Leakage safety risk assessment method for urban functional lighting street lamps

Abstract

The present invention discloses a safety risk assessment method for leakage of urban functional lighting street lamps, which relates to the technical field of urban lighting, including a risk assessment index system and a safety risk assessment model. First, a risk assessment index system must be established, in which a safety risk assessment model must be established. Then, the possibility of risk events is assessed according to the safety risk assessment model, and a risk assessment index system is established. The risk factors affecting street lamp leakage are converted into indicators and divided into three categories: A intrinsic safety factor, B operational safety factor, and C safety management factor. The present invention establishes a complete risk assessment index system for leakage of urban functional lighting street lamps from the three aspects of intrinsic safety, operational safety, and safety management. This system can simultaneously describe the possibility of accidents and the severity of consequences, and fully considers the mutual coupling of different disaster-causing factors, the mutual relationship of various accidents, and the impact of importance on comprehensive risks.

Description

Technical Field

[0001] The present invention relates to the technical field of urban lighting, and in particular to a method for assessing the safety risk of leakage of urban functional lighting street lamps. Background Art

[0002] With the rapid advancement of urbanization in China, population, resources, industries and other factors are further concentrated in cities, and the scale of cities has expanded dramatically, causing urban lighting systems to become more complex. Coupled with the gradual aging of urban power facilities, urban areas frequently experience "urban problems" such as power outages, short circuits, voltage instability, and leakage. Faced with the increasingly heavy pressure of urban operations, the lighting system is constantly undergoing reconstruction, expansion and new construction, and the types, quantity and scale of infrastructure invested are constantly increasing, forming a complex network system. Its complex risk evolution and interactivity are likely to spread rapidly through the network system and produce a cascade effect, that is, a small problem will induce complex risks with high uncertainty, emergence, cross-border and serious hazards under the "butterfly effect", which will lead to large-scale paralysis of the system and even cause large-scale economic losses and casualties.

[0003] In recent years, many accidents involving electric leakage from street lamps have occurred in many places across the country, which has had a negative social impact. With the introduction and development of the concepts of safety management and risk assessment, the use of risk assessment theory to make qualitative and quantitative assessments of the risk of electric leakage from urban functional lighting street lamps, thereby achieving control and management of the entire system, has become a new research direction in recent years.

[0004] At present, the research on the risk assessment of leakage of urban functional lighting street lamps has made some progress. Through field investigations, data analysis and other methods, researchers have conducted in-depth research on the causes, influencing factors and potential risks of street lamp leakage. The problem of street lamp leakage is mainly affected by equipment aging, construction quality, environmental factors and other factors. For example, problems such as aging of wires, loose joints, and insulation damage may increase the risk of leakage; at the same time, factors such as severe weather conditions and damaged underground lines may also aggravate the occurrence of leakage problems.

[0005] Through the review and summary of the theories and methods of risk assessment of leakage current of urban functional lighting street lamps, it is found that the current research is limited to the impact of each independent factor on the risk. The evaluation results only show the importance of independent factors, but do not take into account the mutual connection and influence between the various factors, and have not formed a complete evaluation system and standard. In fact, there is a certain connection between the various factors that affect the risk, and the relevant research on coupling risk assessment is weak. The qualitative evaluation analytic hierarchy process and fuzzy comprehensive evaluation method used are relatively subjective, and they still cannot get rid of the randomness in the evaluation process and the subjective uncertainty and ambiguity of the evaluation experts in the application. This makes the evaluation process very subjective, which reduces the credibility of the results. There is a lack of complete risk assessment process and ideas. Most of them are quantitative calculation models for a certain accident, and there is no universal calculation method and analysis model. For this reason, we propose a safety risk assessment method for leakage current of urban functional lighting street lamps. Summary of the invention

[0006] 1. Technical issues to be solved

[0007] In view of the deficiencies in the prior art, the present invention provides a leakage safety risk assessment method for urban functional lighting street lamps to solve the technical problems of leakage assessment.

[0008] (II) Technical solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0010] The safety risk assessment method of leakage current of urban functional lighting street lamps includes risk assessment index system and safety risk assessment model.

[0011] First, we need to establish a risk assessment indicator system, in which we need to establish a security risk assessment model. Then, we evaluate the possibility of risk events based on the security risk assessment model, and use algorithms to derive a risk level calculation model to achieve the final risk assessment.

