Evaluation method and monitoring device for verifying differentiated configuration effect of lightning arresters of power distribution network

Abstract

The invention relates to an evaluation method and a monitoring device for verifying differentiated configuration effects of lightning arresters of a power distribution network. The lightning arrester monitoring device is installed by collecting the installation number and configuration positions of the lightning arresters of the power distribution network; determining an evaluation index for judging the effectiveness of the differentiated lightning protection scheme; the evaluation indexes are the annual average discharge action times, the annual lightning current amplitude mean value and the ratio of the total leakage current to the resistive leakage current under normal operation; establishing a power distribution network lightning arrester effectiveness evaluation model according to the evaluation index and defining a utilization rate index; and according to the effectiveness evaluation model of the lightning arrester of the power distribution network, the effectiveness grade of the lightning arrester is divided according to the range of the utilization rate index, and a subsequent operation and maintenance and reconstruction scheme of the power distribution network or the same type of power distribution network is formulated. According to the invention, the effectiveness evaluation model of the lightning arrester of the power distribution network can be established and the utilization rate index is defined, so that the effectiveness of the lightning arrester is evaluated.

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: An evaluation method for verifying the effect of differentiated configuration of lightning arresters in a distribution network comprises the following steps: 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, divide the arrester effectiveness level according to the range of utilization index, and formulate subsequent operation and maintenance and transformation plans for the distribution network or the same type of distribution network.

[0005] Further preferably, in step 2, it is necessary to determine the lightning damage risk assessment index and lightning damage risk level classification standard used by the distribution network when formulating a differentiated lightning protection plan.

[0006] Further preferably, 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. Determine that the time period to be counted is 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.

[0007] 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 .

[0008] Step 5.2: First, determine the aging condition of the arrester by the ratio of total leakage current and resistive leakage current; 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 composed of the utilization index S1 of the average annual discharge operation times of the arrester, the utilization index S2 of the mean lightning current amplitude, the utilization index S3 of the total leakage current value, and the utilization index S4 of the resistive leakage current ratio.

[0009] Further preferably, the evaluation criteria of step 5.2 are as shown in formula (1) and formula (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.

[0010] Further optimization, 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 discharge operation times 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 They are respectively the lower limit and upper limit of the range of the mean value of lightning current amplitude corresponding to the lightning damage risk level of the tower.

[0011] Further optimization, in step 5.4, the weight proportion of each utilization index is determined by using 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 consistency of the judgment matrix is ​​passed; thereby determining the weights of the annual average discharge action times utilization index S1 of the lightning arrester, the lightning current amplitude mean utilization index S2, the total leakage current value utilization index S3 and the resistive leakage current proportion utilization index S4.

[0012] More preferably, S1, S2, S3 and S4 are calculated according to different situations.

[0013] The present invention also provides a monitoring device for verifying the differentiated configuration effect of lightning arresters in a distribution network, comprising 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 lightning arresters in the distribution network. The evaluation system executes each step of an evaluation method for verifying the differentiated configuration effect of lightning arresters in the distribution network.

[0014] Further preferably, the lightning arrester monitoring device adopts a LORA wireless remote transmission lightning arrester counter, and the handheld terminal adopts a handheld instrument plastic shell. Through button settings, the number of actions, product address, and clock information of the corresponding lightning arrester counter can be queried. At the same time, the number of actions, product address, and clock information of the lightning arrester counter can be set according to needs.

[0015] The present invention designs a lightning arrester monitoring device for collecting lightning parameters and electrical parameters of the lightning arrester; determines evaluation indicators for judging the effectiveness of differentiated lightning protection schemes; establishes a distribution network lightning arrester effectiveness evaluation model according to the evaluation indicators and defines a utilization index; divides the lightning arrester effectiveness levels according to the range of the utilization index according to the distribution network lightning arrester effectiveness evaluation model, and formulates subsequent operation, maintenance and transformation plans for the distribution network or the same type of distribution networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation examples: Figure 1 This is the appearance diagram of the wireless remote transmission lightning arrester counter; Figure 2 This is the front view of the handheld terminal product.

[0017] Figure 3 This is a schematic diagram of lightning arrester installation. DETAILED DESCRIPTION

[0018] The present invention is further explained in detail below in conjunction with embodiments. Example 1

[0019] An evaluation method for verifying the effect of differentiated configuration of lightning arresters in a distribution network comprises the following steps: 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, divide the arrester effectiveness level according to the range of utilization index, and formulate subsequent operation and maintenance and transformation plans for the distribution network or the same type of distribution network.

