Urban power grid risk early warning method and device facing typhoon meteorological event

Abstract

The invention relates to the technical field of power grid risk early warning, in particular to an urban power grid risk early warning method and device for typhoon meteorological events. According to the method, the fault probability of a line in typhoon weather is calculated by constructing a typhoon wind field model, a power grid initial fault scene is generated according to a line fault probability model, and a high fault probability scene set is obtained after screening; and comprehensively considering a line power flow out-of-limit risk index and a node voltage out-of-limit risk index to carry out risk assessment on a fault scene in the high fault probability scene set, and issuing risk early warning. According to the method, the parameters in the typhoon wind field model are solved based on the undetermined coefficient method according to the historical typhoon data, and the true effectiveness of the simulated typhoon scene is ensured. The risk assessment index adopted by the method is the weighted sum of the line power flow out-of-limit proportion and the node voltage out-of-limit proportion, and compared with a risk assessment index which only considers a single index, the risk assessment index adopted by the method can reflect the risk condition of the system more comprehensively.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid risk early warning, and in particular to a method and device for early warning of urban power grid risks for typhoon meteorological events. Background Art

[0002] The intensification of global climate change has led to a significant increase in the frequency and intensity of typhoon meteorological events, and the safe and stable operation of the power grid faces severe challenges. The city's transmission and distribution grid is mainly responsible for the transmission and supply of electric energy. Most of its equipment is exposed outdoors and is extremely vulnerable to typhoon disasters, which can cause line tripping and equipment damage at the least, or even power supply interruption or even large-scale power outages at the worst. Therefore, it is of great significance to assess the safety risks of the power grid before the typhoon passes and issue corresponding warning information in a timely manner, which is of great significance for making scheduling decisions in advance and improving the power grid's ability to resist typhoons.

[0003] At present, the relevant research on urban power grid risk warning for typhoon meteorological events still has problems such as inaccurate typhoon wind field models and improper selection of risk indicators, which leads to a long risk assessment process and affects the timeliness of warning information release. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problems of inaccurate typhoon wind field model and improper selection of risk indicators in the prior art.

[0005] In order to solve the above technical problems, the present invention provides a method for early warning of urban power grid risks for typhoon meteorological events, comprising:

[0006] S1. Construct a typhoon wind field model and determine the parameters of the typhoon wind field model based on the undetermined coefficient method according to historical typhoon data;

[0007] S2. Obtain the wind speed value at each location of the power grid according to the typhoon wind field model, use an exponential model to characterize the relationship between the power line failure rate and the wind speed, and obtain the line segment failure rate during the typhoon passage; correct the failure rate based on the bathtub curve to obtain the corrected line segment failure rate, and then calculate the line failure probability;

[0008] S3. According to the line failure probability, all possible grid initial failure scenarios are generated through permutations and combinations, the multiple failure probabilities of each grid initial failure scenario are calculated, and all grid initial failure scenarios are screened based on the multiple failure probabilities to obtain a high failure probability scenario set;

[0009] S4. Perform fault simulation on the scenarios in the high fault probability scenario set in turn, comprehensively consider the line power flow over-limit risk index and the node voltage over-limit risk index as risk assessment indicators, calculate the severity of the fault and the risk value of the fault scenario, and perform risk assessment on the selected fault scenarios;

[0010] S5. Issue risk warning information based on the results of the risk assessment.

[0011] In one embodiment of the present invention, in S1, constructing a typhoon wind field model and determining the typhoon wind field model parameters based on the undetermined coefficient method according to historical typhoon data include:

[0012] Construct a typhoon wind field model based on two-dimensional Gaussian distribution, and the wind speed value V at the position (x, y) of a certain line in the wind field w (t) can be expressed as:

[0013]

[0014] Where (x, y) is the coordinate of a point in the wind field, (μ x (t), μ y (t)) is the coordinate of the typhoon center, A 1 and A 2 is the maximum wind speed coefficient, σ 1 and σ 2 is the wind speed attenuation coefficient;

[0015] Since the strong winds that cause line failures are mainly winds perpendicular to the line direction, the effective wind speed V(t) acting on the line is used as the typhoon wind field model:

[0016] V(t)=V w (t)sinθ(t)

[0017] Among them, θ(t) is the angle between the typhoon wind direction and the line direction.

