal breakdown fault, not only losing its function of protecting line equipment but also causing line faults. In production, manual line inspection or lightning arrester monitoring devices are generally used to monitor the operating status of lightning arresters. Existing lightning arrester monitoring devices have the following problems: (1) It is difficult to provide a low-voltage power supply in the operating line. Generally, solar panels and wind power are used to provide power for the device. The power supply method is greatly affected by the weather and cannot ensure the stability and continuity of power supply; (2) Existing lightning arrester monitoring devices can only monitor the total leakage current of the lightning arrester and cannot distinguish between capacitive leakage current and resistive leakage current, making it difficult to clearly identify the deterioration of the lightning arrester; (3) Existing lightning arrester monitoring devices do not have the function of remote data transmission and it is difficult to grasp the operating status of lightning arresters in real time. In response to the existing problems, there is an urgent need for a lightning arrester monitoring device that can operate outdoors all-weather, can provide a stable power supply, accurately distinguish between capacitive leakage current and positive leakage current, accurately count the number of lightning strikes, and upload various data to the background main station in real time. The background main station should draw a leakage current curve based on the uploaded data, comprehensively judge the deterioration degree of the lightning arrester, and issue early warnings and positioning.

[0048] The lightning arrester monitoring device should have accuracy, sensitivity, reliability, economy, and convenience. Accuracy requires that the lightning arrester monitoring device can accurately record the number of discharges of the lightning arrester, and can make an effective response even to weak signals. At the same time, it can accurately measure the total leakage current, resistive leakage current, and lightning current amplitude of the lightning arrester. Sensitivity requires that the response time of the lightning arrester monitoring device should be as short as possible, which is beneficial to maintaining the safety and reliability of the distribution network line. Reliability requires that the lightning arrester monitoring device should have good anti-interference ability and can work stably even in bad weather. At the same time, it can shield external interference signals to a certain extent. Economy requires that the lightning arrester monitoring device can be flexibly installed according to different structures to reduce the installation cost. At the same time, it can have a stable power supply to ensure the normal operation of the lightning arrester monitoring device. Common power-taking methods include direct power-taking from the line or solar energy supply. Convenience requires that the operation method of the lightning arrester monitoring device should be simple and clear, have good data storage and transmission functions, and can long-term store discharge event records and can be wirelessly transmitted to a handheld terminal. The handheld terminal should have good communication stability, can query the action times, address, clock information, etc. of the corresponding wireless remote transmission lightning arrester monitoring device, and can shield external interference signals to a certain extent. In addition, the handheld terminal needs to be repeatedly tested in a specific environment and continuously improved to ensure the stability of communication performance.

[0049] The lightning arrester monitoring device in this embodiment uses the JSY series LORA wireless remote transmission lightning arrester counter, such as Figure 1As shown, this lightning arrester counter can operate outdoors all-weather, has a stable power supply, can accurately distinguish capacitive leakage current and resistive leakage current, count the number of lightning strikes, and upload various data to the background master station in real time. The high-voltage energy-taking and measuring integrated sensor is based on electronic sensor technology, and obtains the low-voltage working power supply through bus voltage division for the operation of the lightning arrester monitoring device. At the same time, it provides a voltage measurement signal, and distinguishes capacitive current and resistive current through the voltage measurement signal. The resistive leakage current is used as the main criterion for the deterioration of the lightning arrester. Different from the traditional scheme of collecting leakage current by means of resistor voltage division, this lightning arrester monitoring device is based on high-precision active current transformer technology, which greatly improves the range and accuracy of collecting leakage current, and provides a more reliable and stable criterion for the deterioration of the lightning arrester. Through a period of operation and data accumulation, the background master station can formulate a more scientific early warning mechanism. Through visual content display, the installation location, operation status and deterioration degree of the line lightning arrester are displayed in real time.

