Power distribution network line disaster fault probability solving method

Abstract

The invention relates to a power distribution network line disaster fault probability solving method. The method comprises the following steps: step 1, determining evaluation basic information; 2, the steady-state probabilities Pn, Pa and Pm of the three kinds of weather are obtained; 3, according to the historical fault data of the power distribution network line and the historical meteorological data of the area where the power distribution network is located, the annual average fault rate lambda avg of the power distribution network line, the proportion Fb of the power distribution network line faults in severe weather and the proportion Fm of the power distribution network line faults in extreme weather are obtained through statistics; 4, respectively calculating the fault rates of the power distribution network line in normal weather, severe weather and extreme weather according to the data; step 5, according to statistical data, assuming that line faults conform to uniform Poisson distribution within a time interval, solving an accumulated fault rate of the element k within delta t time, and deducing a system probability of element outage in a system of N lines; the method has the advantages that the attribute values are quantified, the historical disaster data are clustered, the disaster severity is graded, and the fault rate model is constructed.

Description

Technical Field

[0001] The present invention belongs to the technical field of risk assessment of distribution networks, and in particular relates to a method for solving the probability of failure of distribution network lines. Background Art

[0002] In recent years, extreme weather disasters have occurred frequently, which has had a huge impact on power grid facilities, production and life. In the face of emergencies, especially natural disasters, the vulnerability of the power system is fully exposed, seriously affecting the stability of the power grid and the stable development of the social economy. In addition, Henan Province has complex and changeable topography, with a transition from plains to hilly and mountainous climates from east to west. It has four distinct seasons, simultaneous rain and heat, complex and diverse weather disasters, and frequent meteorological disasters. The safety, stability and reliability of the distribution network system are more susceptible to severe impacts of extreme weather, such as floods, lightning disasters, landslides, mudslides and other natural disasters; therefore, in the context of growing electricity demand and increasingly severe energy challenges, it is more important to consider the huge threat that extreme weather will pose to the safety and stability of the distribution network, which needs to be promoted urgently. The research work on disaster risk assessment in the distribution network area under extreme weather conditions continuously improves the reliability of the distribution network, reduces or even eliminates the harm of extreme weather to the distribution network system, realizes the disaster assessment and optimization decision of the distribution network, and provides more accurate theoretical support for the power company's power facility construction tasks and operation and maintenance work. While reducing the adverse effects of power accidents caused by extreme weather on the social economy, it improves the safety construction and safety management level of the distribution network infrastructure, and ensures that the distribution network can operate safely, stably and efficiently. It has a very forward-looking scientific research value; therefore, it is very necessary to provide a method for solving the probability of failure of distribution network lines that quantifies attribute values, clusters historical disaster data, grades the severity of disasters, and constructs a failure rate model. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a method for solving the probability of failure of distribution network lines caused by disasters by quantifying attribute values, clustering historical disaster data, grading the severity of disasters, and building a failure rate model.

[0004] The object of the present invention is achieved by: a method for solving the probability of a power distribution network line being damaged by a disaster, the method comprising the following steps:

[0005] Step 1: Determine the basic information for evaluation: Based on the historical meteorological statistics and the three-state weather model of the distribution network area, the annual average number of transitions between the three weather states of normal weather, severe weather and extreme weather and the duration of each state are obtained, and the transition rate between the three weather states is solved;

[0006] Step 2: Steady-state probabilities P of three types of weather n, P a , P m :The steady-state probabilities of normal weather, severe weather and extreme weather are solved through the state transition rates between different weather states;

[0007] Step 3: Obtain the annual average failure rate λ of the distribution network line based on the historical failure data of the distribution network line and the historical meteorological data of the distribution network area. avg and the proportion of distribution network line failures occurring in severe weather conditions F b and the ratio F under extreme weather conditions m ;

[0008] Step 4: Calculate the failure rates of distribution network lines in normal weather, bad weather and extreme weather respectively based on the above data;

[0009] Step 5: Based on statistical data, assuming that the line failures in the time interval conform to the uniform Poisson distribution, solve the cumulative failure rate of component k within the Δt time, and derive the system probability of component outages in the system of N lines.

