A method and system for assessing the risk of insulation damage of circuit breakers under multiple lightning strikes

Abstract

The present invention provides a method and system for assessing the risk of insulation damage of circuit breakers under multiple lightning strikes, wherein the method comprises: determining the circuit breaker to be risk assessed, obtaining the relevant parameters of the line where the circuit breaker is located and the electrical plan of the main equipment in the station; according to the relevant parameters and the electrical plan of the main equipment in the station, establishing a simulation model of the wiring of the transmission line and the main equipment of the substation; in the simulation model, judging whether the insulator is broken down by the pilot method; if so, obtaining the relevant parameters of the multiple lightning strikes in the area where the line is located, and calculating the insulation breakdown probability of the circuit breaker according to the Monte Carlo algorithm; judging that the calculated insulation breakdown probability of the circuit breaker is greater than a preset threshold, and completing the insulation damage risk assessment of the circuit breaker according to the judgment result. The present invention provides an important basis for the research on lightning protection of transmission lines.

Description

Technical Field

[0001] The present invention relates to the technical field of lightning protection for power transmission lines in an electric power system, and in particular to a method and system for assessing the risk of insulation damage of a circuit breaker under multiple lightning strikes. Background Art

[0002] Most lightning strikes in nature are multiple lightning strikes. Currently, the only commonly used evaluation index for the hazards of multiple lightning strikes to transmission lines is the lightning trip rate. However, there have been many accidents of equipment being damaged by lightning in existing substations, and the lightning trip rate cannot be used as a differentiated evaluation index for the hazards of multiple lightning strikes to equipment. In addition, in the existing research on the risk assessment of insulation damage to circuit breakers under multiple lightning strikes, the characteristics of multiple lightning strikes have not been considered: multiple lightning strikes are affected by lightning channels, and lightning in the same channel will not follow the laws of the electrical geometry model to hit the transmission line, but will develop along the already formed channel; the process of tripping after the transmission line is affected by lightning strikes has not been considered. In this process, if lightning strikes the line, total reflection occurs at the break of the circuit breaker, generating twice the overvoltage; the insulation tolerance level between the circuit breaker contacts will also change with the change of the contact opening distance. Before the circuit breaker contacts return to the initial opening distance, their impulse withstand voltage level is less than the rated value. Summary of the invention

[0003] To solve the above problems in the prior art, the present invention provides a method and system for assessing the risk of insulation damage of circuit breakers under multiple lightning strikes, which can assess the risk of circuit breakers being subjected to multiple lightning strikes and provide an important basis for the research on lightning protection of transmission lines.

[0004] A first aspect of the present invention provides a method for assessing the risk of insulation damage of a circuit breaker under multiple lightning strikes, comprising:

[0005] Determine the circuit breaker to be risk-assessed, and obtain relevant parameters of the line where the circuit breaker is located and the electrical plan of the main equipment in the station; wherein the relevant parameters include: the model of the tower, the tower height, the cross arm position of the tower, the grounding resistance of the tower, the length of the insulator, the volt-ampere characteristics of the line lightning arrester, the relevant parameters of the conductor, and the relevant parameters of the lightning conductor;

[0006] According to the relevant parameters and the electrical plan of the main equipment in the station, a simulation model of the wiring of the transmission line and the main equipment of the substation is established;

[0007] In the simulation model, the pilot method is used to determine whether the insulator is broken down; if so, multiple lightning strike related parameters of the area where the line is located are obtained, and the probability of insulation breakdown of the circuit breaker is calculated according to the Monte Carlo algorithm;

[0008] It is determined that the calculated probability of circuit breaker insulation breakdown is greater than a preset threshold, and the circuit breaker insulation damage risk assessment is completed based on the determination result.

[0009] Furthermore, the method of judging whether the insulator is broken down by the pilot method includes:

[0010] Applying an external voltage to the insulator and calculating the field strength value after the voltage is applied, when the field strength value is greater than a preset streamer starting field strength value, the streamer starts;

[0011] Determine whether the external voltage exceeds the starting voltage of the continuous pilot, if so, the pilot starts and works continuously;

[0012] The residual gap field strength value is calculated, and it is determined whether the leader undergoes a jump and direct breakdown according to the residual gap field strength value.

