Lightning damage risk assessment method and system for active power distribution network

Abstract

The invention relates to the technical field of lightning damage risk assessment, in particular to an active power distribution network lightning damage risk assessment method and system, and the method comprises the steps: building an active power distribution network lightning stroke simulation calculation model through ATP-EMTP; calculating the lightning resistance level and the flashover rate by using the simulation calculation model; performing risk assessment analysis based on the cloud-to-ground lightning density information; according to the invention, the lightning stroke simulation calculation model of the active power distribution network is established by adopting ATP-EMTP, so that the lightning stroke process of the power distribution network is accurately simulated, and the accuracy of lightning damage risk assessment is improved; through the method of calculating the lightning resistance level and the flashover rate by using the simulation calculation model, the performance evaluation of the photovoltaic side and the line side of the power distribution network under the lightning stroke effect is realized, and potential risks can be found in time; through the means of risk assessment and analysis based on the ground lightning density information, the calculation precision of the lightning flashover rate is improved by combining the ground lightning density data of the photovoltaic side and the line side, and powerful support is provided for lightning damage risk assessment of the power distribution network.

Description

Technical Field

[0001] The present invention relates to the technical field of lightning damage risk assessment, and in particular to a method and system for assessing lightning damage risk in an active power distribution network. Background Art

[0002] Most of the existing distribution network lightning risk assessment methods are based on traditional lightning theory and power system simulation technology, but there are few lightning risk assessment methods for active distribution network systems. Traditional methods mainly consider the lightning risk on the line side and ignore the particularity of the photovoltaic side. Therefore, a more comprehensive and targeted active distribution network lightning risk assessment method is needed.

[0003] Traditional distribution network lightning risk assessment methods mainly focus on faults and flashovers on the line side, but in active distribution network systems, the photovoltaic side is also an important consideration. The failure rate and lightning resistance level of the photovoltaic side under lightning strikes directly affect the stability and safety of the system. Therefore, it is necessary to include the photovoltaic side in the scope of lightning risk assessment. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method for assessing the risk of lightning damage in an active distribution network. By adopting the technology of ATP-EMTP to build a lightning strike simulation calculation model for an active distribution network, accurate simulation of the lightning strike process of the distribution network is achieved, thereby improving the accuracy of lightning damage risk assessment; by using a method of calculating the lightning resistance level and flashover rate using a simulation calculation model, performance evaluation of the photovoltaic side and line side of the distribution network under lightning strikes is achieved, which helps to timely discover potential risks.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a method for assessing the risk of lightning damage in an active distribution network, comprising the following steps:

[0007] Use ATP-EMTP to build an active distribution network lightning strike simulation calculation model;

[0008] Calculate lightning resistance level and flashover rate using simulation calculation model;

[0009] Conduct risk assessment analysis based on ground-to-ground flash density information.

[0010] As a preferred solution of the active distribution network lightning damage risk assessment method described in the present invention, wherein: the use of ATP-EMTP to build an active distribution network lightning strike simulation calculation model is to build a simulation model in ATP-EMTP, which is based on the physical equations and circuit analysis principles of the power system, simulating the electromagnetic process and transmission characteristics between different nodes, and the active distribution network lightning strike simulation calculation model is based on the photovoltaic side and the line side, and is applied to the active distribution network system, including the node voltage and current relationship, the photovoltaic power supply model and the distribution line model;

[0011] The relationship between the node voltage and current is determined based on Ohm's law, as follows:

[0012] V=I·Z

[0013] Where V represents the node voltage, I represents the node current, and Z represents the node impedance;

[0014] The distribution line model is built based on the transmission line model on the line side, and the specific construction is as follows:

[0015] Z=R+jX

[0016] Where R represents the resistance of the line, X represents the reactance of the line, and j represents the imaginary unit;

[0017] The photovoltaic power supply model is built based on the photovoltaic side power supply, and the specific construction is as follows:

[0018] I pv =I pv0 ·(1+α·(T-T0))

[0019] Among them, I pv0 It represents the rated current of the photovoltaic power source, α represents the temperature coefficient, T represents the current temperature data, and T0 represents the reference temperature of the photovoltaic power source.