[0050] This lightning arrester discharge counter is connected in series with the lightning arrester in the power grid to record the number of lightning arrester discharge actions and the leakage current. The application scenario of the lightning arrester is 35kV outdoor line; it adopts high-voltage energy-taking, output power: >3W; the full leakage current measurement range is: 10uA~10mA; the resistive current measurement range is 10uA~10mA; the current measurement accuracy is 1%. This lightning arrester counter uses a stainless steel shell with good sealing performance. The sampling part uses transformer isolation to reduce the induction of large current to small current and send it to the signal processing unit. Inside the signal processing unit, high-speed optocouplers are used for isolation, and a single-chip microcomputer is used for data processing. The 433MHz module is selected to transmit data to the handheld terminal. The product function part uses solar power generation. The solar energy is sealed inside the stainless steel shell to avoid damage to the solar panel caused by the outside. This lightning arrester counter is based on high-precision active current transformer technology, which greatly improves the range and accuracy of collecting leakage current, and provides more reliable and stable judgment data for the deterioration of the lightning arrester.

[0051] The action times, full leakage current and resistive leakage current of the lightning arrester can be queried through the handheld terminal. Such as Figure 2As shown, the handheld terminal uses a plastic shell of a handheld instrument. Through the button settings, the number of actions, product address, and clock information of the corresponding arrester counter can be queried. At the same time, the number of actions, product address, and clock information of the arrester counter can be set according to needs. The handheld terminal keyboard has 10 numbers from 0 to 9, which are used to set the product address, number of actions, and clock calibration. The value setting adopts the method of left shift carry. The function keys of the handheld terminal are used to switch functions. When the "Function" button is pressed, the LCD screen switches between "Query Action Times", "Query Address", "Query Clock Information", "Set Action Times", "Set Product Address", and "Set Clock Information". The confirmation button is the last LCD screen prompt. After the function is completed, click Confirm to enter the next function. For example, in the "Query Action Times" interface, the lower end of the handheld terminal prompts "Please enter the product address". At this time, you can press the 10 buttons 0 to 9 to set the number of actions. After the number of actions is set, click Confirm, which means that the value input is completed. At this time, the LCD screen displays "Please click to confirm and send". The communication distance of the handheld terminal can reach 2km in the open area in theory. It is recommended to set the communication within 1km.

[0052] The arrester monitoring device overcomes the problem that traditional arrester monitoring devices are difficult to accurately distinguish between capacitive current and resistive current, and cannot provide reliable working power supply on site. It can effectively monitor the operating status of 35kV outdoor line arresters, accurately locate the fault point after the arrester shows obvious signs of deterioration, and remind the operation and maintenance personnel to replace it in time. The application of the arrester monitoring device can effectively reduce equipment damage, unexplained tripping, and difficulty in fault location caused by ground current faults, and improve the safety and reliability of line operation.

[0053] In step 2, it is necessary to determine the lightning risk assessment indicators and lightning risk level classification standards used by the distribution network when formulating differentiated lightning protection plans, and record specific data, as shown in Table 1:

[0054] Table 1. Distribution network lightning risk classification standards

[0055]

[0056] Determine the differentiated lightning protection configuration strategies adopted by the distribution network in different corridor environments. Install the lightning arrester monitoring device designed in step 1 for all lightning arresters. The lightning arrester monitoring device should be installed in a location that is easy to observe and maintain, usually in a place that is easily accessible and has a good line of sight. At the same time, avoid mechanical damage and environmental interference from the outside. Ensure the connection polarity is correct during installation.