[0010] Determining the basic evaluation information in step 1 includes the following steps:

[0011] Step 1.1: Obtain historical meteorological statistical data in the area where the distribution network is located;

[0012] Step 1.2: Count the annual average number of transitions between the three weather states of normal weather, severe weather, and extreme weather, as well as the duration of each state, and calculate the transition rate between the three weather states.

[0013] The steady-state probability P of the three weather conditions in step 2 is n , P a , P m The steps include:

[0014] Step 2.1: To find P n , P a , P m We also need to define some quantities: n a is the state transition rate from normal weather to severe weather; a n 、m n 、a m 、m a The meaning of is the same, and the unit is the number of occurrences / h;

[0015] Step 2.2: According to the state transition rate, from equations (1) to (4), the steady-state probabilities of normal weather, bad weather, and extremely bad weather can be obtained: P n =(m a a n +m n an +m n a m ) / D(1),P a =(m a a n +m a n m +m n n a ) / D(2),P m =(n a a m +n m a n +n m a m ) / D(3), D=m a a n +m n a n +m n a m +m a n a +m a n m +m n n a +n a a m +n m a n +n m a m (4).

[0016] The specific formula of step 4 is as follows: n =λ avg (1-F b ) / P n (5), λ a =λ avg F b (1-F m ) / P a (6), λ m =λ avg F b F m / P m (7), where: avg is the annual average failure rate of the line; P n , P a , P m are the steady-state probabilities of normal, severe and extreme weather respectively; F b F is the proportion of failures occurring in bad weather; m It is the percentage of failures caused by extreme weather during severe weather. The annual average failure rate and the above-mentioned related ratios can be obtained through historical outage data statistics.

[0017] The step 5 specifically comprises the following steps:

[0018] Step 5.1: Based on statistical data, assuming that the line faults in the time interval conform to the uniform Poisson distribution, the cumulative failure rate of component k within Δt is: Where P k is the probability of component k being damaged; k is the failure rate of component k determined by the three-state weather model;

[0019] Step 5.2: For a system with N lines, in the i-th system state E i Under the condition of , the system probability calculation formula of component k outage at time t is:

[0020] The method for constructing the three-state weather model in step 1 is to divide the weather conditions that affect the power grid into three categories: normal, severe, and extreme weather, and calculate the state transition rate between the three weather conditions through weather statistical data.

[0021] The method for solving the line fault probability based on the three-state weather model in step 1 includes a method for solving the steady-state fault probability and a method for calculating the probability of equipment outage within the predicted time.

[0022] Beneficial effects of the invention: The invention is a method for solving the probability of failure of distribution network lines. During use, the invention quantifies the attribute values ​​based on the four natural attribute information and historical data of the geology, wind disasters, lightning disasters and floods in the area where the distribution network is located, so as to cluster the historical disaster data, classify the severity of the disaster in the area, and then construct a distribution network failure rate model under different disasters and different weather conditions; the invention adopts a construction method including a three-state weather model and a method for solving the line failure probability based on the three-state weather model, wherein the construction of the three-state weather model is to divide the weather conditions that affect the power grid into three categories: normal, severe and extreme weather, and calculate through weather statistical data, the three categories The state transition rate between weather states; the line fault probability solution calculation method includes a solution method for steady-state fault probability and a calculation method for equipment shutdown probability within the predicted time; the present invention realizes distribution network disaster assessment and optimization decision-making, provides more accurate theoretical support for power company's power facility construction tasks and operation and maintenance work, and while reducing the adverse effects of power accidents caused by extreme weather on the social economy, improves the safety construction and safety management level of distribution network infrastructure, ensures that the distribution network can operate safely, stably and efficiently, and has a very forward-looking scientific research value; the present invention has the advantages of quantifying attribute values, clustering historical disaster data, grading disaster severity, and building a failure rate model. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The process of the method for solving the probability of failure of a power distribution network line in the present invention is as follows Figure 1 .