[0012] Preferably, a risk assessment index system is established to convert the risk factors affecting street lamp leakage into indicators and divide them into three categories: A intrinsic safety factor, B operational safety factor and C safety management factor.

[0013] A Intrinsic safety factors include: cable connectors, grounding system type, average service life and cable insulation material;

[0014] B Operational safety factors include: impact of flooding, environmental humidity, personnel flow, third-party construction activities, road collapse and historical leakage;

[0015] C Safety management elements include: evaluation of the current status of lighting facilities and emergency management level.

[0016] Preferably, A intrinsic safety element

[0017] a1 Grounding system: There are two types of grounding, namely TN system and TT system, according to whether the power supply (system) side is grounded at one point, not grounded (or grounded via high impedance), and whether the ground of the electrical device is directly electrically connected to the ground of the system side. Since both the TT system and the TN system have their advantages and disadvantages, a street lamp grounding solution is proposed based on the actual project and on the basis of maximizing the safety of personnel. It should be noted that the TN system and the TT system cannot be mixed in the same system, and the grounding failure is determined when the grounding resistance is >4Ω after repeated measurement;

[0018] a2 Average service life: After the street lamps and control cabinet parts are overused, the electrical components or parts may deteriorate, age, and cause electrical faults such as leakage and short circuit. The aging, short circuit, and leakage of the internal circuits of the distribution cabinet may cause fires, seriously threatening people's lives and property safety.

[0019] a3 Cable insulation material: Common cable insulation layers are divided into polyvinyl chloride (PVC), rubber (EPR) and cross-linked polyethylene (XLPE), which can maintain good flexibility and elasticity in a wide temperature range;

[0020] a4 Cable joint: Due to design, planning, construction and other reasons, there are different numbers of cable joints in the circuit. The wiring method and location are the two main factors affecting leakage. It is generally believed that wiring in the lamp pole is safer than in the wiring well, and heat shrink protection is better than dry bag protection;

[0021] a5 scheme design: The details are as follows:

[0022] (1) The design of the street lamp power supply network should meet the planning requirements and should adopt a dedicated transformer for power supply;

[0023] (2) The transformer should be a three-phase distribution transformer with a connection group of D, yn11;

[0024] (3) The three-phase load should be balanced;

[0025] (4) The road lighting power distribution system should have short-circuit protection and overload protection, should adopt TT system or TN-S system, and should comply with the current national standard "Low Voltage Power Distribution Design Specification" GB 50054;

[0026] (5) The road lighting power distribution system should be powered by underground cable lines;

[0027] (6) All exposed conductive parts of metal lamp poles and components, lamp housings, power distribution and control boxes, etc. should be connected to protective conductors.

[0028] a6 Construction quality: After the completion of the lighting project, it is necessary to undergo project quality completion acceptance and system completion acceptance and comply with relevant regulations.

[0029] Preferably, B operation safety factor

[0030] b1 Impact of flooding: After flooding, the electrical equipment inside the control box is easily corroded by moisture, resulting in reduced insulation performance, and even short circuit, leakage and other faults, thus affecting the normal operation of the equipment. When leakage accidents occur in street lamp lines and control boxes around the flooding point, the risk and possibility of accidents will be increased;

[0031] b2 Environmental humidity: Too high humidity will deteriorate the insulation material, causing cracks or defects in the protective layer on the surface of the wire, which will lead to leakage. A humid environment will cause the metal material on the surface of the wire to rust, thereby increasing the resistance of the wire and causing leakage. When the humidity is too high, the dust and impurities in the electrical appliance may become excellent conductors due to humidity. When the power is on, the soaked dust and impurities are very likely to be broken down by the current, which may not only cause combustion, but also cause poor contact of the power plug, causing leakage, short circuit, sparks, etc.

[0032] b3 Personnel flow rate: The personnel flow rate index can be used to evaluate the traffic capacity of a place. When a street light line or control box leaks electricity, the traffic flow rate will affect the severity of the accident consequences. The maximum flow rate is often selected as the basis for risk assessment;

[0033] b4 Third-party construction activities: Third-party construction may cause abnormal status, destruction and damage to power line components, which may lead to safety problems in the line;

[0034] b5 Impact of road collapse: The hidden danger of road collapse can easily lead to the collapse of street lamp poles, affect the safety of lines, and cause leakage accidents;

[0035] b6 Historical leakage situation: The historical leakage times can reflect the danger of the line or control box where the street lamp is located. The more leakage times, the greater the risk of accidents.