[0013] Furthermore, the insulation breakdown probability of the circuit breaker is calculated according to the Monte Carlo algorithm, including:

[0014] The number of lightning channels, the number of lightning strikes in each lightning channel, the position of the lightning leader relative to the line corridor, and the lightning current amplitude of each lightning strike are generated according to the Monte Carlo algorithm;

[0015] After determining the lightning strike points of multiple lightning strikes, determine whether the lightning current exceeds the strike back and shielding lightning withstand levels of the line; if the lightning current exceeds the strike back and shielding lightning withstand levels of the line, determine whether the lightning strike event causes insulation breakdown of the circuit breaker, and calculate the probability of insulation breakdown.

[0016] Furthermore, after completing the circuit breaker insulation damage risk assessment according to the judgment result, the method further includes:

[0017] If the insulation damage risk of the circuit breaker does not meet the lightning protection requirements, the grounding resistance, lightning protection angle, number of lightning conductors, insulator length, and type of lightning arrester are optimized, and the optimized results are brought into the evaluation method for recalculation until the results meet the lightning protection requirements.

[0018] A second aspect of the present invention provides a risk assessment system for insulation damage of circuit breakers under multiple lightning strikes, comprising:

[0019] A parameter acquisition module is used to determine the circuit breaker to be risk assessed, and obtain the relevant parameters of the line where the circuit breaker is located and the electrical plan of the main equipment in the station; wherein the relevant parameters include: the model of the tower, the tower height, the cross arm position of the tower, the grounding resistance of the tower, the length of the insulator, the volt-ampere characteristics of the line lightning arrester, the relevant parameters of the conductor, and the relevant parameters of the lightning conductor;

[0020] A simulation model building module, used to build a simulation model of the wiring of the transmission line and the main equipment of the substation according to the relevant parameters and the electrical plan of the main equipment in the station;

[0021] An insulator breakdown judgment module is used to judge whether the insulator is broken down by the pilot method in the simulation model; if so, obtain multiple lightning strike related parameters of the area where the line is located, and calculate the circuit breaker insulation breakdown probability according to the Monte Carlo algorithm;

[0022] The risk assessment module is used to determine whether the calculated probability of circuit breaker insulation breakdown is greater than a preset threshold, and complete the circuit breaker insulation damage risk assessment based on the judgment result.

[0023] Furthermore, the insulator breakdown judgment module is also used for:

[0024] Applying an external voltage to the insulator and calculating the field strength value after the voltage is applied, when the field strength value is greater than a preset streamer starting field strength value, the streamer starts;

[0025] Determine whether the external voltage exceeds the starting voltage of the continuous pilot, if so, the pilot starts and works continuously;

[0026] The residual gap field strength value is calculated, and it is determined whether the leader undergoes a jump and direct breakdown according to the residual gap field strength value.

[0027] Furthermore, the insulator breakdown judgment module is also used for:

[0028] The number of lightning channels, the number of lightning strikes in each lightning channel, the position of the lightning leader relative to the line corridor, and the lightning current amplitude of each lightning strike are generated according to the Monte Carlo algorithm;

[0029] After determining the lightning strike points of multiple lightning strikes, determine whether the lightning current exceeds the strike back and shielding lightning withstand levels of the line; if the lightning current exceeds the strike back and shielding lightning withstand levels of the line, determine whether the lightning strike event causes insulation breakdown of the circuit breaker, and calculate the probability of insulation breakdown.

[0030] Furthermore, the multiple lightning circuit breaker insulation damage risk assessment system further includes:

[0031] The optimization module is used to optimize the grounding resistance, lightning conductor protection angle, number of lightning conductors, insulator length, and type of lightning arrester if the insulation damage risk of the circuit breaker does not meet the lightning protection requirements, and bring the optimized results into the evaluation method for recalculation until the results meet the lightning protection requirements.

[0032] A third aspect of the present invention provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, the method for assessing insulation damage risk of circuit breakers under multiple lightning strikes as described in any one of the first aspects above is implemented.

[0033] A fourth aspect of the present invention provides a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the multiple lightning circuit breaker insulation damage risk assessment method as described in any one of the first aspects above.