[0057] The lightning hazard risk assessment index adopted by the distribution network evaluated in this embodiment is the ground flash density. The distribution of the ground flash density in the area where a certain distribution network is located from 2019 to 2022. The differential lightning protection scheme adopted classifies the lightning hazard risk level into A - E. Among them, the A - level corresponds to the lowest lightning hazard risk, and the E - level is the highest. The specific classification criteria are shown in Table 2:

[0058] Table 2. Classification Criteria for Ground Flash Density

[0059]

[0060] The lightning protection devices selected for this distribution network to adopt differential lightning protection are YH5WX17 / 50 type conventional zinc oxide arresters, YH5WS - 17 / 45TLF type new type of arrester that can be replaced while energized, lightning protection post insulators, puncture - type arc - proof fittings, as well as lightning conductors and coupling ground wires. The specific situation of the differential lightning protection configuration schemes adopted in different corridor environments of this distribution network is shown in Table 3. Figure 3 As shown in the lightning arrester installation schematic diagram, the lightning arrester is installed vertically with the terminal downwards, and the grounding device is reliably connected. For the lightning arrester counter designed in Step 1 of the lightning arrester installation, the lightning arrester counter should be installed in a position convenient for observation and maintenance. Usually, a place that is easy to access and has a good line of sight is selected. At the same time, it should be protected from external mechanical damage and environmental interference. During installation, it is necessary to ensure that the connection polarity is correct.

[0061] Table 3. Lightning Protection Configuration Strategies for Different Corridor Environments

[0062]

[0063] In Step 3, the lightning arrester counter is used to monitor the discharge operation times, lightning current amplitude of the lightning arrester, as well as the total leakage current and the proportion of resistive leakage current under normal operation. The time period to be counted is from Y1 to Y n after the distribution network has undergone differential lightning protection layout. The annual average values are taken for the discharge operation times and lightning current amplitude, and the current measured values are taken for the total leakage current and the proportion of resistive leakage current. The recorded data is shown in Table 4:

[0064] Table 4. Relevant Parameters of Each Lightning Arrester in the Distribution Network

[0065]

[0066] In Table 4, m n is the discharge operation times of lightning arrester n, n n is the lightning current amplitude of lightning arrester n, I n is the total leakage current of lightning arrester n, d n is the proportion of resistive leakage current of lightning arrester n.

[0067] Under normal operation, the total leakage current and the proportion of resistive leakage current of the lightning arrester are very small. If they are very large, it indicates that there are problems such as aging and moisture absorption of the internal components of the lightning arrester. At this time, if the abnormal lightning arrester cannot be quickly taken out of operation, it may cause the power system to collapse in a short time; the annual average number of discharge operations and the average value of annual lightning current amplitude of the lightning arrester can further reflect the lightning damage risk of the towers at different locations. For the towers with a high lightning damage risk level in the differential lightning protection, the average number of discharge operations and the average value of annual lightning current amplitude during their subsequent operation should also be high. By monitoring the annual average number of discharge operations and the average value of annual lightning current amplitude, a better maintenance plan and replacement strategy for the lightning arrester can be formulated to ensure the stable and safe operation of the power system; therefore, in step 4 of this embodiment, the evaluation indexes for judging the effectiveness of differential lightning protection are determined as the annual average number of discharge operations, the average value of annual lightning current amplitude, and the proportion of total leakage current and resistive leakage current under normal operation.

[0068] In step 5 of this embodiment, the effectiveness evaluation model of the distribution network lightning arrester is established according to the evaluation indexes and the utilization rate index is defined, and the specific steps are as follows;

[0069] Step 5.1: According to the data statistically analyzed in step 3, collect the annual average number of discharge operations m of the lightning arrester to be evaluated a , the average value of annual lightning current amplitude n a , and the total leakage current I under normal operation a and the proportion of resistive leakage current d a .

[0070] Step 5.2: First, judge the aging condition of the lightning arrester through the proportion of total leakage current and resistive leakage current. The specific evaluation criteria are shown in Table 5, and the judgment criteria are shown in formulas (1) and (2):

[0071] (1);

[0072] (2);

[0073] It can be obtained from formulas (1) and (2) that when and only when the total leakage current is less than or equal to the total leakage current threshold I and the proportion of resistive leakage current is less than the resistive leakage current proportion threshold d, the performance of the lightning arrester is considered good. In this embodiment, the total leakage current threshold I is taken as 50 μA, and the resistive leakage current proportion threshold d is taken as 15%. For the lightning arrester with serious aging, it should be taken out of operation and replaced in time.

