CN110929391A - A method and system for calculating the failure rate of distribution network under typhoon disaster - Google Patents

Abstract

The invention provides a method and system for calculating the failure rate of a distribution network under a typhoon disaster. The method includes: respectively establishing a probability density function model representing the typhoon intensity and a probability distribution function model of the typhoon duration; establishing a distribution network under the typhoon disaster Failure rate calculation model; based on the distribution network failure rate calculation model, calculate the total probability of load loss during the duration of the typhoon disaster. The present invention simultaneously considers the uncertainty of typhoon intensity and duration, and analyzes the physical principles of different types of faults in the distribution network caused by typhoon disasters, and has high accuracy. This method is used to model the failure rate of the distribution network. The influence of the typhoon intensity and duration on the failure rate of the distribution network is comprehensively considered. The operation status of the distribution network under typhoon disasters is depicted, and the accuracy of the failure rate model of the distribution network is greatly improved by using the advantages of the joint driving of the data model.

Description

A method and system for calculating the failure rate of distribution network under typhoon disaster

technical field

The invention belongs to the technical field of power grid configuration, and in particular relates to a method and system for calculating the failure rate of a distribution network under typhoon disasters.

Background technique

Predicting the failure rate of the distribution network under extreme events is an important means to improve the ability of the distribution network to cope with extreme meteorological disasters. The commonly used methods include the failure rate modeling method based on historical data and the failure rate modeling method based on the disaster mechanism. Failure rate modeling method fused with data model.

The failure rate modeling method based on historical data mainly analyzes the correlation between multi-dimensional random variables, uses regression analysis, fuzzy expert system, maximum expected value (EM) and other methods, and obtains multi-dimensional random variable failure by analyzing historical data and forecast data. The joint probability distribution of the rates. This type of method is driven by data, is not restricted by the disaster-causing mechanism and the dynamic process of disasters, and is completely separated from the physical model, which greatly reduces the difficulty of modeling the failure rate. However, due to the lack of modeling of the disaster-causing mechanism and the dynamic process of disasters, this type of method is difficult to reflect the development and change process of disasters and the causal relationship of equipment failures in the distribution network. Due to the low probability of extreme events and few historical data, such methods The prediction accuracy of is usually low.

The failure rate modeling method based on the disaster mechanism mainly analyzes the disaster mechanism and the dynamic process of the disaster, and uses the physical model to describe the impact of the disaster on the distribution network, and then establishes the mechanism model and dynamic change model of the failure rate of the distribution network. Taking the failure model of typhoon as an example, related research analyzes the wind speed, wind direction, and geographic location data of previous typhoons, and uses the outage prediction model to simulate the impact of future typhoon transit, and predict the outage scope and outage probability of the line. However, due to the complexity of the disaster mechanism model and the large differences in the disaster mechanism of different disasters, the modeling of this type of method is difficult and lacks generality. It is often difficult to accurately reflect the failure rate of distribution network equipment under extreme events.

SUMMARY OF THE INVENTION

To overcome the above-mentioned existing problems or at least partially solve the above-mentioned problems, embodiments of the present invention provide a method and system for calculating the failure rate of a distribution network under typhoon disasters.

An embodiment of the present invention provides a method for calculating the failure rate of a distribution network under a typhoon disaster, including:

Based on the historical data of typhoon wind speed and rainfall intensity under typhoon disaster, establish a probability density function model to characterize typhoon intensity;

Establish the probability distribution function model of typhoon duration;

Based on the probability density function model representing the typhoon intensity and the probability distribution function model of the typhoon duration, establish a calculation model of the failure rate of the distribution network under the typhoon disaster;

Based on the distribution network failure rate calculation model, the total probability of load loss during the duration of the typhoon disaster is calculated.

On the basis of the above technical solutions, the present invention can also make the following improvements.

