Method and device for evaluating a gas pipeline

Abstract

The application relates to a kind of gas pipeline evaluation method and device, the method comprises: current signal is emitted to gas pipeline by transmitter, and the current value at detection position is obtained;According to the current value of emission position and the current value of the detection position, the current attenuation coefficient of the gas pipeline is calculated;According to the current attenuation coefficient, current frequency, self-induction of the gas pipeline, longitudinal resistance of the gas pipeline and the capacitance between the gas pipeline and ground, the transverse resistance of the gas pipeline is calculated;According to the transverse resistance of the gas pipeline and the diameter of the gas pipeline, the insulation characteristic parameter of the gas pipeline is calculated;According to the size relation between the insulation characteristic parameter and preset threshold value, whether the gas pipeline leaks is determined.The application can judge whether the gas pipeline leaks, and the process does not involve human factors, so the accuracy of the judgment result is relatively high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipeline, in particular to a gas pipeline evaluation method and device. BACKGROUND

[0002] At present, there are various methods for evaluating gas pipelines at home and abroad, such as qualitative evaluation method, semi-quantitative evaluation method and quantitative evaluation method. These evaluation methods have the following characteristics:

[0003] (1) Although there has been some research on the corrosion degree rating of gas pipelines at home and abroad, the calculation model for the corrosion grading evaluation of gas pipelines is still incomplete. The corrosion evaluation of gas pipelines focuses on the possibility of pipeline corrosion failure and the consequence evaluation after corrosion failure, and is mostly based on one aspect without forming a comprehensive and accurate comprehensive evaluation system.

[0004] (2) The reliability and accuracy of these evaluation methods cannot be guaranteed. At present, the evaluation of gas pipelines is based on the occurrence probability of influencing factors by experts, which is highly subjective. Alternatively, the probability of pipeline accidents is calculated by a large amount of engineering data using the Bayesian method, which requires a large amount of data support.

[0005] (3) The cascading effect of underground pipelines is crucial to the evaluation of the corrosion grade of gas pipelines, and the research on the cascading effect probability of gas pipeline corrosion failure is still shallow. At present, the related research at home and abroad is still in its infancy and has not been included in the evaluation system.

[0006] (4) The intelligentization and convenience of gas pipeline corrosion evaluation need to be further improved, and the calculation amount of the gas pipeline corrosion evaluation system is large, and the calculation process is complex, which brings difficulty to the corrosion evaluation. SUMMARY

[0007] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides a gas pipeline evaluation method and device.

[0008] In a first aspect, the present application provides a gas pipeline evaluation method, comprising:

[0009] transmitting a current signal to the gas pipeline through a transmitter, and acquiring a current value at a detection position;

[0010] calculating a current attenuation coefficient of the gas pipeline according to the current value of the transmission position and the current value of the detection position;

[0011] calculating a transverse resistance of the gas pipeline according to the current attenuation coefficient, the current frequency, the self-inductance of the gas pipeline, the longitudinal resistance of the gas pipeline and the capacitance between the gas pipeline and the ground;

[0012] calculate an insulation characteristic parameter of the gas pipeline according to the transverse resistance of the gas pipeline and a diameter of the gas pipeline;

[0013] determine whether the gas pipeline leaks according to a size relationship between the insulation characteristic parameter and a preset threshold.

[0014] In a second aspect, an embodiment of the present application provides a gas pipeline evaluation device, comprising:

[0015] A first obtaining module is configured to transmit a current signal to the gas pipeline through a transmitter and obtain a current value at a detection position;

[0016] A first calculating module is configured to calculate a current attenuation coefficient of the gas pipeline according to the current value at the transmission position and the current value at the detection position;

[0017] A second calculating module is configured to calculate a transverse resistance of the gas pipeline according to the current attenuation coefficient, a current frequency, a self-inductance of the gas pipeline, a longitudinal resistance of the gas pipeline and a capacitance between the gas pipeline and the ground;

[0018] A third calculating module is configured to calculate an insulation characteristic parameter of the gas pipeline according to the transverse resistance of the gas pipeline and a diameter of the gas pipeline;

[0019] A first determining module is configured to determine whether the gas pipeline leaks according to a size relationship between the insulation characteristic parameter and a preset threshold.

[0020] The gas pipeline evaluation method and device provided by the embodiments of the present application have the following beneficial effects when combined:

[0021] (1) In the embodiments of the present application, a current signal is transmitted to the gas pipeline through a transmitter, so as to calculate a current attenuation coefficient of the gas pipeline according to the current value at the transmission position and the current value at the detection position, and then calculate a transverse resistance of the gas pipeline according to the current attenuation coefficient, a current frequency, a self-inductance of the gas pipeline, a longitudinal resistance of the gas pipeline and a capacitance between the gas pipeline and the ground, and then calculate an insulation characteristic parameter of the gas pipeline according to the transverse resistance of the gas pipeline and a diameter of the gas pipeline, and finally determine whether the gas pipeline leaks according to a size relationship between the insulation characteristic parameter and a preset threshold. Through this process, it can be determined whether the gas pipeline leaks. This process does not involve human factors, so the accuracy of the determination result is relatively high.