[0034] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0035] The present invention provides a method and system for assessing the risk of insulation damage of a circuit breaker under multiple lightning strikes, wherein the method comprises: determining a circuit breaker to be risk assessed, obtaining relevant parameters of a line where the circuit breaker is located and an electrical plan of main equipment in a station; wherein the relevant parameters include: a tower model, a tower height, a cross arm position of a tower, a tower grounding resistance, an insulator length, a line arrester volt-ampere characteristic, relevant parameters of a conductor, and relevant parameters of a lightning conductor; according to the relevant parameters and the electrical plan of the main equipment in the station, establishing a simulation model of the wiring of a transmission line and a main equipment of a substation; in the simulation model, judging whether an insulator is broken down by a pilot method; if so, obtaining relevant parameters of multiple lightning strikes in the area where the line is located, and calculating the probability of insulation breakdown of the circuit breaker according to a Monte Carlo algorithm; judging that the calculated probability of insulation breakdown of the circuit breaker is greater than a preset threshold, and completing the risk assessment of insulation damage of the circuit breaker according to the judgment result. The present invention expands the lightning risk evaluation index that previously only used the lightning tripping rate as the only standard, and can also be used as one of the evaluation indicators for the difference of multiple lightning strikes on equipment; it takes into account the two damage mechanisms of external insulation damage and internal insulation damage of the circuit breaker, and also takes into account the relationship between the timing of multiple lightning strikes and the disconnection timing of the circuit breaker, so that the damage probability of the circuit breaker is more in line with the actual situation; it can provide an important basis for the research on lightning protection of transmission lines. If the risk is too high, it is necessary to adjust the variable parameters in the transmission line: lightning protection angle, number of lightning conductors, insulator length, type of lightning arrester, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a flow chart of a method for risk assessment of insulation damage of circuit breakers under multiple lightning strikes provided by a certain embodiment of the present invention;

[0038] Figure 2 is a flow chart of a method for assessing insulation damage risk of circuit breakers under multiple lightning strikes provided by another embodiment of the present invention;

[0039] Figure 3 A transmission line and substation main equipment wiring simulation model provided by a certain embodiment of the present invention;

[0040] Figure 4 A tower multi-wave impedance equivalent simulation model provided by a certain embodiment of the present invention;

[0041] Figure 5 is a flowchart of a pilot method for determining whether an insulator is broken down, provided by a certain embodiment of the present invention;

[0042] Figure 6 is a timing diagram of external insulation tolerance of a circuit breaker provided by a certain embodiment of the present invention;

[0043] Figure 7 It is a structural diagram of an electronic device provided by a certain embodiment of the present invention. DETAILED DESCRIPTION

[0044] 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.

[0045] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0046] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0047] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0048] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0049] The first aspect.

[0050] See also Figure 1 An embodiment of the present invention provides a method for assessing the risk of insulation damage of a circuit breaker under multiple lightning strikes, comprising:

[0051] S10, determine the circuit breaker to be risk assessed, obtain the relevant parameters of the line where the circuit breaker is located and the electrical plan of the main equipment in the station. The relevant parameters include: the model of the tower, the tower height, the cross arm position of the tower, the grounding resistance of the tower, the length of the insulator, the volt-ampere characteristics of the line lightning arrester, the relevant parameters of the conductor, and the relevant parameters of the lightning conductor.

[0052] S20. Establish a simulation model of the wiring of the transmission line and the main equipment of the substation according to the relevant parameters and the electrical plan of the main equipment in the station.

[0053] S30. In the simulation model, determine whether the insulator is broken down by the pilot method; if so, obtain multiple lightning strike related parameters of the area where the line is located, and calculate the circuit breaker insulation breakdown probability according to the Monte Carlo algorithm.

[0054] Preferably, the step of judging whether the insulator is broken down by the pilot method includes:

[0055] Applying an external voltage to the insulator and calculating the field strength value after the voltage is applied, when the field strength value is greater than a preset value of the streamer starting field strength, the streamer starts;

[0056] Determine whether the external voltage exceeds the starting voltage of the continuous pilot, if so, the pilot starts and works continuously;

[0057] The residual gap field strength value is calculated, and it is determined whether the leader undergoes a jump and direct breakdown according to the residual gap field strength value.

[0058] Preferably, calculating the insulation breakdown probability of the circuit breaker according to the Monte Carlo algorithm includes:

[0059] The number of lightning channels, the number of lightning strikes in each lightning channel, the position of the lightning leader relative to the line corridor, and the magnitude of the lightning current of each lightning strike are generated based on the Monte Carlo algorithm;

[0060] After determining the lightning strike points of multiple lightning strikes, determine whether the lightning current exceeds the strike back and shielding lightning withstand levels of the line; if the lightning current exceeds the strike back and shielding lightning withstand levels of the line, determine whether the lightning strike event causes insulation breakdown of the circuit breaker, and calculate the probability of insulation breakdown.

[0061] S40, determining that the calculated probability of circuit breaker insulation breakdown is greater than a preset threshold, and completing circuit breaker insulation damage risk assessment according to the determination result.