[0020] As a preferred solution of the active distribution network lightning risk assessment method described in the present invention, wherein: the calculation of the lightning resistance level and the flashover rate using the simulation calculation model is to calculate the photovoltaic side lightning resistance level and the line side flashover lightning resistance level using the established active distribution network lightning strike simulation calculation model; the photovoltaic side lightning resistance level is the possibility of a fault in the photovoltaic system under a lightning strike event, and the voltage and current on the photovoltaic side under the action of lightning strike are calculated to further evaluate the lightning resistance level of the fault. The specific calculation formula is as follows:

[0021]

[0022] Among them, I pv Represents the photovoltaic side current, I pv0 Indicates the rated current of the photovoltaic power source, V pvRepresents the voltage on the photovoltaic side, Z pv Represents the impedance of the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level. The PV-side lightning protection level is classified by calculating the ratio between the PV-side current and the rated current of the PV power source. The specific classification is as follows:

[0023] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0≤I gg When it is less than 0.6, it means that the current on the photovoltaic side is small and there is no danger of fault. At this time, the lightning resistance level of the photovoltaic side is level one;

[0024] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0.6≤I gg When <0.8, it means that the current on the photovoltaic side is within the safe range and there is no risk of failure. At this time, the lightning protection level of the photovoltaic side is level 2;

[0025] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0.8≤I gg When <1, it means that there is current on the photovoltaic side and there is a risk of fault. You need to pay attention to fault prevention at all times. At this time, the lightning resistance level of the photovoltaic side is level 3;

[0026] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 1≤I gg When it is displayed, it means that the current on the photovoltaic side exceeds the safety upper limit. Immediately notify relevant personnel to carry out maintenance to reduce the risk of failure.

[0027] As a preferred solution of the active distribution network lightning risk assessment method described in the present invention, the line side flashover lightning resistance level refers to the possibility of flashover of the line under the action of lightning, and the lightning resistance level of the line side is reflected by calculating the flashover rate of the line side. The specific calculation formula is as follows:

[0028]

[0029] Among them, T represents the line inspection period, I i represents the line current at the time of the ith lightning strike, I0 represents the rated current of the line, V i represents the line voltage at the time of the i-th lightning strike, V0 represents the rated line voltage, m and n represent the line characteristic parameters, which are determined by the line material, and λ represents the calculated line side flashover rate. The line side lightning withstand level is graded by taking the inverse of the calculated line side flashover rate. The specific classification is as follows:

[0030] When the calculated line side flashover rate satisfies the formula 0≤λ<0.001, it means that the current line side flashover rate is low and there is no danger of fault. At this time, the line side lightning withstand level is level one;

[0031] When the calculated line-side flashover rate satisfies the formula 0.001≤λ<0.01, it means that the current line-side flashover rate is within the safe range and there is no danger of fault. At this time, the line-side lightning withstand level is level 2.

[0032] When the calculated line-side flashover rate satisfies the formula 0.01≤λ<0.1, it means that the current line-side flashover rate fluctuates within the safe range, and there is a risk of fault occurrence. Relevant personnel are notified to make precautionary preparations. At this time, the lightning resistance level of the line side is level three;

[0033] When the calculated line-side flashover rate satisfies the formula 0.1≤λ, it means that the current line-side flashover rate exceeds the upper limit of the safety range, and relevant personnel are immediately notified for maintenance. At this time, the line-side lightning resistance level is level four.

[0034] As a preferred solution of the lightning risk assessment method for an active distribution network described in the present invention, wherein: the risk assessment analysis based on ground-to-ground lightning density information is performed by combining the ground-to-ground lightning density information, calculating the failure rate of the photovoltaic side itself when lightning strikes the photovoltaic side, the flashover rate of the line side itself when lightning strikes the line side, and the failure rate of the photovoltaic side, and summarizing the calculation results to obtain the total lightning flashover rate of each tower on the photovoltaic side and the line side, and performing quantitative risk assessment on the active distribution network system through the lightning flashover rate; the ground-to-ground lightning density information includes the ground-to-ground lightning density on the photovoltaic side and the ground-to-ground lightning density on the line side, the ground-to-ground lightning density on the photovoltaic side is achieved by installing a ground-to-ground lightning monitoring device in the photovoltaic system, monitoring and collecting the ground-to-ground lightning density in the photovoltaic side area, and the ground-to-ground lightning density on the line side is achieved by installing a lightning locating device to monitor and collect the ground-to-ground lightning density around the line.