[0022] (2) In one embodiment, a plurality of factors affecting the corrosion degree of the gas pipeline, a plurality of corrosion levels of the corrosion degree of the gas pipeline are determined, then a single-factor evaluation matrix corresponding to each factor in the factor set and a first weight vector are obtained, the first weight vector corresponding to each factor in the factor set is multiplied by the single-factor evaluation matrix of the factor, to obtain a membership vector corresponding to the factor, and then the membership vectors corresponding to the respective factors are spliced into a judgment matrix, and then the product of the second weight vector corresponding to the factor set and the judgment matrix is calculated to obtain a factor evaluation vector, and the maximum element value corresponding to the factor is selected from the factor evaluation vector, and the corrosion level corresponding to the factor is taken as the corrosion level of the gas pipeline. This process takes into account a plurality of factors that affect the corrosion level of the gas pipeline, thereby forming an evaluation system that is more in line with actual conditions.

[0023] (3) In one embodiment, the subjectivity of the first weight vector is judged, and the first weight vector is modified when the subjectivity is relatively high, until the subjectivity of the first weight vector is reduced to a reasonable range, thereby greatly weakening the human factor and making the evaluation of the corrosion level of the gas pipeline more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

[0026] Figure 1 The flowchart of the gas pipeline evaluation method in one embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0028] In a first aspect, the embodiments of the present application provide a gas pipeline evaluation method, as shown in Figure 1The method comprises steps A110-A150 as follows:

[0029] A110, transmitting a current signal to the gas pipeline through a transmitter, and acquiring a current value at a detection position;

[0030] It can be understood that the transmitter transmits a current signal along the length direction of the gas pipeline, and the current signal is affected by the pipeline material and the outer anticorrosive material in the gas pipeline, so the current size will be attenuated.

[0031] Among them, a detection position is selected on the gas pipeline, and the current size at the detection position is detected.

[0032] Among them, the current size transmitted by the transmitter is the current value at the transmission position.

[0033] A120, calculating a current attenuation coefficient of the gas pipeline according to the current value at the transmission position and the current value at the detection position;

[0034] It can be understood that the farther the distance between the detection position and the transmission position, the greater the degree of attenuation of the current value, and the closer the distance between the detection position and the transmission position, the smaller the attenuation of the current value.

[0035] In one embodiment, the first calculation formula can be used to calculate the current attenuation coefficient, and the first calculation formula is:

[0036]

[0037] In the formula, I is the current value at the detection position, I0 is the current value at the transmission position, x is the distance between the detection position and the transmission position, is the current attenuation coefficient, and N is the protection potential value of the gas pipeline.

[0038] In the first calculation formula, I, I0, x and N are known parameters, is an unknown parameter, and the size of can be obtained by the above first calculation formula.

[0039] Among them, the protection potential value N of the gas pipeline is the potential difference between the gas pipeline and the ground.

[0040] In actual scenarios, several detection positions can be selected in the length direction of the gas pipeline, for example, three detection positions, and according to the three detection positions and the transmission position, three current attenuation coefficients of the gas pipeline are calculated respectively, and then the average value of the three current attenuation coefficients of the gas pipeline is calculated as the final current attenuation coefficient.

[0041] A130, calculating the transverse resistance of the gas pipeline according to the current attenuation coefficient, the current frequency, the self-inductance of the gas pipeline, the longitudinal resistance of the gas pipeline, and the capacitance between the gas pipeline and the ground;

[0042] In one embodiment, the transverse resistance of the gas pipeline can be calculated by using a second calculation formula, which is:

[0043]

[0044] wherein, is the current attenuation coefficient, f is the current frequency, L is the self-inductance of the gas pipeline, R is the longitudinal resistance of the gas pipeline, G is the transverse resistance of the gas pipeline, and C is the capacitance between the gas pipeline and the ground.

[0045] In the second calculation formula, f, L, and C are known parameters, and G is an unknown parameter. The size of G can be obtained by using the above-mentioned second calculation formula.

[0046] wherein, the current frequency is the frequency of the current signal transmitted by the transmitter.

[0047] wherein, the longitudinal resistance refers to the resistance value of the gas pipeline along the unit length direction.

[0048] wherein, the transverse resistance refers to the resistance value of the gas pipeline along the unit radial direction.

[0049] A140, calculating the insulation characteristic parameter of the gas pipeline according to the transverse resistance of the gas pipeline and the diameter of the gas pipeline;

[0050] In one embodiment, the insulation characteristic parameter of the gas pipeline can be calculated by using a third calculation formula, which is:

[0051] R g = π·D / G

[0052] wherein, R g is the insulation characteristic parameter of the gas pipeline, D is the diameter of the gas pipeline, and G is the transverse resistance of the gas pipeline.

[0053] In the third calculation formula, R g is an unknown parameter, and D and G are known parameters. The size of R g can be obtained by using the above-mentioned third calculation formula.

[0054] The insulation characteristic parameter is a parameter value representing the insulation characteristic of the gas pipeline. The gas pipeline is generally made of metal or alloy, and thus the insulation characteristic parameter represents the insulation characteristic of the metal or alloy. In the method provided in the embodiment of the present application, the gas pipeline serves as an anode, and thus the method can also be referred to as an anode sacrificial method.

[0055] A150, determining whether the gas pipeline leaks according to the size relationship between the insulation characteristic parameter and a preset threshold value.

[0056] In one embodiment, A150 can specifically include:

[0057] If the insulation characteristic parameter is greater than the preset threshold value, the gas pipeline leaks; otherwise, the gas pipeline does not leak.