[0074] Step 5.3: Use the annual average number of lightning arrester discharge operations, the average value of lightning current amplitude, the total leakage current, and the proportion of resistive leakage current to judge the effectiveness of the distribution network lightning arrester. For poles and towers in different lightning damage risk levels, different evaluation criteria should be adopted. The evaluation criteria for the effectiveness of the distribution network lightning arrester are shown in Table 5, and the judgment criteria are shown in Equations (3) and (4). When the annual average number of lightning arrester discharge operations, the average value of lightning current amplitude, the total leakage current, and the proportion of resistive leakage current meet Equation (3) or Equation (4), it is considered that the distribution network lightning arrester is effective:

[0075] , , , (3);

[0076] Or:

[0077] , , , (4);

[0078] In Equations (3) and (4), m x and m y are respectively the lower limit value and the upper limit value of the annual average number of lightning arrester discharge operations interval corresponding to the lightning damage risk level of the pole and tower; n x and n y are respectively the lower limit value and the upper limit value of the average value of lightning current amplitude interval corresponding to the lightning damage risk level of the pole and tower. From Equations (3) and (4), it can be obtained that after the differential lightning protection configuration of the distribution network, if the proportion of the total leakage current and the resistive leakage current is within the specified interval, and one of the annual average number of lightning arrester discharge operations and the average value of lightning current amplitude is within the interval corresponding to its lightning damage risk level in Table 5, and the other value is less than the maximum value of the corresponding interval of the distribution network lightning arrester effectiveness evaluation standard, it is considered that the distribution network lightning arrester is effective and the utilization effect of the lightning arrester is good. In Table 5, m1~m 15 are the lower limit value or the upper limit value of the annual average number of lightning arrester discharge operations interval corresponding to different lightning damage risk levels of poles and towers, and n1~n 15 are the lower limit value and the upper limit value of the average value of lightning current amplitude interval corresponding to the lightning damage risk level of the pole and tower. Table 6 is the specific evaluation standard of this embodiment.

[0079] Table 5. Evaluation Criteria for the Effectiveness of Distribution Network Lightning Arresters

[0080]

[0081] Table 6. Examples of Evaluation Criteria for the Effectiveness of Distribution Network Lightning Arresters

[0082]

[0083] Step 5.4: For the lightning arresters evaluated as ineffective in Step 5.3, define a utilization rate index S to quantify their effectiveness. The utilization rate index S consists of the annual average discharge operation times utilization rate index S1 of the lightning arrester, the mean lightning current amplitude utilization rate index S2, the full leakage current value utilization rate index S3, and the resistive leakage current proportion utilization rate index S4. The specific calculation methods are as follows:

[0084] First, use the analytic hierarchy process to determine the weight ratios of each utilization rate index. Before using the analytic hierarchy process, it is necessary to rank the importance of the four indicators. According to the determined importance ranking, define the scale difference between adjacent important indicators as p, and construct an n*n order judgment matrix:

[0085]

[0086] The elements in the judgment matrix satisfy: (1) a ij >0; (2) a ij =1 / a ji ; (3) a ii =1. a ij is the importance ratio of index i to index j, i, j ∈ {1, 2, 3,..., n}, a ji is the importance ratio of index j to index i, a ii is the importance ratio of index i itself, and the value is determined according to the scale method. The meaning of the scale method is shown in Table 7.

[0087] Table 7. Meaning of "1-9 scale method"

[0088]

[0089] According to the constructed judgment matrix, use the square root method to solve the weights of each indicator. The calculation method is as follows:

[0090] First, calculate the 1 / n power of the product of each row of the judgment matrix to obtain an n-dimensional weight vector. The calculation formula is shown in Equation (5):

[0091] (5);

[0092] Among them, is the weight vector of the indicator;

[0093] Normalize the above vector to obtain the normalized weight vector, that is, obtain the weights corresponding to each indicator. The calculation formula is shown in Equation (6):

[0094] (6);

[0095] Among them, is the normalized weight vector of the indicator;

[0096] Subsequently, the consistency ratio CR value is solved according to the consistency index CI and the random consistency index RI value to determine whether the consistency of the judgment matrix passes.