[0024] Figure 2 The process of the method for solving the probability of failure of a distribution network line in the present invention is as follows Figure 2 . DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Example 1

[0027] like Figure 1-2 As shown, a method for solving the probability of a power distribution network line being damaged by a disaster is provided, wherein the method comprises the following steps:

[0028] Step 1: Determine the basic information for evaluation: Based on the historical meteorological statistics and the three-state weather model of the distribution network area, the annual average number of transitions between the three weather states of normal weather, severe weather and extreme weather and the duration of each state are obtained, and the transition rate between the three weather states is solved;

[0029] Step 2: Steady-state probabilities P of three types of weather n , P a , P m :The steady-state probabilities of normal weather, severe weather and extreme weather are solved through the state transition rates between different weather states;

[0030] Step 3: Obtain the annual average failure rate λ of the distribution network line based on the historical failure data of the distribution network line and the historical meteorological data of the distribution network area. avg and the proportion of distribution network line failures occurring in severe weather conditions F b and the ratio F under extreme weather conditions m ;

[0031] Step 4: Calculate the failure rates of distribution network lines in normal weather, bad weather and extreme weather respectively based on the above data;

[0032] Step 5: Based on statistical data, assuming that the line failures in the time interval conform to the uniform Poisson distribution, solve the cumulative failure rate of component k within the Δt time, and derive the system probability of component outages in the system of N lines.

[0033] The present invention is a method for solving the probability of failure of distribution network lines. In use, the present invention quantifies the attribute values ​​based on the four natural attribute information and historical data of the geology, wind disasters, lightning disasters and floods in the area where the distribution network is located, so as to cluster the historical disaster data, classify the severity of the disaster in the area, and then construct a distribution network failure rate model under different disasters and different weather conditions; the present invention adopts a construction method including a three-state weather model and a method for solving the line failure probability based on the three-state weather model, wherein the construction of the three-state weather model is to divide the weather conditions that affect the power grid into three categories: normal, severe and extreme weather, and calculate the three weather conditions through weather statistical data. state transition rate between them; the line fault probability solution calculation method includes a solution method for steady-state fault probability and a calculation method for equipment shutdown probability within the predicted time; the present invention realizes distribution network disaster assessment and optimization decision-making, provides more accurate theoretical support for power company's power facility construction tasks and operation and maintenance work, and while reducing the adverse effects of power accidents caused by extreme weather on the social economy, improves the safety construction and safety management level of distribution network infrastructure, ensures that the distribution network can operate safely, stably and efficiently, and has a very forward-looking scientific research value; the present invention has the advantages of quantifying attribute values, clustering historical disaster data, grading disaster severity, and building a failure rate model.

[0034] Example 2

[0035] like Figure 1-2 As shown, a method for solving the probability of failure of distribution network lines, the method comprising the following steps:

[0036] Step 1: Determine the basic information for evaluation: Based on the historical meteorological statistics and the three-state weather model of the distribution network area, the annual average number of transitions between the three weather states of normal weather, severe weather and extreme weather and the duration of each state are obtained, and the transition rate between the three weather states is solved;

[0037] Step 2: Steady-state probabilities P of three types of weather n , P a , P m :The steady-state probabilities of normal weather, severe weather and extreme weather are solved through the state transition rates between different weather states;

[0038] Step 3: Obtain the annual average failure rate λ of the distribution network line based on the historical failure data of the distribution network line and the historical meteorological data of the distribution network area. avg and the proportion of distribution network line failures occurring in severe weather conditions F b and the ratio F under extreme weather conditions m ;

[0039] Step 4: Calculate the failure rates of distribution network lines in normal weather, bad weather and extreme weather respectively based on the above data;

[0040] Step 5: Based on statistical data, assuming that the line failures in the time interval conform to the uniform Poisson distribution, solve the cumulative failure rate of component k within the Δt time, and derive the system probability of component outages in the system of N lines.

[0041] In this embodiment, the weather statistics are derived from the annual average number of transitions of normal weather, bad weather, and extremely bad weather and the duration of each state provided by the local meteorological bureau;

[0042] The historical statistical data of the failure rate of the distribution network lines are derived from the failure rate statistical data of the unit equipment required to be evaluated provided by the power grid company;

[0043] The state transition rate is set based on weather statistics; the annual average failure rate of equipment is λ avg , and F b and F m All of these can be directly derived from the historical statistical data of equipment failure rates.

