Coupling real-time risk assessment method, model and equipment for diffusion of fuel gas to power pipeline

Abstract

The invention discloses a coupling real-time risk assessment method for diffusion of fuel gas to a power pipeline, and belongs to the field of risk assessment. The method comprises the following steps that S1, a gas pipeline and a power pipeline are subjected to pipe section division; s2, gas leakage types are judged, different diffusion boundary dangerousness is obtained, and soil permeability and road surface correction factors are calculated; s3, acquiring coupling risk influence factors of the gas pipeline and the power pipeline; s4, obtaining the coupling risk of the gas pipeline and the power pipeline; s5, different correction coefficients are set according to different power pipeline laying modes, the cross section area of fuel gas gathering in the different power pipeline laying modes is calculated, the fuel gas diffusion speed is calculated, the plugging correction factor of the power pipeline is obtained, and the maximum distance from the fuel gas diffusion to the dangerous concentration is calculated; and S6, obtaining the risk of the power pipeline. According to the invention, a basis can be provided for troubleshooting, early warning and processing of a gas-to-power pipeline diffusion coupling accident, occurrence of a fire explosion accident can be prevented, and city safety is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of risk assessment, and in particular to a coupled real-time risk assessment method, model and device for gas diffusion into a power pipeline. Background Art

[0002] Urban gas pipelines and power pipelines are important basic municipal facilities in modern cities and important lifelines of cities. my country's urban gas pipelines and power pipelines are very complex and have high environmental risks. Due to the limited equipment, construction, technology and management level in the early stage, a large number of facilities have problems such as aging and damage. In addition, due to poor management, a large amount of missing engineering data, and large personnel changes, the number of coverings and buildings around the pipelines has increased, posing great risks to urban safety.

[0003] Due to the flammable and explosive nature of gas, once a gas pipeline leaks, the flammable gas easily spreads to the adjacent underground space and accumulates, which can easily cause coupling accidents with adjacent pipelines. When the gas leak spreads to the adjacent power pipeline, due to short circuits, overloads, poor contact of the power cables, etc., it may cause abnormal discharge of the pipeline, high temperature overheating, etc. Therefore, the risk of cable channel explosion is relatively high under the coupling of fuel leakage and power pipeline accidents.

[0004] At present, the risk assessment of gas pipelines and power pipelines is relatively broad, without specifically considering the risks of the two under coupling factors. The existing risk assessment system for gas pipelines divides the pipeline into several sections, scores the factors that cause pipeline failure, such as third-party damage, pipeline corrosion, design and misoperation, and then combines the accident probability and severity indicators of the consequences with the consequences of pipeline failure to form a relative risk value. This assessment system only considers the risk factors of the gas pipeline before the accident occurs, but does not consider the impact of the gas pipeline leak on the adjacent power pipeline.

[0005] For example, CN112633552B discloses a method and system for identifying and assessing the hidden dangers of coupling between gas pipelines and surrounding pipelines, which can identify the hidden dangers of coupling between gas pipelines and surrounding pipelines through comprehensive analysis of gas leakage, gas diffusion and accumulation, vulnerability analysis of surrounding pipelines, ignition possibility, explosion consequence analysis, and emergency response capabilities, and achieve qualitative and quantitative processing of the risks of gas pipelines and surrounding pipelines. However, its assessment system is still only for gas pipelines and surrounding pipelines, and it considers less the factors affecting gas leakage diffusion and power channel coupling, lacks the judgment of gas leakage type, the influence of diffusion process, and the judgment of gas diffusion risk in power pipelines. Summary of the invention

[0006] The technical problem to be solved by the present invention is how to conduct real-time assessment of the risk of gas leakage diffusion and power channel coupling under the coupling of multiple factors, so as to prevent the occurrence of fire and explosion accidents and ensure the safety of the city and residents.

[0007] In order to solve the above problems, the present invention provides a coupled real-time risk assessment method for gas diffusion to power pipelines, comprising the following steps:

[0008] S1: According to the underground pipeline network diagram of the city's gas pipelines and power pipelines, pipe sections are divided to obtain various division units;

[0009] S2: Determine the gas leakage type T according to the real-time monitoring data of the gas channel in each unit, and combine the time t of the gas leakage to obtain different diffusion boundary hazards P(T, t), and calculate the soil permeability Ks of different soils and the pavement correction factor R of different pavement types. road ;

[0010] S3: Determine the coupling mode of gas pipelines and power pipelines, and obtain the risk impact factor R(d,h) of the coupling between gas pipelines and power pipelines. Where C is a constant, d is the horizontal distance between the gas pipeline and the power pipeline, i.e. the coupling spacing, h is the buried depth of the gas pipeline, and λ is used to control the impact of the coupling spacing and buried depth on the risk;

[0011] S4: Obtain the quantitative risk R of the coupling between gas pipelines and power pipelines, R = P(T, t)·Ks·R road R(d,h), and normalize R;

[0012] S5: Real-time monitoring of the power pipelines of each unit is carried out. Different correction coefficients S are set for different power pipeline laying methods, and the cross-sectional area A of gas accumulation under different power pipeline laying methods is calculated. m The power pipeline sensor monitors and calculates the speed of gas diffusion, and determines the blocking type of the power pipeline, including the blocked state and the unblocked state, and obtains the blocking correction factor L; calculates the maximum distance D of gas diffusion to a dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, and φ is the environmental correction factor;

[0013] S6: Obtain the quantitative risk R of power pipelines d , R d =D b ·A m ·S·L, and to R d Normalize.