[0036] Optimum, C safety management elements

[0037] c1 Evaluation of the current status of lighting facilities: The maintenance unit shall evaluate the current status of lighting facilities in accordance with the relevant provisions of this Regulation based on the results of facility inspections, repairs and examinations. The evaluation results are divided into three categories: maintenance, improvement and renewal. The subsequent transformation of lighting facilities evaluated as improvement and renewal is not within the scope of maintenance work;

[0038] c2 Safety management and emergency response capabilities: refers to the management and maintenance units' identification and assessment of risks, daily safety management work and emergency response levels. These factors determine the response and handling capabilities after a leakage event.

[0039] Preferably, the safety risk assessment model, the risk assessment established by it includes three processes: risk identification, risk analysis and risk evaluation. This guide adopts the hierarchical analysis method to sort the evaluation indicators from high to low in order of importance, and the weight coefficient can be used to distinguish the importance of each evaluation indicator.

[0040] The risk factors affecting street lamp leakage are converted into indicators and divided into three categories: intrinsic safety factors, operational safety factors and safety management factors.

[0041] Preferably, the intrinsic safety factors include: cable joints, grounding system type, average service life and cable insulation material; operational safety factors include: impact of flooding, environmental humidity, personnel flow, third-party construction activities, road collapse impact and historical leakage; safety management factors include: current status evaluation of lighting facilities and emergency management level. Based on the index classification, evaluation indicators are proposed.

[0042] Preferably, each evaluation indicator is sorted in descending order of importance. A weight coefficient can be used to distinguish the importance of each evaluation indicator. The weight coefficient can be determined by combining multiple methods. This evaluation method selects the method of "determining weight values ​​by sorting evaluation indicators by importance" to determine the indicator weight. The calculation formula is shown below.

[0043]

[0044] Where, S-weight coefficient;

[0045] n-the number of evaluation indicators;

[0046] m-importance ranking number, m <n,

[0047] An evaluation index system is established based on the specific circumstances of each indicator. When evaluating a specific road, not all of the 12 indicators listed may be included in the evaluation. More important indicators can be selected for ranking.

[0048] Preferably, the risk level calculation model,

[0049] The overall assessment risk value F of leakage of urban functional lighting street lamps should be calculated and determined according to the following formula:

[0050] Wherein, Xij is the score of a single evaluation index, i=1, 2, 3, 4, 5; j=1, 2, ··.·, n, where n is the number of important indicators corresponding to the i-th evaluation index. After calculating the F value, the overall risk level of street lamp leakage and the corresponding countermeasures should be determined according to Table 1-2.

[0051] Preferably, the safety management level is also taken into consideration, including the third-party construction and safety management level indicators. The risk factors of the system are deeply identified from the dimensions of inherent risks that cause risk events, external disturbance risks, risk prevention and control, and a complete set of evaluation indicator systems with multi-factor coupling are established to meet the needs of urban lifeline risk assessment.

[0052] At the same time, in order to reduce the impact of human subjective judgment on the risk assessment results during the assessment process, a quantitative risk assessment method is analyzed and proposed based on the superposition of various risks, the influence range of the accident evolution model, the risk scenario and the characteristics of the data itself, according to the physical models and physical laws of different accidents. The method can be divided into three parts: accident possibility analysis, consequence analysis and risk assessment, and has good practicality.

[0053] (III) Beneficial effects

[0054] The present invention follows the technical route of "research - establishment of index system - modeling simulation - engineering application" to carry out risk assessment method research on leakage of urban functional lighting street lamps. Based on the mining and analysis of various data such as historical accident data of lighting control cabinets and ancillary facilities, monitoring data, operation and maintenance records, external environment, etc., a complete risk assessment index system for leakage of urban functional lighting street lamps is established from the three aspects of intrinsic safety, operational safety, and safety management. This system can simultaneously describe the possibility of accidents and the severity of consequences, and fully considers the mutual coupling of different disaster-causing factors, the mutual relationship of various accidents, and the impact of their importance on comprehensive risks.

[0055] In terms of risk assessment, researchers usually use a combination of qualitative and quantitative methods to determine the main sources and influencing factors of leakage risks through field visits and expert consultations; and use mathematical models and statistical analysis tools to quantitatively assess leakage risks. These assessment results can provide a basis for decision-making for urban management departments and formulate targeted preventive measures and management strategies.