[0097] The calculation method of CI is as follows:

[0098] First, multiply the column vectors of the judgment matrix by the elements of the corresponding columns of the standardized weight vector to obtain a new consistency judgment matrix as follows:

[0099]

[0100] b ij is the element in the i-th row and j-th column of the consistency judgment matrix, where i, j ∈ {1, 2, 3, …, n}. Add the elements of each row of the consistency judgment matrix to obtain a new vector , are the 1st, 2nd, …, n-th elements of the new vector respectively. Subsequently, multiply the elements of each column of the standardized weight vector by n to obtain a new vector , are the 1st, 2nd, …, n-th elements of the new vector respectively. The maximum eigenvalue can be obtained by Equation (7):

[0101] (7);

[0102] Finally, the consistency index CI can be obtained according to Equation (8):

[0103] (8);

[0104] In Equation (8), n is the matrix order.

[0105] The value of RI can be obtained by looking up the table, as shown in Table 8.

[0106] Table 8. RI value table

[0107]

[0108] According to the values of CI and RI, CR can be obtained by Equation (9):

[0109] (9);

[0110] When CR = 0, it is considered that this matrix has perfect consistency; when CR < 0.1, it is considered that the consistency of the matrix is acceptable; when CR ≥ 0.1, it is considered that the consistency of the matrix is unacceptable, indicating that there is a logical error in the judgment matrix at this time, and the elements of the judgment matrix need to be re-determined.

[0111] In this embodiment, four indicators are defined and sorted in descending order of importance as the average lightning current amplitude, the number of lightning arrester discharge operations, the proportion of resistive leakage current, and the total leakage current. The scale difference between adjacent important indicators is defined as 1, and a 4×4 judgment matrix is constructed:

[0112]

[0113] According to the constructed judgment matrix, the weights of each indicator are solved by the square root method according to Equation (5), and the weight vector =(2.21, 1.32, 0.76, 0.45) is obtained. Then, according to Equation (6), the above vector is normalized to obtain the normalized weight vector =(0.47, 0.28, 0.16, 0.09).

[0114] Multiply the column vectors of the obtained judgment matrix by the elements of the corresponding columns of the normalized weight vector to obtain the normalized judgment matrix, as shown below:

[0115]

[0116] Add the elements of each row of the normalized judgment matrix to obtain the vector =(1.81, 1.105, 0.637, 0.3805). Subsequently, multiply the elements of each column of the normalized weight vector by 4 to obtain a vector =(1.88, 1.12, 0.64, 0.36). According to the vectors and the maximum eigenvalue λ max = 4.03 is obtained by Equation (7). According to λ max and the matrix order, CI = 0.011 is obtained by Equation (8). By looking up the table, RI = 0.90 is obtained. CR = 0.012 is obtained by Equation (9), and CR < 0.1, so the consistency of the judgment matrix is acceptable.

[0117] In summary, the weights of the utilization rate index S1 of the annual average number of lightning arrester discharge operations, the utilization rate index S2 of the average lightning current amplitude, the utilization rate index S3 of the total leakage current value, and the utilization rate index S4 of the proportion of resistive leakage current are determined to be 0.28, 0.47, 0.09, and 0.16 respectively. That is, the calculation formula of the utilization rate index S is:

[0118] (10);

[0119] Subsequently, S1, S2, S3, and S4 are calculated according to different situations:

[0120] Case 1:

