Power grid safety assessment method and system

Abstract

The invention belongs to the technical field of power grid safety, and discloses a power grid safety assessment method, which comprises the following specific steps of: 1, acquiring data, setting a monitoring period, and monitoring the network state, the power transmission network state, the power distribution network state and the weather state of a power grid in real time every other monitoring period; the invention also provides a power grid safety assessment method and system, and the method achieves the real-time monitoring of a power grid network state, a power transmission network state, a power distribution network state and a weather state through the arrangement of an acquisition module, a transmission module, a grade assessment module, a threshold setting module, a comparison module and a report generation module. And after calculation and evaluation, comparing with a set safety level threshold, and then generating a safety level evaluation report to complete safety evaluation of the power grid, so that the safety evaluation of the power grid is more comprehensive and accurate, and the situation that regular inspection and safety evaluation of each part of the power grid need to be carried out manually in the traditional power grid safety is avoided. And meanwhile, the elimination and solving efficiency of power grid faults is also improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid safety, and in particular relates to a power grid safety assessment method and system. Background Art

[0002] The whole composed of substations of various voltages and transmission and distribution lines in the power system is called power grid, or grid for short. It includes three units: substation, transmission and distribution. According to the different roles of the grid in the power system, the grid is divided into transmission grid and distribution grid. The transmission grid is composed of transmission equipment and substation equipment. The transmission equipment mainly includes transmission lines, poles, insulator strings, overhead lines, etc.; the substation equipment mainly includes transformers, reactors, capacitors, circuit breakers, grounding switches, lightning arresters, voltage transformers, current transformers, as well as power protection, monitoring, control and communication systems.

[0003] In the process of using the power grid, in order to evaluate the safety of the power grid, it is necessary to adopt corresponding evaluation methods. The traditional power grid safety assessment method mainly relies on manual regular inspections and safety assessments of each part of the power grid. However, this method has low working efficiency and is too dependent on manual operation. The efficiency of solving and eliminating power grid faults is low. In addition, there are certain disadvantages in manual inspection. The inspection is not comprehensive, and some potential safety hazards cannot be discovered in time. Therefore, it needs to be improved. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for evaluating power grid security to solve the problems raised in the above background technology.

[0005] In order to achieve the above object, the present invention provides the following technical solution: a method for evaluating power grid security, the specific steps are as follows:

[0006] Step 1: Data Collection

[0007] Set a monitoring cycle, and conduct real-time monitoring of the network status, transmission network status, distribution network status and weather status of the power grid every other monitoring cycle to obtain real-time status data of the network, transmission network, distribution network and weather;

[0008] Step 2: Evaluate the network status index

[0009] The received network status data: the target object of abnormal attack, the attack means used by abnormal attack and the consequences of abnormal attack are analyzed, and the power grid network security level is evaluated using a quantitative risk assessment model, which is divided into the first level (90-100), the second level (80-90), the third level (70-80), the fourth level (60-70) and the fifth level (below 60);

[0010] Step 3: Evaluate the transmission grid status index

[0011] Analyze and record the received transmission network status data: line single-phase grounding fault, line three-phase current imbalance fault, line overload fault, lightning fault, wind yaw discharge fault and icing fault, and evaluate the transmission network fault level according to the type of fault. The transmission network fault level is specifically divided into the first level, the second level and the third level;

[0012] Step 4: Evaluate the distribution network status index

[0013] The received distribution network status data: power supply reliability, voltage quality and equipment health index are analyzed and calculated, and the distribution network safety level is calculated and evaluated using the distribution network status index formula. The distribution network safety level is specifically divided into the first level (80-100), the second level (60-80) and the third level (below 60);

[0014] Step 5: Evaluate the weather condition index

[0015] The received weather status data: rainfall index, wind speed index and temperature index are analyzed. According to historical data and weather status data, the relationship model between power grid line failure rate and weather status is used to calculate the failure rate of power grid lines in bad weather, so as to evaluate the weather safety level. The weather safety level is specifically divided into the first level (90-100), the second level (80-90), the third level (70-80), the fourth level (60-70) and the fifth level (below 60);

