A distribution network reliability assessment system and method

Abstract

The present invention relates to the field of distribution network reliability assessment, and in particular to a distribution network reliability assessment system and method. Based on electrical parameter data, a dynamic failure rate calculation algorithm is used to calculate the basic failure rate of each node in the distribution network; further, the failure probability of the distribution network node and the failure impact transfer matrix elements are calculated; based on the failure probability of the distribution network node and the failure impact transfer matrix elements, a distribution network reliability assessment algorithm is used to calculate the reliability value of the distribution network; and the reliability value of the distribution network is compared with a set reliability threshold to assess the reliability level of the distribution network. The technical problems that the impact of various dynamic factors on the distribution network during operation cannot be reflected in real time are solved; the assessment of the failure probability of the distribution network ignores the dynamic impact of environmental conditions and equipment aging on the failure probability; the nonlinear correlation between nodes and the impact of load flow are ignored; and the distribution network reliability assessment method does not consider the technical problems comprehensively.

Description

Technical Field

[0001] The present invention relates to the field of distribution network reliability assessment, and in particular to a distribution network reliability assessment system and method. Background Art

[0002] With the progress of society and the development of science and technology, the demand for electricity is growing. As an important part of the power system, the reliability of the distribution network is particularly important. The reliability of the distribution network not only affects the electricity users' experience, but also is related to the economic benefits of the power company and social public safety. Therefore, the research on distribution network reliability assessment methods has become a key issue in the power industry.

[0003] By combining information technology and computer technology to build an efficient and accurate evaluation system, we can comprehensively analyze and evaluate the reliability level of the distribution network, discover the weak links and potential risks in the distribution network, put forward improvement suggestions and optimization plans, improve the operation safety and stability of the distribution network, and provide strong support for the development of the power industry. In the future, with the continuous advancement of technology and the in-depth application of it, distribution network reliability assessment will play a more important role in the fields of smart grids and smart cities.

[0004] However, the existing evaluation system still has the following technical problems when analyzing and evaluating the reliability level of the distribution network: using historical data and static models to estimate the failure rate of each node cannot reflect in real time the impact of various dynamic factors on the distribution network during operation, resulting in insufficient accuracy and real-time performance in the calculation of the failure rate; the existing evaluation of the failure probability of the distribution network ignores the dynamic impact of environmental conditions and equipment aging on the failure probability, resulting in the evaluation results being difficult to reflect the actual situation; estimating fault propagation based on simple topological structures or static node connection relationships easily ignores the nonlinear correlation between nodes and the impact of load flow direction; the distribution network reliability evaluation method is not comprehensive enough, resulting in insufficient comprehensiveness and accuracy in the distribution network reliability evaluation. Summary of the invention

[0005] The present invention provides a distribution network reliability assessment system and method to solve the problems that the failure rate of each node is estimated using historical data and a static model, which cannot reflect the influence of various dynamic factors on the distribution network in real time during operation, resulting in insufficient accuracy and real-time performance of the failure rate calculation; the assessment of the failure probability of the distribution network ignores the dynamic influence of environmental conditions and equipment aging on the failure probability, resulting in the assessment result being difficult to reflect the actual situation; the nonlinear correlation between nodes and the influence of load flow direction are easily ignored when estimating fault propagation based on a simple topological structure or a static node connection relationship; and the distribution network reliability assessment method is not comprehensive enough, resulting in insufficient comprehensiveness and accuracy of the distribution network reliability assessment.