[0044] Determining the basic evaluation information in step 1 includes the following steps:

[0045] Step 1.1: Obtain historical meteorological statistical data in the area where the distribution network is located;

[0046] Step 1.2: Count the annual average number of transitions between the three weather states of normal weather, severe weather, and extreme weather, as well as the duration of each state, and calculate the transition rate between the three weather states.

[0047] The steady-state probability P of the three weather conditions in step 2 is n , P a , P m The steps include:

[0048] Step 2.1: To find P n , P a , P m We also need to define some quantities: n a is the state transition rate from normal weather to severe weather; a n 、m n 、a m 、m a The meaning of is the same, and the unit is the number of occurrences / h;

[0049] Step 2.2: According to the state transition rate, from equations (1) to (4), the steady-state probabilities of normal weather, bad weather, and extremely bad weather can be obtained: P n =(m aa n +m n a n +m n a m ) / D(1),P a =(m a a n +m a n m +m n n a ) / D(2),P m =(n a a m +n m a n +n m a m ) / D(3), D=m a a n +m n a n +m n a m +m a n a +m a n m +m n n a +n a a m +n m a n +n m a m (4).

[0050] The specific formula of step 4 is as follows: n =λ avg (1-F b ) / P n (5), λ a =λ avg F b (1-F m ) / P a (6), λ m =λ avg F b F m / P m (7), where: avg is the annual average failure rate of the line; P n , P a , P m are the steady-state probabilities of normal, severe and extreme weather respectively; F b F is the proportion of failures occurring in bad weather; mIt is the percentage of failures caused by extreme weather during severe weather. The annual average failure rate and the above-mentioned related ratios can be obtained through historical outage data statistics.

[0051] The step 5 specifically comprises the following steps:

[0052] Step 5.1: Based on statistical data, assuming that the line faults in the time interval conform to the uniform Poisson distribution, the cumulative failure rate of component k within Δt is: Where P k is the probability of component k being damaged; k is the failure rate of component k determined by the three-state weather model;

[0053] Step 5.2: For a system with N lines, in the i-th system state E i Under the condition of , the system probability calculation formula of component k outage at time t is:

[0054] The method for constructing the three-state weather model in step 1 is to divide the weather conditions that affect the power grid into three categories: normal, severe, and extreme weather, and calculate the state transition rate between the three weather conditions through weather statistical data.

[0055] The method for solving the line fault probability based on the three-state weather model in step 1 includes a method for solving the steady-state fault probability and a method for calculating the probability of equipment outage within the predicted time.

[0056] The present invention is a method for solving the probability of failure of distribution network lines. In use, the present invention quantifies the attribute values ​​based on the four natural attribute information and historical data of the geology, wind disasters, lightning disasters and floods in the area where the distribution network is located, so as to cluster the historical disaster data, classify the severity of the disaster in the area, and then construct a distribution network failure rate model under different disasters and different weather conditions; the present invention adopts a construction method including a three-state weather model and a method for solving the line failure probability based on the three-state weather model, wherein the construction of the three-state weather model is to divide the weather conditions that affect the power grid into three categories: normal, severe and extreme weather, and calculate the three weather conditions through weather statistical data. state transition rate between them; the line fault probability solution calculation method includes a solution method for steady-state fault probability and a calculation method for equipment shutdown probability within the predicted time; the present invention realizes distribution network disaster assessment and optimization decision-making, provides more accurate theoretical support for power company's power facility construction tasks and operation and maintenance work, and while reducing the adverse effects of power accidents caused by extreme weather on the social economy, improves the safety construction and safety management level of distribution network infrastructure, ensures that the distribution network can operate safely, stably and efficiently, and has a very forward-looking scientific research value; the present invention has the advantages of quantifying attribute values, clustering historical disaster data, grading disaster severity, and building a failure rate model.