[0016] Step 6: Compare with the set threshold

[0017] The safety level threshold of the network status index is set to the second level, the safety level threshold of the transmission network status index is set to the first level, the safety level threshold of the distribution network status index is set to the first level, and the safety level threshold of the weather status index is set to the second level; the assessed power grid network security level, transmission network fault level, distribution network security level, and weather security level are compared with the set security level thresholds. If the result is greater than the level threshold, it means that the power grid security index is low;

[0018] Step 7: Generate a security level assessment report

[0019] Generate a security level assessment report based on the comparison results;

[0020] Step 8: Exception handling

[0021] In response to power grid network problems, the security of the power grid network is enhanced by strengthening security, reducing information system resource usage, increasing system defense time, and slowing down the speed of external attacks, thereby improving the ability to resist attacks;

[0022] For the status of the transmission network, the single-phase grounding fault of the line can be solved by finding the fault point through the test pulling method and isolating it to restore the operation of other lines; the three-phase current imbalance fault of the line can be solved by checking the line joint condition and shutting down the line or adjusting the grid operation mode when necessary; the overload fault of the line can be solved by adjusting the grid operation mode, notifying the power plant to adjust the output or letting the receiving system cut off some unimportant loads; lightning strike faults can be prevented by installing lightning arresters and selecting flat terrain; wind-induced discharge faults can be prevented by avoiding the installation of protrusions and timely calibrating the distance between the tower heads; ice-covered faults can be solved by avoiding construction in areas with severe ice-covered areas;

[0023] In case of problems with the distribution network status, relevant personnel are dispatched directly to the fault point for repairs.

[0024] Preferably, the monitoring cycle described in step 1 is set to once every two days by default, which is adjusted according to the specific environment of the power grid.

[0025] Preferably, the risk assessment model described in step 2 uses the risk value to calculate when evaluating the power grid network security level, and the specific calculation formula used is:

[0026] Risk value (R) = event probability (P) * time loss (L)

[0027] In the formula, the event probability (P) represents the possibility of an abnormal network attack, which is evaluated through historical data, industry trends, security knowledge and expert opinions; the event loss (L) represents the loss caused by the abnormal network attack, including direct economic loss, business interruption loss and reputation loss.

[0028] Preferably, the specific classification method of the transmission network fault level described in step three is the first level: safe and fault-free; the second level: lightning strike fault, wind discharge fault and icing fault; the third level: single-phase grounding fault, line three-phase current imbalance fault and line overload fault.

[0029] Preferably, the power supply reliability calculation formula described in step 4 is:

[0030]

[0031] In the formula, RSA is the power supply reliability, T is the total time of the statistical period (in hours), and T i停 is the duration of the ith power outage, and n is the number of power outages.

[0032] Preferably, the voltage quality calculation formula described in step 4 is:

[0033]

[0034] In the formula, V is the voltage quality, U is the actual voltage, and UN is the rated voltage, U1, u2, U3 are the amplitudes of the three-phase voltages.

[0035] Preferably, the equipment health index calculation formula in step 4 is:

[0036]

[0037] In the formula, H is the equipment health index at the current moment, H0 is the initial health index set when the equipment is put into operation, B is the aging rate of the equipment, which reflects the rate at which the equipment performance declines over time, T is the current year to be calculated, and T0 is the year corresponding to T, which is generally the year when the equipment is put into operation.

[0038] Preferably, the distribution network status index calculation formula described in step 4 is:

[0039] Distribution network status index = w RSA *RSA+w v *V+w H *H

[0040] In the formula, w RSA is the weight of power supply reliability, w RSA =0.5, w v is the voltage quality weight, w v =0.3, w H is the weight of the device health status, w H =0.2, RSA is the power supply reliability, V is the voltage quality, and H is the equipment health status.

[0041] Preferably, the relationship model calculation formula between the power grid line failure rate and weather conditions described in step 5 is:

[0042] labmda wc (s) = labmda n f(s)

[0043] In the formula, labmda wc (s) represents the line failure rate under weather state s, labmda n represents the average line failure rate under normal weather conditions, and f(s) is the failure rate growth factor under weather state s.