[0035] As a preferred solution of the active distribution network lightning risk assessment method described in the present invention, the failure rate of the photovoltaic side itself when the photovoltaic side is struck by lightning is the probability of failure of the photovoltaic system under the action of lightning calculated in combination with the ground lightning density on the photovoltaic side. The specific calculation formula is as follows:

[0036] η pv =I gg ×D pv

[0037] Among them, D pv Indicates the density information of ground flash on the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level, which is obtained by calculating the ratio between the PV-side current and the rated current of the PV power source, η pv Indicates the failure rate of the photovoltaic side itself;

[0038] The flashover rate of the line side itself when lightning strikes the line side is a combination of the ground flash density on the line side and the flashover rate on the line side. The specific calculation formula is as follows:

[0039]

[0040] Where, λ represents the calculated line side flashover rate, D s represents the ground flash density on the line side, L represents the line length, λ s Indicates the calculated line side self-flashover rate;

[0041] The photovoltaic side failure rate is the probability of failure of the photovoltaic system in a unit time. The specific calculation formula is as follows:

[0042]

[0043] Among them, D pv Indicates the density information of ground flash on the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level, which is obtained by calculating the ratio between the PV-side current and the rated current of the PV power source. Represents the photovoltaic side fault coefficient, which is determined by the structural material and has a value of 0.5, λ pv Represents the calculated PV side failure rate.

[0044] As a preferred solution of the active distribution network lightning risk assessment method described in the present invention, the quantitative risk assessment of the active distribution network system through the lightning flashover rate is to calculate the total number of tower tripping times according to the total lightning flashover rate, and complete the quantitative risk assessment of the active distribution network system according to the total number of tower tripping times, and the total number of tower tripping times is calculated by calculating the sum of the number of tower tripping times and the number of tripping times caused by lightning, and the specific calculation is as follows:

[0045]

[0046] Among them, t i represents the number of trips caused by the ith lightning strike, t pvi represents the number of self-tripping for the i-th time, λ T represents the total lightning flashover rate, λ pv represents the calculated PV side failure rate, P r It represents the average number of lightning tripping times of the whole line, T R It represents the total number of tower tripping times. According to the calculated total number of tower tripping times, the active distribution network system is quantitatively evaluated for risk, as follows:

[0047] When the total number of tower tripping times satisfies the formula 0<T R ≤0.5P r At this time, the area at the tower pole is classified as a Class A low-risk tower pole area;

[0048] When the total number of tower tripping times meets the formula 0.5P r <T R≤P r At this time, the area at the tower pole is classified as a Class B medium-risk tower pole area;

[0049] When the total tripping times of the tower pole meet the formula P r <T R ≤1.5P r At this time, the area at the tower pole is classified as a Class C high-risk tower pole area;

[0050] When the total number of tower tripping times meets the formula 1.5P r <T R At this time, the area at the tower pole is divided into a Class D ultra-high risk tower pole area.

[0051] Another object of the present invention is to provide an active distribution network lightning damage risk assessment system, which can improve the calculation accuracy of lightning flashover rate by combining ground-to-ground lightning density data on the photovoltaic side and the line side through risk assessment and analysis based on ground-to-ground lightning density information, and provide strong support for lightning damage risk assessment of distribution networks; by grading the lightning resistance level of the photovoltaic side, the safety status of the photovoltaic system under lightning strikes can be clearly understood, providing an effective basis for fault prevention for operation and maintenance personnel.

[0052] As a preferred solution of the active distribution network lightning damage risk assessment system described in the present invention, it includes: a model building module, a lightning resistance level and flashover rate calculation module and a risk assessment module; the model building module is used to build an active distribution network lightning strike simulation calculation model in ATP-EMTP; the lightning resistance level and flashover rate calculation module calculates the lightning resistance level and flashover rate using the active distribution network lightning strike simulation calculation model; the risk assessment module performs lightning damage risk assessment on the active distribution network based on ground lightning density information.

[0053] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, steps of a method for assessing the risk of lightning damage in an active power distribution network are implemented.

[0054] A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of a method for assessing the risk of lightning damage in an active power distribution network.

[0055] The beneficial effects of the present invention are as follows: the present invention realizes accurate simulation of the lightning strike process of the distribution network by adopting the technology of ATP-EMTP to build a lightning strike simulation calculation model for an active distribution network, thereby improving the accuracy of lightning damage risk assessment; by using the method of using the simulation calculation model to calculate the lightning resistance level and the flashover rate, the performance evaluation of the photovoltaic side and the line side of the distribution network under the action of lightning strike is realized, which is helpful to timely discover potential risks; by means of risk assessment and analysis based on ground lightning density information, the ground lightning density data of the photovoltaic side and the line side are combined, the calculation accuracy of the lightning flashover rate is improved, and strong support is provided for the lightning damage risk assessment of the distribution network; by grading the lightning resistance level of the photovoltaic side, the safety status of the photovoltaic system under the action of lightning strike can be clearly understood, and an effective fault prevention basis is provided for operation and maintenance personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0057] Figure 1 The present invention is a schematic diagram of the overall method steps of an active distribution network lightning damage risk assessment method.

[0058] Figure 2 This is a risk assessment classification standard diagram of an overall method for risk assessment of lightning damage in an active power distribution network according to the present invention.