[0020] During operation, the arrester gradually deteriorates, and its insulation performance decreases, which will lead to an increase in leakage current. Severely deteriorated arresters may have internal breakdown failures. Not only will they lose the function of protecting line equipment, but they will also cause line failures. In production, manual line patrol or arrester monitoring devices are generally used to monitor the operating status of the arrester. The existing arrester monitoring devices have the following problems: (1) It is difficult to provide low-voltage power supply in the operating line, and solar panels and wind power are generally used to provide working power for the device. The energy supply method is greatly affected by the weather, and the stability and continuity of power supply cannot be guaranteed; (2) The existing arrester monitoring device can only monitor the total leakage current of the arrester, and cannot distinguish between capacitive leakage current and resistive leakage current, making it difficult to clearly distinguish the degradation of the arrester; (3) The existing arrester monitoring device does not have the function of remote data transmission, making it difficult to grasp the operating status of the arrester in real time. In view of the existing problems, there is an urgent need for an arrester monitoring device that can operate outdoors all day long, provide a stable power supply, accurately distinguish between capacitive leakage current and positive leakage current, accurately count lightning times, and upload various data to the background master station in real time. The background master station should draw the leakage current curve based on the uploaded data, comprehensively judge the degree of arrester degradation and issue early warning and positioning.

[0021] The arrester monitoring device should be accurate, sensitive, reliable, economical and convenient. Accuracy requires that the arrester monitoring device can accurately record the number of discharges of the arrester, and can respond effectively even to weak signals, and can accurately measure the total leakage current, resistive leakage current and lightning current amplitude of the arrester. Sensitivity requires that the response time of the arrester monitoring device should be as short as possible, which is conducive to maintaining the safety and reliability of the distribution network line. Reliability requires that the arrester monitoring device should have good anti-interference performance, and can work stably even in bad weather, and can shield external interference signals to a certain extent. Economy requires that the arrester monitoring device can be flexibly installed according to different structures to reduce installation costs, and at the same time, there can be a stable power supply for the normal operation of the arrester monitoring device. Common energy-taking methods include direct line energy-taking or solar energy supply. Convenience requires that the operation of the arrester monitoring device should be simple and clear, with good data storage and transmission functions, and can keep the discharge event records for a long time, and can be transmitted to the handheld terminal via wireless remote transmission. The handheld terminal should have good communication stability, be able to query the corresponding wireless remote transmission arrester monitoring device's action times, address, clock information, etc., and be able to 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.

[0022] The arrester monitoring device of this embodiment adopts JSY series LORA wireless remote transmission arrester counter, such as Figure 1 As shown in the figure, this arrester counter can operate outdoors all day long, has a stable power supply, can accurately distinguish capacitive leakage current from 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 acquisition and measurement integrated sensor is based on electronic sensor technology, and obtains low-voltage working power supply for the arrester monitoring device through bus voltage division. At the same time, it provides a voltage measurement signal, and distinguishes capacitive current from resistive current through the voltage measurement signal. Resistive leakage current is used as the main criterion for arrester degradation. Unlike the traditional solution that uses resistance voltage division to collect leakage current, the arrester monitoring device is based on high-precision active current transformer technology, which greatly improves the range and accuracy of collected leakage current, and provides a more reliable and stable criterion for arrester degradation. After 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, operating status and degree of degradation of the line arrester are displayed in real time.

[0023] This arrester discharge counter is connected in series with the arrester in the power grid to record the number of arrester discharge actions and leakage current. The arrester is used in 35kV outdoor lines; it uses high voltage energy, and the output power is >3W; the full leakage current measurement range is: 10uA~10mA; the resistive current measurement range is 10uA~10mA; the current measurement accuracy is 1%. The arrester counter uses a stainless steel shell with good sealing performance. The sampling part uses a mutual inductor to isolate the large current, reduce the induction to a small current, and send it to the signal processing unit. The signal processing unit uses a high-speed optocoupler for isolation, uses a single-chip microcomputer for data processing, and selects a 433MHz module to transmit the data to the handheld terminal. The product function part uses solar energy to obtain electricity, and the solar energy is sealed inside the stainless steel shell to avoid damage to the solar panel caused by the outside. The arrester counter is based on high-precision active current transformer technology, which greatly improves the range and accuracy of the collected leakage current, and provides more reliable and stable judgment data for the degradation of the arrester.

[0024] The number of arrester actions, total leakage current and resistive leakage current can be checked through the handheld terminal. Figure 2 As 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.

[0025] 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.

[0026] 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: Table 1. Distribution network lightning risk classification standards

[0027] 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.