[0044] A power grid security assessment system includes a collection module, a transmission module, a level assessment module, a threshold setting module, a comparison module and a report generation module, wherein:

[0045] Collection module: used to monitor and collect data on power grid network status, transmission network status, distribution network status and weather status;

[0046] Transmission module: used to transmit data information;

[0047] Level assessment module: used to calculate data and assess the power grid network security level, transmission network fault level, distribution network security level and weather security level;

[0048] Threshold setting module: used to set the safety level thresholds of network status index, transmission network status index, distribution network status index and weather status index;

[0049] Comparison module: used to compare the calculated and evaluated power grid network security level, transmission network fault level, distribution network security level and weather security level with the set security level threshold;

[0050] Report generation module: used to generate an electronic version of the security level assessment report and print the electronic version of the security level assessment report into a paper version.

[0051] The beneficial effects of the present invention are as follows:

[0052] The present invention realizes real-time monitoring of the power grid network status, transmission network status, distribution network status and weather status by setting up an acquisition module, a transmission module, a level assessment module, a threshold setting module, a comparison module and a report generation module, and compares the calculated and evaluated status with the set safety level threshold, and then generates a safety level assessment report to complete the safety assessment of the power grid, thereby making the safety assessment of the power grid more comprehensive and accurate, getting rid of the traditional power grid safety need to rely on manual regular inspections and safety assessments of various parts of the power grid, and at the same time improving the efficiency of troubleshooting and solving power grid faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of the present invention;

[0054] Figure 2 This is a system block diagram of the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] like Figure 1 As shown, the embodiment of the present invention provides a method for evaluating power grid security, and the specific steps are as follows:

[0057] Step 1: Data Collection

[0058] Set a monitoring cycle, and conduct real-time monitoring of the network status, transmission network status, distribution network status and weather status of the power grid every other monitoring cycle to obtain real-time status data of the network, transmission network, distribution network and weather;

[0059] Step 2: Evaluate the network status index

[0060] The received network status data: the target object of abnormal attack, the attack means used by abnormal attack and the consequences of abnormal attack are analyzed, and the power grid network security level is evaluated using a quantitative risk assessment model, which is divided into the first level (90-100), the second level (80-90), the third level (70-80), the fourth level (60-70) and the fifth level (below 60);

[0061] Step 3: Evaluate the transmission grid status index

[0062] Analyze and record the received transmission network status data: line single-phase grounding fault, line three-phase current imbalance fault, line overload fault, lightning fault, wind yaw discharge fault and icing fault, and evaluate the transmission network fault level according to the type of fault. The transmission network fault level is specifically divided into the first level, the second level and the third level;

[0063] Step 4: Evaluate the distribution network status index

[0064] The received distribution network status data: power supply reliability, voltage quality and equipment health index are analyzed and calculated, and the distribution network safety level is calculated and evaluated using the distribution network status index formula. The distribution network safety level is specifically divided into the first level (80-100), the second level (60-80) and the third level (below 60);

[0065] Step 5: Evaluate the weather condition index

[0066] The received weather status data: rainfall index, wind speed index and temperature index are analyzed. According to historical data and weather status data, the relationship model between power grid line failure rate and weather status is used to calculate the failure rate of power grid lines in bad weather, so as to evaluate the weather safety level. The weather safety level is specifically divided into the first level (90-100), the second level (80-90), the third level (70-80), the fourth level (60-70) and the fifth level (below 60);

[0067] Step 6: Compare with the set threshold

[0068] The safety level threshold of the network status index is set to the second level, the safety level threshold of the transmission network status index is set to the first level, the safety level threshold of the distribution network status index is set to the first level, and the safety level threshold of the weather status index is set to the second level; the assessed power grid network security level, transmission network fault level, distribution network security level, and weather security level are compared with the set security level thresholds. If the result is greater than the level threshold, it means that the power grid security index is low;

[0069] Step 7: Generate a security level assessment report

[0070] Generate a security level assessment report based on the comparison results;

[0071] Step 8: Exception handling

[0072] In response to power grid network problems, the security of the power grid network is enhanced by strengthening security, reducing information system resource usage, increasing system defense time, and slowing down the speed of external attacks, thereby improving the ability to resist attacks;

[0073] For the status of the transmission network, the single-phase grounding fault of the line can be solved by finding the fault point through the test pulling method and isolating it to restore the operation of other lines; the three-phase current imbalance fault of the line can be solved by checking the line joint condition and shutting down the line or adjusting the grid operation mode when necessary; the overload fault of the line can be solved by adjusting the grid operation mode, notifying the power plant to adjust the output or letting the receiving system cut off some unimportant loads; lightning strike faults can be prevented by installing lightning arresters and selecting flat terrain; wind-induced discharge faults can be prevented by avoiding the installation of protrusions and timely calibrating the distance between the tower heads; ice-covered faults can be solved by avoiding construction in areas with severe ice-covered areas;

[0074] In case of problems with the distribution network status, relevant personnel are dispatched directly to the fault point for repairs.