[0006] A distribution network reliability assessment system and method of the present invention specifically include the following technical solutions:

[0007] A distribution network reliability assessment method comprises the following steps:

[0008] S1: Based on the electrical parameter data of each node in the distribution network obtained in real time, the basic failure rate of each node in the distribution network is calculated using a dynamic failure rate calculation algorithm;

[0009] S2: Based on the basic failure rate of each node in the distribution network, combined with the environmental data of the distribution network area and the initial commissioning time of the distribution network equipment, the distribution network node failure probability dynamic evaluation algorithm is used to calculate the distribution network node failure probability;

[0010] S3: Based on the probability of node failure in the distribution network, the node fault propagation evaluation algorithm is used to calculate the elements of the fault impact transfer matrix;

[0011] S4: Based on the failure probability of distribution network nodes and the elements of the fault impact transfer matrix, the reliability value of the distribution network is calculated using the distribution network reliability assessment algorithm; a reliability threshold is set, and the reliability level of the distribution network is evaluated by comparing the calculated reliability value of the distribution network with the reliability threshold.

[0012] Preferably, the S1 specifically includes:

[0013] The dynamic fault rate calculation algorithm standardizes the electrical parameter data of each node in the distribution network and calculates the degree of deviation of the electrical parameter data of each node in the distribution network relative to the normal operating range.

[0014] Preferably, the S2 specifically includes:

[0015] The dynamic evaluation algorithm of distribution network node failure probability converts the linear combination of failure influence factors into nonlinear failure probability by using exponential function to obtain the distribution network node failure probability.

[0016] Preferably, the S3 specifically includes:

[0017] The node fault propagation assessment algorithm evaluates the propagation path and impact range of faults in the distribution network based on the failure probability of nodes in the distribution network, the connection strength between nodes, the load flow direction, the time decay effect and the nonlinear correlation between nodes.

[0018] Preferably, the S3 specifically includes:

[0019] The connection strength between nodes is based on the physical and logical topology of the distribution network. The load flow direction quantifies the load transmission between nodes through the load flow direction factor. The time decay effect describes the phenomenon that the impact of faults gradually weakens over time through the time decay factor, and introduces the time decay coefficient to control the decay speed. The nonlinear correlation between nodes is based on the joint effect of the connection strength and load flow between nodes, captures the correlation between nodes, and describes the interaction between nodes through the hyperbolic tangent function.

[0020] Preferably, the S4 specifically includes:

[0021] The distribution network reliability assessment algorithm calculates the reliability value of the distribution network based on the failure probability of each node in the distribution network, the elements of the fault impact transfer matrix, and the redundancy of the distribution network.

[0022] A distribution network reliability assessment system includes the following parts:

[0023] Data acquisition module, dynamic fault rate calculation module, fault probability dynamic assessment module, node fault propagation assessment module, distribution network reliability assessment module;

[0024] Data acquisition module: obtains the electrical parameter data of each node in the distribution network in real time, and outputs the electrical parameter data to the dynamic failure rate calculation module; obtains the environmental data of the area where the distribution network is located and the initial commissioning time of the distribution network equipment, and outputs the environmental data and the initial commissioning time of the distribution network equipment to the dynamic failure probability assessment module;

[0025] Dynamic failure rate calculation module: Based on the electrical parameter data, the basic failure rate of each node in the distribution network is calculated using the dynamic failure rate calculation algorithm, and the basic failure rate of each node in the distribution network is output to the failure probability dynamic evaluation module;

[0026] Fault probability dynamic assessment module: Based on environmental data, the initial commissioning time of distribution network equipment and the basic failure rate of each node in the distribution network, the distribution network node fault probability dynamic assessment algorithm is used to calculate the distribution network node fault probability, and the distribution network node fault probability is output to the node fault propagation assessment module and the distribution network reliability assessment module;

[0027] Node fault propagation assessment module: Based on the distribution network node failure probability, the node fault propagation assessment algorithm is used to calculate the fault impact transfer matrix elements, and the fault impact transfer matrix elements are output to the distribution network reliability assessment module;

[0028] Distribution network reliability assessment module: Based on the failure probability of distribution network nodes and the elements of the fault impact transfer matrix, the reliability value of the distribution network is calculated using the distribution network reliability assessment algorithm; a reliability threshold is set, and the reliability level of the distribution network is assessed by comparing the calculated reliability value of the distribution network with the reliability threshold.