[0018] The unknown parameters in the typhoon wind field model include A 1 , A 2 , σ 1 and σ 2 , according to the central wind speed V of the typhoon in the historical typhoon data c 、Radius R of level 7 wind circle 7 and its corresponding wind speed V 7 , Radius of level 10 wind circle R 10 and its corresponding wind speed V 10 And the radius of the 12th wind circle R 12 and its corresponding wind speed V 12 , assuming t 0 The coordinates of the typhoon center are (0, 0) at this moment, and the equation group is established:

[0019]

[0020] Solve the equations to get the typhoon wind field model parameter A 1 , A2 , σ 1 and σ 2 .

[0021] In one embodiment of the present invention, in S2, the expression of the line segment failure rate during the typhoon transit is:

[0022]

[0023] Among them, λ i (t) represents the failure rate of the ith line section under typhoon weather, V i (t) represents the effective wind speed of the ith line segment, V d is the line design wind speed, L i is the length of the ith line segment, a and b are the historical fault coefficients of the line segment;

[0024] The failure rate and service time of electrical equipment during their lifespan obey the bathtub curve. Therefore, the service time of the line is taken into account, and the failure rate of the line segment during the typhoon period is corrected based on the bathtub curve. The Weibull distribution is used to represent the failure rate correction coefficient of the aging degree of the line segment:

[0025]

[0026] Among them, ρ i represents the fault rate correction coefficient of the ith line section, T is the commissioning time of the line section, t 1 is the start time of the occasional failure period, t 2 is the start time of the wear-out failure period, β is the model coefficient;

[0027] The line segment failure rate during the typhoon period is corrected according to the failure rate correction coefficient to obtain the corrected line segment failure rate λ′ i (t) = ρ i λ i (t).

[0028] In one embodiment of the present invention, in S2, the line failure probability is:

[0029]

[0030] Where n is the number of line segments into which the line is divided; P seg_i (t) is the failure probability of the line section during the typhoon, expressed as:

[0031]

[0032] According to the line failure probability, the multiple failure probability of the initial failure scenario of the power grid is obtained as follows:

[0033]

[0034] Among them, P lines_m (t) represents the probability that m lines fail successively within time t.

[0035] In one embodiment of the present invention, in S3, the screening of all power grid initial fault scenarios based on multiple fault probabilities to obtain a high fault probability scenario set includes:

[0036] Set the baseline probability threshold p, and determine the threshold correction coefficient based on the typhoon wind speed:

[0037]

[0038] Among them, α is the threshold correction coefficient, V is the typhoon wind speed, V 1 and V 2 are the lower and upper limits of the reference wind speed range, respectively, and γ is the linear model coefficient;

[0039] The corrected probability threshold is p′=αp;

[0040] The initial fault scenarios of the power grid with multiple fault probabilities greater than the corrected probability threshold are selected to obtain a high fault probability scenario set.

[0041] In one embodiment of the present invention, in S4, fault simulation is performed on the scenarios in the high fault probability scenario set in turn, and the line power flow over-limit risk index and the node voltage over-limit risk index are comprehensively considered as risk assessment indicators to calculate the severity of the fault and the risk value of the fault scenario, including:

[0042] The line power flow over-limit risk index expression is:

[0043]

[0044] Among them, S k is the actual power flow value of line k, is the upper limit of the power flow of line k, η k is the base capacity weight coefficient of line k, N is the total number of lines in the power grid;

[0045] The node voltage over-limit risk indicator expression is:

[0046]

[0047] Among them, U l is the actual voltage amplitude at node l, is the upper limit of the voltage amplitude at node l, is the weight coefficient of the reference voltage amplitude of node l, M is the number of line grid nodes;

[0048] The severity of the fault is S = S over +U over ;

[0049] The risk value expression of the fault scenario is R=P lines_m ×S.