[0059] Figure 3 The present invention is a schematic diagram of the overall structure of an active distribution network lightning damage risk assessment system. DETAILED DESCRIPTION

[0060] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0061] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0062] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0063] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0064] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] Example 1

[0067] Reference Figure 1-2 , which is a first embodiment of the present invention, provides a method for assessing lightning risk in an active distribution network, comprising the following steps:

[0068] S1: Use ATP-EMTP to build an active distribution network lightning strike simulation calculation model.

[0069] Specifically, the use of ATP-EMTP to build an active distribution network lightning strike simulation calculation model is to build a simulation model in ATP-EMTP, which is based on the physical equations of the power system and the circuit analysis principles, and simulates the electromagnetic process and transmission characteristics between different nodes. The active distribution network lightning strike simulation calculation model is based on the photovoltaic side and the line side, and is applied to the active distribution network system, including the relationship between node voltage and current, the photovoltaic power supply model and the distribution line model.

[0070] Furthermore, the relationship between the node voltage and current is determined based on Ohm's law, as follows:

[0071] V=I·Z

[0072] Where V represents the node voltage, I represents the node current, and Z represents the node impedance;

[0073] The distribution line model is built based on the transmission line model on the line side, and the specific construction is as follows:

[0074] Z=R+jX

[0075] Where R represents the resistance of the line, X represents the reactance of the line, and j represents the imaginary unit;

[0076] The photovoltaic power supply model is built based on the photovoltaic side power supply, and the specific construction is as follows:

[0077] I pv =I pv0 ·(1+α·(T-T0))

[0078] Among them, I pv0 It represents the rated current of the photovoltaic power source, α represents the temperature coefficient, T represents the current temperature data, and T0 represents the reference temperature of the photovoltaic power source.

[0079] S2: Calculate the lightning resistance level and flashover rate using the simulation calculation model.

[0080] Specifically, the use of a simulation calculation model to calculate the lightning resistance level and the flashover rate is to use a built active distribution network lightning strike simulation calculation model to calculate the photovoltaic side fault lightning resistance level and the line side flashover lightning resistance level.

[0081] Furthermore, the photovoltaic side lightning resistance level is the possibility of a fault in the photovoltaic system under a lightning strike event. The lightning resistance level of the fault is evaluated by calculating the voltage and current of the photovoltaic side under the action of lightning. The specific calculation formula is as follows:

[0082]

[0083] Among them, I pv Represents the photovoltaic side current, I pv0 Indicates the rated current of the photovoltaic power source, V pv Represents the voltage on the photovoltaic side, Z pv Represents the impedance of the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level. The PV-side lightning protection level is classified by calculating the ratio between the PV-side current and the rated current of the PV power source. The specific classification is as follows:

[0084] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0≤I gg When it is less than 0.6, it means that the current on the photovoltaic side is small and there is no danger of fault. At this time, the lightning resistance level of the photovoltaic side is level one;

[0085] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0.6≤I gg When <0.8, it means that the current on the photovoltaic side is within the safe range and there is no risk of failure. At this time, the lightning protection level of the photovoltaic side is level 2;

[0086] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0.8≤I gg When <1, it means that there is current on the photovoltaic side and there is a risk of fault. You need to pay attention to fault prevention at all times. At this time, the lightning resistance level of the photovoltaic side is level 3;

[0087] When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 1≤I gg When it is displayed, it means that the current on the photovoltaic side exceeds the safety upper limit. Immediately notify relevant personnel to carry out maintenance to reduce the risk of failure.

[0088] Furthermore, the flashover lightning resistance level of the line side refers to the possibility of flashover of the line under the action of lightning. The lightning resistance level of the line side is reflected by calculating the flashover rate of the line side. The specific calculation formula is as follows:

[0089]

[0090] Among them, T represents the line inspection period, I i represents the line current at the time of the ith lightning strike, I0 represents the rated current of the line, V i represents the line voltage at the time of the i-th lightning strike, V0 represents the rated line voltage, m and n represent the line characteristic parameters, which are determined by the line material, and λ represents the calculated line side flashover rate. The line side lightning withstand level is graded by taking the inverse of the calculated line side flashover rate. The specific classification is as follows:

[0091] When the calculated line side flashover rate satisfies the formula 0≤λ<0.001, it means that the current line side flashover rate is low and there is no danger of fault. At this time, the line side lightning withstand level is level one;

[0092] When the calculated line-side flashover rate satisfies the formula 0.001≤λ<0.01, it means that the current line-side flashover rate is within the safe range and there is no danger of fault. At this time, the line-side lightning withstand level is level 2.