Based on the historical data of typhoon wind speed and rainfall intensity under typhoon disaster, establishing a probability density function model to characterize typhoon intensity includes:

The time-varying probability vector V(t) of typhoon wind speed and rainfall intensity is expressed as:

V(t)=[V _wind (t) V _rain (t)];

where V _wind (t) is the probability vector of typhoon wind speed at time t, and V _rain (t) is the probability vector of rainfall intensity at time t;

The probability density function ρ(V(t)) of V(t) is obtained by fitting the historical data of typhoon wind speed and rainfall intensity.

Further, the establishment of the probability distribution function model of the typhoon duration includes:

By judging whether the typhoon intensity at time t is reduced to the lowest level standard, the probability distribution function model of the typhoon duration is established.

Further, establishing the probability distribution function model of the typhoon duration by judging whether the typhoon intensity at time t is reduced to the lowest level standard includes:

The typhoon duration T is expressed as:

T=t _end -t _begin ;

通过如下公式得到：In the formula: t _begin is the start time of the typhoon, t _end is the end time of the typhoon, and the boundary value of the β confidence interval

Obtained by the following formula:

分别为台风风速、降雨强度的条件置信区间上限，V_wmin为台风风速的最低等级标准，V_rmin为降雨强度的最低等级标准；where:

are the upper limit of the conditional confidence interval of typhoon wind speed and rainfall intensity, respectively, V _wmin is the minimum level standard of typhoon wind speed, and V _rmin is the minimum level standard of rainfall intensity;

分别为台风风速、降雨强度的条件置信区间下限；where:

are the lower limits of the conditional confidence intervals for typhoon wind speed and rainfall intensity, respectively;

Then the β confidence interval of the typhoon duration T is

Further, based on the probability density function model representing the typhoon intensity and the probability distribution function model of the typhoon duration, the power distribution network failure rate calculation model established under the typhoon disaster includes:

Build the pole failure rate model, overhead line failure rate model, insulator failure rate model and transformer failure rate model respectively;

According to the pole failure rate model, the overhead line failure rate model, the insulator failure rate model and the transformer failure rate model, the distribution network failure rate calculation model is obtained.

Further, establishing the pole failure rate model includes:

Establish a functional function with the pole state as the basic variable:

Z1=R1-S1;

In the formula: R1 is the flexural strength of the pole, S1 is the internal stress of the pole caused by the wind load, which is related to the wind speed and wind direction;

Among them, R1 is the Gauss distribution of the bending strength of the pole obeying the following formula:

In the formula: μ _P is the mean value of the flexural strength of the concrete pole, δ _P is the standard deviation of the flexural strength of the concrete pole, β and υ can be measured by actual operation experience or destructive test, and M _u is the flexural strength of the concrete pole. Bearing capacity check bending moment;

The probability of normal operation of the pole at time t is:

Then the failure rate of the pole at time t is

Further, establishing the overhead line failure rate model includes:

Calculate the dead weight L _G and the maximum bearing stress L _Desm of the overhead line:

In the formula: L _v is the vertical span of the overhead line, G ₀ is the mass of the overhead line per unit length, T _m is the breaking force, determined by the model of the overhead line, and K is the safety factor;

The function function with the status of the overhead line as the basic variable is as follows:

Z2=R2-S2;

R2=L _G +L _Desm ;

In the formula: R2 is the tensile strength of the overhead line, S2 is the internal stress of the overhead line caused by the wind load, which is related to the wind speed and wind direction;

The failure rate of the overhead line at time t is:

In the formula: μ _P is the mean value of the tensile strength of the overhead wire, and δ _P is the standard deviation of the tensile strength of the overhead wire.

Further, the establishment of the insulator failure rate model:

The critical value of rainfall _Aζ for insulator flashover is expressed as:

In the formula: U _ζ is the critical value of the flashover voltage of the insulator; P is the current ambient air pressure; P ₀ is the standard atmospheric pressure, a, b, and c are all constants;

The flashover probability of a single insulator is:

In the formula: F(V _rain (t)) is the probability distribution function of rainfall intensity, which is obtained by the following formula:

Further, the transformer failure rate model includes:

The critical value of rainfall A _ζ1 for spark discharge of transformer insulating oil and the critical value of rainfall A _ζ2 for breakdown of oil-impregnated paper are respectively expressed as:

In the formula: W ₁ is the moisture content of the transformer insulating oil, W ₂ is the moisture content of the transformer oil-impregnated paper, N is the rainfall duration, that is, the typhoon disaster duration t _total , a ₁ , a ₂ , b ₁ , b ₂ , n ₁ and _n2 are both constants;

The discharge probability of the insulating oil spark at time t is:

The breakdown probability of oil-impregnated paper at time t is:

Then the total failure rate of the distribution transformer is:

_{Ph(t)=P h1 (} t)+P _h2 (t)-P _h1 (t)P _h2 (t).