[0062] In a specific implementation of the embodiment of the present invention, the step S40 further includes:

[0063] If the insulation damage risk of the circuit breaker does not meet the lightning protection requirements, the grounding resistance, lightning protection angle, number of lightning conductors, insulator length, and type of lightning arrester are optimized, and the optimized results are brought into the evaluation method for recalculation until the results meet the lightning protection requirements.

[0064] The present invention expands the lightning risk evaluation index that previously only used the lightning tripping rate as the only standard, and can also be used as one of the evaluation indicators for the difference of multiple lightning strikes on equipment; it takes into account the two damage mechanisms of external insulation damage and internal insulation damage of the circuit breaker, and also takes into account the relationship between the timing of multiple lightning strikes and the disconnection timing of the circuit breaker, so that the damage probability of the circuit breaker is more in line with the actual situation; it can provide an important basis for the research on lightning protection of transmission lines. If the risk is too high, it is necessary to adjust the variable parameters in the transmission line: lightning protection angle, number of lightning conductors, insulator length, type of lightning arrester, etc.

[0065] See also Figure 2 In another embodiment of the present invention, the present invention provides a method for assessing the risk of insulation damage of a circuit breaker under multiple lightning strikes, comprising:

[0066] S1. Select the circuit breaker that needs to be risk assessed, and collect statistics on the tower model, height, crossarm position, conductor and lightning conductor related parameters, tower grounding resistance, insulator length, line lightning arrester volt-ampere characteristics, and electrical plan of the main equipment in the station.

[0067] S2. Build the transmission line and substation main equipment wiring model in the EMTP simulation software to calculate the overvoltage generated by the lightning intrusion wave at the circuit breaker. Figure 3 As shown in the figure, the lightning current waveform parameters are set to the standard lightning wave, with a wave head time of 1.2μs and a wave tail time of 50μs; the lightning channel wave impedance is 300Ω; the tower model includes the inductance model, the single wave impedance model, the multi-wave impedance model, etc. The multi-wave impedance model is used here, and the wave response characteristics of the model are closest to the wave response characteristics of the actual measured tower. Among them, the tower multi-wave impedance equivalent model is as follows Figure 4 As shown, the wave impedance of each part can be calculated according to formula (1) and formula (2):

[0068]

[0069] r ek =2 1 / 8 (r lk 1 / 3 r B 2 / 3 ) 1 / 4 (R lk 1 / 3 R B 2 / 3 ) 3 / 4(2);

[0070] Where h k 、r lk , R lk 、r B , R B is the size of the corresponding part of the tower. For towers with brackets, the bracket part is also equivalent according to the distributed parameters, and the equivalent wave impedance of the bracket part can be calculated according to formula (3):

[0071] Z Lk =9Z lK (k=1,2,3,4) (3);

[0072] The wave impedance of the cross arm can be calculated according to formula (4):

[0073] Z Ak =60ln(2h k / r Ak )(k=1,2,3,4) (4);

[0074] Where h k is the height of the cross arm; r Ak is the equivalent radius of the cross arm.

[0075] In addition, due to the high frequency of lightning, the JMarti frequency model is needed to build the line model in EMTP. The pilot method is used as the criterion for insulator breakdown and flashover. The process of the pilot method to determine whether the insulator is broken down is as follows: Figure 5 As shown. The leader method is a method of calculating flashover based on the development of gap leaders, combining the physical process of long air gap discharge to judge insulation flashover. First, when the insulator field strength is greater than the streamer starting field strength, the streamer begins to develop. When the applied voltage exceeds the starting voltage of the continuous leader, a leader channel appears. During the development of the leader, if the residual gap field strength is less than the leader development field strength, the leader development stagnates. When the residual gap is less than a certain critical value Hf, it can be considered that the leader has a jump and direct breakdown.

[0076] Finally, the circuit breakers, disconnectors, current transformers, transformers and other equipment inside the substation are equivalent to an entrance capacitor.

[0077] S3. Collect relevant parameters of multiple lightning strikes in the area where the transmission line is located: Statistical parameters of multiple lightning strikes in the area where the transmission line is located, such as: probability density distribution function f1(I1) of the lightning current amplitude of the first lightning strike; probability density distribution function f2(I2) of the lightning current amplitude of the subsequent lightning strike; lightning strike point location J(x); probability density distribution function H(a) of the number of lightning strike channels; probability density distribution function g(n) of the number of lightning strikes in each lightning channel; time interval t(n) between two lightning strikes. Among them, the probability density function of the lightning current amplitude conforms to the log-normal distribution; the position of the lightning strike point relative to the line corridor basically conforms to the uniform distribution; the probability density distribution function H(a) of the number of lightning strike channels; the probability density distribution function g(n) of the number of lightning strikes in each lightning channel can be obtained from the lightning location system data.