[0050] In one embodiment of the present invention, in S5, issuing risk warning information includes:

[0051] According to the results of the risk assessment, risk warning information is issued including the probability of scenario failure, severity and scenario risk value, and graded warnings are issued in proportion to the risk value.

[0052] The present invention also provides a city power grid risk warning device for typhoon meteorological events, comprising:

[0053] A wind field model building module is used to build a typhoon wind field model and determine the typhoon wind field model parameters based on the undetermined coefficient method according to historical typhoon data;

[0054] A line fault assessment module is used to obtain the wind speed value at each location of the power grid according to the typhoon wind field model, use an exponential model to characterize the relationship between the power line failure rate and the wind speed, and obtain the line segment failure rate during the typhoon period; correct the failure rate based on the bathtub curve to obtain the corrected line segment failure rate, and then calculate the line failure probability;

[0055] A fault scenario generation module is used to generate all possible grid initial fault scenarios through permutations and combinations according to the line fault probability, calculate the multiple fault probabilities of each grid initial fault scenario, and screen all grid initial fault scenarios based on the multiple fault probabilities to obtain a high fault probability scenario set;

[0056] The power grid risk assessment module is used to perform fault simulation on the scenarios with high fault probability in sequence, comprehensively consider the line flow over-limit risk index and the node voltage over-limit risk index as risk assessment indicators, calculate the severity of the fault and the risk value of the fault scenario, and perform risk assessment on the selected fault scenarios;

[0057] The warning information release module is used to release risk warning information based on the results of the risk assessment.

[0058] The above technical solution of the present invention has the following advantages compared with the prior art:

[0059] The present invention discloses a method for early warning of urban power grid risks for typhoon meteorological events. The method calculates the failure probability of a line under typhoon weather by constructing a typhoon wind field model, generates an initial power grid failure scenario according to the line failure probability model, obtains a high failure probability scenario set after screening, and comprehensively considers the line flow over-limit risk index and the node voltage over-limit risk index to conduct risk assessment on the failure scenarios in the high failure probability scenario set, and issues a risk warning. Among them, the present invention solves the parameters in the typhoon wind field model based on the undetermined coefficient method according to historical typhoon data, ensures the true effectiveness of the simulated typhoon scenario, and improves the accuracy of the wind field model in calculating the wind speed. The risk assessment index used in the present invention is the weighted sum of the line flow over-limit ratio and the node voltage over-limit ratio. Compared with the risk assessment index that only considers a single index, the risk assessment index used in the present invention can more comprehensively reflect the risk situation of the system.

[0060] The urban power grid risk warning method for typhoon meteorological events described in the present invention takes into account the aging degree of the line when calculating the probability of line failure under typhoon weather, thereby improving the accuracy of failure probability calculation and further improving the accuracy of fault warning.

[0061] The urban power grid risk warning method for typhoon meteorological events described in the present invention adopts a probability threshold dynamically adjusted according to the typhoon intensity to screen the initial power grid failure scenarios, and selects scenarios with high failure probability for the next step of risk assessment, thereby significantly improving the efficiency of risk assessment without reducing the accuracy of risk assessment.