[0075] The present invention monitors the network status, transmission network status, distribution network status and weather status of the power grid in real time by setting a monitoring cycle, then performs calculation and evaluation based on the monitored data and compares it with the set safety level threshold, thereby evaluating the safety performance of the power grid, and handles the corresponding faults based on the generated safety evaluation report, making the power grid safety evaluation more comprehensive and accurate, getting rid of the traditional power grid safety need to rely on manual regular inspections and safety evaluations of various parts of the power grid, and at the same time improving the efficiency of troubleshooting and solving power grid faults.

[0076] The monitoring cycle in step one is set to once every two days by default, and is adjusted according to the specific environment of the power grid.

[0077] By adjusting the monitoring cycle according to the actual environment of the power grid, it is beneficial to improve the accuracy of the power grid security assessment, thereby increasing the persuasiveness of the power grid security assessment and maintaining the normal operation of the power grid.

[0078] Among them, the risk assessment model in step 2 uses the risk value to calculate when evaluating the network security level of the power grid. The specific calculation formula used is:

[0079] Risk value (R) = event probability (P) * time loss (L)

[0080] In the formula, the event probability (P) represents the possibility of an abnormal network attack, which is evaluated through historical data, industry trends, security knowledge and expert opinions; the event loss (L) represents the loss caused by the abnormal network attack, including direct economic loss, business interruption loss and reputation loss.

[0081] By calculating the risk value, the security level of the power grid network can be evaluated based on the size of the risk faced by the power grid network.

[0082] Among them, the specific classification method of the transmission network fault level in step three is the first level: safe and fault-free; the second level: lightning fault, wind discharge fault and icing fault; the third level: single-phase grounding fault, line three-phase current imbalance fault and line overload fault.

[0083] The lower the level of the transmission network fault, the easier it is to eliminate and resolve the fault.

[0084] The power supply reliability calculation formula in step 4 is:

[0085]

[0086] In the formula, RSA is the power supply reliability, T is the total time of the statistical period (in hours), and T i停 is the duration of the ith power outage, and n is the number of power outages.

[0087] Power supply reliability can reflect the sustainability of power supply in the distribution network, thus determining the number of power outages in the distribution network.

[0088] The voltage quality calculation formula in step 4 is:

[0089]

[0090] In the formula, V is the voltage quality, U is the actual voltage, and U N is the rated voltage, U1, u2, U3 are the amplitudes of the three-phase voltages.

[0091] Voltage quality can reflect the utilization rate of electric energy in the distribution network, thus providing a data basis for subsequent optimization of the distribution network.

[0092] The calculation formula for the device health index in step 4 is:

[0093]

[0094] In the formula, H is the equipment health index at the current moment, H0 is the initial health index set when the equipment is put into operation, B is the aging rate of the equipment, which reflects the rate at which the equipment performance declines over time, T is the current year to be calculated, and T0 is the year corresponding to T, which is generally the year when the equipment is put into operation.

[0095] The calculation of the equipment health index can determine the current quality and usable time of the equipment.

[0096] Among them, the calculation formula of the distribution network status index in step 4 is:

[0097] Distribution network status index = w RSA *RSA+w v *V+w H *H

[0098] In the formula, w RSA is the weight of power supply reliability, w RSA =0.5, w v is the voltage quality weight, w v =0.3, w H is the weight of the device health index, w H =0.2, RSA is the power supply reliability, V is the voltage quality, and H is the equipment health index.

[0099] The distribution network status index can be calculated comprehensively by taking into account the three aspects of power supply reliability, voltage quality and equipment health index. At the same time, the weights of power supply reliability, voltage quality and equipment health index can be adjusted according to actual conditions.