[0078] S4. Monte Carlo method is a statistical calculation method. It uses mathematical methods to generate random variable sampling sequences with different distributions based on the probability density distribution function of different parameters, inputs them into the model with solution parameters, and finally gives the statistical estimate of the numerical solution of the problem. Here, the Monte Carlo method is used to generate 100,000 random lightning strike events, and the electrical geometry model is combined to determine the location of the transmission line and calculate the probability of insulation breakdown of the circuit breaker. The step S4 includes steps S41 to S44:

[0079] S41. First, the number of lightning channels a and the number of lightning strikes n in each lightning channel of a lightning strike event are randomly generated according to the Monte Carlo method; the position x of the lightning leader head relative to the line corridor is generated; the lightning current amplitude of each lightning strike is generated. The electrical geometry model is used to determine the position of the first lightning strike point in each lightning channel, and the subsequent lightning strikes in the channel will still hit this lightning strike point.

[0080] According to the electrical geometry model, when the distance between the lightning leader and the ground target reaches a certain critical value, the lightning will hit the ground target. This critical value is called the strike distance. The strike distance for the lightning conductor and the conductor can be calculated by formula (5).

[0081]

[0082] Where k and p are calculation coefficients. my country's standards stipulate that the strike distance coefficients for conductors and lightning arresters are k = 10 and p = 0.65. Since the electric field strength near the ground is smaller than the electric field strength near the conductor, the strike distance of the lightning leader to the conductor is greater than the strike distance to the ground. The strike distance to the ground is given by formula (6).

[0083]

[0084] Where y c is the average height of the conductor (m); I Lis the lightning current amplitude (kA). When the distance between the lightning leader and the object reaches the strike distance, the lightning will discharge to the object. As the lightning current amplitude increases, the exposed arc segment becomes smaller and smaller until it is completely shielded by the lightning conductor and the ground. If the electrical geometry model is used to determine that lightning will not strike the conductor, then continue to determine whether lightning strikes the lightning conductor or the top of the tower to cause a counterattack.

[0085] S42. After determining the lightning strike point of multiple lightning strikes, determine whether the lightning current exceeds the lightning resistance level of the line's counter-strike and winding strike according to the pilot method. If it exceeds the lightning resistance level of the line, continue to determine whether the insulator has established a stable power frequency arc. The arc establishment rate η is related to the average electric field strength E in the arc path, and is also related to the instantaneous value of the power frequency voltage at the moment of flashover and the deionization condition. Based on test and operation experience, the arc establishment rate η can be calculated according to formula (7).

[0086] η=4.5E 0.75 -14(%) (7);

[0087] Where, E is the average operating voltage (effective value) gradient of the insulator string (kV / m). For the neutral point effective grounding system:

[0088]

[0089] BIL=ψ(ξ(t(n)-t1-t2-L(n) / v)) (8);

[0090] In the formula, u e is the line rated voltage (effective value) (kV); l is the insulation distance (m).

[0091] S43. If a lightning strike has not yet caused arcing at both ends of the insulator, the circuit breaker will not trip. In this case, the circuit breaker's external insulation withstand level (relative to phase, relative to ground) is considered. If the circuit breaker side voltage calculated by the simulation model does not exceed the circuit breaker's external insulation impulse withstand voltage, it is considered that the circuit breaker will not have an insulation breakdown accident;

[0092] If a lightning strike causes the insulator to break down and an arc is established, the line relay protection system will control the circuit breaker to trip, and this time is recorded as time 0. For subsequent lightning strikes, the time t(n) when the lightning strikes the conductor must be considered. Suppose that the circuit breaker starts to operate after t1 time has passed since the arc was established in the line; the function of the circuit breaker opening distance changing with time is L CB =ζ(t); the full opening time between the two contacts of the circuit breaker is t2; the function of the impulse voltage withstand level between the circuit breaker contacts with the opening distance is BIL=ψ(L CB); the distance between the lightning strike point and the circuit breaker is L(n); let the propagation speed of the lightning wave on the line be v. Then when the lightning intrusion wave reaches the circuit breaker break after the circuit breaker is disconnected, if the arc between the circuit breaker contacts has been extinguished, the BIL between the two contacts at the circuit breaker break can be expressed by formula (9).