[0062] The urban power grid risk warning method for typhoon meteorological events described in the present invention provides warning information covering the probability of occurrence of fault scenarios, fault severity and scenario risk values, which can provide a comprehensive reference for dispatching personnel to make preventive control decisions and ensure the safe and stable operation of the power grid in typhoon weather. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0064] Figure 1 It is a framework diagram of a method for early warning of urban power grid risks for typhoon meteorological events according to the present invention;

[0065] Figure 2 Schematic diagram of the impact of a typhoon on a city power grid in an embodiment of the present invention;

[0066] Figure 3 It is a graph of the probability of overhead line failure during a typhoon crossing according to the present invention;

[0067] Figure 4The present invention is a risk assessment flow chart of a method for early warning of urban power grid risks for typhoon meteorological events. DETAILED DESCRIPTION

[0068] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0069] Embodiment 1

[0070] Reference Figure 1 As shown, the present invention provides a method for early warning of urban power grid risks for typhoon meteorological events, comprising:

[0071] S1. Construct a typhoon wind field model and determine the typhoon wind field model parameters based on the undetermined coefficient method according to historical typhoon data.

[0072] In typhoon events, the dominant non-electrical factor that causes damage to power grid equipment is wind speed. Therefore, the first step in evaluating the impact of typhoons on the power grid is to construct a typhoon wind field model and obtain the wind speed at the location of each power grid device.

[0073] At present, the commonly used typhoon wind field models include Batts wind field model, YanMeng wind field model, wind field model based on two-dimensional Gaussian distribution, etc. Batts model and YanMeng are professional models in the field of meteorology, with high precision and complexity.

[0074] The wind farm model based on two-dimensional Gaussian distribution is also a widely used model. Although it is not as accurate as the professional wind farm model, it provides multiple adjustable model parameters, such as typhoon impact radius, maximum wind speed and wind speed attenuation rate. These model parameters can be obtained from historical typhoon meteorological data by the undetermined coefficient method, making the model highly applicable to inverting specific typhoon scenarios. Therefore, this example uses this wind farm model. The schematic diagram of the impact of typhoon wind farm on the power grid is shown in the figure below. Figure 2 shown.

[0075] In urban power grids, overhead lines are often high outdoors and are the equipment most vulnerable to typhoons and failures. Therefore, this example mainly discusses overhead lines.

[0076] In the typhoon wind field model based on two-dimensional Gaussian distribution, the wind speed value V at the position (x, y) of a certain line in the wind field is w (t) can be expressed as:

[0077]

[0078] Where (x, y) is the coordinate of a point in the wind field, (μx (t), μ y (t)) is the coordinate of the typhoon center, A 1 and A 2 is the maximum wind speed coefficient, σ 1 and σ 2 is the wind speed attenuation coefficient.

[0079] Since the strong winds that cause line failures are mainly winds perpendicular to the line direction, the effective wind speed V(t) acting on the line is used as the typhoon wind field model:

[0080] V(t)=V w (t)sinθ(t)

[0081] Among them, θ(t) is the angle between the typhoon wind direction and the line direction.

[0082] The parameters in the typhoon wind field model based on two-dimensional Gaussian distribution include A 1 , A 2 , σ 1 and σ 2 , that is, 4 equations need to be established to solve the above 4 unknown parameters.

[0083] The meteorological department provides the central wind speed, the radius of the seventh-level wind circle, the radius of the tenth-level wind circle, and the radius of the twelfth-level wind circle of the typhoon. This embodiment obtains the typhoon data of a certain historical landing on the coast from the meteorological department website, and according to the central wind speed V c 、Radius R of level 7 wind circle 7 and its corresponding wind speed V 7 , Radius of level 10 wind circle R 10 and its corresponding wind speed V 10 And the radius of the 12th wind circle R 12 and its corresponding wind speed V 12 , assuming t 0 The coordinates of the typhoon center are (0, 0) at this moment. Establish a system of equations and solve the unknown coefficients:

[0084]

[0085] After solving the equations, the wind field model parameters A applicable to this specific typhoon scenario are obtained: 1 , A 2 , σ 1 and σ 2 , thus making the inversion simulation more realistic.

[0086] S2. Obtain the wind speed value at each location of the power grid according to the typhoon wind field model, use an exponential model to characterize the relationship between the power line failure rate and the wind speed, and obtain the line segment failure rate during the typhoon passage; correct the failure rate based on the bathtub curve to obtain the corrected line segment failure rate, and then calculate the line failure probability.