[0014] Preferably, in step S2, the process of determining the type of gas leakage is as follows: selecting a monitoring point, calculating the gas concentration change rate v at the point n , define the volume correction factor Where V0 is the standard well volume, V is the actual gas well volume, and v n To make a correction: v n修正 =k1·v n , define the change rate thresholds α and β; compare v n Correction and change rate thresholds α and β, if v n修正 ≤α, then the gas leakage type T is small hole leakage, if α <v n修正 ≤β, then the gas leakage type T is large hole leakage, if v n修正 >β, then the gas leakage type T is fracture leakage.

[0015] The present invention corrects the gas concentration change rate by using a volume correction coefficient, thereby eliminating the influence of volume on the concentration change rate and making the monitoring results of gas wells with different volumes comparable.

[0016] Preferably, the diffusion boundary hazard Among them, χ, ε, γ are adjustment parameters, Q small , Q large , Q rupture They are the gas leakage amounts of small hole leakage, large hole leakage and fracture leakage respectively.

[0017] The present invention determines the type of gas leakage and specifically obtains the diffusion boundary hazard of different gas leakage types, and obtains the soil permeability of different soils and the pavement correction factor of different pavement types through calculation, so as to more accurately perform quantitative risk assessment of the coupling of gas pipelines and power pipelines.

[0018] Preferably, in step S2, the soil permeability Where D 10 is the effective particle size, ψ is the water density, μ is the fluid dynamic viscosity coefficient, e is the soil porosity, and N is a constant; the pavement correction factor where k hard >1.

[0019] Preferably, in step S3, the coupling mode of the gas pipeline and the power pipeline includes a parallel coupling mode and a cross coupling mode.

[0020] Preferably, in step S5, the laying methods of the power pipeline include direct burial, casing and power trench, and the correction coefficient corresponding to the direct burial is S direct , the correction factor corresponding to the casing method is S casing , the correction coefficient corresponding to the power channel method is Strench .

[0021] Preferably, in the casing mode, the cross-sectional area A of the gas gathering casing =n·πr 2 , where n is the number of pipes in the casing, r is the radius of the casing pipe; in the power trench mode, the cross-sectional area A of the gas gathering trench =w·h, where w is the width of the power trench and h is the height of the power trench.

[0022] Preferably, in step S5, the blocking correction factor Where L blocked >1,L unblocked <1.

[0023] Corresponding to the above method, the present invention also provides a coupled real-time risk assessment model for gas diffusion to power pipelines, comprising the following modules:

[0024] Division unit module: used to divide the pipe sections according to the underground pipe network diagram of the city's gas pipelines and power pipelines to obtain each division unit;

[0025] Obtaining diffusion boundary hazard module: It is used to determine the gas leakage type T according to the real-time monitoring data of the gas channel in each unit, and obtain different diffusion boundary hazards P(T, t) based on the time t of the gas leakage, and calculate the soil permeability Ks of different soils and the pavement correction factor R of different pavement types. road ;

[0026] Calculation module for coupling risk impact factor: used to determine the coupling mode of gas pipelines and power pipelines, and obtain the coupling risk impact factor R(d,h) of gas pipelines and power pipelines. Where C is a constant, d is the horizontal distance between the gas pipeline and the power pipeline, i.e. the coupling spacing, h is the buried depth of the gas pipeline, and λ is used to control the impact of the coupling spacing and buried depth on the risk;

[0027] Coupling risk acquisition module: used to obtain the quantitative real-time risk R of gas pipeline and power pipeline coupling, R = P(T,t)·Ks·R road R(d,h), and normalize R;

[0028] Power pipeline monitoring module: used to monitor the power pipelines of each unit in real time, set different correction coefficients S for different power pipeline laying methods, and calculate the cross-sectional area A of gas accumulation under different power pipeline laying methods m, calculate the speed of gas diffusion based on real-time monitoring data, and determine the blocking type of the power pipeline, including blocking state and non-blocking state, and obtain the blocking correction factor L; calculate the maximum distance D of gas diffusion to dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, and φ is the environmental correction factor;

[0029] Power pipeline risk acquisition module: used to obtain the quantitative real-time risk R of power pipelines d , R d =D b ·A m ·S·L, and to R d Normalize.

[0030] The present invention also provides a terminal device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the coupled real-time risk assessment method for gas diffusion to power pipelines as described above.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] (1) By correcting the gas concentration change rate through the volume correction coefficient, different leakage types can be distinguished more accurately, and the diffusion boundary hazard of different gas leakage types can be obtained. By analyzing the impact of factors such as different soil types and road surface types on gas diffusion, a more comprehensive and accurate quantitative risk assessment of the coupling of gas pipelines and power pipelines can be performed;

[0033] (2) Based on the detection data, the gas leakage and power pipeline coupling risks in the gas diffusion process are evaluated in real time, realizing dynamic real-time risk assessment, so that the assessment results can reflect the current risk situation in a timely manner, effectively improving the efficiency of pipeline safety management, and effectively preventing accidents and ensuring the safety of residents and property;

[0034] (3) By calculating the quantitative risk of power pipelines, the risk of gas diffusion in power pipelines can be evaluated. In conjunction with monitoring equipment, the diffusion and accumulation of gas in power pipelines can be predicted, providing a basis for accident investigation, early warning, and handling. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of the intelligent terminal device in Example 3 of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of 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.