[0121] If the annual average number of discharge operations of the lightning arrester and the mean value of the lightning current amplitude are less than the minimum value in the corresponding interval of the effectiveness evaluation standard for distribution network lightning arresters (Table 5), and the proportion of the total leakage current and the resistive leakage current is within the interval, that is, m a <m x 、n a <n x 、I a <I and d a <d, it means that the utilization rate of the lightning arrester is low. In subsequent operation and maintenance, the number of operation and maintenance can be reduced, and the installation of the lightning arrester can be decreased. At this time, the calculation methods of S1, S2, S3, and S4 are as follows:

[0122] For S1 and S2, the calculation formula of their utilization rate index is as follows:

[0123] (11);

[0124] (12);

[0125] For S3 and S4, because they are within the corresponding interval range of the effectiveness evaluation standard for distribution network lightning arresters, the values of S3 and S4 are taken as 0.

[0126] At this time, the value range of S is [0, 1), and the closer its value is to 1, the smaller the utilization rate of the lightning arrester represents, that is, the greater the redundancy of the lightning arrester.

[0127] Case 2:

[0128] If there are indicators among the annual average number of discharge operations of the lightning arrester, the mean value of the lightning current amplitude, the total leakage current, and the proportion of the resistive leakage current that are greater than the maximum value in the corresponding interval of the effectiveness evaluation standard for distribution network lightning arresters (Table 5), it means that the lightning arrester is over-utilized, which is not conducive to the safety and stability of the distribution network. In subsequent operation and maintenance, the number of operation and maintenance needs to be increased, and the installation quantity of the lightning arrester needs to be increased. At this time, the calculation methods of S1, S2, S3, and S4 are as follows:

[0129] For the indicators greater than the maximum value in the corresponding interval of the effectiveness evaluation standard for distribution network lightning arresters, the calculation formula of their utilization rate index is as follows:

[0130] (13);

[0131] (14);

[0132] (15);

[0133] (16);

[0134] For an index less than the maximum value of the corresponding interval of the effectiveness evaluation standard of the distribution network lightning arrester, the utilization rate index is taken as 0.

[0135] At this time, the value range of S is (0, ∞), and the larger its value, the more serious the overloading utilization of the lightning arrester, that is, the less effective the lightning protection effect of the lightning arrester.

[0136] Step 6: According to the effectiveness evaluation model of the distribution network lightning arrester, divide the effectiveness level of the lightning arrester based on the range of the utilization rate index, and formulate the operation and maintenance and transformation plans for the subsequent or similar lines of this line. The specific steps are as follows:

[0137] Case 1:

[0138] If the annual average discharge operation times and the average value of lightning current amplitude of the lightning arrester are less than the minimum value of the corresponding interval in the effectiveness evaluation standard of the distribution network lightning arrester (Table 5), and the proportion of the total leakage current and the resistive leakage current is within the interval, that is, the utilization rate of the lightning arrester is low. At this time, the value range of the utilization rate index S is [0, 1), and the closer its value is to 1, the lower its utilization rate. The effectiveness level division of the lightning arrester and the subsequent operation and maintenance and transformation plans of the line at this time are shown in Table 6.

[0139] Table 6. Effectiveness level division of the lightning arrester in Case 1 and subsequent operation and maintenance and improvement plans of the line

[0140]

[0141] Among them, b1, b2, b3,..., b n-1 are the 1st, 2nd, 3rd,..., nth utilization rate index thresholds in Case 1 respectively.

[0142] Case 2:

[0143] If there is an index greater than the maximum value of the corresponding interval in the effectiveness evaluation standard of the distribution network lightning arrester (Table 5) among the annual average discharge operation times, the average value of lightning current amplitude, the total leakage current and the proportion of the resistive leakage current of the lightning arrester, that is, the lightning arrester is overloaded. At this time, the value range of the utilization rate index S is (0, ∞), and the larger its value, the greater the overloading degree of the lightning arrester. The effectiveness level division of the lightning arrester and the subsequent operation and maintenance and transformation plans of the line at this time are shown in Table 9.