[0058] To improve safety, the aging state grade specified in SY / T 5918-2004 “Technical Specification for Repairing External Anti-corrosion Layer of Buried Steel Pipeline” can be reclassified. For example, R g When the value is lower than 4000, the pipeline leakage problem needs to be considered, and personnel needs to be arranged for maintenance. That is, the preset threshold value can be but is not limited to 4000.

[0059] To verify the feasibility of the above steps, 70 excavation points are selected for the Qingdao Jiaozhou-Huangshan high-pressure pipeline, and 30 excavation points are selected for Jiulong pressure regulating station-Chengyangmen station, and the result verifies that the prediction accuracy is 90%.

[0060] The above method can be used to determine whether the gas pipeline leaks, but when there is no leakage, the corrosion grade of the gas pipeline needs to be further determined. Therefore, in one embodiment, when the gas pipeline does not leak, the corrosion grade of the gas pipeline can be determined by the following steps A210-A280:

[0061] A210, determining a plurality of factors affecting the corrosion degree of the gas pipeline; wherein the plurality of factors form a factor set, each factor includes at least one influencing factor, and one factor in the plurality of factors is the insulation characteristic parameter;

[0062] In actual scenarios, there are other factors affecting the corrosion degree of the gas pipeline, such as soil resistivity, pipeline burial depth, pipeline service life, soil moisture, soil oxygen content, and soil pH value. The soil resistivity further includes a plurality of factors, such as soil type, water content, salt content, temperature, and tightness of the soil. These factors can be detected by the four-electrode sounding method commonly used in engineering.

[0063] Considering the measurability and representativeness of the indicators, five factors S1, S2, S3, S4 and S5 are finally selected, which form a factor set. Among them:

[0064] S1 refers to the degree of soil corrosion, and S1 includes five influencing factors: soil resistivity S11, soil moisture S12, PH value S13, pipe-to-ground potential S14, and soil oxygen content S15. The pipe-to-ground potential refers to the potential difference between the gas pipeline and the ground;

[0065] S2 refers to the insulation characteristic parameter mentioned above;

[0066] S3 refers to the operating state of the gas pipeline, and S3 includes two influencing factors: temperature S31 and pressure S32;

[0067] S4 refers to the service time of the gas pipeline;

[0068] S5 refers to the number of maintenance times of the gas pipeline.

[0069] A210, a plurality of corrosion levels of the corrosion degree of the gas pipeline are determined; wherein the plurality of corrosion levels form a corrosion level set;

[0070] In one scenario, the corrosion levels are divided into five levels: low, lower, medium, higher, and high, which form a corrosion level set. The higher the level, the more serious the corrosion of the gas pipeline. The corrosion level set is specifically represented as V={V1, V2, …, V5}.

[0071] Referring to Table 1 below, the correspondence between the value range of each influencing factor in each factor and the corrosion level can be seen:

[0072] Table 1

[0073]

[0074] It can be understood that in Table 1 above, the critical value is higher.

[0075] A220, a single-factor evaluation matrix corresponding to each factor in the factor set is obtained; wherein the number of rows of the single-factor evaluation matrix is a, the number of columns is b, a is equal to the number of influencing factors in the factor, and b is equal to the number of corrosion levels in the corrosion level set. The element r ij ij of the i-th row and the j-th column in the single-factor evaluation matrix is the percentage of experts who think that the i-th influencing factor of the factor has an influence on the gas pipeline at the j-th corrosion level;

[0076] For example, the single-factor evaluation matrix R1 corresponding to the first factor S1 has 5 rows and 5 columns, and the element rof the 1st row and the 1st column is the percentage of experts who think that the first influencing factor of the first factor has an influence on the gas pipeline at the first corrosion level.11 The size of 0.3 indicates that 30% of the experts believe that the soil resistivity S11 in the first factor S1 has a low impact on the gas pipeline.

[0077] For example, the third factor S3 corresponds to R3, the number of rows of the matrix is 2, the number of columns is 5, and the element r 12 The size of 0.4 indicates that 40% of the experts believe that the temperature S31 in the third factor S3 has a low impact on the gas pipeline.

[0078] The number of rows of the single-factor evaluation matrix of the other factors S2, S4, and S5 is 1, and the number of columns is 5.

[0079] As can be seen, a large number of experts are needed in this step to evaluate the impact of each factor on the gas pipeline, and then the single-factor evaluation matrix is summarized.

[0080] A230, obtaining a first weight vector corresponding to each factor in the factor set, each weight value in the first weight vector corresponding to each impact factor in the factor;

[0081] That is, there is a first weight vector for each factor, and the number of weight values in the first weight vector is the same as the number of impact factors in the factor. For example, the first weight vector corresponding to the first factor is A1=(a1, a2, a3, a4, a5), and the sum of the weight values is 1. The first weight vector corresponding to the third factor includes two weight values, and the sum of the two weight values is 1. The first weight vector corresponding to each of the other factors S2, S4, and S5 includes only one weight value, and the weight value is 1.

[0082] These weight values can be obtained by the rater according to experience.