[0093] When the calculated line-side flashover rate satisfies the formula 0.01≤λ<0.1, it means that the current line-side flashover rate fluctuates within the safe range, and there is a risk of fault occurrence. Relevant personnel are notified to make precautionary preparations. At this time, the lightning resistance level of the line side is level three;

[0094] When the calculated line-side flashover rate satisfies the formula 0.1≤λ, it means that the current line-side flashover rate exceeds the upper limit of the safety range, and relevant personnel are immediately notified for maintenance. At this time, the line-side lightning resistance level is level four.

[0095] S3: Conduct risk assessment analysis based on ground-to-ground flash density information.

[0096] Specifically, the risk assessment analysis based on ground-to-ground lightning density information is performed by combining the ground-to-ground lightning density information to calculate the failure rate of the photovoltaic side itself when lightning strikes the photovoltaic side, the flashover rate of the line side itself when lightning strikes the line side, and the failure rate of the photovoltaic side, and the calculation results are summarized to obtain the total lightning flashover rate of each tower on the photovoltaic side and the line side, and the active distribution network system is quantitatively assessed by the lightning flashover rate.

[0097] Furthermore, the ground-to-ground lightning density information includes the ground-to-ground lightning density on the photovoltaic side and the ground-to-ground lightning density on the line side. The ground-to-ground lightning density on the photovoltaic side is achieved by installing ground-to-ground lightning monitoring equipment in the photovoltaic system to monitor and collect the ground-to-ground lightning density in the photovoltaic side area. The ground-to-ground lightning density on the line side is achieved by installing a lightning locating device to monitor and collect the ground-to-ground lightning density around the line.

[0098] It should be noted that the failure rate of the photovoltaic side itself when the photovoltaic side is struck by lightning is the probability of failure of the photovoltaic system under the action of lightning calculated in combination with the ground lightning density on the photovoltaic side. The specific calculation formula is as follows:

[0099] η pv =I gg ×D pv

[0100] Among them, D pv Indicates the density information of ground flash on the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level, which is obtained by calculating the ratio between the PV-side current and the rated current of the PV power source, η pv Indicates the failure rate of the photovoltaic side itself;

[0101] The flashover rate of the line side itself when lightning strikes the line side is a combination of the ground flash density on the line side and the flashover rate on the line side. The specific calculation formula is as follows:

[0102]

[0103] Where, λ represents the calculated line side flashover rate, D s represents the ground flash density on the line side, L represents the line length, λs Indicates the calculated line side self-flashover rate;

[0104] The photovoltaic side failure rate is the probability of failure of the photovoltaic system in a unit time. The specific calculation formula is as follows:

[0105]

[0106] Among them, D pv Indicates the density information of ground flash on the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level, which is obtained by calculating the ratio between the PV-side current and the rated current of the PV power source. Represents the photovoltaic side fault coefficient, which is determined by the structural material and has a value of 0.5, λ pv Represents the calculated PV side failure rate.

[0107] Furthermore, the total lightning flashover rate of each tower on the photovoltaic side and the line side is calculated by calculating the total number of lightning flashovers on each tower per unit time, by calculating the sum of the failure rate on the photovoltaic side and the flashover rate on the line side. The specific calculation formula is as follows:

[0108] λ T =λ pv +λ

[0109] Among them, λ pv represents the calculated PV side failure rate, λ represents the calculated line side flashover rate, λ T Indicates the total lightning flashover rate.

[0110] Furthermore, the quantitative risk assessment of the active distribution network system by the lightning flashover rate is to calculate the total number of tower tripping according to the total lightning flashover rate, and complete the quantitative risk assessment of the active distribution network system according to the total number of tower tripping. The total number of tower tripping is calculated by the sum of the number of tower tripping itself and the number of tripping caused by lightning, and the specific calculation is as follows:

[0111]

[0112] Among them, t i represents the number of trips caused by the ith lightning strike, t pvi represents the number of self-tripping for the i-th time, λ T represents the total lightning flashover rate, λ pv represents the calculated PV side failure rate, P r It represents the average number of lightning tripping times of the whole line, T R It represents the total number of tower tripping times. According to the calculated total number of tower tripping times, the active distribution network system is quantitatively evaluated for risk, as follows:

[0113] When the total number of tower tripping times satisfies the formula 0<TR ≤0.5P r At this time, the area at the tower pole is classified as a Class A low-risk tower pole area;

[0114] When the total tripping times of the tower pole meet the formula 0.5P r <T R ≤P r At this time, the area at the tower pole is classified as a Class B medium-risk tower pole area;

[0115] When the total tripping times of the tower pole meet the formula P r <T R ≤1.5P r At this time, the area at the tower pole is classified as a Class C high-risk tower pole area;

[0116] When the total number of tower tripping times meets the formula 1.5P r <T R At this time, the area at the tower pole is divided into a Class D ultra-high risk tower pole area.