Further, according to the pole failure rate model, the overhead line failure rate model, the insulator failure rate model and the transformer failure rate model, the distribution network failure rate calculation model includes:

P _∑ =Max(P _r (t)+P _l (t))+P _g +P _h (t), t∈[0,t _total ];

In the formula, P _∑ is the total probability of load loss during the typhoon disaster duration, P _r (t) is the failure rate of the pole at time t, P _l (t) is the failure rate of the overhead line at time t, P _g is the flashover probability of a single insulator, and P _h (t) is the failure rate of the transformer at time t.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a flowchart of a method for calculating the failure rate of a distribution network under a typhoon disaster provided by an embodiment of the present invention;

FIG. 2 is a connection block diagram of a system for calculating the failure rate of a distribution network under a typhoon disaster provided by an embodiment of the present invention.

Detailed ways

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

In an embodiment of the present invention, a method for calculating the failure rate of a distribution network under a typhoon disaster is provided. FIG. 1 is a schematic diagram of the overall flow of the method for calculating the failure rate of a distribution network under a typhoon disaster provided by an embodiment of the present invention, and the method includes:

Based on the historical data of typhoon wind speed and rainfall intensity under typhoon disaster, establish a probability density function model to characterize typhoon intensity;

Establish the probability distribution function model of typhoon duration;

Based on the probability density function model representing the typhoon intensity and the probability distribution function model of the typhoon duration, establish a calculation model of the failure rate of the distribution network under the typhoon disaster;

Based on the distribution network failure rate calculation model, the total probability of load loss during the duration of the typhoon disaster is calculated.

It is understandable that the existing extreme disaster modeling methods jointly driven by data models all use data and physical methods to model the same problem repeatedly, and realize the fusion of data models and physical models through mutual iterative revisions. There are still data The problem of high demand and insufficient model accuracy.

The embodiment of the present invention proposes a method for calculating the failure rate of distribution network under extreme disaster conditions, such as typhoon disaster, and divides the analysis of distribution network failure rate under typhoon disaster into probability modeling of meteorological data and failure mechanism construction. model two independent parallel sub-problems; fit the historical data of typhoon disasters to obtain the predicted values of typhoon intensity and typhoon duration under typhoon disasters; propose an analysis method based on the typhoon disaster mechanism for the modeling of failure rate , by analyzing the influence of the current typhoon intensity and typhoon disaster duration on the failure rate of distribution network towers, overhead lines, insulators and transformers, the comprehensive failure rate model of the distribution network under typhoon disasters is obtained.

The probability density functions representing typhoon intensity and typhoon duration are established respectively, and then the calculation model of distribution network failure rate under typhoon disaster is established. Using the calculation model of distribution network failure rate, the total probability of load loss during typhoon disaster duration is calculated. .

The embodiment of the present invention simultaneously considers the uncertainty of typhoon intensity and duration, and analyzes the physical principles of different types of faults in the distribution network caused by typhoon disasters, and has high accuracy. This method is used to model the failure rate of the distribution network. The influence of the typhoon intensity and duration on the failure rate of the distribution network is comprehensively considered. The operation status of the distribution network under typhoon disasters is depicted, and the accuracy of the failure rate model of the distribution network is greatly improved by using the advantages of the joint driving of the data model.

On the basis of the above embodiment, in the embodiment of the present invention, in the modeling process of typhoon disaster intensity, historical data of characteristic quantities such as typhoon wind speed and rainfall intensity are analyzed, and a probability density function representing typhoon intensity is obtained by fitting, and further through Conditional value-at-risk is introduced to solve the confidence interval of each characteristic quantity.