[0056] With the continuous development of technology, some new assessment methods and tools have gradually been applied to the risk assessment of leakage of urban functional lighting street lamps. The use of Internet of Things technology to conduct real-time monitoring and data analysis of street lamps can more accurately assess the risk of leakage. Combining artificial intelligence and machine learning algorithms to mine and analyze large amounts of data can discover the potential patterns and trends of leakage risks, providing a more scientific basis for risk assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0058] Figure 1It is a flowchart of the overall risk assessment of the analytic hierarchy process of the leakage safety risk assessment method of urban functional lighting street lamps of the present invention. DETAILED DESCRIPTION

[0059] The embodiments of the present application solve the problems of leakage assessment in the prior art by providing a leakage safety risk assessment method for urban functional lighting street lamps, including a risk assessment index system and a safety risk assessment model. By using the Internet of Things technology to perform real-time monitoring and data analysis on street lamps, the leakage risk can be assessed more accurately. By combining artificial intelligence and machine learning algorithms to mine and analyze large amounts of data, the potential patterns and trends of leakage risks can be discovered, providing a more scientific basis for risk assessment.

[0060] Example 1

[0061] The technical solution in the embodiment of the present application is to solve the above-mentioned problem of risk assessment of leakage, and the overall idea is as follows:

[0062] In view of the problems existing in the prior art, the present invention provides a method for evaluating the safety risk of leakage of urban functional lighting street lamps, including a risk evaluation index system and a safety risk evaluation model.

[0063] First, we need to establish a risk assessment indicator system, in which we need to establish a security risk assessment model. Then, we evaluate the possibility of risk events based on the security risk assessment model, and use algorithms to derive a risk level calculation model to achieve the final risk assessment.

[0064] 1. Establish a risk assessment indicator system

[0065] There are many factors that affect the leakage of street lights. From the perspective of the intrinsic safety of street lights, these factors include various components, line wiring stability, insulation layer material, leakage protection design, etc. From the perspective of operational safety, these factors include the impact of flooding, third-party construction, historical leakage times, road collapse, etc. In addition, management and emergency response capabilities are also important factors that affect the consequences of accidents.

[0066] The risk factors affecting street lamp leakage are converted into indicators and divided into three categories: A intrinsic safety factors, B operational safety factors and C safety management factors.

[0067] A Intrinsic safety factors include: cable connectors, grounding system type, average service life and cable insulation material;

[0068] B Operational safety factors include: impact of flooding, environmental humidity, personnel flow, third-party construction activities, road collapse and historical leakage;

[0069] C Safety management elements include: evaluation of the current status of lighting facilities and emergency management level.

[0070] Based on the coupled and chain disaster characteristics of urban lifeline systems, the present invention conducts identification and analysis from the dimensions of inherent risks that trigger risk events, external disturbance risks, risk prevention and control, etc., based on the ontological characteristics of the accident knowledge graph and combined with the current characteristics of urban operations, on the basis of analysis methods such as checklist method, scenario analysis method, and fault tree method. On the basis of traditional unilateral risk factors, the factors affecting the safety risk level of related facility systems are integrated, the functional coupling relationship and physical coupling relationship of risks are considered, and then a scientific and reasonable urban lifeline risk assessment indicator system is constructed.

[0071] A. Intrinsic safety elements

[0072] a1 Grounding system: According to the "Urban Road Lighting Design Standard" (CJJ45-2015), the grounding form of the road lighting distribution system should adopt the TT system or TN-S system; according to the "Urban Road Lighting Engineering Construction and Acceptance Regulations" (CJJ89-2012), the TT system must be equipped with a leakage protection device, and the TN-S system requires reliable protection when a single-phase short circuit occurs. According to the power supply (system) side single-point grounding, no grounding (or high-impedance grounding) and whether the ground of the electrical device is directly electrically connected to the system side, it can be divided into two types of grounding, namely the TN system and the TT system. Since both the TT system and the TN system have their advantages and disadvantages, combined with the actual project, on the basis of maximizing the safety of personnel, a street lamp grounding solution is proposed. It should be noted that in the same system, the TN system and the TT system cannot be mixed, and the grounding failure is determined by repeated grounding resistance>4Ω.

[0073] a2 Average service life: After the street lamps and control cabinet parts are overused, the electrical components or parts may deteriorate and age, leading to electrical faults such as leakage and short circuit. Aging, short circuit and leakage of the internal circuits of the distribution cabinet can cause fires, seriously threatening people's lives and property safety.