[0100] Among them, the calculation formula of the relationship model between the power grid line failure rate and weather conditions in step 5 is:

[0101] labmda wc (s) = labmda n f(s)

[0102] In the formula, labmda wc (s) represents the line failure rate under weather state s, labmda n represents the average line failure rate under normal weather conditions, and f(s) is the failure rate growth factor under weather state s.

[0103] By calculating the relationship model between the power grid line failure rate and weather conditions, the probability of power grid failure in severe weather conditions can be inferred.

[0104] like Figure 2 As shown, an embodiment of the present invention provides a power grid security assessment system, including a collection module, a transmission module, a level assessment module, a threshold setting module, a comparison module and a report generation module, wherein:

[0105] Collection module: used to monitor and collect data on power grid network status, transmission network status, distribution network status and weather status;

[0106] Transmission module: used to transmit data information;

[0107] Level assessment module: used to calculate data and assess the power grid network security level, transmission network fault level, distribution network security level and weather security level;

[0108] Threshold setting module: used to set the safety level thresholds of network status index, transmission network status index, distribution network status index and weather status index;

[0109] Comparison module: used to compare the calculated and evaluated power grid network security level, transmission network fault level, distribution network security level and weather security level with the set security level threshold;

[0110] Report generation module: used to generate an electronic version of the security level assessment report and print the electronic version of the security level assessment report into a paper version.

[0111] The acquisition module, transmission module, level assessment module, threshold setting module, comparison module and report generation module of the present invention can realize real-time monitoring of the power grid network status, transmission network status, distribution network status and weather status, and send the monitored data to the level assessment module through the transmission module for calculation and evaluation. After the threshold is set by the threshold setting module, the comparison is performed in the comparison module and the result is sent to the report generation module to generate a security level assessment report, thereby completing the assessment of the power grid security.

[0112] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0113] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating power grid security, characterized in that: The specific steps are as follows: Step 1: Data Collection Set a monitoring cycle, and conduct real-time monitoring of the network status, transmission network status, distribution network status and weather status of the power grid every other monitoring cycle to obtain real-time status data of the network, transmission network, distribution network and weather; Step 2: Evaluate the network status index The received network status data: the target object of abnormal attack, the attack means used by abnormal attack and the consequences of abnormal attack are analyzed, and the power grid network security level is evaluated using a quantitative risk assessment model, which is divided into the first level (90-100), the second level (80-90), the third level (70-80), the fourth level (60-70) and the fifth level (below 60); Step 3: Evaluate the transmission grid status index Analyze and record the received transmission network status data: line single-phase grounding fault, line three-phase current imbalance fault, line overload fault, lightning fault, wind yaw discharge fault and icing fault, and evaluate the transmission network fault level according to the type of fault. The transmission network fault level is specifically divided into the first level, the second level and the third level; Step 4: Evaluate the distribution network status index The received distribution network status data: power supply reliability, voltage quality and equipment health index are analyzed and calculated, and the distribution network safety level is calculated and evaluated using the distribution network status index formula. The distribution network safety level is specifically divided into the first level (80-100), the second level (60-80) and the third level (below 60); Step 5: Evaluate the weather condition index The received weather status data: rainfall index, wind speed index and temperature index are analyzed. According to historical data and weather status data, the relationship model between power grid line failure rate and weather status is used to calculate the failure rate of power grid lines in bad weather, so as to evaluate the weather safety level. The weather safety level is specifically divided into the first level (90-100), the second level (80-90), the third level (70-80), the fourth level (60-70) and the fifth level (below 60); Step 6: Compare with the set threshold The safety level threshold of the network status index is set to the second level, the safety level threshold of the transmission network status index is set to the first level, the safety level threshold of the distribution network status index is set to the first level, and the safety level threshold of the weather status index is set to the second level; the assessed power grid network security level, transmission network fault level, distribution network security level, and weather security level are compared with the set security level thresholds. If the result is greater than the level threshold, it means that the power grid security index is low; Step 7: Generate a security level assessment report Generate a security level assessment report based on the comparison results; Step 8: Exception handling In response to power grid network problems, the security of the power grid network is enhanced by strengthening security, reducing information system resource usage, increasing system defense time, and slowing down the speed of external attacks, thereby improving the ability to resist attacks; For transmission network status problems, the single-phase grounding fault of the line can be solved by finding the fault point and isolating it through the test pull method to restore the operation of other lines; the three-phase current imbalance fault of the line can be solved by checking the line joint condition and shutting down the line or adjusting the grid operation mode when necessary; Solve the line overload fault by adjusting the grid operation mode, notifying the power plant to adjust the output or asking the receiving system to cut off some unimportant loads; prevent lightning strike faults by installing lightning arresters and choosing flat terrain; prevent wind-induced discharge faults by avoiding installing protrusions and timely calibrating the distance to the tower head; solve the icing fault by avoiding construction in areas with severe icing; In case of problems with the distribution network status, relevant personnel are dispatched directly to the fault point for repairs.