[0038] Example 1

[0039] like Figure 1 As shown, it is a flow chart of the whole embodiment. This embodiment provides a coupled real-time risk assessment method for gas diffusion to power pipelines. The specific process is as follows:

[0040] Step 1: First, according to the underground pipeline network diagram of gas and power channels, the gas pipeline and power pipeline are divided into different units. The division principles are as follows:

[0041] (1) Divide into different units based on pipe diameter, pipe age and pipe material;

[0042] (2) Divide into different units based on road intersections or administrative district boundaries;

[0043] (3) The pipes connected by the kit are divided into different units at the connection points;

[0044] (4) According to the different pipeline laying methods and ground hardening conditions, it is divided into different units.

[0045] The gas pipe properties and power pipeline properties within the divided units are extracted to obtain key factors affecting the spread of gas leakage, such as gas pipeline pressure and burial depth, which are used as data support for gas leakage and spread risk assessment.

[0046] Steps 2-4 of this embodiment are performed to obtain the quantitative real-time risk of gas leakage and coupling of adjacent power pipelines.

[0047] Step 2: Determine the gas leakage type T based on the real-time monitoring data of the gas channel in each unit, and combine the time t of the gas leakage to obtain different diffusion boundary hazards P(T, t), and calculate the soil permeability Ks of different soils and the pavement correction factor R of different pavement types. road , the specific process is as follows:

[0048] S201: Determine the type of gas leakage: In the current urban lifeline work, gas leakage monitoring equipment is arranged in the gas well. The gas leakage monitoring equipment obtains real-time monitoring data of the gas channel and analyzes the gas concentration change rate v after the gas leakage. n:The functional relationship between the gas concentration M(t) and the time t is linear or exponential. The discrete concentration data M(t1), M(t2),..., M(t n ), the rate of change of gas concentration per unit time is approximately calculated using the numerical differentiation method:

[0049] Because the volume of the gas well will affect the rate of change of the gas concentration, this embodiment also uses a volume correction coefficient to adjust the monitored gas concentration change rate v n Correction: Let the volume of the gas well be V, and assume that the concentration change rate is inversely proportional to the volume of the gas well, that is, the larger the volume, the smaller the concentration change per unit time, and define a volume correction coefficient k1, Where V0 is the standard well volume, V is the actual gas well volume, and then v n To make a correction:

[0050] Define the change rate thresholds α and β, and compare v n Correction and change rate thresholds α and β, if v n修正 ≤α, then the gas leakage type T is small hole leakage, if α <v n修正 ≤β, then the gas leakage type T is large hole leakage, if v n修正 >β, in this case, the gas leakage type T is fracture leakage;

[0051] S202: Combining the gas leakage type T and the gas leakage time t, different diffusion boundary hazards P(T, t) are obtained. Among them, χ, ε, and γ are adjustment parameters, reflecting the influence of environmental conditions on gas diffusion, Q small , Q large , Q rupture They are the gas leakage from small hole leakage, large hole leakage and fracture leakage respectively;

[0052] The diffusion of small hole leakage is relatively slow. The longer the leakage time, the larger the diffusion radius. The calculation formula for the gas leakage of small hole leakage is: Where k is the gas adiabatic coefficient, which is 1.334 in this embodiment, R is the gas constant, T B is the temperature before the gas leak, P B is the pressure before the gas leak, A is the area of ​​the leak, C d is the orifice flow correction coefficient, which is determined according to the shape of the leak: when the leak is circular, C d =1.00, when the leakage port is a triangle, C d =0.95, when the leak is rectangular, C d =0.90, when the leakage port is an internal corrosion shrinking hole, 0.9 <Cd <1.0, when the leakage port is damaged by external force and gradually expanded, 0.6 <C d <0.9, M is the molar mass of the gas;

[0053] When a large hole leaks, the gas diffuses faster. For actual high-pressure or low-pressure gas transmission pipelines, as the hole diameter increases, the pressure P at the center of the leak port increases. B Much smaller than the pressure P at the starting point of the pipeline A , but still greater than the critical pressure P c At this time, the leakage process becomes a critical flow in the pipeline and the leakage hole. The calculation formula for the gas leakage of large hole leakage is: Where T A is the gas temperature at the starting point of the pipeline, P A is the pressure at the starting point of the pipeline, where Ma A is the Mach number at the starting point of the pipeline;

[0054] When the pipeline is disturbed by external forces or overpressure, a large rupture will occur, resulting in a large area of ​​gas leakage. Generally, the leakage port is 80%-100% of the pipeline cross-sectional area. When a pipeline leaks, the pipeline leakage port area is large, resulting in a large instantaneous gas leakage, which significantly reduces the pressure in the pipeline. For an ideal gas insulated pipeline, the calculation formula for the gas leakage due to the rupture is: Where m is the mass flow rate of the gas, Y g is the gas expansion coefficient, g c is the gravitational constant, ρ A is the gas density in the pipeline, P C is the pressure at the starting point of the pipeline, P D is the gas pressure at the leak point in the pipeline, ∑K f is the difference loss term, Where f is the friction coefficient, d is the inner diameter of the pipe, and L is the pipe length;