[0117] It should be noted that in order to further distinguish the lightning strike risks borne by different towers, the possible lightning strike failures are further distinguished. The specific distinctions are as follows:

[0118] Level I risk towers indicate the lowest risk, with a theoretical trip rate of 0, meaning that lightning strikes here will basically not cause line flashover or PV side failures, and lightning strikes on the PV side will not cause flashover of this level of towers;

[0119] II1 level risk towers are: Lightning strikes here will cause line flashover, but will not cause faults on the photovoltaic side, nor will they be affected by lightning intrusion waves on the photovoltaic side;

[0120] II2 level risk towers are: Lightning strikes here will not cause line flashover, but will cause faults on the photovoltaic side, and will not cause tripping on the photovoltaic side;

[0121] II3 level risk towers indicate that lightning strikes here will not cause line flashover or PV side failure, but will be affected by lightning strikes and cause tripping;

[0122] Level III1 risk means that lightning strikes here will not cause line flashover, but will cause faults on the PV side, and there is a risk of tripping caused by lightning strikes on the PV;

[0123] Level III2 risk means that lightning strikes here only cause flashover on the line side and will not affect the PV side, but the PV side may be tripped by lightning.

[0124] Level III3 risk means that lightning strikes here may affect both the line side and the PV side, but will not be affected by lightning strikes on the PV side;

[0125] Level IV risk indicates that lightning strikes here may affect both the line side and the photovoltaic side, and there is a possibility that the photovoltaic side will be affected by lightning strikes.

[0126] Example 2

[0127] Reference Figure 3 , which is a second embodiment of the present invention, provides an active distribution network lightning damage risk assessment system, including a model building module, a lightning resistance level and flashover rate calculation module and a risk assessment module;

[0128] Specifically, the model building module is used to build an active distribution network lightning strike simulation calculation model in ATP-EMTP; the lightning resistance level and flashover rate calculation module uses the active distribution network lightning strike simulation calculation model to calculate the lightning resistance level and flashover rate; the risk assessment module performs lightning damage risk assessment on the active distribution network based on ground lightning density information.

[0129] Furthermore, the model building module is the first step of the active distribution network lightning damage risk assessment system. The active distribution network lightning strike simulation calculation model is built using ATP-EMTP, including a data collection unit, a model building unit, a node voltage and current relationship combing unit, a distribution line unit and a photovoltaic power supply unit. The data collection unit collects basic data of the active distribution network before the model building begins, including tower location, line length, span information and photovoltaic system access points; the model building unit is used to describe the principle of building a model in ATP-EMTP, including the principle of building a model based on the physical equations of the power system and circuit analysis. The simulation process of the analysis principle is as follows. The constructed model will include the node voltage and current relationship, the photovoltaic power supply model and the distribution line model; the node voltage and current relationship combing unit is based on Ohm's law, describing the relationship between node voltage, current and impedance, and simulating the electromagnetic process between nodes through these relationships; the distribution line unit is constructed based on the transmission line model on the line side, including parameters such as line resistance and reactance, which are used to simulate the transmission characteristics of the line; the photovoltaic power supply unit is constructed based on the characteristics of the photovoltaic side power supply, including parameters such as the rated current and temperature coefficient of the photovoltaic power supply, which are used to simulate the electromagnetic characteristics of the photovoltaic side;

[0130] The lightning resistance level and flashover rate calculation module is used to calculate the lightning resistance level and flashover rate by using the built model after the simulation model is built. For the photovoltaic side, the lightning resistance level of the photovoltaic system is evaluated by calculating the voltage and current under the action of lightning strike; for the line side, the lightning resistance performance of the line is reflected by calculating the flashover rate of the line; the calculation results will directly affect the subsequent risk assessment analysis;

[0131] The lightning resistance level and flashover rate calculation module performs lightning damage risk assessment and analysis of the active distribution network based on the calculation results of the lightning resistance level and flashover rate and the ground lightning density information; the lightning resistance level and flashover rate calculation module comprehensively considers factors such as the photovoltaic side's own failure rate, the line side's own flashover rate and the total lightning flashover rate, and performs quantitative risk assessment on the distribution network system; the assessment result can provide important guidance for the lightning protection design and operation and maintenance of the distribution network.

[0132] It should be noted that this system realizes the lightning risk assessment of active distribution network through the close cooperation and interaction of various modules. From simulation model construction to risk assessment analysis, to result display and early warning, each module plays an indispensable role, together forming a complete and efficient lightning risk assessment system.