[0028] The lightning damage risk assessment index used in the distribution network evaluated in this embodiment is the ground-to-ground lightning density. The ground-to-ground lightning density distribution in the area where a distribution network is located from 2019 to 2022, and the differentiated lightning protection scheme used classifies the lightning damage risk level into A~E, among which, the lightning damage risk corresponding to grade A is the lowest, and grade E is the highest. The specific classification standards are shown in Table 2: Table 2. Ground-to-ground lightning density classification standards

[0029] The lightning protection devices selected for this distribution network using differentiated lightning protection are YH5WX17 / 50 conventional zinc oxide arresters, YH5WS-17 / 45TLF new live replaceable arresters, lightning protection support insulators, piercing arc protection hardware, lightning arresters and coupling ground wires. The specific situation of the differentiated lightning protection configuration schemes adopted by this distribution network in different corridor environments is shown in Table 3. Figure 3 This is a schematic diagram of lightning arrester installation. The lightning arrester is installed vertically, the terminal is facing downward, and the grounding device is reliably connected. For the lightning arrester counter designed in step 1 of lightning arrester installation, the lightning arrester counter should be installed in a location that is easy to observe and maintain. Usually, a place that is easy to access and has a good line of sight should be selected. At the same time, it should be avoided from external mechanical damage and environmental interference. During installation, ensure that the connection polarity is correct.

[0030] Table 3. Lightning protection configuration strategies for different corridor environments

[0031] 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. nIn the 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 ratio are taken as the current measured values. The recorded data are shown in Table 4: Table 4. Parameters of each arrester in the distribution network

[0032] In Table 4, m n is the number of discharge operations of arrester n, n n is the lightning current amplitude of arrester n, I n Total leakage current of arrester n, d n The resistive leakage current ratio of arrester n.

[0033] Under normal operation, the total leakage current and resistive leakage current of the arrester account for a very small proportion. If a large proportion occurs, it indicates that the internal components of the arrester are aging, damp, etc. At this time, if the abnormal arrester cannot be quickly withdrawn from operation, it may cause the power system to be paralyzed in a short period of time; the annual average number of discharge actions and the annual average lightning current amplitude of the arrester can further reflect the lightning damage risk of the towers at different locations. For towers with a high lightning damage risk level in differentiated lightning protection, the average number of discharge actions and the average annual lightning current amplitude in subsequent operation should also be high. By monitoring the average annual number of discharge actions and the average annual lightning current amplitude, the maintenance plan and replacement strategy of the arrester can be better formulated to ensure the stability and safe operation of the power system; therefore, step 4 of this embodiment determines that the evaluation indicators for judging the effectiveness of differentiated lightning protection are the average annual number of discharge actions, the average annual lightning current amplitude, and the proportion of total leakage current and resistive leakage current under normal operation.

[0034] In step 5 of this embodiment, the effectiveness evaluation model of the lightning arrester in the distribution network is established according to the evaluation index and the utilization index is defined. The specific steps are as follows: Step 5.1: Based on the data collected in step 3, 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 .

[0035] Step 5.2: First, the aging condition of the arrester is determined by the total leakage current and the resistive leakage current ratio. The specific evaluation criteria are shown in Table 5, and the evaluation criteria are shown in Formula (1) and Formula (2): (1); (2); From equations (1) and (2), it can be obtained that 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 this embodiment, the total leakage current threshold I is taken as 50uA and the resistive leakage current ratio threshold d is taken as 15%. For severely aged arresters, they should be removed from operation and replaced in a timely manner.

[0036] 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 judge the effectiveness of the distribution network arrester. Different evaluation standards should be used for towers at different lightning damage risk levels. The evaluation standards for the effectiveness of the distribution network arrester are shown in Table 5. The evaluation standards are 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 and upper limits of the lightning current amplitude mean interval corresponding to the tower lightning damage risk level. It can be obtained from formula (3) and formula (4) that after the distribution network is configured with differentiated lightning protection, if the total leakage current and resistive leakage current ratio are within the specified range, one of the annual average discharge operation times of the lightning arrester and the lightning current amplitude mean 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 interval corresponding to the distribution network lightning arrester effectiveness evaluation standard, then the distribution network lightning arrester is considered to be effective and the lightning arrester utilization effect is good. In Table 5, m1~m 15 is the lower or upper limit of the annual average discharge operation times of the arrester corresponding to the different tower lightning damage risk levels, n1~n 15 are the lower limit and upper limit of the lightning current amplitude mean value interval corresponding to the tower lightning damage risk level. Table 6 is the specific evaluation criteria of this embodiment.