[0074] a3 Cable insulation material: Common cable insulation layers are divided into polyvinyl chloride (PVC), rubber (EPR) and cross-linked polyethylene (XLPE). Polyvinyl chloride is a commonly used insulating material, widely used in low to medium voltage power cables, communication cables and control cables, etc., and has poor tolerance to heat and flame; Butyl rubber is an elastic insulating material with excellent electrical properties and chemical resistance. It can maintain good flexibility and elasticity in a wide temperature range; Cross-linked polyethylene has excellent electrical properties, high temperature stability and heat resistance, and can withstand higher voltage and current loads.

[0075] a4 Cable joints: Due to design, planning, construction and other reasons, there are different numbers of cable joints in the circuit. The wiring method and location are the two main factors affecting leakage. It is generally believed that wiring in the light pole is safer than wiring in the wiring well, and heat shrink protection is better than dry bag protection.

[0076] a5 Design: The Urban Road Lighting Design Standard has clear requirements for the design of lighting power supply. The power supply requirements for different levels of loads should comply with the provisions of the current national standard "Power Supply and Distribution System Design Specification" GB 50052. The details are as follows: (1) The design of the street light power supply network should comply with the planning requirements, and it is advisable to use a dedicated transformer for power supply; (2) The transformer should be a three-phase distribution transformer with a connection group of D, yn11; (3) The three-phase load should be balanced; (4) The road lighting distribution system should have short-circuit protection and overload protection, and should use the TT system or TN-S system, and should comply with the current national standard "Low Voltage Distribution Design Specification" GB 50054; (5) The road lighting distribution system should be powered by underground cable lines; (6) The exposed conductive parts of metal lamp poles and components, lamp housings, distribution and control boxes, etc. should be connected to protective conductors.

[0077] a6 Construction quality: After the completion of the lighting project, it is necessary to undergo project quality completion acceptance and system completion acceptance and comply with relevant regulations.

[0078] B Operational safety elements

[0079] b1 Impact of waterlogging: After flooding, the electrical equipment inside the control box is easily corroded by moisture, resulting in reduced insulation performance, and even short circuit, leakage and other faults, thus affecting the normal operation of the equipment. When leakage accidents occur in street lamp lines and control boxes around the flooded points, the risks and possibility of accidents will be increased.

[0080] b2 Environmental humidity: Excessive humidity will deteriorate the insulation material, causing cracks or defects in the protective layer on the surface of the wire, which will lead to leakage. A humid environment will cause the metal material on the surface of the wire to rust, thereby increasing the resistance of the wire and causing leakage. When the humidity is too high, the dust and impurities in the electrical appliance may become excellent conductors due to humidity. When the power is on, the soaked dust and impurities are very likely to be broken down by the current, which may not only cause combustion, but also cause poor contact of the power plug, causing leakage, short circuit, sparks, etc. Therefore, in a humid environment, special attention should be paid to the protection and inspection of the wires, as well as the moisture-proof measures of the electrical appliances, to ensure personal safety and the normal operation of the equipment.

[0081] b3 Personnel flow rate: Personnel flow rate indicators can be used to evaluate the traffic capacity of a place. Usually, personnel flow rate indicators include maximum flow rate, average flow rate and instantaneous flow rate. When a street light line or control box leaks electricity, the traffic flow rate will affect the severity of the accident consequences. The maximum flow rate is often selected as the evaluation basis in risk assessment.

[0082] b4 Third-party construction activities: Third-party construction activities may cause abnormal conditions, destruction and damage to power line components, which may lead to safety problems in the lines. The higher the frequency, the greater the risk of accidents.

[0083] b5 Impact of road collapse: The hidden danger of road collapse can easily lead to street lamp pole collapse accidents, affect line safety, and cause electric leakage accidents.

[0084] b6 Historical leakage situation: The historical leakage times can reflect the danger of the line or control box where the street lamp is located. The more leakage times, the greater the risk of accidents.

[0085] C Safety Management Elements

[0086] c1 Evaluation of the current status of lighting facilities: According to the "Urban Road Lighting Facility Maintenance Regulations", the maintenance unit shall evaluate the current status of lighting facilities in accordance with the relevant provisions of this regulation based on the results of facility inspections, repairs and examinations. The evaluation results are divided into three categories: maintenance, improvement and renewal. The subsequent transformation of lighting facilities evaluated as improvement and renewal is not within the scope of maintenance work.