Claims

1. A method for solving the probability of a power distribution network line being damaged by a disaster, characterized in that: The method comprises the following steps: Step 1: Determine the basic information for evaluation: Based on the historical meteorological statistics and the three-state weather model of the distribution network area, the annual average number of transitions between the three weather states of normal weather, severe weather and extreme weather and the duration of each state are obtained, and the transition rate between the three weather states is solved; Step 2: Steady-state probabilities P of three types of weather n , P a , P m :The steady-state probabilities of normal weather, severe weather and extreme weather are solved through the state transition rates between different weather states; Step 3: Obtain the annual average failure rate λ of the distribution network line based on the historical failure data of the distribution network line and the historical meteorological data of the distribution network area. avg and the proportion of distribution network line failures occurring in severe weather conditions F b and the ratio F under extreme weather conditions m ; Step 4: Calculate the failure rates of distribution network lines in normal weather, bad weather and extreme weather respectively based on the above data; Step 5: Based on statistical data, assuming that the line failures in the time interval conform to the uniform Poisson distribution, solve the cumulative failure rate of component k within the Δt time, and derive the system probability of component outages in the system of N lines.

2. A method for solving the probability of a power distribution network line being damaged by a disaster as claimed in claim 1, characterized in that: Determining the basic evaluation information in step 1 includes the following steps: Step 1.1: Obtain historical meteorological statistical data in the area where the distribution network is located; Step 1.2: Count the annual average number of transitions between the three weather states of normal weather, severe weather, and extreme weather, as well as the duration of each state, and calculate the transition rate between the three weather states.

3. A method for solving the probability of a power distribution network line being damaged by a disaster as claimed in claim 1, characterized in that: The steady-state probability P of the three weather conditions in step 2 is n , P a , P m The steps include: Step 2.1: To find P n , P a , P m We also need to define some quantities: n a is the state transition rate from normal weather to severe weather; a n 、m n 、a m 、m a The meaning of is the same, and the unit is the number of occurrences / h; Step 2.2: According to the state transition rate, from equations (1) to (4), the steady-state probabilities of normal weather, bad weather, and extremely bad weather can be obtained: P n =(m a a n +m n a n +m n a m ) / D(1),P a =(m a a n +m a n m +m n n a ) / D(2),P m =(n a a m +n m a n +n m a m ) / D(3), D=m a a n +m n a n +m n a m +m a n a +m a n m +m n n a +n a a m +n m a n +n m a m (4).

4. A method for solving the probability of a power distribution network line being damaged by a disaster as claimed in claim 1, characterized in that: The specific formula of step 4 is as follows: n =λ avg (1-F b ) / P n (5), λ a =λ avg F b (1-F m ) / P a (6), λ m =λ avg F b F m / P m (7), where: avg is the annual average failure rate of the line; P n , P a , P m are the steady-state probabilities of normal, severe and extreme weather respectively; F b F is the proportion of failures occurring in bad weather; m It is the percentage of failures caused by extreme weather during severe weather. The annual average failure rate and the above-mentioned related ratios can be obtained through historical outage data statistics.

5. A method for solving the probability of a power distribution network line being damaged by a disaster as claimed in claim 1, characterized in that: The step 5 specifically comprises the following steps: Step 5.1: Based on statistical data, assuming that the line faults in the time interval conform to the uniform Poisson distribution, the cumulative failure rate of component k within Δt is: Where P k is the probability of damage to component k; k is the failure rate of component k determined by the three-state weather model; Step 5.2: For a system with N lines, in the i-th system state E i Under the condition of , the system probability calculation formula of component k outage at time t is:

6. A method for solving the probability of a power distribution network line being damaged by a disaster as claimed in claim 1, characterized in that: The method for constructing the three-state weather model in step 1 is to divide the weather conditions that affect the power grid into three categories: normal, severe, and extreme weather, and calculate the state transition rate between the three weather conditions through weather statistical data.

7. A method for solving the probability of a power distribution network line being damaged by a disaster as claimed in claim 6, characterized in that: The method for solving the line fault probability based on the three-state weather model in step 1 includes a method for solving the steady-state fault probability and a method for calculating the probability of equipment outage within the predicted time.

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