[0055] S203: Calculate soil permeability: After gas leaks, it will diffuse in the soil. The properties of the soil will affect the diffusion rate of the gas. Therefore, the influence factor of the soil depends on the properties of the soil. According to the permeability theory, the properties of different soils can be comprehensively expressed as soil permeability Ks. The calculation formula is: Where D 10 is the effective particle size, ψ is the water density, μ is the fluid dynamic viscosity coefficient, e is the soil porosity, and N is a constant. The permeability of the soil reflects the tightness of the soil. The tighter the soil, the worse its permeability. On the contrary, the looser the soil, the better its permeability. After the gas leaks, the diffusion movement is faster, and the diffusion and migration ability is also faster.

[0056] S204: Calculate the road surface correction factor R for different road surface typesroad : There are significant differences in the impact of hardened pavement (such as concrete or asphalt) and non-hardened pavement (such as sand or grass) on the diffusion of gas leakage;

[0057] Hardened pavement usually restricts the vertical diffusion of gas, causing the gas to diffuse mainly along the horizontal plane, while non-hardened pavement allows gas to diffuse more freely in the vertical direction. For hardened pavement, it can be considered that it has a stronger inhibitory effect on diffusion, and it is difficult for gas to penetrate the pavement. More diffusion develops in the horizontal direction, and the diffusion range increases. A correction factor is set. For non-hardened pavement, the gas has a stronger diffusivity, and the correction factor is set to 1, indicating no inhibitory effect. Specifically, the pavement correction factor where k hard A constant representing the effect of hardened pavement on diffusion, usually k hard >1.

[0058] Step 3: The coupling relationship between the gas pipeline and the power pipeline lies in the adjacent mode of the composite buried area, that is, the coupling mode of the gas pipeline and the power pipeline in the composite buried area. The buried relationship between the gas pipeline and the power pipeline is parallel laying and cross laying. There is a certain spacing between the couplings. At the same time, the buried depth of the pipeline will also be considered when burying the pipeline;

[0059] In order to describe the coupling risk of gas leakage spreading to the power channel, the coupling risk impact factor is calculated: based on the relationship between the burial depth and the coupling risk impact factor, the closer the spacing and the shallower the burial depth, the greater the coupling risk;

[0060] It is assumed that the risk of gas leakage and diffusion has an exponential inverse relationship with the coupling spacing and burial depth of gas pipelines and power pipelines: Where R(d,h) is the size of the coupling risk impact factor, C is a constant, d is the horizontal distance between the gas pipeline and the power pipeline, that is, the coupling spacing, h is the buried depth of the gas pipeline, and λ is an undetermined coefficient used to control the impact of the coupling spacing and buried depth on the risk;

[0061] For cross laying: Among them C cross is a constant for the cross-coupling of gas pipelines and power pipelines;

[0062] For parallel laying: Among them C parallel is a constant for the case where the gas pipeline and the power pipeline are coupled in parallel.

[0063] Step 4: Use soil characteristics, road surface type and coupling risk influencing factors as correction coefficients to conduct risk assessment of gas pipelines and adjacent power channels: Calculate the quantitative risk R of gas leakage and coupling of adjacent power pipelines, R = P(T, t)·Ks·R roadR(d,h), in order to facilitate risk quantification and classification, the risk value R is normalized to the interval [0,1], and the normalization formula is: Where R norm is the normalized risk value, R max and R min They are the maximum and minimum values ​​of the risk value respectively. The maximum value is calculated by setting the most unfavorable situation of gas leakage and correction parameters, and the minimum value is calculated by setting the most favorable situation. The minimum value time is 15 minutes and the maximum value time is 24 hours.

[0064] The risk of gas diffusion in the power channel is affected by the area of ​​the power channel and the distance it can diffuse. The larger the channel area, the higher the relative risk. The power pipeline may be blocked or unblocked. After the power channel is blocked, the gas will gather in a section of the power pipeline. When the blockage is missing, the gas will continue to spread in the power channel, which is relatively risky. The area of ​​the power pipeline is divided into casing laying and cable trench laying, and the gas diffusion distance;

[0065] Steps 5-6 in this embodiment are executed to obtain the quantitative real-time risk of the power pipeline.