[0087] c2 Safety management and emergency response capabilities: refers to the management and maintenance units' identification and assessment of risks, daily safety management work and emergency response levels. These factors determine the response and handling capabilities after a leakage event.

[0088] 2. Establishment of Security Risk Assessment Model

[0089] APossibility of risk events

[0090] Risk assessment includes three processes: risk identification, risk analysis and risk evaluation. This guide adopts the analytic hierarchy process to sort the evaluation indicators from high to low in order of importance, and the weight coefficient can be used to distinguish the importance of each evaluation indicator.

[0091] The risk factors affecting street lamp leakage are converted into indicators and divided into three categories: intrinsic safety factors, operational safety factors and safety management factors.

[0092] The intrinsically safe elements include: cable joints, grounding system types, average service life, and cable insulation materials; the operation safety elements include: the impact of accumulated flooding, environmental humidity, pedestrian traffic flow, third-party construction activities, road collapse impact, and historical leakage conditions; the safety management elements include: the current situation assessment of lighting facilities and the emergency management level. Based on the index classification, evaluation indicators are proposed.

[0093] As Figure 1 shown, sort the evaluation indicators in descending order of importance. The importance of each evaluation indicator can be distinguished by using a weight coefficient. The weight coefficient can be determined by comprehensively applying various methods. This evaluation method selects the method of "determining the weight value according to the importance ranking of evaluation indicators" to determine the index weight, and the calculation formula is as follows.

[0094]

[0095] In the formula, S - weight coefficient;

[0096] n - number of evaluation indicator items;

[0097] m - importance ranking number, m < n.

[0098] Establish an evaluation index system according to the specific situation of each index. See Table 1-1. When evaluating a specific road, not all 12 indicators listed in Table 1-1 necessarily participate in the evaluation. Relatively important indicators can be selected for ranking.

[0099] Table 1-1 Overall Risk Assessment Index System for Leakage of Urban Functional Lighting Street Lamps by Analytic Hierarchy Process

[0100]

[0101]

[0102]

[0103]

[0104] B. Risk Level Calculation Model

[0105] The overall evaluation risk value F of the leakage of urban functional lighting street lamps should be calculated and determined according to the following formula:

[0106] F = ∑Xij

[0107] Xij - Rij * Sij

[0108] In the formula, Xij is the score of a single evaluation indicator, i=1, 2, 3, 4, 5; j=1, 2,..., n, where n is the number of important indicators corresponding to the i-th type of evaluation indicators. After calculating the F value, the overall risk level of street lamp leakage and the corresponding countermeasures should be determined according to Table 1-2.

[0109] Table 1-2 Overall risk classification standards and countermeasures of urban lighting analytic hierarchy process

[0110]

[0111] Through the combing and summarizing of the existing risk assessment theories and methods, the present invention, based on the characteristics of the accident knowledge graph ontology, combines the current system operation characteristics, accident history data, professional knowledge and basic data and information in the fields involved, and on the basis of the laws of accident evolution, while ensuring scientificity and operability, follows the principles of relative completeness, relative independence and principal component, to establish a scientific and reasonable risk assessment indicator system, and evaluates the possibility of risk occurrence from multiple indicators of intrinsic safety and operational safety.

[0112] In addition, in order to comprehensively improve the level of safe operation and accident prevention capabilities, the safety management level is also taken into consideration. The two indicators of third-party construction and safety management level are considered. The risk factors of the system are deeply identified from the dimensions of inherent risks that cause risk events, external disturbance risks, and risk prevention and control. A complete set of evaluation indicators with multi-factor coupling is established to meet the needs of urban lifeline risk assessment.

[0113] At the same time, in order to reduce the impact of human subjective judgment on the risk assessment results during the assessment process, a quantitative risk assessment method is analyzed and proposed based on the superposition of various risks, the influence range of the accident evolution model, the risk scenario and the characteristics of the data itself, according to the physical models and physical laws of different accidents. The method can be divided into three parts: accident possibility analysis, consequence analysis and risk assessment, and has good practicality.

[0114] The present invention follows the technical route of "research - establishment of index system - modeling simulation - engineering application" to carry out risk assessment method research on leakage of urban functional lighting street lamps. Based on the mining and analysis of various data such as historical accident data of lighting control cabinets and ancillary facilities, monitoring data, operation and maintenance records, external environment, etc., a complete risk assessment index system for leakage of urban functional lighting street lamps is established from the three aspects of intrinsic safety, operational safety, and safety management. This system can simultaneously describe the possibility of accidents and the severity of consequences, and fully considers the mutual coupling of different disaster-causing factors, the mutual relationship of various accidents, and the impact of their importance on comprehensive risks.