[0083] A240, multiplying the first weight vector corresponding to each factor in the factor set and the single-factor evaluation matrix of the factor to obtain a membership degree vector corresponding to the factor; wherein the number of membership degrees in the membership degree vector is equal to the number of corrosion levels in the corrosion level set, and each membership degree in the membership degree vector corresponding to each factor represents the probability that the factor belongs to the corrosion level corresponding to the membership degree;

[0084] For example, for the first factor S1, the corresponding first weight vector A1 is multiplied by the single-factor evaluation matrix R1 of S1 to obtain the membership degree vector B1 corresponding to S1. That is, B1 = A1 · R1. For example, A1 is a 1-row 5-column vector, R1 is a 5-row 5-column matrix, and thus the obtained B1 is a 1-row 5-column vector. Each membership degree in the membership degree vector B1 corresponds to a corrosion grade, and each membership degree represents the probability or possibility that the factor S1 belongs to the corrosion grade corresponding to the membership degree.

[0085] For example, for the third factor S3, the corresponding first weight vector A3 is multiplied by the single-factor evaluation matrix R3 of S3 to obtain the membership degree vector B3 corresponding to S3. That is, B3 = A3 · R3. For example, A3 is a 1-row 2-column vector, R3 is a 2-row 5-column matrix, and thus the obtained B3 is a 1-row 5-column vector. Each membership degree in the membership degree vector B3 corresponds to a corrosion grade, and each membership degree represents the probability or possibility that the factor S3 belongs to the corrosion grade corresponding to the membership degree.

[0086] For example, for the second factor S2, the corresponding first weight vector A2 is multiplied by the single-factor evaluation matrix R2 of S2 to obtain the membership degree vector B2 corresponding to S2. That is, B2 = A2 · R2 = 1 · R2 = R2. For example, A2 is a 1-row 1-column vector, R2 is a 1-row 5-column matrix, and thus the obtained B2 is a 1-row 5-column vector. Each membership degree in the membership degree vector B2 corresponds to a corrosion grade, and each membership degree represents the probability or possibility that the factor S2 belongs to the corrosion grade corresponding to the membership degree.

[0087] It can be seen that the membership degree vectors corresponding to the fourth factor S4 and the fifth factor are also 1-row 5-column vectors.

[0088] In an embodiment, before performing the multiplication of the first weight vector corresponding to each factor in the set of factors and the single-factor evaluation matrix of the factor, the following can also be performed: dividing each element in each column of the single-factor evaluation matrix of each factor by the square sum of all element values in the column to obtain the normalized value of the element in the column, and the normalized values of the elements in the single-factor evaluation matrix form a normalized single-factor evaluation matrix.

[0089] For example, each element value in the first column of the single-factor evaluation matrix R1 of the first factor is divided by the square sum of the elements in the first column to normalize the element values in the first column, and the same is true for other columns, thereby realizing the normalization of the entire single-factor evaluation matrix R1.

[0090] Correspondingly, the step of multiplying the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the factor can include: multiplying the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the element after normalization.

[0091] In one embodiment, after multiplying the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the factor, and before splicing the membership degree vectors corresponding to the respective factors into a judgment matrix, the following steps can be further performed:

[0092] For each factor, selecting the maximum membership degree in the membership degree vector corresponding to the factor;

[0093] According to the maximum membership degree and the order of the first weight vector corresponding to the element, determining whether the subjectivity of the first weight vector corresponding to the element exceeds a subjective limit value;

[0094] If yes, modifying the weight values in the first weight vector, and returning to the step of multiplying the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the factor;

[0095] Otherwise, performing the step of splicing the membership degree vectors corresponding to the respective factors into a judgment matrix.

[0096] That is, in order to overcome the subjectivity of evaluation, the consistency of the first weight vector is checked, so as to determine whether the first weight vector is reasonable. Specifically, the first weight vector corresponding to each factor with the number of influence factors greater than 1 needs to be judged for reasonableness.

[0097] For example, for the first weight vector of factor S1, the maximum membership degree λ max in the membership degree vector corresponding to the factor is selected. The first weight vector includes 5 weight values, and the order n of the first weight vector is 5. A consistency index CI can be calculated by using the two parameters and the following calculation formula:

[0098]

[0099] Then, another consistency index RI is found according to Table 2 as follows:

[0100] Table 2

[0101]

[0102] Further, a ratio between the consistency index CI and the RI is calculated. If CI / RI>0.10, it indicates that the subjectivity is strong. Whether the subjectivity exceeds the subjective limit value. At this time, the first weight vector can be modified. After modification, it is returned to A240 to obtain a new membership degree vector. According to the new membership degree vector, it is judged again whether the subjectivity of the first weight vector meets the requirements. If CI / RI is less than or equal to 0.10, it meets the requirements. A250 can be executed. Otherwise, the first weight vector is modified. Then it is returned to A240. The cycle is continued until the subjectivity of the modified first weight vector meets the requirements.

[0103] In this way, the judgment accuracy of the final corrosion degree can be greatly reduced due to the excessive subjectivity in the first weight vector.

[0104] A250, the membership degree vectors corresponding to the factors are spliced into an evaluation matrix. The number of rows of the evaluation matrix is equal to the number of factors in the factor set. The number of columns of the evaluation matrix is equal to the number of corrosion levels in the corrosion level set.

[0105] For example, five membership degree vectors corresponding to five factors can be spliced into a 5x5 evaluation matrix W. The first row is the membership degree vector of the first factor. The second row is the membership degree vector of the second factor. The third row is the membership degree vector of the third factor. The fourth row is the membership degree vector of the fourth factor. The fifth row is the membership degree vector of the fifth factor.