Specifically, based on the historical data of typhoon wind speed and rainfall intensity under typhoon disasters, establishing a probability density function model representing typhoon intensity includes:

In the modeling process of typhoon disaster intensity, the time-varying probability vector V(t) of typhoon wind speed and rainfall intensity is expressed as:

V(t)=[V _wind (t) V _rain (t)];

where V _wind (t) is the probability vector of typhoon wind speed at time t, and V _rain (t) is the probability vector of rainfall intensity at time t.

Based on the historical data of typhoon wind speed and rainfall intensity, the probability density function model ρ(V(t)) of V(t) is obtained.

其临界值为：The probability density function ρ(V(t)) of V(t) is obtained by fitting the historical data of typhoon wind speed and rainfall intensity, and then a conditional confidence interval with a confidence level of β based on CVaR is formed.

Its critical value is:

为置信区间的临界值，可以表示为如下形式：where:

is the critical value of the confidence interval, which can be expressed in the following form:

In the formula: φ ^up and φ ^low are the probability that V(t) does not exceed the threshold value α at time t, which can be expressed as:

On the basis of the above embodiments, in the embodiment of the present invention, establishing a probability distribution function model of typhoon duration includes:

By judging whether the typhoon intensity at time t is reduced to the lowest level standard, the probability distribution function model of the typhoon duration is established.

Among them, by judging whether the typhoon intensity at time t is reduced to the lowest level standard, the probability distribution function model of the typhoon duration is established, including:

The typhoon duration T is expressed as:

T=t _end -t _begin ;

通过如下公式得到：In the formula: t _begin is the start time of the typhoon, t _end is the end time of the typhoon, and the boundary value of the β confidence interval

Obtained by the following formula:

分别为台风风速、降雨强度的条件置信区间上限，V_wmin为台风风速的最低等级标准，V_rmin为降雨强度的最低等级标准；where:

are the upper limit of the conditional confidence interval of typhoon wind speed and rainfall intensity, respectively, V _wmin is the minimum level standard of typhoon wind speed, and V _rmin is the minimum level standard of rainfall intensity;

分别为台风风速、降雨强度的条件置信区间下限；where:

are the lower limits of the conditional confidence intervals for typhoon wind speed and rainfall intensity, respectively;

Then the β confidence interval of the typhoon duration T is

On the basis of the above embodiments, in the embodiment of the present invention, based on the probability density function model representing the typhoon intensity and the probability distribution function model of the typhoon duration, the calculation model of the distribution network failure rate established under the typhoon disaster includes:

Build the pole failure rate model, overhead line failure rate model, insulator failure rate model and transformer failure rate model respectively;

According to the pole failure rate model, the overhead line failure rate model, the insulator failure rate model and the transformer failure rate model, the distribution network failure rate calculation model is obtained.

It is understandable that in typhoon weather, the combined effect of wind and rain will greatly increase the failure rate of the distribution network, mainly including the following two aspects: the force of the strong wind on the tower or overhead line exceeds its load capacity, which will lead to the collapse of the pole. , disconnection; rainfall will cause the surface resistance of the insulator to drop, causing flashover, and it will also cause the transformer to get wet and cause an insulation accident. Therefore, in the embodiment of the present invention, the pole failure rate model, the overhead line failure rate model, the insulator failure rate model and the transformer failure rate model are respectively established based on the probability density function model representing the typhoon intensity and the probability distribution function model of the typhoon duration. Then, the calculation model of the distribution network failure rate is established, and finally the total failure rate of the distribution network under the typhoon disaster is calculated according to the calculation model of the distribution network failure rate.

On the basis of the above embodiments, in the embodiment of the present invention, the specific process of establishing a pole failure rate model is as follows:

During the continuation of the typhoon disaster, the effective wind speed at point P on the distribution line at time t can be expressed as

where V _wind (t) is the wind eye wind speed at time t, R _eye is the eye radius, and L _P is the straight-line distance from point P to the center of the typhoon.