[0029] The beneficial effects of the technical solution of the present invention are:

[0030] 1. By acquiring the electrical parameter data of each node in real time and using a dynamic failure rate calculation algorithm, the basic failure rate of each node can be accurately evaluated and the actual operating status of the distribution network can be reflected in a timely manner.

[0031] 2. The dynamic evaluation algorithm of distribution network node failure probability is combined with the basic failure rate of distribution network nodes, environmental data and the initial commissioning time of equipment. By converting the linear combination of failure influencing factors into nonlinear failure probabilities, the failure probability of nodes can be accurately evaluated, which improves the accuracy and flexibility of distribution network failure probability evaluation in complex environments, thereby enhancing the reliability evaluation capability of distribution networks.

[0032] 3. The node fault propagation assessment algorithm can accurately assess the fault propagation path and impact range in the distribution network by considering the connection strength, load flow direction, time attenuation effect and nonlinear correlation between nodes, ensuring the accuracy and dynamics of the fault transmission assessment, which helps maintenance personnel predict the fault propagation path and take preventive measures.

[0033] 4. The distribution network reliability assessment algorithm can comprehensively consider the failure probability of each node, the fault impact transfer matrix and the redundancy of the distribution network, and dynamically calculate the reliability value of the distribution network. By comparing the calculation results with the preset reliability threshold, the reliability level of the distribution network at a specific time point can be clearly assessed, thereby deciding whether measures need to be taken to improve the reliability of the assessment system, making the operation and maintenance of the distribution network scientific and reasonable. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a structural diagram of a distribution network reliability assessment system according to the present invention;

[0035] Figure 2 The present invention is a flow chart of a distribution network reliability assessment method. DETAILED DESCRIPTION

[0036] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0038] The specific scheme of a distribution network reliability assessment system and method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0039] Refer to the attached Figure 1 , which shows a structure diagram of a distribution network reliability assessment system provided by an embodiment of the present invention, the system includes the following parts:

[0040] Data acquisition module, dynamic fault rate calculation module, fault probability dynamic assessment module, node fault propagation assessment module, distribution network reliability assessment module;

[0041] Data acquisition module: obtains the electrical parameter data of each node of the distribution network in real time from the monitoring system of the distribution network, outputs the electrical parameter data to the dynamic failure rate calculation module, obtains the environmental data of the area where the distribution network is located from the meteorological data system, obtains the initial commissioning time of the distribution network equipment from the distribution network equipment maintenance system, and outputs the environmental data and the initial commissioning time of the distribution network equipment to the dynamic failure probability assessment module;

[0042] Dynamic failure rate calculation module: Based on the electrical parameter data of the data acquisition module, the basic failure rate of each node in the distribution network is calculated using the dynamic failure rate calculation algorithm, and the basic failure rate of each node in the distribution network is output to the failure probability dynamic evaluation module;

[0043] Fault probability dynamic assessment module: Based on the environmental data of the data acquisition module, the initial commissioning time of the distribution network equipment and the basic failure rate of each node in the distribution network of the dynamic failure rate calculation module, the distribution network node failure probability is calculated using the distribution network node failure probability dynamic assessment algorithm, and the distribution network node failure probability is output to the node fault propagation assessment module and the distribution network reliability assessment module;

[0044] Node fault propagation assessment module: Based on the distribution network node fault probability of the fault probability dynamic assessment module, the node fault propagation assessment algorithm is used to calculate the fault impact transfer matrix elements, and the fault impact transfer matrix elements are output to the distribution network reliability assessment module;

[0045] Distribution network reliability assessment module: Based on the distribution network node failure probability of the fault probability dynamic assessment module and the fault impact transfer matrix elements of the node fault propagation assessment module, the distribution network reliability value is calculated using the distribution network reliability assessment algorithm, a reliability threshold is set, and the reliability level of the distribution network is evaluated by comparing the calculated distribution network reliability value with the preset reliability threshold.