[0144] Table 9. Effectiveness level division of the lightning arrester in Case 2 and subsequent operation and maintenance and improvement plans of the line

[0145]

[0146] Among them, c1, c2, c3,..., c n-1 are the 1st, 2nd, 3rd,..., n - 1th utilization rate index thresholds in Case 2 respectively.

[0147] The subsequent operation and maintenance and improvement plans for the lines formulated in Case 1 and Case 2 of this example are shown in Table 10 and Table 11 respectively:

[0148] Table 10. Example of the subsequent operation and maintenance and improvement plan for the Case 1 line

[0149]

[0150] Table 11. Example of the subsequent operation and maintenance and improvement plan for the Case 2 line

[0151]

[0152] Another embodiment of the present invention further provides a monitoring device for verifying the differential configuration effect of distribution network lightning arresters, including a lightning arrester counter and a handheld terminal. The handheld terminal wirelessly and remotely collects the lightning parameters and electrical parameters recorded by the lightning arrester counter. The handheld terminal is built-in with an evaluation system for the differential configuration effect of distribution network lightning arresters, and the evaluation system executes each step of an evaluation method for verifying the differential configuration effect of distribution network lightning arresters.

[0153] Those skilled in the art can easily understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution networks, characterized in that: The following steps are involved: Step 1: According to the evaluation requirements of the differentiated configuration effects of lightning arresters in distribution networks, a lightning arrester monitoring device for collecting lightning parameters and electrical parameters of lightning arresters is designed; Step 2: Select the distribution network that needs to be evaluated for the effect of differentiated lightning protection configuration, collect the number and configuration location of lightning arresters installed in the distribution network, and install a lightning arrester monitoring device; Step 3: Count the lightning parameters and electrical parameters of each lightning arrester in the distribution network that has experienced thunderstorm weather for at least one year; the parameters include the number of discharge actions, the amplitude of lightning current, and the proportion of total leakage current and resistive leakage current under normal operation; Step 4: Determine the evaluation indicators for judging the effectiveness of the differentiated lightning protection scheme; the evaluation indicators are the annual average number of discharge operations, the annual average lightning current amplitude, and the proportion of total leakage current and resistive leakage current under normal operation; Step 5: Establish a distribution network arrester effectiveness evaluation model based on the evaluation indicators and define the utilization index; Step 6: Based on the distribution network arrester effectiveness evaluation model, the arrester effectiveness levels are divided according to the range of the utilization index, and the subsequent operation and maintenance and transformation plan of the distribution network or the same type of distribution network is formulated; Step 5 includes the following sub-steps: Step 5.1: Collect the annual average discharge operation times m of the arrester to be evaluated a , annual lightning current amplitude average value n a , and the total leakage current I under normal operation a and resistive leakage current ratio d a ; Step 5.2: First, determine the aging condition of the arrester by the total leakage current and the resistive leakage current ratio; Step 5.3: Use the annual average number of discharge operations of the arrester, the average value of the lightning current amplitude, the total leakage current and the resistive leakage current ratio to determine the effectiveness of the arrester in the distribution network; Step 5.4: For the arresters that are evaluated as ineffective in step 5.3, define the utilization index S to quantify their effectiveness. The utilization index S is obtained by summing the utilization index S1 of the average annual discharge operation times of the arrester, the utilization index S2 of the average lightning current amplitude, the utilization index S3 of the total leakage current value, and the utilization index S4 of the resistive leakage current ratio according to the weights; The evaluation criteria of step 5.2 are shown in equations (1) and (2): (1)； (2)； The arrester is considered to have good performance if and only if the total leakage current is less than or equal to the total leakage current threshold I and the resistive leakage current ratio is less than the resistive leakage current ratio threshold d; In step 5.3, for towers at different lightning risk levels, the evaluation criteria are as shown in formula (3) and formula (4). When the annual average number of discharge operations of the arrester, the average value of the lightning current amplitude, the total leakage current and the resistive leakage current ratio meet formula (3) or formula (4), the distribution network arrester is considered to be effective: ， ， ， (3)； or: ， ， ， (4)； In formula (3) and formula (4), m x and m y are the lower and upper limits of the annual average discharge operation times of the arrester corresponding to the tower lightning damage risk level; n x and n y are the lower limit and upper limit of the lightning current amplitude mean value interval corresponding to the tower lightning damage risk level; Calculate S1, S2, S3 and S4 according to different situations: Case 1: m a <m x 、n a <n x ,I a <I and d a <d, then the calculation methods of S1, S2, S3 and S4 are as follows: ； ； Set S3 and S4 to 0; Case 2: If there are indicators among the annual average number of discharge operations of the arrester, the average value of the lightning current amplitude, the total leakage current and the resistive leakage current ratio that are greater than the maximum value of the corresponding interval of the distribution network arrester effectiveness evaluation standard, the calculation method of S1, S2, S3 and S4 is as follows: For indicators that are greater than the maximum value of the interval corresponding to the evaluation standard for the effectiveness of distribution network lightning arresters, the calculation formula for the utilization index is as follows: ； ； ； ； For indicators that are less than the maximum value of the interval corresponding to the distribution network arrester effectiveness evaluation standard, the utilization index is taken as 0.