The wind load at point P can be expressed as the wind load w _x (t) on the conductor at time t, the wind load ws (t) on the tower and the wind load w _z ( _t ) on the insulator:

为风向与导线之间的夹角，β为风振系数，μ_S为风荷载体型系数，A为杆塔结构构件迎风面的投影面积，n₁为单相导线所用的绝缘子串数，n₂为每串绝缘子的片数，A_P为每片绝缘子的受风面积。In the formula: α is the non-uniformity coefficient of the overhead line wind pressure, μ _z is the wind pressure height variation coefficient, μ _SC is the body shape coefficient of the overhead line, d is the outer diameter of the conductor of the overhead line, l _H is the horizontal span,

is the angle between the wind direction and the conductor, β is the wind vibration coefficient, μ _S is the wind load body type coefficient, A is the projected area of the windward surface of the tower structural member, n ₁ is the number of insulator strings used for single-phase conductors, and n ₂ is the The number of insulators in each string, A _P is the wind receiving area of each insulator.

The bending moment at any section of the pole shaft can be expressed as:

为截面至杆身风压合力作用点的高度，m_x为由扰度产生的附加弯矩系数，F为杆身投影面积，D₀为电杆稍径；D_x为电杆截面直径。where w _xz (t) is the sum of the wind load of the conductor and the wind load of the insulator, w _sv (t) is the combined wind load of the conductor tower and the insulator, h ₁ is the distance from the section to the top of the pole,

is the height from the cross section to the point of action of the resultant wind pressure on the shaft, _mx is the additional bending moment coefficient generated by the disturbance, F is the projected area of the shaft, _D0 is the slightly diameter of the pole; _Dx is the diameter of the cross-section of the pole.

During the continuous typhoon, the excessive wind load will cause the bending moment at the section of the pole shaft to exceed its bending strength, causing the pole to collapse. In order to describe the failure rate of the pole, a functional function with the state of the pole as the basic variable is established:

Z1=R1-S1;

In the formula: R1 is the flexural strength of the pole, S1 is the internal stress of the pole caused by the wind load, which is related to the wind speed and wind direction;

Among them, R1 is the Gauss distribution of the bending strength of the pole obeying the following formula:

In the formula: μ _P is the mean value of the flexural strength of the concrete pole, δ _P is the standard deviation of the flexural strength of the concrete pole, β and υ can be measured through actual operation experience or destructive tests, and M _u is the flexural strength of the concrete pole. Bearing capacity check bending moment;

The probability of normal operation of the pole at time t is:

Then the failure rate of the pole at time t is

On the basis of the above embodiments, in the embodiment of the present invention, during the continuous typhoon, the excessive wind load will cause the bending moment of the overhead line to exceed its bending strength, causing the line to break. In order to describe the failure rate of the overhead line, it is first necessary to calculate the dead weight L _G and the maximum bearing stress L _Desm of the overhead line:

In the formula: L _v is the vertical span of the overhead line, G ₀ is the mass of the overhead line per unit length, T _m is the breaking force, determined by the model of the overhead line, and K is the safety factor;

By analogy to the failure rate modeling process of electric poles, the functional function with the status of the overhead line as the basic variable can be obtained as shown in the formula, which can be expressed as:

Z2=R2-S2;

R2=L _G +L _Desm ;

In the formula: R2 is the tensile strength of the overhead line, S2 is the internal stress of the overhead line caused by the wind load, which is related to the wind speed and wind direction;

Then the failure rate of the overhead line at time t is:

In the formula: μ _P is the mean value of the tensile strength of the overhead wire, and δ _P is the standard deviation of the tensile strength of the overhead wire.