[0106] That is, the number of rows of the evaluation matrix is equal to the number of factors. The number of columns is equal to the number of corrosion levels.

[0107] A260, the product of the second weight vector corresponding to the factor set and the evaluation matrix is calculated to obtain a factor evaluation vector. Each element value in the factor evaluation vector corresponds to each factor in the factor set. Each element value in the factor evaluation vector is the evaluation value of the corresponding factor in the factor set. Each weight value in the second weight vector corresponds to each factor in the factor set.

[0108] The second weight vector corresponds to the factor set. For example, the factor set includes five factors. The second weight vector also includes five weight values. The five weight values correspond to the five factors one by one. The second weight vector is given by the evaluator according to experience. For example, the second weight vector is A'.

[0109] Herein the second weight vector A' is multiplied with the evaluation matrix W to obtain the factor evaluation vector E, i.e. E=A'·W, since A' is a vector of 1 row and 5 columns, and the evaluation matrix W is a matrix of 5 rows and 5 columns, thus E is a vector of 1 row and 5 columns. It can be seen that each element value in the factor evaluation vector E corresponds to one factor in the factor set, i.e. the first element value in E corresponds to the first factor, and the fifth element value in E corresponds to the fifth factor. Each element value in the factor evaluation vector E indicates the evaluation value of the factor corresponding to the element value.

[0110] A270、from the factor evaluation vector, the maximum element value is selected, and the corrosion grade corresponding to the factor corresponding to the maximum element value is taken as the corrosion grade of the gas pipeline.

[0111] For example, the second element value in the factor evaluation vector E is the largest among the 5 element values, thus the corrosion degree corresponding to S2, the insulation characteristic parameter corresponding to the second element value, is the corrosion degree of the gas pipeline. If the current insulation characteristic parameter is 3000, which is within the range of 2000-4000, the corresponding corrosion grade is medium, thus the corrosion grade of the gas pipeline is medium.

[0112] Further, the method provided by the embodiment of the present application can further comprise:

[0113] According to the corrosion grade of the gas pipeline, the corresponding gas pipeline replacement time is determined; wherein the higher the evaluation grade is, the shorter the gas pipeline replacement time is.

[0114] For example, the corrosion grades: low, lower, medium, higher, and high correspond to the gas pipeline replacement times: <5 years, <3 years, <1 year, <1 month, and immediate repair respectively. The gas pipeline replacement time is recorded in the safety monitoring system stored in the company, and a priority order is set in time sequence from short to long, and then the maintenance personnel is reminded in advance.

[0115] It can be seen that the method provided by the embodiment of the present application is based on accumulated historical data, and considers the influence of multiple variables, such as pipeline burial depth, pipeline service life, negative potential of pile, and pipeline pressure. A pipeline corrosion grading and evaluation system more in line with actual conditions is created, which is an accurate evaluation system through testing. Through this evaluation system, the time for replacing equipment can be calculated, and the evaluation system is more practical. Human factors are greatly weakened in the evaluation system, so that the gas pipeline corrosion evaluation is more accurate.

[0116] In the second aspect, the embodiment of the present application provides a gas pipeline evaluation device, comprising:

[0117] The first acquisition module is configured to emit a current signal to the gas pipeline through the transmitter, and acquire the current value at the detection position.

[0118] a first calculation module configured to calculate a current attenuation coefficient of the gas pipeline according to a current value at a transmitting position and a current value at a detecting position;

[0119] a second calculation module configured to calculate a transverse resistance of the gas pipeline according to the current attenuation coefficient, a current frequency, a self-inductance of the gas pipeline, a longitudinal resistance of the gas pipeline, and a capacitance between the gas pipeline and the ground;

[0120] a third calculation module configured to calculate an insulation characteristic parameter of the gas pipeline according to the transverse resistance of the gas pipeline and a diameter of the gas pipeline;

[0121] a first determination module configured to determine whether the gas pipeline is leaking according to a size relationship between the insulation characteristic parameter and a preset threshold.

[0122] In an embodiment, the first calculation module is configured to calculate the current attenuation coefficient by using a first calculation formula, the first calculation formula being:

[0123]

[0124] wherein I is the current value at the detecting position, I0 is the current value at the transmitting position, x is a distance between the detecting position and the transmitting position, is the current attenuation coefficient, and N is a protection potential value of the gas pipeline.

[0125] In an embodiment, the second calculation module is configured to calculate the transverse resistance of the gas pipeline by using a second calculation formula, the second calculation formula being:

[0126]

[0127] wherein is the current attenuation coefficient, f is the current frequency, L is the self-inductance of the gas pipeline, R is the longitudinal resistance of the gas pipeline, G is the transverse resistance of the gas pipeline, and C is the capacitance between the gas pipeline and the ground.

[0128] In an embodiment, the third calculation module is configured to calculate the insulation characteristic parameter of the gas pipeline by using a third calculation formula, the third calculation formula being:

[0129] R g = π·D / G

[0130] wherein R g is the insulation characteristic parameter of the gas pipeline, D is the diameter of the gas pipeline, and G is the transverse resistance of the gas pipeline.

[0131] In one embodiment, the first determining module is configured to determine that the gas pipeline has a leak if the insulation characteristic parameter is greater than the preset threshold value; otherwise, the gas pipeline has no leak.