[0037] Table 5. Evaluation criteria for effectiveness of lightning arresters in distribution networks

[0038] Table 6. Examples of evaluation criteria for effectiveness of lightning arresters in distribution networks

[0039] 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 composed of 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. The specific calculation method is as follows: First, the weight 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 between adjacent importance indicators is defined as p, and an n*n-order judgment matrix is ​​constructed:

[0040] The elements in the judgment matrix satisfy: (1) a ij >0; (2) a ij =1 / a ji ; (3) a ii =1. 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. The meaning of the scaling method is shown in Table 7.

[0041] Table 7. Meaning of “1-9 scale method”

[0042] According to the constructed judgment matrix, the square root method is used to solve the weight of each indicator. The calculation method is as follows: First, calculate the 1 / nth power of the product of each row of the judgment matrix to obtain an n-dimensional weight vector. The calculation formula is shown in formula (5): (5); in, is the weight vector of the indicator; Normalizing the above vectors can obtain the standardized weight vector, that is, the weight corresponding to each indicator. The calculation formula is shown in formula (6): (6); in, is the standardized weight vector of the indicator; Then, 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 is ​​passed.

[0043] The CI calculation method is as follows: First, multiply the column vectors of the judgment matrix by the standardized weight vector The elements of the corresponding columns are used to obtain a new consistency judgment matrix, as shown below:

[0044] b ij is the element in the i-th row and j-th column of the consistency judgment matrix, i, j∈{1,2,3,…,n}, and the elements of each row of the consistency judgment matrix are added to obtain a new vector , The new vectors The 1st, 2nd, ..., nth elements of Multiply each column element by n to get a new vector , The new vectors The 1st, 2nd, ..., nth element of . The largest eigenvalue It can be obtained by formula (7): (7); Finally, according to formula (8), the consistency index CI can be obtained: (8); In formula (8), n is the matrix order.

[0045] The value of RI can be obtained by looking up the table, as shown in Table 8.

[0046] Table 8. RI value table

[0047] According to the values ​​of CI and RI, CR can be obtained by formula (9): (9); When CR=0, the matrix is ​​considered to be completely consistent; when CR<0.1, the consistency of the matrix is ​​considered to be acceptable; when CR≥0.1, the consistency of the matrix is ​​considered to be unacceptable, which means that there is a logical error in the judgment matrix and the elements of the judgment matrix need to be re-determined.

[0048] This embodiment defines four indicators, which are ranked from the highest to the lowest in terms of importance: average lightning current amplitude, number of arrester discharge operations, resistive leakage current ratio, and total leakage current. The scale difference of adjacent importance indicators is defined as 1, and a 4*4 judgment matrix is ​​constructed:

[0049] According to the constructed judgment matrix, the square root method is used to solve the weight of each indicator according to formula (5) to obtain the weight vector =(2.21,1.32,0.76,0.45). Then, the above vector is normalized according to formula (6) to obtain the normalized weight vector =(0.47,0.28,0.16,0.09).

[0050] Multiply the column vectors of the obtained judgment matrix by the standardized weight vector The elements of the corresponding columns obtain the standardized judgment matrix as shown below:

[0051] Add the elements of each row of the standardized judgment matrix to get the vector =(1.81,1.105,0.637,0.3805), and then normalize the weight vector Multiply each column element by 4 to get a vector =(1.88,1.12,0.64,0.36). According to the vector and The maximum eigenvalue λ is obtained by formula (7): max =4.03. According to λ max The matrix order is calculated from formula (8) to obtain CI=0.011. By looking up the table, we know that RI=0.90. From formula (9), we get CR=0.012, CR<0.1, and the consistency of the judgment matrix is ​​acceptable.

[0052] In summary, the weights of the annual average discharge operation times utilization index S1 of the arrester, the lightning current amplitude mean utilization index S2, the total leakage current value utilization index S3 and the resistive leakage current ratio utilization index S4 are determined to be 0.28, 0.47, 0.09 and 0.16 respectively, that is, the calculation formula of the utilization index S is: (10); Then, S1, S2, S3 and S4 are calculated according to different situations: Case 1: If the annual average number of discharge operations of the arrester and the average lightning current amplitude are less than the minimum value of the corresponding interval in the evaluation standard of the effectiveness of the arrester in the distribution network (Table 5), the total leakage current and the resistive leakage current ratio are 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 arrester is low. In the subsequent operation and maintenance, the number of operation and maintenance can be reduced, and the installation of the arrester can be reduced. At this time, the calculation method of S1, S2, S3 and S4 is as follows: For S1 and S2, the calculation formula of their utilization index is as follows: (11); (12); For S3 and S4, since they are within the corresponding interval of the distribution network arrester effectiveness evaluation standard, S3 and S4 are set to 0.