[0066] Step 5: Conduct real-time monitoring of the power pipelines of each unit, set different correction coefficients S for different power pipeline laying methods, and calculate the cross-sectional area A of gas accumulation under different power pipeline laying methods. m , calculate the speed of gas diffusion based on real-time monitoring data, and determine the blocking type of the power pipeline, including blocking state and non-blocking state, and obtain the blocking correction factor L; calculate the maximum distance D of gas diffusion to dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, φ is the environmental correction factor, and the specific process is:

[0067] S501: Different correction coefficients S are set for different power pipeline laying methods, specifically:

[0068] In the direct burial mode, that is, the power pipeline has no independent space, the cable is in direct contact with the soil, and the possibility of gas diffusion to the cable is low. However, when the gas concentration is high, it may still be dangerous. The correction factor at this time is set to S direct In this embodiment, S direct =1;

[0069] In the casing mode: there are usually multiple circular channels (pipes) inside the casing, which increases the diffusion path and accumulation space of the gas. In this case, the gas may accumulate in the casing, resulting in local high concentration, with medium risk. The correction factor is set to S casing In this embodiment, Scasing =1.5;

[0070] In the case of electric trench: the space is large (rectangular cross section), gas leaks easily accumulate and are difficult to be discharged quickly. At this time, due to the closed channel and large diffusion space, the risk is high, and the correction coefficient is set to S trench In this embodiment, S trench =2;

[0071] Usually S direct casing trench ;

[0072] S502: Calculate the cross-sectional area A of the gas accumulation under different power pipeline laying methods m : Under direct burial method, the cross-sectional area A where the gas gathers direct =πr 2 , where r is the radius of the power pipeline; in the casing method, the cross-sectional area A where the gas gathers casing =n·πl 2 , where n is the number of pipes in the casing, l is the radius of the casing pipe; in the power trench mode, the cross-sectional area A of the gas gathering trench =w·h, where w is the width of the power trench and h is the height of the power trench.

[0073] S503: Calculate the gas diffusion speed v(x) based on the real-time monitoring data of the power pipeline: Assume that the sensors are arranged at Z nodes along the power pipeline, and the position of each node is x i (distance along the diffusion direction), and its corresponding response time is t i (The time required for the sensor to detect a certain concentration threshold), the calculation formula for the gas diffusion velocity v(x) is: Calculate the average diffusion velocity for all responding sensor locations

[0074] S504: Determine the type of blockage of the power pipeline: including blocked state and unblocked state; in the blocked state, the gas diffusion range is limited and it is easy to accumulate locally, resulting in high local concentration. The diffusion speed and range are significantly suppressed, but the risk may increase locally. In the unblocked state, the gas can diffuse freely along the power channel, the diffusion range is larger, but the concentration is lower, the overall diffusion speed is faster, and the risk is more evenly distributed.

[0075] S505: Obtaining a blocking correction factor L, Where L blocked >1,L unblocked <1.

[0076] ​​S506: Calculate the maximum distance D that the gas can diffuse to a dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, φ is the environmental correction factor, which is affected by environmental characteristics (such as temperature, humidity, power pipeline obstacles, etc.), usually 0<φ<10;

[0077] Step 6: Obtain the quantitative real-time risk R of the power pipeline d , R d =D b ·A m ·S·L, and to R d Normalize, the normalization formula is: Where R norm 'Quantitative risk R of power pipelines d Normalized risk value, R d，max and R d，min The risk value R d The maximum and minimum values ​​are calculated by setting the most unfavorable gas leakage and correction parameters, and the minimum value is calculated by setting the most favorable situation. The minimum time is 15 minutes and the maximum time is 24 hours.

[0078] This embodiment uses real-time monitoring data and takes into account the factors of gas leakage diffusion and power pipeline coupling, thereby achieving a rapid and real-time assessment of the leakage and diffusion of gas into the power pipeline. It can not only conduct a comprehensive risk assessment of the gas pipeline and the adjacent power channel, but also assess the gas diffusion risk in the power channel, providing a basic guarantee for the safe operation of the city's lifeline.

[0079] Example 2

[0080] Corresponding to Example 1, this embodiment provides a coupled real-time risk assessment model for gas diffusion to power pipelines, including the following modules:

[0081] Division unit module: used to divide the pipe sections according to the underground pipe network diagram of the city's gas pipelines and power pipelines to obtain each division unit;

[0082] Obtaining diffusion boundary hazard module: It is used to determine the gas leakage type T according to the real-time monitoring data of the gas channel in each unit, and obtain different diffusion boundary hazards P(T, t) based on the time t of the gas leakage, and calculate the soil permeability Ks of different soils and the pavement correction factor R of different pavement types. road , specifically including the following units:

[0083] Leakage type determination unit: used to determine the type of gas leakage, obtain the real-time monitoring data of the gas channel from the gas leakage monitoring equipment, and analyze and obtain the gas concentration change rate v after the gas leakage n :The functional relationship between the gas concentration M(t) and the time t is linear or exponential. The discrete concentration data M(t1), M(t2),..., M(t n ), the rate of change of gas concentration per unit time is approximately calculated using the numerical differentiation method:

[0084] Because the volume of the gas well will affect the rate of change of the gas concentration, this embodiment also uses a volume correction coefficient to adjust the monitored gas concentration change rate v n Correction: Let the volume of the gas well be V, and assume that the concentration change rate is inversely proportional to the volume of the gas well, that is, the larger the volume, the smaller the concentration change per unit time, and define a volume correction coefficient k1, Where V0 is the standard well volume, V is the actual gas well volume, and then v n To make a correction:

[0085] Define the change rate thresholds α and β, and compare v n Correction and change rate thresholds α and β, if v n修正 ≤α, then the gas leakage type T is small hole leakage, if α <v n修正 ≤β, then the gas leakage type T is large hole leakage, if v n修正 >β, in this case, the gas leakage type T is fracture leakage;