[0132] In one embodiment, the device further comprises:

[0133] a grade determining module configured to determine a corrosion grade of the gas pipeline when the gas pipeline has no leak; the grade determining module comprises:

[0134] a first determining unit configured to determine a plurality of factors affecting the corrosion degree of the gas pipeline; wherein the plurality of factors form a factor set, each factor includes at least one influencing factor, and one factor in the plurality of factors is the insulation characteristic parameter;

[0135] a second determining unit configured to determine a plurality of corrosion grades of the corrosion degree of the gas pipeline; wherein the plurality of corrosion grades form a corrosion grade set;

[0136] a first obtaining unit configured to obtain a single-factor evaluation matrix corresponding to each factor in the factor set; wherein the single-factor evaluation matrix has a number of rows a and a number of columns b, a is equal to the number of influencing factors in the factor, and b is equal to the number of corrosion grades in the corrosion grade set, and an element r ij in the ith row and jth column of the single-factor evaluation matrix represents that a jth corrosion grade of the gas pipeline is affected by an ith influencing factor of the factor by a probability of r ij ;

[0137] a second obtaining unit configured to obtain a first weight vector corresponding to each factor in the factor set, wherein each weight value in the first weight vector corresponds to each influencing factor in the factor;

[0138] a first calculating unit configured to multiply the first weight vector corresponding to each factor in the factor set and the single-factor evaluation matrix of the factor to obtain a membership degree vector corresponding to the factor; wherein the number of membership degrees in the membership degree vector is equal to the number of corrosion grades in the corrosion grade set, and each membership degree in the membership degree vector corresponding to each factor represents a probability that the factor belongs to a corrosion grade corresponding to the membership degree;

[0139] a first splicing unit configured to splice the membership degree vectors corresponding to the factors into a judgment matrix; wherein the number of rows of the judgment matrix is equal to the number of factors in the factor set, and the number of columns of the judgment matrix is equal to the number of corrosion grades in the corrosion grade set;

[0140] a second computing unit configured to calculate a product of a second weight vector corresponding to the factor set and the judgment matrix to obtain a factor evaluation vector, each element value in the factor evaluation vector corresponding to each factor in the factor set, and each element value in the factor evaluation vector being an evaluation value of the corresponding factor in the factor set, each weight value in the second weight vector corresponding to each factor in the factor set;

[0141] a grade determining unit configured to select a maximum element value from the factor evaluation vector, and take a corrosion grade corresponding to the factor corresponding to the maximum element value as the corrosion grade of the gas pipeline.

[0142] In an embodiment, the first computing unit is further configured to, before multiplying the first weight vector corresponding to each factor in the factor set and the single-factor evaluation matrix of the factor, divide each element in each column in the single-factor evaluation matrix of each factor by a square sum of all element values in the column to obtain a normalized value of the element in the column, and form a normalized single-factor evaluation matrix from the normalized values of the elements in the single-factor evaluation matrix. Correspondingly, the multiplication of the first weight vector corresponding to each factor in the factor set and the single-factor evaluation matrix of the factor in the first computing unit comprises multiplication of the first weight vector corresponding to each factor in the factor set and the normalized single-factor evaluation matrix of the element.

[0143] In an embodiment, the grade determining module further comprises:

[0144] a subjective judgment unit configured to, after the first computing unit multiplies the first weight vector corresponding to each factor in the factor set and the single-factor evaluation matrix of the factor, and before the first splicing unit splices the membership degree vectors corresponding to the factors into a judgment matrix, select, for each factor, a maximum membership degree in the membership degree vector corresponding to the factor, and determine whether subjectivity of the first weight vector corresponding to the element exceeds a subjective limit value according to the maximum membership degree and an order of the first weight vector corresponding to the element. If yes, the weight values in the first weight vector are modified, and the multiplication of the first weight vector corresponding to each factor in the factor set and the single-factor evaluation matrix of the factor in the first computing unit is returned to. Otherwise, the first splicing unit splices the membership degree vectors corresponding to the factors into a judgment matrix is entered.

[0145] In an embodiment, the grade determining module further comprises:

[0146] a time determining unit configured to determine a corresponding gas pipeline replacement time according to the corrosion grade of the gas pipeline, wherein the higher the evaluation grade is, the shorter the gas pipeline replacement time is.

[0147] It can be understood that the explanations, specific embodiments, advantages, examples, and the like of the device provided by the embodiments of the present application can refer to the corresponding parts of the method provided by the first aspect, and will not be described here.

[0148] In a third aspect, a computer readable medium is provided, and the computer readable medium stores computer instructions. When the computer instructions are executed by a processor, the processor executes the method provided by the first aspect.

[0149] Specifically, a system or device equipped with a storage medium can be provided, and the storage medium stores software program codes for implementing the functions of any of the above embodiments, and the computer (or CPU or MPU) of the system or device reads and executes the program codes stored in the storage medium.

[0150] In this case, the program codes read from the storage medium can implement the functions of any of the above embodiments, and thus the program codes and the storage medium storing the program codes constitute a part of the present application.

[0151] The storage medium for providing the program codes includes a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program codes can be downloaded from a server computer via a communication network.

[0152] In addition, it should be clear that not only the program codes read by the computer can be executed, but also part or all of the actual operations can be completed by the operating system and the like operating on the computer based on the instructions of the program codes, thereby implementing the functions of any of the above embodiments.