[0046] Refer to the attached Figure 2 , which shows a flow chart of a distribution network reliability assessment method provided by an embodiment of the present invention, the method comprising the following steps:

[0047] S1. Based on the electrical parameter data of each node in the distribution network obtained in real time, a dynamic failure rate calculation algorithm is used to calculate the basic failure rate of each node in the distribution network;

[0048] Obtain electrical parameter data of each node of the distribution network in real time from the monitoring system of the distribution network, such as voltage, current, and load;

[0049] According to the electrical parameter data of each node in the distribution network, the basic failure rate of each node in the distribution network is calculated using a dynamic failure rate calculation algorithm;

[0050] The dynamic failure rate calculation algorithm aims to evaluate the basic failure rate of each node in the distribution network in real time to reflect the actual operation status of the distribution network, and to determine the degree of deviation of the electrical parameter data of each node in the distribution network from the normal operation range by standardizing the electrical parameter data of each node in the distribution network; the standardization process is to compare the current voltage, current and load values ​​with the corresponding nominal values ​​or maximum design values;

[0051] The specific calculation formula for the basic failure rate of each node in the distribution network is:

[0052]

[0053] in, Representation Node In time Basic failure rate; Represents the baseline failure rate, determined based on data provided by the equipment manufacturer; Representation Node In time Voltage value; Indicates the nominal voltage value, which is specified by the design parameters of the equipment; Representation Node In time The absolute value of the voltage deviation is used to measure the deviation of the actual node voltage from the nominal voltage; Representation Node In time The ratio of the voltage deviation to the nominal voltage value is used to standardize the voltage deviation to evaluate the relative impact of the voltage deviation on the basic failure rate; Representation Node In time The current value; Representation Node The maximum allowable current value; Representation Node In time The ratio of the current value to the maximum allowable current value is used to standardize the current value and quantify the impact of the current on the basic failure rate; Representation Node In time The load value; Representation Node Maximum load capacity; Representation Node In time The ratio of load to maximum load capacity is used to normalize load values ​​and quantify the impact of load on basic failure rate;

[0054] S2. Based on the basic failure rate of each node in the distribution network, combined with the environmental data of the area where the distribution network is located and the initial commissioning time of the distribution network equipment, the distribution network node failure probability is calculated using the distribution network node failure probability dynamic evaluation algorithm;

[0055] In order to provide accurate and timely distribution network node failure probability in a complex distribution network environment, environmental data of the distribution network area, such as temperature data and environmental disturbance data, are obtained from the meteorological data system; the initial commissioning time of the distribution network equipment is obtained from the distribution network equipment maintenance system;

[0056] Based on the basic failure rate of each node in the distribution network, the environmental data of the area where the distribution network is located, and the initial commissioning time of the distribution network equipment, the failure probability of the distribution network node is calculated using the dynamic evaluation algorithm of the distribution network node failure probability;

[0057] The distribution network node failure probability dynamic evaluation algorithm uses an exponential function to convert the linear combination of failure influence factors into nonlinear failure probabilities. The failure influence factors include environmental influence factors and equipment aging factors, so as to achieve dynamic evaluation of the failure probability of each node in the distribution network.

[0058] The environmental impact factor calculates the periodic changes of environmental impacts according to the current time, such as temperature changes between day and night, and seasonal changes; calculates the degree of change of the current temperature relative to the nominal temperature according to the current temperature data; reflects the impact of sudden environmental events, such as thunderstorms and strong winds, on the probability of failure of distribution network nodes through sudden environmental disturbances, and increases the flexibility of environmental impact factors;

[0059] The equipment aging factor is based on the initial commissioning time of the distribution network equipment, combined with the distribution network equipment aging rate constant and exponential function, reflecting the increase in the probability of distribution network node failure caused by the aging of the distribution network equipment over time;