[0115] In terms of risk assessment, researchers usually use a combination of qualitative and quantitative methods to determine the main sources and influencing factors of leakage risks through field visits and expert consultations; and use mathematical models and statistical analysis tools to quantitatively assess leakage risks. These assessment results can provide a basis for decision-making for urban management departments and formulate targeted preventive measures and management strategies.

[0116] With the continuous development of technology, some new assessment methods and tools have gradually been applied to the risk assessment of leakage of urban functional lighting street lamps. The use of Internet of Things technology to conduct real-time monitoring and data analysis of street lamps can more accurately assess the risk of leakage. Combining artificial intelligence and machine learning algorithms to mine and analyze large amounts of data can discover the potential patterns and trends of leakage risks, providing a more scientific basis for risk assessment.

[0117] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A method for assessing the safety risk of leakage current of urban functional lighting street lamps, characterized by: Including risk assessment indicator system and safety risk assessment model, First, we need to establish a risk assessment indicator system, in which we need to establish a security risk assessment model. Then, we evaluate the possibility of risk events based on the security risk assessment model, and use algorithms to derive a risk level calculation model to achieve the final risk assessment.

2. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 1, characterized in that: The risk assessment index system is established to convert the risk factors affecting street lamp leakage into indicators and divide them into three categories: A intrinsic safety factor, B operational safety factor and C safety management factor. A Intrinsic safety factors include: cable connectors, grounding system type, average service life and cable insulation material; B Operational safety factors include: impact of flooding, environmental humidity, personnel flow, third-party construction activities, road collapse and historical leakage; C Safety management elements include: evaluation of the current status of lighting facilities and emergency management level.

3. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 2, characterized in that: The A intrinsic safety elements include the following a1 Grounding system: There are two types of grounding, namely TN system and TT system, according to whether the power supply (system) side is grounded at one point, not grounded (or grounded via high impedance), and whether the ground of the electrical device is directly electrically connected to the ground of the system side. Since both the TT system and the TN system have their advantages and disadvantages, a street lamp grounding solution is proposed based on the actual project and on the basis of maximizing the safety of personnel. It should be noted that the TN system and the TT system cannot be mixed in the same system, and the grounding failure is determined when the grounding resistance is >4Ω after repeated measurement; a2 Average service life: After the street lamps and control cabinet parts are overused, the electrical components or parts may deteriorate, age, and cause electrical failures. The aging, short circuit, leakage, and other problems of the internal circuits of the distribution cabinet may cause fires. a3 Cable insulation material: Common cable insulation layers are divided into polyvinyl chloride (PVC), rubber (EPR) and cross-linked polyethylene (XLPE), which can maintain good flexibility and elasticity in a wide temperature range; a4 Cable joint: Due to design, planning, construction and other reasons, there are different numbers of cable joints in the circuit. The wiring method and location are the two main factors affecting leakage. It is generally believed that wiring in the lamp pole is safer than in the wiring well, and heat shrink protection is better than dry bag protection; a5 Scheme design: The details are as follows: (1) The design of the street lamp power supply network should comply with the planning requirements and should adopt a dedicated transformer for power supply; (2) The transformer should be a three-phase distribution transformer with a connection group of D, yn11; (3) The three-phase load should be balanced; (4) The road lighting distribution system should have short-circuit protection and overload protection, and should adopt a TT system or a TN-S system; (5) The road lighting distribution system should adopt underground cable lines for power supply; (6) The exposed conductive parts of metal lamp poles and components, lamp housings, distribution and control boxes, etc. should be connected to protective conductors. a6 Construction quality: After the completion of the lighting project, it is necessary to undergo project quality completion acceptance and system completion acceptance and comply with relevant regulations.

4. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 2, characterized in that: The B operational safety elements include the following b1 Impact of flooding: After flooding, the electrical equipment inside the control box is easily corroded by moisture, resulting in reduced insulation performance and even short circuit, leakage and other faults; b2 Environmental humidity: Too high humidity will deteriorate the insulation material, causing cracks or defects in the protective layer on the surface of the wire, which will lead to leakage. A humid environment will cause the metal material on the surface of the wire to rust, thereby increasing the resistance of the wire and causing leakage. When the humidity is too high, the dust and impurities in the electrical appliance may become excellent conductors due to moisture. When the power is on, the soaked dust and impurities are easily broken down by the current, which may not only cause combustion, but also cause poor contact of the power plug, thereby causing leakage, short circuit, sparks, etc. b3 Personnel flow rate: The personnel flow rate index can be used to evaluate the traffic capacity of a place. When a street light line or control box leaks electricity, the traffic flow rate will affect the severity of the accident consequences. The maximum flow rate is often selected as the basis for risk assessment; b4 Third-party construction activities: Third-party construction may cause abnormal status, destruction and damage to power line components, which may lead to safety problems in the line; b5 Impact of road collapse: The hidden danger of road collapse can easily lead to the collapse of street lamp poles, affect the safety of lines, and cause leakage accidents; b6 Historical leakage situation: The historical leakage times reflect the danger of the line or control box where the street lamp is located. The more leakage times, the greater the risk of accidents.

5. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 2, characterized in that: The C safety management elements include the following c1 Evaluation of the current status of lighting facilities: The maintenance unit shall evaluate the current status of lighting facilities in accordance with the relevant provisions of this Regulation based on the results of facility inspections, repairs and examinations. The evaluation results are divided into three categories: maintenance, improvement and renewal. The subsequent transformation of lighting facilities evaluated as improvement and renewal is not within the scope of maintenance work; c2 Safety management and emergency response capabilities: refers to the management and maintenance units' identification and assessment of risks, daily safety management work and emergency response levels. These factors determine the response and handling capabilities after a leakage event.

6. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 1, characterized in that: The risk assessment model established by the safety risk assessment includes three processes: risk identification, risk analysis and risk evaluation. This guide adopts the hierarchical analysis method to sort the evaluation indicators from high to low in order of importance. The importance of each evaluation indicator can be distinguished by weight coefficient. The risk factors affecting street lamp leakage are converted into indicators and divided into three categories: intrinsic safety factors, operational safety factors and safety management factors.

7. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 6, characterized in that: The intrinsic safety factors include: cable joints, grounding system types, average service life and cable insulation layer materials; operational safety factors include: impact of accumulated water, environmental humidity, personnel traffic flow, third-party construction activities, road collapse impact and historical leakage conditions; safety management factors include: evaluation of the current status of lighting facilities and emergency management level. Based on the indicator classification, evaluation indicators are proposed.

8. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 6, characterized in that: The evaluation indicators are sorted in descending order of importance. The importance of each evaluation indicator can be distinguished by a weight coefficient. The weight coefficient can be determined by a combination of multiple methods. This evaluation method selects the method of "determining weight values ​​by sorting the evaluation indicators by importance" to determine the indicator weight. The calculation formula is shown below. In the formula, S is the weight coefficient; n is the number of evaluation indicators; m is the importance ranking number, m <n, An evaluation index system is established based on the specific circumstances of each indicator. When evaluating a specific road, not all of the 12 indicators listed may be included in the evaluation. More important indicators can be selected for ranking.

9. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps as claimed in claim 8, characterized in that: The risk level calculation model, The overall assessment risk value F of leakage of urban functional lighting street lamps should be calculated and determined according to the following formula: In the formula, Xij is the score of a single evaluation index, i=1, 2, 3, 4, 5; j=1, 2, ··.·, n, where n is the number of important indicators corresponding to the i-th type of evaluation index. After calculating the F value, the overall risk level of street lamp leakage and the corresponding countermeasures should be determined according to Table 1-2.

10. The method for evaluating the risk of leakage current safety of urban functional lighting street lamps according to claim 8, characterized in that: The safety management level is also taken into consideration, including the third-party construction and safety management level indicators. The risk factors of the system are deeply identified from the dimensions of inherent risks that cause risk events, external disturbance risks, and risk prevention and control, and a complete set of evaluation indicator systems with multi-factor coupling is established to meet the needs of urban lifeline risk assessment. At the same time, in order to reduce the impact of human subjective judgment on the risk assessment results during the assessment process, a quantitative risk assessment method is analyzed and proposed based on the superposition of various risks, the influence range of the accident evolution model, risk scenarios and the characteristics of the data itself, according to the physical models and physical laws of different accidents. The method can be divided into three parts: accident possibility analysis, consequence analysis and risk assessment.

Images