[0087] This embodiment takes an overhead line as an example. Assuming that a line consists of n sections, the failure rate of each line section in typhoon weather can be expressed by an exponential model:

[0088]

[0089] Among them, λ i (t) represents the failure rate of the ith line section under typhoon weather, V i (t) represents the effective wind speed of the ith line segment, V d is the line design wind speed, L i is the length of the ith line segment, a and b are the historical fault coefficients of the line segment.

[0090] The failure rate of overhead lines is not only related to the wind speed, but also has a great relationship with the aging degree of the line itself. Figure 3 As shown, there is a macroscopic regularity between the failure rate and service time of electrical equipment during its life cycle, and the two obey a bathtub curve with high sides and low middle.

[0091] A large number of studies have shown that the aging degree of equipment is closely related to the years of operation of the equipment. The Weibull distribution is usually used to represent the failure rate correction coefficient of the aging degree of the line section:

[0092]

[0093] Among them, ρ i represents the fault rate correction coefficient of the ith line section, T is the commissioning time of the line section; t 1 is the start time of the occasional failure period, t 2 is the start time of the wear and tear failure period, which can be obtained from historical experience; β is the model coefficient.

[0094] The line segment failure rate during the typhoon period is corrected according to the failure rate correction coefficient to obtain the corrected line segment failure rate:

[0095] λ′ i (t) = ρ i λ i (t)

[0096] The probability of power equipment failure follows an exponential distribution, so the probability of line segment failure during a typhoon can be obtained from the corrected line segment failure rate:

[0097]

[0098] An overhead line is regarded as a series combination of n line segments. Based on the reliability theory of series systems, the line failure probability is obtained from the line segment failure probability:

[0099]

[0100] Wherein, n is the number of line segments into which the line is divided.

[0101] The construction of the equipment failure probability model under the above typhoon event takes into account the aging degree of the equipment and improves the accuracy of the model.

[0102] S3. According to the line failure probability, all possible grid initial failure scenarios are generated through permutations and combinations, the multiple failure probabilities of each grid initial failure scenario are calculated, and all grid initial failure scenarios are screened based on the multiple failure probabilities to obtain a high failure probability scenario set.

[0103] S2 gives a modified overhead line failure probability model under typhoon meteorological events. Based on this model, the probability of failure of any line under typhoon meteorological events can be calculated. Considering that typhoons may cause multiple lines to fail one after another, the generation of fault scenarios should take multiple faults into account.

[0104] In this implementation example, multiple failures are considered to be consecutive failures without causal relationship, rather than chain events. Therefore, the probability of m lines failing successively within time t can be expressed as:

[0105]

[0106] Based on the above-mentioned single and cascading failure probability model of overhead lines, all possible failure scenarios under the influence of typhoon meteorological events can be generated, and the probability of occurrence of each scenario can be calculated. The total number of failure scenarios is:

[0107]

[0108] Where N is the total number of power lines. Indicates the number of scenarios where no line failure occurs. Indicates the number of scenarios where a line fails. Indicates the number of scenarios where N-1 lines fail. Indicates the number of scenarios where N lines fail.

[0109] Obviously, when N is large, the total number of scenarios generated will be extremely large, and it is impossible to conduct risk assessment on each scenario. Therefore, it is necessary to screen the massive fault scenarios generated and use the screened scenarios as the high-probability fault scenario set of the power grid caused by the typhoon.

[0110] A relatively simple screening method is to set a probability threshold and only conduct risk assessment on scenarios with a probability greater than the threshold. Compared with a fixed probability threshold, this embodiment adopts a probability threshold that is dynamically adjusted with the typhoon intensity, which can avoid the imbalance of the number of scenarios caused by excessive or insufficient wind speed. Specifically, the baseline probability threshold p is first set, and then the threshold correction coefficient is determined according to the wind speed.