[0060] The specific calculation formula for the failure probability of distribution network nodes is:

[0061]

[0062] in, Representation Node In time Probability of failure; represents an exponential function, which is used to convert the linear combination of fault influence factors into nonlinear fault probability, wherein the fault influence factors include environmental influence factors and equipment aging factors; Representation Node In time Basic failure rate; It represents the equipment aging factor, which reflects the increase in the probability of failure of distribution network nodes caused by the aging of distribution network equipment over time. The exponential function is used to describe the nonlinear effect of the aging of distribution network equipment on the probability of failure of distribution network nodes. Indicates the aging rate constant of distribution network equipment, which can be set according to the specific implementation scenario and is not limited here; Indicates the initial commissioning time of the distribution network equipment; It represents the environmental impact factor, which reflects the impact of environmental conditions on the failure probability of distribution network nodes. The specific calculation formula is:

[0063] in, It means that the periodic changes of ambient temperature are simulated by the sine function, such as temperature changes between day and night and seasonal changes; Represents the angular frequency in the sine function, which is used to adjust the period of the sine function to ensure that it corresponds to the periodic changes of the actual ambient temperature; Indicates the ambient temperature change cycle; Represents the natural logarithmic function, which is used to adjust the effect of the deviation between the ambient temperature and the nominal temperature so that the effect of the temperature deviation conforms to the logarithmic growth law; Indicates at time Ambient temperature; It indicates the nominal temperature, which is specified by the design parameters of the equipment; Indicates the maximum ambient temperature allowed by the equipment, which is specified by the design parameters of the equipment; Indicates the lowest ambient temperature allowed by the equipment, which is specified by the design parameters of the equipment; Indicates time The sudden environmental disturbance is a dimensionless value, which is used to reflect the impact of sudden environmental events on the failure probability of distribution network nodes and increase the flexibility of environmental impact factors;

[0064] By calculating the failure probability of distribution network nodes, changes in distribution network operation can be reflected in a timely manner, improving the real-time and flexibility of reliability assessment.

[0065] S3. Based on the probability of node failure in the distribution network, the node fault propagation evaluation algorithm is used to calculate the elements of the fault impact transfer matrix;

[0066] Based on the failure probability of distribution network nodes, a node fault propagation evaluation algorithm is used to calculate the elements of the fault impact transfer matrix; the node fault propagation evaluation algorithm accurately evaluates the propagation path and impact range of the fault in the distribution network by comprehensively considering the failure probability of nodes in the distribution network, the connection strength between nodes, the load flow direction, the time decay effect and the nonlinear correlation between nodes;

[0067] The connection strength between the nodes is based on the physical and logical topological structure of the distribution network, reflecting the tightness of the physical connection or functional connection between the nodes;

[0068] The load flow direction quantifies the load transmission between nodes through a load flow direction factor;

[0069] The time decay effect uses a time decay factor to describe the phenomenon that the fault impact gradually weakens over time, and introduces a time decay coefficient to control the decay speed, ensuring that it can be close to the actual fault propagation characteristics, and ensuring the dynamics and accuracy of the fault impact transmission;

[0070] The nonlinear correlation between nodes can capture the potential complex correlation between nodes by considering the joint effect of the connection strength and load flow direction between nodes; the complex interaction relationship between nodes is described by the hyperbolic tangent function, which can effectively capture the nonlinear relationship between nodes, thereby accurately reflecting the node interaction in the actual distribution network;

[0071] The specific calculation formula of the fault impact transfer matrix elements is:

[0072]