[0053] At this time, the value range of S is [0, 1), and the closer its value is to 1, the lower the utilization rate of the lightning arrester is, that is, the greater the redundancy of the lightning arrester is.

[0054] Case 2: If the annual average number of discharge actions of the arrester, the average value of the lightning current amplitude, the total leakage current and the resistive leakage current ratio are greater than the maximum value of the corresponding interval in the distribution network arrester effectiveness evaluation standard (Table 5), it means that the arrester is overloaded, which is not conducive to the safety and stability of the distribution network. In the subsequent operation and maintenance, it is necessary to increase the number of operation and maintenance and increase the number of installed arresters. At this time, 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: (13); (14); (15); (16); 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.

[0055] At this time, the value range of S is (0, ∞), and the larger its value is, the more serious the overload utilization of the lightning arrester is, that is, the less effective the lightning protection of the lightning arrester is.

[0056] Step 6: Based on the distribution network arrester effectiveness evaluation model, the arrester effectiveness level is divided according to the range of the utilization index, and the operation and maintenance and transformation plan for the subsequent or similar lines of the line is formulated. The specific steps are as follows: Case 1: If the annual average number of discharge operations of the arrester and the average lightning current amplitude are less than the minimum value of the corresponding interval in the distribution network arrester effectiveness evaluation standard (Table 5), the total leakage current and resistive leakage current ratio are within the interval, that is, the utilization rate of the arrester is low. At this time, the value range of the utilization index S is [0, 1), and the closer its value is to 1, the lower its utilization rate. The effectiveness level classification of the arrester at this time and the subsequent operation and maintenance and transformation plan of the line are formulated as shown in Table 6.

[0057] Table 6. Classification of arrester effectiveness in case 1 and subsequent line operation and maintenance and improvement plan

[0058] Among them, b1, b2, b3, …, b n-1 They are the 1st, 2nd, 3rd, ..., nth utilization index thresholds for case 1 respectively.

[0059] Case 2: If the annual average number of discharge actions of the arrester, the average value of the lightning current amplitude, the total leakage current and the resistive leakage current ratio are greater than the maximum value of the corresponding interval in the distribution network arrester effectiveness evaluation standard (Table 5), the arrester is overloaded. At this time, the value range of the utilization index S is (0, ∞), and the larger its value, the greater the degree of arrester overload. The effectiveness level classification of the arrester at this time and the subsequent operation and maintenance and transformation plan of the line are formulated as shown in Table 9.

[0060] Table 9. Classification of arrester effectiveness in case 2 and subsequent line operation and maintenance and improvement plan

[0061] Among them, c1, c2, c3, …, c n-1 They are the 1st, 2nd, 3rd, ..., n-1th utilization index thresholds for case 2 respectively.

[0062] The subsequent line operation and maintenance and improvement plans formulated in Case 1 and Case 2 of this example are shown in Table 10 and Table 11 respectively: Table 10. Example of subsequent operation and improvement plan for line in case 1

[0063] Table 11. Example of subsequent operation and improvement plan for line in case 2

[0064] Another embodiment of the present invention also provides a monitoring device for verifying the differentiated configuration effect of distribution network lightning arresters, including 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 distribution network lightning arresters. The evaluation system executes each step of an evaluation method for verifying the differentiated configuration effect of distribution network lightning arresters.

[0065] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles 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, divide the arrester effectiveness level according to the range of utilization index, and formulate subsequent operation and maintenance and transformation plans for the distribution network or the same type of distribution network.

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: 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 ratio of total leakage current and resistive leakage current; 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 composed of the utilization index S1 of the average annual discharge operation times of the arrester, the utilization index S2 of the mean lightning current amplitude, the utilization index S3 of the total leakage current value, and the utilization index S4 of the resistive leakage current ratio.

5. The evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution network according to claim 4 is characterized in that: 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.

6. The evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution network according to claim 5 is characterized in that: 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 They are respectively the lower limit and upper limit of the range of the mean value of lightning current amplitude corresponding to the lightning damage risk level of the tower.

7. The evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution network according to claim 6 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.

8. The evaluation method for verifying the effect of differentiated configuration of lightning arresters in distribution network according to claim 4 is characterized in that: 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 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 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.

9. 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 1-8.

10. The monitoring device according to claim 9, 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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