On the basis of the above embodiments, in the embodiment of the present invention, an insulator failure rate model is established:

The critical value of rainfall _Aζ for insulator flashover is expressed as:

In the formula: U _ζ is the critical value of the flashover voltage of the insulator; P is the current ambient air pressure; P ₀ is the standard atmospheric pressure, a, b, and c are all constants;

The flashover probability of a single insulator is:

In the formula: F(V _rain (t)) is the probability distribution function of rainfall intensity, which is obtained by the following formula:

On the basis of the above embodiments, in this embodiment of the present invention, the transformer failure rate model includes:

The critical value of rainfall A _ζ1 for spark discharge of transformer insulating oil and the critical value of rainfall A ₂ for breakdown of oil-impregnated paper are respectively expressed as:

In the formula: W ₁ is the moisture content of the transformer insulating oil, W ₂ is the moisture content of the transformer oil-impregnated paper, N is the rainfall duration, that is, the typhoon disaster duration t _total , a ₁ , a ₂ , b ₁ , b ₂ , n ₁ and _n2 are both constants;

The discharge probability of the insulating oil spark at time t is:

The breakdown probability of oil-impregnated paper at time t is:

in,

Then the total failure rate of the distribution transformer is:

_{Ph(t)=P h1 (} t)+P _h2 (t)-P _h1 (t)P _h2 (t).

On the basis of the above embodiments, in the embodiment of the present invention, the calculation model of the distribution network failure rate obtained according to the pole failure rate model, the overhead line failure rate model, the insulator failure rate model and the transformer failure rate model includes:

P _∑ =Max(P _r (t)+P _l (t))+P _g +P _h (t), t∈[0,t _total ];

In the formula, P _∑ is the total probability of load loss during the typhoon disaster duration, P _r (t) is the failure rate of the pole at time t, P _l (t) is the failure rate of the overhead line at time t, P _g is the flashover probability of a single insulator, and P _h (t) is the failure rate of the transformer at time t.

The following will describe in detail the method for calculating the failure rate of the distribution network under typhoon disaster provided by the embodiment of the present invention.

Before constructing the probability density function representing typhoon intensity and constructing the probability density distribution function of typhoon duration in this embodiment of the present invention, it is necessary to provide basic information of the power distribution network, including topology structure, overhead line type, geographic distribution, etc.; The basic information of the typhoon, including the landing position, running track and speed, etc. The specific working process is as follows:

Step 1: Load the typhoon historical data, including the time series change process of typhoon wind speed, rainfall intensity and typhoon duration.

Step 2: Establish a statistical model of typhoon disasters. The historical data of typhoon wind speed, rainfall intensity and other characteristic quantities are analyzed, and the probability density function characterizing typhoon intensity is obtained by GMM fitting. Furthermore, the confidence interval of each feature quantity is obtained by introducing the conditional risk value, and the probability distribution of the typhoon duration is obtained by judging whether the typhoon intensity has dropped below the minimum level standard (typhoon center wind force level 12).

The third step: establish a distribution network failure rate model based on the disaster mechanism. Considering the disaster mechanism of typhoon disaster, the failure rate model of various components such as poles, overhead lines, insulators, and distribution transformers is established, and the total failure rate of the distribution network under typhoon disasters is obtained. Due to the combined effect of wind and rain in typhoon weather, the failure rate of the distribution network will greatly increase, mainly including the following two aspects: the force of the strong wind on the tower or overhead line exceeds its load capacity, which will lead to the collapse of the pole and the broken line; Rainfall will cause the surface resistance of the insulator to drop, causing flashover to occur, and it will also cause the transformer to get wet and cause an insulation accident.

The beneficial effects of the present invention are:

(1) A statistical model for typhoon intensity and duration has been established, and multiple disasters are considered concurrent, which can fully reflect the combined effect of typhoon and rainstorm;

(2) The provided modeling method of distribution network failure rate under typhoon disaster comprehensively considers the damage effect of typhoon disaster on different components of distribution network, and has high accuracy;

(3) With the increasing variety of active distribution network components, it is possible to adapt to the active distribution network by supplementing the failure rate model of new components (the components in the embodiment of the present invention mainly include poles, overhead lines, insulators and distribution transformers). The requirements of the power grid are scalable;

In short, the present invention only needs to provide the typhoon historical data and basic information of the distribution network, fit the predicted values of the typhoon intensity and duration, establish different failure rate models for different components of the distribution network, and obtain the The failure rate of the components is finally summed to obtain the total failure rate of the distribution network, and the modeling of the failure rate of the distribution network under the typhoon disaster driven by the data model can greatly improve the accuracy of the existing model.