[0153] In addition, it can be understood that the program codes read from the storage medium can be written into the memory provided in the expansion board inserted into the computer or the memory provided in the expansion module connected to the computer, and then part or all of the actual operations can be executed by the CPU and the like installed on the expansion board or the expansion module based on the instructions of the program codes, thereby implementing the functions of any of the above embodiments.

[0154] It can be understood that the explanations, specific embodiments, advantages, examples, and the like of the computer readable medium provided by the embodiments of the present application can refer to the corresponding parts of the method provided by the first aspect, and will not be described here.

[0155] In a fourth aspect, an embodiment of the present application provides a computing device, comprising: at least one memory and at least one processor; the at least one memory is configured to store a machine readable program; the at least one processor is configured to invoke the machine readable program to execute the method provided in the first aspect.

[0156] It can be understood that the explanation of the device related to the content, the specific implementation, the beneficial effects, the examples and the like provided in the embodiments of the present application refer to the corresponding parts in the method provided in the first aspect, and will not be repeated here.

[0157] Each of the embodiments in the specification is described in a progressive manner, and the same and similar parts between each of the embodiments can be referred to each other. Each of the embodiments mainly describes the difference from other embodiments. Especially, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the related parts can refer to the part of the method embodiments.

[0158] Those skilled in the art should realize that, in one or more examples described above, the functions described in the present application can be realized by hardware, software, a plug-in or any combination thereof. When realized by software, the functions can be stored in a computer readable medium or transmitted as one or more instructions or codes on the computer readable medium.

[0159] The above specific embodiments further explain the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement and the like made on the basis of the technical solutions of the present application should be included in the protection scope of the present application.

Claims

1. A method of gas pipeline assessment, characterised in that, The method comprises the following steps: transmitting a current signal to the gas pipeline through a transmitter, and obtaining a current value at a detection position; calculating a current attenuation coefficient of the gas pipeline according to the current value at the transmission position and the current value at the detection position; calculating a transverse resistance of the gas pipeline according to the current attenuation coefficient, a current frequency, a self-inductance of the gas pipeline, a longitudinal resistance of the gas pipeline, and a capacitance between the gas pipeline and the ground; calculating an insulation characteristic parameter of the gas pipeline according to the transverse resistance of the gas pipeline and a diameter of the gas pipeline; determining whether the gas pipeline leaks according to a size relationship between the insulation characteristic parameter and a preset threshold value; when the gas pipeline does not leak, determining a corrosion grade of the gas pipeline by the following steps: determining a plurality of factors affecting the corrosion degree of the gas pipeline; wherein the plurality of factors form a factor set, each factor includes at least one influence factor, and one of the plurality of factors is the insulation characteristic parameter; determining a plurality of corrosion grades of the corrosion degree of the gas pipeline; wherein the plurality of corrosion grades form a corrosion grade set; Obtain the single-factor evaluation matrix corresponding to each factor in the factor set; wherein the single-factor evaluation matrix has 'a' rows and 'b' columns, where 'a' is equal to the number of influencing factors in that factor, and 'b' is equal to the number of corrosion levels in the corrosion level set. The element 'r' in the i-th row and j-th column of the single-factor evaluation matrix... ij For r ij % of experts believe that the i-th influencing factor has the j-th corrosion level on the gas pipeline; obtaining a first weight vector corresponding to each factor in the factor set, wherein each weight value in the first weight vector corresponds to each influence factor in the factor; multiplying the first weight vector corresponding to each factor in the factor set and the single-factor evaluation matrix of the factor to obtain a membership degree vector corresponding to the factor; wherein the number of membership degrees in the membership degree vector is equal to the number of corrosion grades in the corrosion grade set, and each membership degree in the membership degree vector corresponding to each factor represents the probability that the factor belongs to the corrosion grade corresponding to the membership degree; splicing the membership degree vectors corresponding to each factor into a judgment matrix; wherein the number of rows of the judgment matrix is equal to the number of factors in the factor set, and the number of columns of the judgment matrix is equal to the number of corrosion grades in the corrosion grade set; calculating the product of a second weight vector corresponding to the factor set and the judgment matrix to obtain a factor evaluation vector, wherein each element value in the factor evaluation vector corresponds to each factor in the factor set, and each element value in the factor evaluation vector is the evaluation value of the corresponding factor in the factor set, and each weight value in the second weight vector corresponds to each factor in the factor set; selecting the maximum element value from the factor evaluation vector, and taking the corrosion grade corresponding to the factor corresponding to the maximum element value as the corrosion grade of the gas pipeline.

2. The method of claim 1, wherein, The first calculation formula is used to calculate the current attenuation coefficient, and the first calculation formula is: In the formula, I is the current value of the detection position, I0 is the current value of the emission position, x is the distance between the detection position and the emission position, is the current attenuation coefficient, and N is the protection potential value of the gas pipeline.

3. The method of claim 1, wherein, The second calculation formula is used to calculate the transverse resistance of the gas pipeline, and the second calculation formula is: wherein is the current decay coefficient, f is the current frequency, L is the self-inductance of the gas pipe, R is the longitudinal resistance of the gas pipe, G is the transverse resistance of the gas pipe, and C is the capacitance between the gas pipe and ground.