[0111] Set the baseline probability threshold p, and determine the threshold correction coefficient based on the typhoon wind speed:

[0112]

[0113] Among them, α is the threshold correction coefficient, V is the typhoon wind speed, V 1 and V 2 are the lower and upper limits of the benchmark wind speed range, and γ is the linear model coefficient.

[0114] When the wind speed is within the reference wind speed interval, the threshold correction coefficient is 1; when the wind speed exceeds the reference wind speed interval, the threshold correction coefficient is less than 1; when the wind speed is lower than the reference wind speed interval, the threshold correction coefficient is greater than 1, and the threshold correction coefficient is linearly related to the wind speed.

[0115] The corrected probability threshold is the product of the base probability threshold and the correction coefficient, expressed as:

[0116] p′=αp

[0117] After determining the corrected probability threshold, the initial fault scenarios of the power grid with multiple fault probabilities greater than the corrected probability threshold are selected to obtain a set of high fault probability scenarios. Only the scenarios in the set of high fault probability scenarios need to be risk assessed. This processing method significantly improves the efficiency of the assessment without reducing the assessment accuracy.

[0118] S4. Perform fault simulation on the scenarios with high fault probability in sequence, comprehensively consider the line flow over-limit risk index and node voltage over-limit risk index as risk assessment indicators, calculate the severity of the fault and the risk value of the fault scenario, and conduct risk assessment on the selected fault scenarios. Figure 4 shown.

[0119] The line power flow over-limit risk index expression is:

[0120]

[0121] Among them, S k is the actual power flow value of line k, is the upper limit of the power flow of line k, η k is the baseline capacity weight coefficient of line k, and N is the total number of lines in the power grid.

[0122] The node voltage over-limit risk indicator expression is:

[0123]

[0124] Among them, U l is the actual voltage amplitude at node l, is the upper limit of the voltage amplitude at node l, is the weight coefficient of the reference voltage amplitude of node l, and M is the number of line grid nodes.

[0125] Taking into account the risk index of line power flow over-limit and node voltage over-limit, based on the classic risk theory, the safety risk assessment index of each scenario under typhoon meteorological events is defined as follows:

[0126] R=P lines_m ×S

[0127] Where R is the risk value corresponding to the scenario, P lines_m is the probability of the scenario failure, S is the severity of the failure, and S = S over +U over .

[0128] The risk assessment index used in this embodiment is the weighted sum of the line power flow over-limit ratio and the node voltage over-limit ratio. Compared with the risk assessment method that only considers a single index, this method can more comprehensively reflect the risk situation of the line.

[0129] S5. Based on the results of the risk assessment, early warning information including the probability of scenario failure, severity and scenario risk value is issued, and graded warnings are carried out in proportion to the risk value.

[0130] The release format of the warning information in this embodiment is shown in Table 1.

[0131]

[0132] Table 1. Warning information release format

[0133] The warning information provided in this embodiment covers the probability of occurrence of fault scenarios, fault severity, and scenario risk values, which can provide a comprehensive reference for dispatchers to make preventive control decisions and ensure the safe and stable operation of the power grid in typhoon weather.

[0134] Embodiment 2

[0135] This embodiment provides a city power grid risk warning device for typhoon meteorological events, including:

[0136] A wind field model building module is used to build a typhoon wind field model and determine the typhoon wind field model parameters based on the undetermined coefficient method according to historical typhoon data;

[0137] A line fault assessment module is used to obtain the wind speed value at each location of the power grid according to the typhoon wind field model, use an exponential model to characterize the relationship between the power line failure rate and the wind speed, and obtain the line segment failure rate during the typhoon period; correct the failure rate based on the bathtub curve to obtain the corrected line segment failure rate, and then calculate the line failure probability;

[0138] A fault scenario generation module is used to generate all possible grid initial fault scenarios through permutations and combinations according to the line fault probability, calculate the multiple fault probabilities of each grid initial fault scenario, and screen all grid initial fault scenarios based on the multiple fault probabilities to obtain a high fault probability scenario set;

[0139] The power grid risk assessment module is used to perform fault simulation on the scenarios with high fault probability in sequence, comprehensively consider the line flow over-limit risk index and the node voltage over-limit risk index as risk assessment indicators, calculate the severity of the fault and the risk value of the fault scenario, and perform risk assessment on the selected fault scenarios;

[0140] The warning information release module is used to release risk warning information based on the results of the risk assessment.