2. A method for evaluating power grid security according to claim 1, characterized in that: The monitoring cycle described in step 1 defaults to once every two days, which is adjusted according to the specific environment of the power grid.

3. A method for evaluating power grid security according to claim 1, characterized in that: The risk assessment model described in step 2 uses the risk value to calculate when evaluating the network security level of the power grid. The specific calculation formula used is: Risk value (R) = event probability (P) * time loss (L) In the formula, the event probability (P) represents the possibility of an abnormal network attack, which is evaluated through historical data, industry trends, security knowledge and expert opinions; the event loss (L) represents the loss caused by the abnormal network attack, including direct economic loss, business interruption loss and reputation loss.

4. A method for evaluating power grid security according to claim 1, characterized in that: The specific classification method of the transmission network fault level described in step 3 is level 1: safe and fault-free; Level 2: Lightning strike fault, wind deflection discharge fault and ice cover fault; Level 3: single-phase grounding fault, line three-phase current unbalance fault and line overload fault.

5. The method for evaluating power grid security according to claim 1, characterized in that: The power supply reliability calculation formula described in step 4 is: In the formula, RSA is the power supply reliability, T is the total time of the statistical period (in hours), and T i停 is the duration of the ith power outage, and n is the number of power outages.

6. A method for evaluating power grid security according to claim 1, characterized in that: The voltage quality calculation formula described in step 4 is: In the formula, V is the voltage quality, U is the actual voltage, and U N is the rated voltage, U1, U2, U3 are the amplitudes of the three-phase voltages.

7. A method for evaluating power grid security according to claim 1, characterized in that: The device health index calculation formula described in step 4 is: In the formula, H is the equipment health index at the current moment, H0 is the initial health index set when the equipment is put into operation, B is the aging rate of the equipment, which reflects the rate at which the equipment performance declines over time, T is the current year to be calculated, and T0 is the year corresponding to T, which is generally the year when the equipment is put into operation.

8. A method for evaluating power grid security according to claim 1, characterized in that: The calculation formula of the distribution network status index described in step 4 is: Distribution network status index = w RSA *RSA+w v *V+w H *H In the formula, w RSA is the weight of power supply reliability, w RSA =0.5, w v is the voltage quality weight, w v =0.3, w H is the weight of the device health status, w H =0.2, RSA is the power supply reliability, V is the voltage quality, and H is the equipment health status.

9. A method for evaluating power grid security according to claim 1, characterized in that: The calculation formula of the relationship model between the power grid line failure rate and weather conditions described in step 5 is: labmda wc (s)=labmda n f(s) In the formula, labmda wc (s) represents the line failure rate under weather state s, labmda n represents the average line failure rate under normal weather conditions, and f(s) is the failure rate growth factor under weather state s.

10. A power grid security assessment system, characterized in that: It includes an acquisition module, a transmission module, a level evaluation module, a threshold setting module, a comparison module and a report generation module, among which: Collection module: used to monitor and collect data on power grid network status, transmission network status, distribution network status and weather status; Transmission module: used to transmit data information; Level assessment module: used to calculate data and assess the power grid network security level, transmission network fault level, distribution network security level and weather security level; Threshold setting module: used to set the safety level thresholds of network status index, transmission network status index, distribution network status index and weather status index; Comparison module: used to compare the calculated and evaluated power grid network security level, transmission network fault level, distribution network security level and weather security level with the set security level threshold; Report generation module: used to generate an electronic version of the security level assessment report and print the electronic version of the security level assessment report into a paper version.

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