4. The method of claim 1, wherein, The third calculation formula is used to calculate the insulation characteristic parameter of the gas pipeline, and the third calculation formula is: R g = π · D / G In the formula, R g is an insulation characteristic parameter of the gas pipeline, D is a diameter of the gas pipeline, and G is a transverse resistance of the gas pipeline.

5. The method of claim 1, wherein, The determination of whether the gas pipeline leaks according to the size relationship between the insulation characteristic parameter and the preset threshold value comprises: if the insulation characteristic parameter is greater than the preset threshold value, the gas pipeline leaks; otherwise, the gas pipeline does not leak.

6. The method of claim 1, wherein, Before multiplying the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the factor, the method further comprises: Dividing each element in each column in the single-factor evaluation matrix of each factor by the square sum of all element values in the column to obtain the normalized value of the element in the column, and the normalized values of the elements in the single-factor evaluation matrix form a normalized single-factor evaluation matrix; Correspondingly, the multiplication of the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the factor comprises multiplication of the first weight vector corresponding to each factor in the factor set with the normalized single-factor evaluation matrix of the element.

7. The method of claim 1, wherein, After the multiplication of the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the factor, and before the splicing of the membership vectors corresponding to the factors into a judgment matrix, the method further comprises: For each factor, selecting the maximum membership in the membership vector corresponding to the factor; According to the maximum membership and the order of the first weight vector corresponding to the element, determining whether the subjectivity of the first weight vector corresponding to the element exceeds a subjective limit value; If yes, modifying the weight values in the first weight vector, and returning to the step of multiplying the first weight vector corresponding to each factor in the factor set with the single-factor evaluation matrix of the factor; Otherwise, executing the step of splicing the membership vectors corresponding to the factors into a judgment matrix.

8. The method of claim 1, wherein, Further comprising: According to the corrosion grade of the gas pipeline, determining the corresponding gas pipeline replacement time; wherein the higher the corrosion grade, the shorter the gas pipeline replacement time.

9. A gas pipeline evaluation apparatus, characterized by, Comprise: The first acquisition module is used for transmitting a current signal to the gas pipeline through the transmitter, and acquiring the current value at the detection position; The first calculation module is used for calculating the current attenuation coefficient of the gas pipeline according to the current value at the transmission position and the current value at the detection position; The second calculation module is used for calculating the transverse resistance of the gas pipeline according to the current attenuation coefficient, the current frequency, the self-inductance of the gas pipeline, the longitudinal resistance of the gas pipeline, and the capacitance between the gas pipeline and the ground; The third calculation module is used for calculating the insulation characteristic parameter of the gas pipeline according to the transverse resistance of the gas pipeline and the diameter of the gas pipeline; The first determination module is used for determining whether the gas pipeline leaks according to the size relationship between the insulation characteristic parameter and the preset threshold value; The device further comprises: The grade determination module is used for determining the corrosion grade of the gas pipeline when the gas pipeline is not leaking; the grade determination module comprises: The first determination unit is used for determining a plurality of factors affecting the corrosion degree of the gas pipeline; wherein the plurality of factors form a factor set, each factor includes at least one influencing factor, and one factor in the plurality of factors is the insulation characteristic parameter; The second determination unit is used for determining a plurality of corrosion grades of the corrosion degree of the gas pipeline; wherein the plurality of corrosion grades form a corrosion grade set. The first obtaining unit is configured to obtain a single-factor evaluation matrix corresponding to each factor in the factor set; wherein the single-factor evaluation matrix has a row number a and a column number b, a is equal to the number of influence factors in the factor, b is equal to the number of corrosion levels in the corrosion level set, and an element r ij of the single-factor evaluation matrix in the ith row and the jth column is equal to the percentage of experts who think that the ith influence factor of the factor has an influence level on the gas pipeline equal to the jth corrosion level. ij of the single-factor evaluation matrix in the ith row and the jth column is equal to the percentage of experts who think that the ith influence factor of the factor has an influence level on the gas pipeline equal to the jth corrosion level. The second obtaining unit is configured to obtain a first weight vector corresponding to each factor in the factor set, wherein each weight value in the first weight vector corresponds to each influence factor in the factor. The first calculation unit is configured to multiply the first weight vector corresponding to each factor in the factor set with a single-factor evaluation matrix of the factor to obtain a membership degree vector corresponding to the factor, wherein the number of membership degrees in the membership degree vector is equal to the number of corrosion levels in the corrosion level set, and each membership degree in the membership degree vector corresponding to each factor represents a probability that the factor belongs to a corrosion level corresponding to the membership degree. The first splicing unit is configured to splice the membership degree vectors corresponding to the factors into an evaluation matrix, wherein the number of rows of the evaluation matrix is equal to the number of factors in the factor set, and the number of columns of the evaluation matrix is equal to the number of corrosion levels in the corrosion level set. The second calculation unit is configured to calculate a product of a second weight vector corresponding to the factor set and the evaluation matrix to obtain a factor evaluation vector, wherein each element value in the factor evaluation vector corresponds to each factor in the factor set, and each element value in the factor evaluation vector is an evaluation value of a corresponding factor in the factor set, and each weight value in the second weight vector corresponds to each factor in the factor set. The level determination unit is configured to select a maximum element value from the factor evaluation vector, and determine a corrosion level corresponding to a factor corresponding to the maximum element value as the corrosion level of the gas pipeline.

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