[0093] BIL=ψ(ξ(t(n)-t1+L(n) / v))t(n)+L / v>t1+t2 (9);

[0094] If the arc has not been completely extinguished at the circuit breaker break, the insulation withstand level outside the circuit breaker should be considered. Figure 6 shown.

[0095] S44. According to the calculation in the previous steps, if there is a lightning strike in a certain lightning strike event that causes the internal insulation or external insulation of the circuit breaker to break down, then y k =1; otherwise y k = 0. After N samplings (N>100 0000), we can get the probability estimate:

[0096]

[0097] The more random sampling times are used here, the smaller the probability dispersion is, and the closer it is to the true value. The probability of circuit breaker damage R (times / (100km·a)) of the transmission line can be expressed as:

[0098] R=200N g P(11);

[0099] Where N g is the ground lightning density (times / (km 2 a)).

[0100] S5. Compare the calculated probability of circuit breaker damage with the probability of circuit breaker damage of other lines to obtain the lines with higher risks. If the requirements are not met, the adjustable parameters such as grounding resistance, lightning protection angle, number of lightning conductors, insulator length, and type of lightning arrester can be optimized. The optimized results are brought into the evaluation method for recalculation until the results meet the lightning protection requirements.

[0101] The present invention proposes a risk assessment method for insulation damage of circuit breakers under multiple lightning strikes taking into account the lightning tripping process, which expands the lightning risk assessment index that previously only used the lightning tripping rate as the only standard, and can also be used as one of the assessment indicators for equipment differences due to multiple lightning strikes; the present invention also takes into account two damage mechanisms, namely external insulation damage and internal insulation damage of the circuit breaker, and also takes into account the relationship between the timing of multiple lightning strikes and the disconnection timing of the circuit breaker, so that the damage probability of the circuit breaker is more in line with the actual situation; the present invention can provide an important basis for the research on lightning protection of transmission lines. If the risk is too high, it is necessary to adjust the variable parameters in the transmission line: lightning conductor protection angle, number of lightning conductors, insulator length, type of lightning arrester, etc.

[0102] The second aspect.

[0103] An embodiment of the present invention provides a system for assessing the risk of insulation damage of circuit breakers under multiple lightning strikes, comprising:

[0104] The parameter acquisition module is used to determine the circuit breaker to be risk assessed, and obtain the relevant parameters of the line where the circuit breaker is located and the electrical plan of the main equipment in the station. The relevant parameters include: the model of the tower, the tower height, the cross arm position of the tower, the grounding resistance of the tower, the length of the insulator, the volt-ampere characteristics of the line lightning arrester, the relevant parameters of the conductor, and the relevant parameters of the lightning conductor.

[0105] The simulation model establishment module is used to establish a simulation model of the wiring of the transmission line and the main equipment of the substation according to the relevant parameters and the electrical plan of the main equipment in the station.

[0106] The insulator breakdown judgment module is used to judge whether the insulator is broken down by the pilot method in the simulation model; if so, obtain the multiple lightning strike related parameters of the area where the line is located, and calculate the circuit breaker insulation breakdown probability according to the Monte Carlo algorithm.

[0107] Preferably, the insulator breakdown judgment module is further used for:

[0108] Applying an external voltage to the insulator and calculating the field strength value after the voltage is applied, when the field strength value is greater than a preset streamer starting field strength value, the streamer starts;

[0109] Determine whether the external voltage exceeds the starting voltage of the continuous pilot, if so, the pilot starts and works continuously;

[0110] The residual gap field strength value is calculated, and it is determined whether the leader undergoes a jump and direct breakdown according to the residual gap field strength value.

[0111] Preferably, the insulator breakdown judgment module is further used for:

[0112] The number of lightning channels, the number of lightning strikes in each lightning channel, the position of the lightning leader relative to the line corridor, and the lightning current amplitude of each lightning strike are generated according to the Monte Carlo algorithm;

[0113] After determining the lightning strike points of multiple lightning strikes, determine whether the lightning current exceeds the strike back and shielding lightning withstand levels of the line; if the lightning current exceeds the strike back and shielding lightning withstand levels of the line, determine whether the lightning strike event causes insulation breakdown of the circuit breaker, and calculate the probability of insulation breakdown.

[0114] The risk assessment module is used to determine whether the calculated probability of circuit breaker insulation breakdown is greater than a preset threshold, and complete the circuit breaker insulation damage risk assessment based on the judgment result.