[0133] Furthermore, if the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0134] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0135] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0136] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0137] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0138] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A lightning risk assessment method for active distribution network. Features: The following steps are included: Use ATP-EMTP to build an active distribution network lightning strike simulation calculation model; Calculate lightning resistance level and flashover rate using simulation calculation model; Conduct risk assessment analysis based on ground-to-ground flash density information.

2. A method for assessing lightning risk in an active power distribution network as claimed in claim 1, Features: The use of ATP-EMTP to build an active distribution network lightning strike simulation calculation model is to build a simulation model in ATP-EMTP, which is based on the physical equations and circuit analysis principles of the power system to simulate the electromagnetic process and transmission characteristics between different nodes. The active distribution network lightning strike simulation calculation model is based on the photovoltaic side and the line side, and is applied to the active distribution network system, including the node voltage and current relationship, the photovoltaic power supply model and the distribution line model; The relationship between the node voltage and current is determined based on Ohm's law, as follows: V=I·Z Where V represents the node voltage, I represents the node current, and Z represents the node impedance; The distribution line model is built based on the transmission line model on the line side, and the specific construction is as follows: Z=R+jX Where R represents the resistance of the line, X represents the reactance of the line, and j represents the imaginary unit; The photovoltaic power supply model is built based on the photovoltaic side power supply, and the specific construction is as follows: I pv =I pv0 ·(1+α·(T-T 0 )) Among them, I pv0 represents the rated current of the photovoltaic power source, α represents the temperature coefficient, T represents the current temperature data, T 0 Indicates the reference temperature of the photovoltaic power source.

3. A method for assessing lightning damage risk in an active distribution network as claimed in claim 2, Features: The calculation of the lightning resistance level and flashover rate using the simulation calculation model is to use the established active distribution network lightning simulation calculation model to calculate the photovoltaic side lightning resistance level and the line side flashover lightning resistance level; the photovoltaic side lightning resistance level is the possibility of a fault in the photovoltaic system under a lightning strike event, and the voltage and current of the photovoltaic side under the action of lightning strike are calculated to evaluate the lightning resistance level of the fault. The specific calculation formula is as follows: Among them, I pv Represents the photovoltaic side current, I pv0 Indicates the rated current of the photovoltaic power source, V pv Represents the voltage on the photovoltaic side, Z pv Represents the impedance of the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level. The PV-side lightning protection level is classified by calculating the ratio between the PV-side current and the rated current of the PV power source. The specific classification is as follows: When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0≤I gg When it is less than 0.6, it means that the current on the photovoltaic side is small and there is no danger of fault. At this time, the lightning resistance level of the photovoltaic side is level one; When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0.6≤I gg When <0.8, it means that the current on the photovoltaic side is within the safe range and there is no risk of failure. At this time, the lightning protection level of the photovoltaic side is level 2; When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 0.8≤I gg When <1, it means that there is current on the photovoltaic side and there is a risk of fault. You need to pay attention to fault prevention at all times. At this time, the lightning resistance level of the photovoltaic side is level 3; When the ratio between the photovoltaic side current and the rated current of the photovoltaic power source satisfies the formula 1≤I gg When it is displayed, it means that the current on the photovoltaic side exceeds the safety upper limit. Immediately notify relevant personnel to carry out maintenance to reduce the risk of failure.

4. A method for assessing lightning damage risk in an active power distribution network as claimed in claim 3, Features: The flashover lightning resistance level on the line side refers to the possibility of flashover on the line under the action of lightning. The flashover rate on the line side is used to reflect the lightning resistance level on the line side. The specific calculation formula is as follows: Among them, T represents the line inspection period, I i represents the line current at the time of the i-th lightning strike, I 0 Indicates the rated current of the circuit, V i represents the line voltage at the time of the ith lightning strike, V 0 It represents the rated line voltage, m and n represent the line characteristic parameters, which are determined by the line material, and λ represents the calculated line side flashover rate. The line side lightning withstand level is graded by taking the inverse of the calculated line side flashover rate. The specific classification is as follows: When the calculated line side flashover rate satisfies the formula 0≤λ<0.001, it means that the current line side flashover rate is low and there is no danger of fault. At this time, the line side lightning withstand level is level one; When the calculated line-side flashover rate satisfies the formula 0.001≤λ<0.01, it means that the current line-side flashover rate is within the safe range and there is no danger of fault. At this time, the line-side lightning withstand level is level 2. When the calculated line-side flashover rate satisfies the formula 0.01≤λ<0.1, it means that the current line-side flashover rate fluctuates within the safe range, and there is a risk of fault occurrence. Relevant personnel are notified to make precautionary preparations. At this time, the lightning resistance level of the line side is level three; When the calculated line-side flashover rate satisfies the formula 0.1≤λ, it means that the current line-side flashover rate exceeds the upper limit of the safety range, and relevant personnel are immediately notified for maintenance. At this time, the line-side lightning resistance level is level four.