[0086] Diffusion boundary hazard analysis unit: used to combine the gas leakage type T and the gas leakage time t to obtain different diffusion boundary hazards P(T, t), Among them, χ, ε, and γ are adjustment parameters, and the influence of reaction environment conditions on gas diffusion, Q small , Q large , Q rupture They are the gas leakage from small hole leakage, large hole leakage and fracture leakage respectively;

[0087] The diffusion of small hole leakage is relatively slow. The longer the leakage time, the larger the diffusion radius. The calculation formula for the gas leakage of small hole leakage is: Where k is the gas adiabatic coefficient, which is 1.334 in this embodiment, R is the gas constant, T B is the temperature before the gas leak, P B is the pressure before the gas leak, A is the area of ​​the leak, C d is the orifice flow correction coefficient, which is determined according to the shape of the leak: when the leak is circular, C d=1.00, when the leakage port is a triangle, C d =0.95, when the leak is rectangular, C d =0.90, when the leakage port is an internal corrosion shrinking hole, 0.9 <C d <1.0, when the leakage port is damaged by external force and gradually expanded, 0.6 <C d <0.9, M is the molar mass of the gas;

[0088] When a large hole leaks, the gas diffuses faster. For actual high-pressure or low-pressure gas transmission pipelines, as the hole diameter increases, the pressure P at the center of the leak port increases. B Much smaller than the pressure P at the starting point of the pipeline A , but still greater than the critical pressure P c At this time, the leakage process becomes a critical flow in the pipeline and the leakage hole. The calculation formula for the gas leakage of large hole leakage is: Where T A is the gas temperature at the starting point of the pipeline, P A is the pressure at the starting point of the pipeline, where Ma A is the Mach number at the starting point of the pipeline;

[0089] When the pipeline is disturbed by external forces or overpressure, a large rupture will occur, resulting in a large area of ​​gas leakage. Generally, the leakage port is 80%-100% of the pipeline cross-sectional area. When a pipeline leaks, the pipeline leakage port area is large, resulting in a large instantaneous gas leakage, which significantly reduces the pressure in the pipeline. For an ideal gas insulated pipeline, the calculation formula for the gas leakage due to the rupture is: Where m is the mass flow rate of the gas, Y g is the gas expansion coefficient, g c is the gravitational constant, ρ A is the gas density in the pipeline, P C is the pressure at the starting point of the pipeline, P D is the gas pressure at the leak point in the pipeline, ∑K f is the difference loss term, Where f is the friction coefficient, d is the inner diameter of the pipe, and L is the pipe length;

[0090] Get soil permeability unit: used to calculate soil permeability Ks, the formula is: Where D 10 is the effective particle size, ψ is the water density, μ is the fluid dynamic viscosity coefficient, e is the soil porosity, and N is a constant. The permeability of the soil reflects the tightness of the soil. The tighter the soil, the worse its permeability. On the contrary, the looser the soil, the better its permeability. After the gas leaks, the diffusion movement is faster, and the diffusion and migration ability is also faster.

[0091] Get road surface correction factor unit: used to calculate the road surface correction factor R of different road surface types road For hardened pavement, the diffusion range is increased by a correction factor. For non-hardened pavement, the gas diffusion is stronger and the correction factor is set to 1, indicating no inhibition. Specifically, the pavement correction factor where k hard A constant representing the effect of hardened pavement on diffusion, usually k hard >1.

[0092] Calculation module for coupling risk impact factor: used to determine the coupling mode of gas pipelines and power pipelines, and obtain the coupling risk impact factor R(d,h) of gas pipelines and power pipelines. Where C is a constant, d is the horizontal distance between the gas pipeline and the power pipeline, i.e. the coupling spacing, h is the buried depth of the gas pipeline, and λ is used to control the impact of the coupling spacing and buried depth on the risk;

[0093] Coupling risk acquisition module: used to obtain the quantitative real-time risk R of gas pipeline and power pipeline coupling, R = P(T,t)·Ks·R road R(d,h), and normalize R;

[0094] Power pipeline monitoring module: used to monitor the power pipelines of each unit in real time, set different correction coefficients S for different power pipeline laying methods, and calculate the cross-sectional area A of gas accumulation under different power pipeline laying methods m , calculate the speed of gas diffusion based on real-time monitoring data, and determine the blocking type of the power pipeline, including blocking state and non-blocking state, and obtain the blocking correction factor L; calculate the maximum distance D of gas diffusion to dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, φ is the environmental correction factor, and specifically includes the following units:

[0095] Correction coefficient setting unit: used to set different correction coefficients S for different power pipeline laying methods, specifically:

[0096] In the direct burial mode, that is, the power pipeline has no independent space, the cable is in direct contact with the soil, and the possibility of gas diffusion to the cable is low. However, when the gas concentration is high, it may still be dangerous. The correction factor at this time is set to S direct In this embodiment, S direct =1;

[0097] In the casing mode: there are usually multiple circular channels (pipes) inside the casing, which increases the diffusion path and accumulation space of the gas. In this case, the gas may accumulate in the casing, resulting in local high concentration, with medium risk. The correction factor is set to S casing In this embodiment, S casing =1.5;