[0115] Preferably, the multiple lightning circuit breaker insulation damage risk assessment system further includes:

[0116] The optimization module is used to optimize the grounding resistance, lightning conductor protection angle, number of lightning conductors, insulator length, and type of lightning arrester if the insulation damage risk of the circuit breaker does not meet the lightning protection requirements, and bring the optimized results into the evaluation method for recalculation until the results meet the lightning protection requirements.

[0117] The present invention expands the lightning risk evaluation index that previously only used the lightning tripping rate as the only standard, and can also be used as one of the evaluation indicators for the difference of multiple lightning strikes on equipment; it takes into account the two damage mechanisms of external insulation damage and internal insulation damage of the circuit breaker, and also takes into account the relationship between the timing of multiple lightning strikes and the disconnection timing of the circuit breaker, so that the damage probability of the circuit breaker is more in line with the actual situation; it can provide an important basis for the research on lightning protection of transmission lines. If the risk is too high, it is necessary to adjust the variable parameters in the transmission line: lightning protection angle, number of lightning conductors, insulator length, type of lightning arrester, etc.

[0118] The third aspect.

[0119] The present invention provides an electronic device, the electronic device comprising:

[0120] processor, memory, and bus;

[0121] The bus is used to connect the processor and the memory;

[0122] The memory is used to store operation instructions;

[0123] The processor is used to call the operation instruction, and the executable instruction enables the processor to perform operations corresponding to the method for assessing insulation damage risk of circuit breakers under multiple lightning strikes as shown in the first aspect of the present application.

[0124] In an alternative embodiment, an electronic device is provided, such as Figure 7 As shown, Figure 7 The electronic device 5000 shown includes: a processor 5001 and a memory 5003. The processor 5001 and the memory 5003 are connected, such as through a bus 5002. Optionally, the electronic device 5000 may also include a transceiver 5004. It should be noted that in actual applications, the transceiver 5004 is not limited to one, and the structure of the electronic device 5000 does not constitute a limitation on the embodiments of the present application.

[0125] Processor 5001 may be a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. Processor 5001 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0126] The bus 5002 may include a path to transmit information between the above components. The bus 5002 may be a PCI bus or an EISA bus, etc. The bus 5002 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0127] The memory 5003 may be a ROM or other type of static storage device that can store static information and instructions, a RAM or other type of dynamic storage device that can store information and instructions, or an EEPROM, a CD-ROM or other optical disk storage, an optical disk storage (including a compressed optical disk, a laser disk, an optical disk, a digital versatile disk, a Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.

[0128] The memory 5003 is used to store application code for executing the solution of the present application, and the execution is controlled by the processor 5001. The processor 5001 is used to execute the application code stored in the memory 5003 to implement the content shown in any of the above method embodiments.

[0129] Among them, electronic devices include but are not limited to: mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc.

[0130] The fourth aspect.

[0131] The present invention provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, a method for assessing insulation damage risk of circuit breakers under multiple lightning strikes as shown in the first aspect of the present application is implemented.

[0132] Another embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer-readable storage medium is run on a computer, the computer can execute the corresponding content in the aforementioned method embodiment.

Claims

1. A method for assessing the risk of insulation damage of circuit breakers under multiple lightning strikes, characterized in that: include: Determine the circuit breaker to be risk-assessed, and obtain relevant parameters of the line where the circuit breaker is located and the electrical plan of the main equipment in the station; wherein the relevant parameters include: the model of the tower, the tower height, the cross arm position of the tower, the grounding resistance of the tower, the length of the insulator, the volt-ampere characteristics of the line lightning arrester, the relevant parameters of the conductor, and the relevant parameters of the lightning conductor; According to the relevant parameters and the electrical plan of the main equipment in the station, a simulation model of the wiring of the transmission line and the main equipment of the substation is established; In the simulation model, the pilot method is used to determine whether the insulator is broken down; if so, multiple lightning strike related parameters of the area where the line is located are obtained, and the probability of insulation breakdown of the circuit breaker is calculated according to the Monte Carlo algorithm; It is determined that the calculated probability of insulation breakdown of the circuit breaker is greater than a preset threshold value, and the insulation damage risk assessment of the circuit breaker is completed according to the determination result; The method of judging whether the insulator is broken down by the pilot method comprises: Applying an external voltage to the insulator and calculating the field strength value after the voltage is applied, when the field strength value is greater than a preset streamer starting field strength value, the streamer starts; Determine whether the external voltage exceeds the starting voltage of the continuous pilot, if so, the pilot starts and works continuously; The residual gap field strength value is calculated, and it is determined whether the leader undergoes a jump and direct breakdown according to the residual gap field strength value.