5. A method for assessing lightning risk in an active power distribution network as claimed in claim 4, Features: The risk assessment analysis based on the ground-to-ground lightning density information is performed by combining the ground-to-ground lightning density information, calculating the failure rate of the photovoltaic side itself when lightning strikes the photovoltaic side, the flashover rate of the line side itself when lightning strikes the line side, and the failure rate of the photovoltaic side, and summarizing the calculated results to obtain the total lightning flashover rate of each tower on the photovoltaic side and the line side, and performing a quantitative risk assessment on the active distribution network system through the lightning flashover rate; the ground-to-ground lightning density information includes the ground-to-ground lightning density on the photovoltaic side and the ground-to-ground lightning density on the line side. The ground-to-ground lightning density on the photovoltaic side is achieved by installing a ground-to-ground lightning monitoring device in the photovoltaic system to monitor and collect the ground-to-ground lightning density in the photovoltaic side area, and the ground-to-ground lightning density on the line side is achieved by installing a lightning locating device to monitor and collect the ground-to-ground lightning density around the line.

6. A method for assessing lightning risk in an active power distribution network as claimed in claim 5, Features: The failure rate of the photovoltaic side itself when the photovoltaic side is struck by lightning is the probability of failure of the photovoltaic system under the action of lightning strike calculated in combination with the ground lightning density on the photovoltaic side. The specific calculation formula is as follows: or pv =I gg ×D pv Among them, D pv Indicates the density information of ground flash on the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level, which is obtained by calculating the ratio between the PV-side current and the rated current of the PV power source, η pv Indicates the failure rate of the photovoltaic side itself; The flashover rate of the line side itself when lightning strikes the line side is a combination of the ground flash density on the line side and the flashover rate on the line side. The specific calculation formula is as follows: Where, λ represents the calculated line side flashover rate, D s represents the ground flash density on the line side, L represents the line length, λ s Indicates the calculated line side self-flashover rate; The photovoltaic side failure rate is the probability of failure of the photovoltaic system in a unit time. The specific calculation formula is as follows: Among them, D pv Indicates the density information of ground flash on the photovoltaic side, I gg Indicates the calculated PV-side lightning protection level, which is obtained by calculating the ratio between the PV-side current and the rated current of the PV power source. Represents the photovoltaic side fault coefficient, which is determined by the structural material and has a value of 0.5, λ pv Represents the calculated PV side failure rate.

7. A method for assessing lightning risk in an active power distribution network as claimed in claim 6, Features: The quantitative risk assessment of the active distribution network system by the lightning flashover rate is to calculate the total number of tower tripping according to the total lightning flashover rate, and complete the quantitative risk assessment of the active distribution network system according to the total number of tower tripping. The total number of tower tripping is calculated by the sum of the number of tower tripping itself and the number of tripping caused by lightning. The specific calculation is as follows: Among them, t i represents the number of trips caused by the ith lightning strike, t pvi represents the number of self-tripping for the i-th time, λ T represents the total lightning flashover rate, λ pv represents the calculated PV side failure rate, P r It represents the average number of lightning tripping times of the whole line, T R It represents the total number of tower tripping times. According to the calculated total number of tower tripping times, the active distribution network system is quantitatively evaluated for risk, as follows: When the total number of tower tripping times satisfies the formula 0<T R ≤0.5P r At this time, the area at the tower pole is classified as a Class A low-risk tower pole area; When the total number of tower tripping times meets the formula 0.5P r <T R ≤P r At this time, the area at the tower pole is classified as a Class B medium-risk tower pole area; When the total tripping times of the tower pole meet the formula P r <T R ≤1.5P r At this time, the area at the tower pole is classified as a Class C high-risk tower pole area; When the total number of tower tripping times meets the formula 1.5P r <T R At this time, the area at the tower pole is divided into a Class D ultra-high risk tower pole area.

8. A system using the active distribution network lightning risk assessment method as claimed in any one of claims 1 to 7, It is characterized in that Including model building module, lightning resistance level and flashover rate calculation module and risk assessment module; The model building module is used to build an active distribution network lightning strike simulation calculation model in ATP-EMTP; The lightning resistance level and flashover rate calculation module calculates the lightning resistance level and flashover rate using an active distribution network lightning strike simulation calculation model; The risk assessment module performs lightning damage risk assessment on the active distribution network based on ground lightning density information.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program. It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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