2. The evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution networks according to claim 1 is characterized in that: In step 2, it is necessary to determine the lightning damage risk assessment indicators and lightning damage risk level classification standards used by the distribution network when formulating differentiated lightning protection plans.

3. The evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution network according to claim 1 is characterized in that: In step 3, the arrester counter is used to monitor the number of discharge actions of the arrester, the amplitude of the lightning current, and the proportion of the total leakage current and the resistive leakage current under normal operation; the time period to be counted is determined to be Y1~Y2 after the distribution network has undergone differentiated lightning protection arrangements. n In a year, the number of discharge actions and lightning current amplitude are taken as the annual average values, and the total leakage current and resistive leakage current ratios are taken as the current measured values.

4. The evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution network according to claim 1 is characterized in that: In step 5.4, the weight ratio of each utilization index is determined by the hierarchical analysis method. Before using the hierarchical analysis method, the four indicators need to be ranked in importance. According to the determined importance ranking, the scale difference of adjacent importance indicators is defined as p, and an n*n order judgment matrix is ​​constructed. The elements in the judgment matrix satisfy: a ij >0; a ij =1 / a ji ; a ii =1; a ij is the importance ratio of index i to index j, i, j∈{1,2,3,…,n}, a ji is the importance ratio of index j to index i, a ii is the importance ratio of indicator i itself, and the value is determined according to the scaling method; According to the constructed judgment matrix, the square root method is used to solve the weight of each indicator; The consistency ratio CR value is solved according to the consistency index CI and the random consistency index RI value to determine whether the judgment matrix consistency is passed; thereby determining the weights of the arrester's annual average discharge action times utilization index S1, lightning current amplitude mean utilization index S2, total leakage current value utilization index S3 and resistive leakage current ratio utilization index S4.

5. A monitoring device for verifying the effect of differentiated configuration of lightning arresters in a distribution network, characterized in that: It comprises a lightning arrester counter and a handheld terminal, the handheld terminal is used to wirelessly and remotely collect lightning parameters and electrical parameters recorded by the lightning arrester counter, the handheld terminal has a built-in evaluation system for the differentiated configuration effect of the lightning arrester in the distribution network, and the evaluation system executes each step of the evaluation method for verifying the differentiated configuration effect of the lightning arrester in the distribution network as described in any one of claims 1-4.

6. The monitoring device according to claim 5, characterized in that: The arrester monitoring device adopts LORA wireless remote transmission arrester counter, and the handheld terminal adopts the plastic shell of handheld instrument. Through button settings, the action times, product address and clock information of the corresponding arrester counter can be queried. At the same time, the action times, product address and clock information of the arrester counter can be set according to needs.

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