[0098] In the case of electric trench: the space is large (rectangular cross section), gas leaks easily accumulate and are difficult to be discharged quickly. At this time, due to the closed channel and large diffusion space, the risk is high, and the correction coefficient is set to S trench In this embodiment, S trench =2;

[0099] Usually S direct casing trench ;

[0100] Calculation cross-sectional area unit: used to calculate the cross-sectional area A of gas accumulation under different power pipeline laying methods m : Under direct burial method, the cross-sectional area A where the gas gathers direct =πr 2 , where r is the radius of the power pipeline; in the casing method, the cross-sectional area A where the gas gathers casing =n·πl 2 , where n is the number of pipes in the casing, l is the radius of the casing pipe; in the power trench mode, the cross-sectional area A of the gas gathering trench =w·h, where w is the width of the power trench and h is the height of the power trench;

[0101] Diffusion velocity calculation unit: used to calculate the gas diffusion velocity v(x): Assume that the sensor is arranged at Z nodes along the power pipeline, and the position of each node is x i (distance along the diffusion direction), and its corresponding response time is t i (The time required for the sensor to detect a certain concentration threshold), the calculation formula for the gas diffusion velocity v(x) is: Calculate the average diffusion velocity for all responding sensor locations

[0102] Blockage type determination unit: used to determine whether the blockage type of the power pipeline is a blocked state or an unblocked state;

[0103] Obtain blocking correction factor unit: used to obtain blocking correction factor Where L blocked >1,L unblocked <1;

[0104] ​​Calculation of maximum diffusion distance unit: used to calculate the maximum distance D of gas diffusion to dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, φ is the environmental correction factor, which is affected by environmental characteristics (such as temperature, humidity, power pipeline obstacles, etc.), usually 0<φ<10.

[0105] Power pipeline risk acquisition module: used to obtain the quantitative real-time risk R of power pipelines d , R d =D b ·A m ·S·L, and to R d Normalize.

[0106] In this embodiment, the unit division module is first used to divide the gas pipeline and the power pipeline into sections to obtain each division unit; then, the diffusion boundary hazard acquisition module is used to determine the gas leakage type T according to the real-time monitoring data, and the different diffusion boundary hazards are obtained in combination with the time t of the gas leakage, and the soil permeability of different soils and the pavement correction factors of different pavement types are calculated; then, the coupling risk impact factor calculation module is used to obtain the coupling risk impact factor of the gas pipeline and the power pipeline; and then, the coupling risk acquisition module is used to calculate the quantitative real-time risk of the coupling of the gas pipeline and the power pipeline;

[0107] Using the power pipeline monitoring module, different correction coefficients are set for different power pipeline laying methods, and the cross-sectional area of ​​gas accumulation under different power pipeline laying methods is calculated. The gas diffusion speed is calculated based on real-time monitoring data, the plugging type of the power pipeline is determined, the plugging correction factor L is obtained, and the maximum distance D for gas diffusion to a dangerous concentration is calculated. b ; Then, by obtaining the power pipeline risk module, the quantitative real-time risk R of the power pipeline is calculated. d .

[0108] Example 3

[0109] like Figure 2 As shown, this embodiment provides an intelligent terminal device, including an input end, a memory, a processor, a display, a communication interface and an output end. The real-time monitoring data of the gas pipeline is input into the terminal device through the input end and the communication interface. The memory is used to store a computer program for real-time risk assessment of the coupling of gas diffusion to the power pipeline. The processor is used to call and run the computer program stored in the memory to perform risk assessment. The specific assessment method refers to Example 1; and the corresponding quantitative risk situation is displayed through the display, and finally the assessment result of the assessment unit is output through the output end.

[0110] The computer program for performing coupled real-time risk assessment of gas diffusion to power pipelines may also be stored on a computer-readable medium, and the processor controls the computer program to perform risk assessment when it is executed. The specific assessment process also refers to Embodiment 1 of the present invention;

[0111] The computer readable medium may be a computer readable signal medium or a computer readable storage medium, or any combination of a computer readable signal medium and a computer readable storage medium;

[0112] The computer-readable storage medium may be any tangible medium containing a stored program, which may be used by, or in combination with, an instruction execution system, apparatus or device; the computer-readable storage medium includes electrical, magnetic, optical, electromagnetic, infrared or semiconductor systems, apparatuses and devices, and more specifically, the computer-readable storage medium includes an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, an optical storage device, a magnetic storage device, etc., or any combination thereof;

[0113] A computer-readable signal medium may be a data signal included in a baseband or propagated as part of a carrier wave, which carries a computer-readable computer program. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0114] 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 aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these 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.