[0073] in, Representation Node To Node In time The fault impact transfer matrix elements; Representation Node and nodes The strength of the connection between them is based on the physical and logical topology of the distribution network; Indicates the load flow factor, reflected in time node and nodes Load transmission between represents the attenuation factor of the fault effect; Represents the natural exponential function, which is used to characterize the natural decay or growth process; Representation Node and nodes The physical distance between Representation Node In time Probability of failure; It represents the time decay factor, which describes the phenomenon that the impact of a fault gradually weakens over time; is the time decay coefficient, which is used to control the decay speed; Represents a nonlinear association function, used to represent nodes and nodes The complex interactive relationship between them is calculated as follows:

[0074]

[0075] in, Represents the nonlinear amplification factor, which is used to control the degree of nonlinear correlation; represents the hyperbolic tangent function, which is used to transform a linear combination of inputs into a nonlinear output; It represents the network sensitivity parameter, which is used to adjust the influence of the connection strength between nodes and the load flow factor on the nonlinear correlation function;

[0076] S4. Based on the failure probability of distribution network nodes and the elements of the failure impact transfer matrix, a distribution network reliability evaluation algorithm is used to calculate the reliability value of the distribution network; a reliability threshold is set, and the reliability level of the distribution network is evaluated by comparing the calculated reliability value of the distribution network with the reliability threshold;

[0077] Based on the failure probability of distribution network nodes and the elements of the fault impact transfer matrix, the reliability value of the distribution network is calculated using the distribution network reliability assessment algorithm;

[0078] The distribution network reliability assessment algorithm determines the reliability of the distribution network by considering the failure probability of each node in the distribution network, the elements of the failure impact transfer matrix, and the redundancy of the distribution network;

[0079] The redundancy of the distribution network reflects the fault tolerance of the entire distribution network, that is, whether the distribution network can maintain normal operation through backup paths or redundant designs when a node fails;

[0080] The specific calculation formula of the reliability value of the distribution network is:

[0081]

[0082] in, Indicates at time Reliability value of distribution network; Indicates the number of nodes; Indicates the cumulative sum of the reliability of all nodes; Representation Node In time Probability of failure; Representation Node To Node In time The fault impact transfer matrix elements; Representation Node For all nodes in the distribution network The cumulative effect of the transmission of the failure impact; It represents the redundancy of the distribution network in the event of a fault, which is obtained by analyzing the redundant design of the network and the number of backup paths. It is a technical means well known to those skilled in the art and will not be described in detail here;

[0083] Set a reliability threshold , can be determined based on the specific application scenarios or industry standards of the distribution network and is not limited here;

[0084] The calculated reliability value of the distribution network is compared with the reliability threshold For comparison, if , then the distribution network is considered to be at time In a reliable state, otherwise, the distribution network is considered to be in a reliable state at time It is in an unreliable state and measures need to be taken to improve reliability;

[0085] By setting a threshold and comparing it with the calculated reliability value, the reliability level of the distribution network can be explicitly assessed.

[0086] In summary, a distribution network reliability assessment system and method are completed.