Referring to FIG. 2 , in another embodiment of the present invention, a system for calculating the failure rate of a distribution network under a typhoon disaster is provided, and the system is used to implement the methods in the foregoing embodiments. Therefore, the descriptions and definitions in the foregoing embodiments of the calculation of the failure rate of the distribution network under the typhoon disaster can be used for the understanding of each execution module in the embodiments of the present invention. 2 is a schematic diagram of the overall structure of a power distribution network failure rate calculation system under a typhoon disaster provided by an embodiment of the present invention, and the system includes:

The first establishment module 21 is to establish a probability density function model representing typhoon intensity based on the historical data of typhoon wind speed and rainfall intensity under typhoon disaster;

The second establishment module 22 is used to establish the probability distribution function model of the typhoon duration;

The third establishment module 23 is used to establish the calculation model of the failure rate of the distribution network under the typhoon disaster based on the probability density function model representing the typhoon intensity and the probability distribution function model of the typhoon duration;

The calculation module 24 is configured to calculate the total probability of load loss during the duration of the typhoon disaster based on the distribution network failure rate calculation model.

The system for calculating the failure rate of a distribution network under a typhoon disaster provided by the embodiment of the present invention corresponds to the method for calculating the failure rate of a distribution network under a typhoon disaster provided by the foregoing embodiments. The relevant technical features of the system for calculating the failure rate of a distribution network under a typhoon disaster can be Reference is made to the related technical features of the method for calculating the failure rate of a distribution network under typhoon disaster provided by the foregoing embodiments, which will not be repeated here.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. a power distribution network failure rate calculation method under a typhoon disaster, is characterized in that, comprises: Based on the historical data of typhoon wind speed and rainfall intensity under typhoon disaster, establish a probability density function model to characterize typhoon intensity; Establish the probability distribution function model of typhoon duration; Based on the probability density function model representing the typhoon intensity and the probability distribution function model of the typhoon duration, establish a calculation model of the failure rate of the distribution network under the typhoon disaster; Based on the distribution network failure rate calculation model, the total probability of load loss during the duration of the typhoon disaster is calculated. 2. The method for calculating the failure rate of distribution network under typhoon disaster according to claim 1, is characterized in that, based on the historical data of typhoon wind speed and rainfall intensity under typhoon disaster, establish a probability density function model characterizing typhoon intensity include: The time-varying probability vector V(t) of typhoon wind speed and rainfall intensity is expressed as: V(t)=[V _wind (t) V _rain (t)]; where V _wind (t) is the probability vector of typhoon wind speed at time t, and V _rain (t) is the probability vector of rainfall intensity at time t; The probability density function ρ(V(t)) of V(t) is obtained by fitting the historical data of typhoon wind speed and rainfall intensity. 3. The power distribution network failure rate calculation method under typhoon disaster according to claim 1, is characterized in that, described establishing the probability distribution function model of typhoon duration comprises: By judging whether the typhoon intensity at time t is reduced to the lowest level standard, the probability distribution function model of the typhoon duration is established. 4. the power distribution network failure rate calculation method under typhoon disaster according to claim 3, is characterized in that, described by judging whether the typhoon intensity at time t is reduced to the lowest level standard, the probability distribution function model of establishing typhoon duration time comprises: The typhoon duration T is expressed as: T=t _end -t _begin ; In the formula: t _begin is the start time of the typhoon, t _end is the end time of the typhoon, and the boundary value of the β confidence interval

Obtained by the following formula:

where:

are the upper limit of the conditional confidence interval of typhoon wind speed and rainfall intensity, respectively, V _wmin is the minimum level standard of typhoon wind speed, and V _rmin is the minimum level standard of rainfall intensity;

where:

are the lower limits of the conditional confidence intervals for typhoon wind speed and rainfall intensity, respectively; Then the β confidence interval of the typhoon duration T is