2. A method for assessing insulation damage risk of circuit breakers under multiple lightning strikes as claimed in claim 1, characterized in that: The circuit breaker insulation breakdown probability is calculated based on the Monte Carlo algorithm, including: The number of lightning channels, the number of lightning strikes in each lightning channel, the position of the lightning leader relative to the line corridor, and the magnitude of the lightning current of each lightning strike are generated based on the Monte Carlo algorithm; After determining the lightning strike points of multiple lightning strikes, determine whether the lightning current exceeds the strike back and shielding lightning withstand levels of the line; if the lightning current exceeds the strike back and shielding lightning withstand levels of the line, determine whether the lightning strike event causes insulation breakdown of the circuit breaker, and calculate the probability of insulation breakdown.

3. A method for assessing insulation damage risk of circuit breakers under multiple lightning strikes as claimed in claim 1, characterized in that: After completing the circuit breaker insulation damage risk assessment according to the judgment result, the method further includes: If the insulation damage risk of the circuit breaker does not meet the lightning protection requirements, the grounding resistance, lightning protection angle, number of lightning conductors, insulator length, and type of lightning arrester are optimized, and the optimized results are brought into the evaluation method for recalculation until the results meet the lightning protection requirements.

4. A risk assessment system for insulation damage of circuit breakers under multiple lightning strikes, characterized in that: include: A parameter acquisition module is used to determine the circuit breaker to be risk assessed, and obtain the relevant parameters of the line where the circuit breaker is located and the electrical plan of the main equipment in the station; wherein the relevant parameters include: the model of the tower, the tower height, the cross arm position of the tower, the grounding resistance of the tower, the length of the insulator, the volt-ampere characteristics of the line lightning arrester, the relevant parameters of the conductor, and the relevant parameters of the lightning conductor; A simulation model building module, used to build a simulation model of the transmission line and substation main equipment wiring according to the relevant parameters and the electrical plan of the main equipment in the station; An insulator breakdown judgment module is used to judge whether the insulator is broken down by the pilot method in the simulation model; if so, obtain multiple lightning strike related parameters of the area where the line is located, and calculate the circuit breaker insulation breakdown probability according to the Monte Carlo algorithm; A risk assessment module, used to determine whether the calculated probability of insulation breakdown of the circuit breaker is greater than a preset threshold, and to complete the circuit breaker insulation damage risk assessment according to the determination result; The insulator breakdown judgment module is also used for: Applying an external voltage to the insulator and calculating the field strength value after the voltage is applied, when the field strength value is greater than a preset streamer starting field strength value, the streamer starts; Determine whether the external voltage exceeds the starting voltage of the continuous pilot, if so, the pilot starts and works continuously; The residual gap field strength value is calculated, and it is determined whether the leader undergoes a jump and direct breakdown according to the residual gap field strength value.

5. A risk assessment system for insulation damage of circuit breakers under multiple lightning strikes as claimed in claim 4, characterized in that: The insulator breakdown judgment module is also used for: The number of lightning channels, the number of lightning strikes in each lightning channel, the position of the lightning leader relative to the line corridor, and the magnitude of the lightning current of each lightning strike are generated based on the Monte Carlo algorithm; After determining the lightning strike points of multiple lightning strikes, determine whether the lightning current exceeds the strike back and shielding lightning withstand levels of the line; if the lightning current exceeds the strike back and shielding lightning withstand levels of the line, determine whether the lightning strike event causes insulation breakdown of the circuit breaker, and calculate the probability of insulation breakdown.

6. A risk assessment system for insulation damage of circuit breakers under multiple lightning strikes as claimed in claim 4, characterized in that: Also includes: The optimization module is used to optimize the grounding resistance, lightning conductor protection angle, number of lightning conductors, insulator length, and type of lightning arrester if the insulation damage risk of the circuit breaker does not meet the lightning protection requirements, and bring the optimized results into the evaluation system for recalculation until the results meet the lightning protection requirements.

7. An electronic device, characterized in that: The invention comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, the method for assessing insulation damage risk of circuit breakers under multiple lightning strikes as claimed in any one of claims 1 to 3 is implemented.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the insulation damage risk assessment method for circuit breakers under multiple lightning strikes as claimed in any one of claims 1 to 3.

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