[0087] The order of the embodiments of the invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0088] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0089] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A distribution network reliability assessment method, characterized in that: The following steps are involved: S1: Based on the electrical parameter data of each node in the distribution network obtained in real time, a dynamic fault rate calculation algorithm is used to calculate the basic fault rate of each node in the distribution network; in the implementation process of the dynamic fault rate calculation algorithm, the electrical parameter data of each node in the distribution network is standardized to calculate the degree of deviation of the electrical parameter data of each node in the distribution network from the normal operating range; S2: Based on the basic failure rate of each node in the distribution network, combined with the environmental data of the area where the distribution network is located and the initial commissioning time of the distribution network equipment, a dynamic evaluation algorithm for the failure probability of the distribution network node is used. In the implementation process of the dynamic evaluation algorithm for the failure probability of the distribution network node, the linear combination of failure influence factors is converted into nonlinear failure probability by using an exponential function to obtain the failure probability of the distribution network node. The failure influence factors include environmental influence factors and equipment aging factors, and the failure probability of each node in the distribution network is dynamically evaluated; S3: Based on the failure probability of distribution network nodes, the node fault propagation evaluation algorithm is used to calculate the elements of the fault impact transfer matrix; in the implementation process of the node fault propagation evaluation algorithm, the propagation path and impact range of the fault in the distribution network are evaluated based on the failure probability of nodes in the distribution network, the connection strength between nodes, the load flow direction, the time decay effect and the nonlinear correlation between nodes; The strength of the connections between nodes is based on the physical and logical topology of the distribution network; The load flow direction quantifies the load transmission between nodes through the load flow direction factor; the time decay effect describes the phenomenon that the impact of the fault gradually weakens over time through the time decay factor, and introduces the time decay coefficient to control the decay speed; the nonlinear correlation between nodes is based on the joint effect of the connection strength between nodes and the load flow direction, captures the correlation between nodes, and describes the interaction relationship between nodes through the hyperbolic tangent function; The specific calculation formula of the fault impact transfer matrix elements is: Among them, M ij (t) represents the fault impact transfer matrix element from node i to node j at time t; W ij represents the connection strength between node i and node j; F ij (t) represents the load flow factor, which reflects the load transmission between node i and node j at time t; represents the attenuation factor of the fault effect; exp represents the natural exponential function; d ij represents the physical distance between node i and node j; P i (t) represents the probability of node i failing at time t; represents the time decay factor; α is the time decay coefficient; C ij (t) represents the nonlinear correlation function, which represents the complex interaction relationship between node i and node j. The specific calculation formula is: C ij (t)=β·tanh(γ·(W ij +F ij (t))) Among them, β represents the nonlinear amplification coefficient; tanh represents the hyperbolic tangent function; γ represents the network sensitivity parameter; S4: Based on the failure probability of the distribution network nodes and the elements of the failure impact transfer matrix, the distribution network reliability evaluation algorithm is used. In the process of implementing the distribution network reliability evaluation algorithm, the reliability value of the distribution network is calculated based on the failure probability of each node in the distribution network, the elements of the failure impact transfer matrix and the redundancy of the distribution network; A reliability threshold is set, and the reliability level of the distribution network is evaluated by comparing the calculated reliability value of the distribution network with the reliability threshold.

2. A distribution network reliability assessment system, applied to a distribution network reliability assessment method as claimed in claim 1, characterized in that: Includes the following sections: Data acquisition module, dynamic fault rate calculation module, fault probability dynamic assessment module, node fault propagation assessment module, distribution network reliability assessment module; Data acquisition module: obtains the electrical parameter data of each node in the distribution network in real time, and outputs the electrical parameter data to the dynamic failure rate calculation module; obtains the environmental data of the area where the distribution network is located and the initial commissioning time of the distribution network equipment, and outputs the environmental data and the initial commissioning time of the distribution network equipment to the dynamic failure probability assessment module; Dynamic failure rate calculation module: Based on the electrical parameter data, the basic failure rate of each node in the distribution network is calculated using the dynamic failure rate calculation algorithm, and the basic failure rate of each node in the distribution network is output to the failure probability dynamic evaluation module; Fault probability dynamic assessment module: Based on environmental data, the initial commissioning time of distribution network equipment and the basic failure rate of each node in the distribution network, the distribution network node fault probability dynamic assessment algorithm is used to calculate the distribution network node fault probability, and the distribution network node fault probability is output to the node fault propagation assessment module and the distribution network reliability assessment module; Node fault propagation assessment module: Based on the distribution network node failure probability, the node fault propagation assessment algorithm is used to calculate the fault impact transfer matrix elements, and the fault impact transfer matrix elements are output to the distribution network reliability assessment module; Distribution network reliability assessment module: Based on the failure probability of distribution network nodes and the elements of the fault impact transfer matrix, the reliability value of the distribution network is calculated using the distribution network reliability assessment algorithm; a reliability threshold is set, and the reliability level of the distribution network is assessed by comparing the calculated reliability value of the distribution network with the reliability threshold.

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