[0141] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0142] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0143] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0144] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0145] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for early warning of urban power grid risks for typhoon meteorological events, characterized in that: include: S1. Construct a typhoon wind field model and determine the parameters of the typhoon wind field model based on the undetermined coefficient method according to historical typhoon data; S2. Obtain the wind speed value at each location of the power grid according to the typhoon wind field model, use an exponential model to characterize the relationship between the power line failure rate and the wind speed, and obtain the line segment failure rate during the typhoon passage; correct the failure rate based on the bathtub curve to obtain the corrected line segment failure rate, and then calculate the line failure probability; S3. According to the line failure probability, all possible grid initial failure scenarios are generated through permutations and combinations, the multiple failure probabilities of each grid initial failure scenario are calculated, and all grid initial failure scenarios are screened based on the multiple failure probabilities to obtain a high failure probability scenario set; S4. Perform fault simulation on the scenarios in the high fault probability scenario set in turn, comprehensively consider the line power flow over-limit risk index and the node voltage over-limit risk index as risk assessment indicators, calculate the severity of the fault and the risk value of the fault scenario, and perform risk assessment on the selected fault scenarios; S5. Issue risk warning information based on the results of the risk assessment.

2. The urban power grid risk early warning method for typhoon meteorological events according to claim 1 is characterized in that: In S1, the typhoon wind field model is constructed, and the parameters of the typhoon wind field model are determined based on the undetermined coefficient method according to historical typhoon data, including: Construct a typhoon wind field model based on two-dimensional Gaussian distribution, and the wind speed value V at the position (x, y) of a certain line in the wind field w (t) can be expressed as: Among them, (x, y) is the coordinate of a point in the wind field, (μ x (t),μ y (t)) is the coordinate of the typhoon center, A1 and A2 are the maximum wind speed coefficients, σ1 and σ2 are the wind speed attenuation coefficients; Since the strong winds that cause line failures are mainly winds perpendicular to the line direction, the effective wind speed V(t) acting on the line is used as the typhoon wind field model: V(t)=V w (t)sinθ(t) Among them, θ(t) is the angle between the typhoon wind direction and the line direction; The unknown parameters in the typhoon wind field model include A1, A2, σ1 and σ2. According to the central wind speed V of the typhoon in the historical typhoon data, c , the radius of the seventh-level wind circle R7 and its corresponding wind speed V7, the radius of the tenth-level wind circle R 10 and its corresponding wind speed V 10 And the radius of the 12th wind circle R 12 and its corresponding wind speed V 12 , assuming that the coordinates of the typhoon center at time t0 are (0,0), establish the equation group: The typhoon wind field model parameters A1, A2, σ1 and σ2 are obtained by solving the equations.

3. The urban power grid risk early warning method for typhoon meteorological events according to claim 2 is characterized in that: In S2, the expression of line segment failure rate during typhoon passage is: Among them, λ i (t) represents the failure rate of the ith line section under typhoon weather, V i (t) represents the effective wind speed of the ith line segment, V d is the line design wind speed, L i is the length of the ith line segment, a and b are the historical fault coefficients of the line segment; The failure rate and service time of electrical equipment during their lifespan obey the bathtub curve. Therefore, the service time of the line is taken into account, and the failure rate of the line segment during the typhoon period is corrected based on the bathtub curve. The Weibull distribution is used to represent the failure rate correction coefficient of the aging degree of the line segment: Among them, ρ i represents the fault rate correction coefficient of the ith line section, T is the commissioning time of the line section, t1 is the start time of the occasional fault period, t2 is the start time of the wear and tear fault period, and β is the model coefficient; The line segment failure rate during the typhoon period is corrected according to the failure rate correction coefficient to obtain the corrected line segment failure rate λ' i (t) = ρ i λ i (t).