5. The method for calculating the failure rate of distribution network under typhoon disaster according to claim 1, characterized in that, based on the probability density function model characterizing typhoon intensity and the probability distribution function model of typhoon duration, based on the typhoon The calculation model of distribution network failure rate under disaster includes: Build the pole failure rate model, overhead line failure rate model, insulator failure rate model and transformer failure rate model respectively; According to the pole failure rate model, the overhead line failure rate model, the insulator failure rate model and the transformer failure rate model, the distribution network failure rate calculation model is obtained. 6. The method for calculating the failure rate of a distribution network under a typhoon disaster according to claim 5, wherein the establishing a pole failure rate model comprises: Establish a functional function with the pole state as the basic variable: Z1=R1-S1; In the formula: R1 is the flexural strength of the pole, S1 is the internal stress of the pole caused by the wind load, which is related to the wind speed and wind direction; Among them, R1 is the Gauss distribution of the bending strength of the pole obeying the following formula:

In the formula: μ _P is the mean value of the flexural strength of the concrete pole, δ _P is the standard deviation of the flexural strength of the concrete pole, β and υ can be measured through actual operation experience or destructive tests, and M _u is the flexural strength of the concrete pole. Bearing capacity check bending moment; The probability of normal operation of the pole at time t is:

Then the failure rate of the pole at time t is

7. The method for calculating the failure rate of distribution network under typhoon disaster according to claim 5, wherein the establishing an overhead line failure rate model comprises: Calculate the dead weight L _G and the maximum bearing stress L _Desm of the overhead line:

In the formula: L _v is the vertical span of the overhead line, G ₀ is the mass of the overhead line per unit length, T _m is the breaking force, determined by the model of the overhead line, and K is the safety factor; The function function with the status of the overhead line as the basic variable is as follows: Z2=R2-S2; R2=L _G +L _Desm ; In the formula: R2 is the tensile strength of the overhead line, S2 is the internal stress of the overhead line caused by the wind load, which is related to the wind speed and direction; The failure rate of the overhead line at time t is:

In the formula: μ _P is the mean value of the tensile strength of the overhead wire, and δ _P is the standard deviation of the tensile strength of the overhead wire. 8. The method for calculating the failure rate of distribution network under typhoon disaster according to claim 5, wherein the described establishment of an insulator failure rate model: The critical value of rainfall _Aζ for insulator flashover is expressed as:

In the formula: U _ζ is the critical value of the flashover voltage of the insulator; P is the current ambient air pressure; P ₀ is the standard atmospheric pressure, a, b, and c are all constants; The flashover probability of a single insulator is:

In the formula: F(V _rain (t)) is the probability distribution function of rainfall intensity, which is obtained by the following formula:

9. The method for calculating the failure rate of distribution network under typhoon disaster according to claim 5, wherein the transformer failure rate model comprises: Critical value of rainfall for spark discharge of transformer insulating oil

and the critical value of rainfall for oil-impregnated paper to be broken down

They are respectively expressed as:

In the formula: W ₁ is the moisture content of the transformer insulating oil, W ₂ is the moisture content of the transformer oil-impregnated paper, N is the rainfall duration, that is, the typhoon disaster duration t _total , a ₁ , a ₂ , b ₁ , b ₂ , n ₁ and _n2 are both constants; The discharge probability of the insulating oil spark at time t is:

The breakdown probability of oil-impregnated paper at time t is:

Then the total failure rate of the distribution transformer is: _{Ph(t)=P h1 (} t)+P _h2 (t)-P _h1 (t)P _h2 (t). 10. The method for calculating the failure rate of a distribution network under typhoon disasters according to claim 5, wherein the distribution network is obtained according to the pole failure rate model, the overhead line failure rate model, the insulator failure rate model and the transformer failure rate model. The power grid failure rate calculation model includes: P _∑ =Max(P _r (t)+P _l (t))+P _g +P _h (t), t∈[0,t _total ]; In the formula, P _∑ is the total probability of load loss during the duration of the typhoon disaster, P _r (t) is the failure rate of the pole at time t, P _l (t) is the failure rate of the overhead line at time t, P _g is the flashover probability of a single insulator, and P _h (t) is the failure rate of the transformer at time t.

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