Claims

1. A coupled real-time risk assessment method for gas diffusion into power pipelines, characterized in that: The following steps are involved: S1: According to the underground pipeline network diagram of the city's gas pipelines and power pipelines, pipe sections are divided to obtain various division units; S2: Determine the gas leakage type T according to the real-time monitoring data of the gas channel in each unit, and combine the time t of the gas leakage to obtain different diffusion boundary hazards P(T, t), and calculate the soil permeability Ks of different soils and the pavement correction factor R of different pavement types. road ; S3: Determine the coupling mode of gas pipelines and power pipelines, and obtain the risk influencing factors of gas pipeline and power pipeline coupling Where C is a constant, d is the horizontal distance between the gas pipeline and the power pipeline, i.e., the coupling spacing, h is the buried depth of the gas pipeline, and λ is used to control the impact of the coupling spacing and buried depth on the risk; S4: Obtain the quantitative real-time risk R of gas leakage and power pipeline coupling, R = P(T,t)·Ks·R road R(d,h), and normalize R; S5: Real-time monitoring of the power pipelines of each unit is performed. Different correction coefficients S are set for different power pipeline laying methods, and the cross-sectional area A of gas accumulation under different power pipeline laying methods is calculated. m , the power pipeline sensor monitors and calculates the speed of gas diffusion, and determines the blocking type of the power pipeline, including the blocking state and the non-blocking state, and obtains the blocking correction factor L; Calculate the maximum distance D at which the gas diffuses to a dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, and φ is the environmental correction factor; S6: Obtaining quantitative real-time risk R of power pipelines d , R d =D b ·A m ·S·L, and to R d Normalize.

2. The coupled real-time risk assessment method for gas diffusion to power pipelines according to claim 1 is characterized in that: In step S2, the process of determining the type of gas leakage is as follows: selecting a monitoring point, calculating the gas concentration change rate v at the point n , define the volume correction factor Where V0 is the standard well volume, V is the actual gas well volume, and v n To make a correction: v n修正 =k1·v n , define the change rate thresholds α and β; compare v n修正 With the change rate thresholds α and β, if v n修正 ≤α, then the gas leakage type T is small hole leakage, if α <v n修正 ≤β, then the gas leakage type T is large hole leakage, if v n修正 >β, then the gas leakage type T is fracture leakage.

3. The coupled real-time risk assessment method for gas diffusion to power pipelines according to claim 2 is characterized in that: The danger of the proliferation boundary Among them, χ, ε, γ are adjustment parameters, Q small , Q large , Q rupture They are the gas leakage amounts of small hole leakage, large hole leakage and fracture leakage respectively.

4. The coupled real-time risk assessment method for gas diffusion to power pipelines according to claim 1 is characterized in that: In step S2, the soil permeability Where D 10 is the effective particle size, ψ is the water density, μ is the fluid dynamic viscosity coefficient, e is the soil porosity, and N is a constant; the pavement correction factor where k hard >1.

5. The coupled real-time risk assessment method for gas diffusion to power pipelines according to claim 1 is characterized in that: In step S3, the coupling modes of the gas pipeline and the power pipeline include a parallel coupling mode and a cross coupling mode.

6. The coupled real-time risk assessment method for gas diffusion to power pipelines according to claim 1 is characterized in that: In step S5, the laying methods of the power pipeline include direct burial, casing and power trench. The correction coefficient corresponding to the direct burial method is S direct , the correction factor corresponding to the casing method is S casing , the correction coefficient corresponding to the power channel method is S trench .

7. The coupled real-time risk assessment method for gas diffusion to power pipelines according to claim 6 is characterized in that: In the casing method, the cross-sectional area A where the gas gathers casing =n·πr 2 , where n is the number of pipes in the casing, r is the radius of the casing pipe; in the power trench mode, the cross-sectional area A of the gas gathering trench =w·h, where w is the width of the power trench and h is the height of the power trench.

8. The coupled real-time risk assessment method for gas diffusion to power pipelines according to claim 1 is characterized in that: In step S5, the blocking correction factor Where L blocked >1,L unblocked <1.

9. A coupled real-time risk assessment model for gas diffusion into power pipelines, characterized in that: Includes the following modules: Division unit module: used to divide the pipe sections according to the underground pipe network diagram of the city's gas pipelines and power pipelines to obtain each division unit; Diffusion boundary hazard acquisition module: used to determine the gas leakage type T according to the real-time monitoring data of the gas channel in each unit, and obtain different diffusion boundary hazards P(T, t) based on the time t of the gas leakage, and calculate the soil permeability Ks of different soils and the pavement correction factor R of different pavement types. road ; Calculation module for coupling risk impact factor: used to determine the coupling mode of gas pipelines and power pipelines, and obtain the coupling risk impact factor R(d,h) of gas pipelines and power pipelines. Where C is a constant, d is the horizontal distance between the gas pipeline and the power pipeline, i.e., the coupling spacing, h is the buried depth of the gas pipeline, and λ is used to control the impact of the coupling spacing and buried depth on the risk; Coupling risk acquisition module: used to obtain the quantitative real-time risk R of gas pipeline and power pipeline coupling, R = P(T,t)·Ks·R road R(d,h), and normalize R; Power pipeline monitoring module: used to monitor the power pipelines of each unit in real time, set different correction coefficients S for different power pipeline laying methods, and calculate the cross-sectional area A of gas accumulation under different power pipeline laying methods m , calculate the gas diffusion speed according to the real-time monitoring data, and determine the plugging type of the power pipeline, including the plugging state and the non-plugging state, and obtain the plugging correction factor L; Calculate the maximum distance D at which the gas diffuses to a dangerous concentration b , in is the average diffusion velocity of the gas, t is the time of gas leakage, and φ is the environmental correction factor; Power pipeline risk acquisition module: used to obtain the quantitative real-time risk R of power pipelines d , R d =D b ·A m ·S·L, and to R d Normalize.

10. A terminal device, characterized in that: The method comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 8.

Images