4. The urban power grid risk early warning method for typhoon meteorological events according to claim 3 is characterized in that: In S2, the line failure probability is: Where n is the number of line segments into which the line is divided; P seg_i (t) is the failure probability of the line section during the typhoon, expressed as: According to the line failure probability, the multiple failure probability of the initial failure scenario of the power grid is obtained as follows: Among them, P lines_m (t) represents the probability that m lines fail successively within time t.

5. The method for early warning of urban power grid risks for typhoon meteorological events according to claim 4 is characterized in that: In S3, all power grid initial fault scenarios are screened based on the multiple fault probabilities to obtain a high fault probability scenario set, including: Set the baseline probability threshold p, and determine the threshold correction coefficient based on the typhoon wind speed: Among them, α is the threshold correction coefficient, V is the typhoon wind speed, V1 and V2 are the lower and upper limits of the benchmark wind speed range, and γ is the linear model coefficient; The corrected probability threshold is p' = αp; The initial fault scenarios of the power grid with multiple fault probabilities greater than the corrected probability threshold are selected to obtain a high fault probability scenario set.

6. The urban power grid risk early warning method for typhoon meteorological events according to claim 5 is characterized in that: In S4, fault simulation is performed on the scenarios in the high fault probability scenario set in turn, and the line power flow over-limit risk index and the node voltage over-limit risk index are comprehensively considered as risk assessment indicators to calculate the severity of the fault and the risk value of the fault scenario, including: The line power flow over-limit risk index expression is: Among them, S k is the actual power flow value of line k, is the upper limit of the power flow of line k, η k is the base capacity weight coefficient of line k, N is the total number of lines in the power grid; The node voltage over-limit risk indicator expression is: Among them, U l is the actual voltage amplitude at node l, is the upper limit of the voltage amplitude at node l, is the weight coefficient of the reference voltage amplitude of node l, M is the number of line grid nodes; The severity of the fault is S = S over +U over ; The risk value expression of the fault scenario is R=P lines_m ×S.

7. The method for early warning of urban power grid risks for typhoon meteorological events according to claim 6 is characterized in that: In S5, risk warning information released includes: According to the results of the risk assessment, risk warning information is issued including the probability of scenario failure, severity and scenario risk value, and graded warnings are issued in proportion to the risk value.

8. A risk warning device for urban power grids facing typhoon meteorological events, characterized in that: include: A wind field model building module is used to build a typhoon wind field model and determine the typhoon wind field model parameters based on the undetermined coefficient method according to historical typhoon data; A line fault assessment module is used to obtain the wind speed value at each location of the power grid according to the typhoon wind field model, use an exponential model to characterize the relationship between the power line failure rate and the wind speed, and obtain the line segment failure rate during the typhoon period; correct the failure rate based on the bathtub curve to obtain the corrected line segment failure rate, and then calculate the line failure probability; A fault scenario generation module is used to generate all possible grid initial fault scenarios through permutations and combinations according to the line fault probability, calculate the multiple fault probabilities of each grid initial fault scenario, and screen all grid initial fault scenarios based on the multiple fault probabilities to obtain a high fault probability scenario set; The power grid risk assessment module is used to perform fault simulation on the scenarios with high fault probability in sequence, comprehensively consider the line flow over-limit risk index and the node voltage over-limit risk index as risk assessment indicators, calculate the severity of the fault and the risk value of the fault scenario, and perform risk assessment on the selected fault scenarios; The warning information release module is used to release risk warning information based on the results of the risk assessment.

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