Pressure Early Warning Method and System for Power Plant Boiler Pressure Pipelines

Abstract

This invention provides a method and system for early warning of pressure in power plant boiler pressure pipelines, belonging to the field of pressure measurement technology for pressure pipelines. The method includes: applying an alternating current to a first eddy current detection coil group wound around the power plant boiler pressure pipeline to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group; matching the obtained normalized impedance response signal amplitude with a pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline; and controlling the corresponding generator to reduce load when the pressure value of the power plant boiler pressure pipeline reaches a preset pressure value. This invention is based on non-contact detection of stress in power plant boiler pressure pipelines, avoiding interference in stress detection, thereby enabling accurate early warning of pressure in power plant boiler pressure pipelines.

Description

Technical Field

[0001] This invention relates to the field of pressure measurement technology for pressure pipelines, and specifically to a pressure early warning method and system for pressure pipelines in power plant boilers. Background Technology

[0002] Pressure pipelines are tubular devices used to transport gases or liquids under pressure, enduring high temperatures, high pressures, and corrosive conditions. Power plant boiler pressure pipelines are generally made of metal, with high-temperature, high-pressure steam as the internal working medium. During use, erosion and creep can cause defects such as localized thinning and material degradation (manifested as reduced wall thickness or hardness at straight sections and bends). Both of these changes reduce the pressure pipeline's ability to withstand the stress of the internal working medium. If the stress exceeds a critical value, the pressure pipeline will be unable to withstand the working stress, leading to pipe expansion, deformation, and even bursting failure, resulting in a serious equipment accident. Therefore, stress monitoring of pressure pipelines is essential.

[0003] Currently, the main method is to receive signals such as stress and noise from pressure pipelines by installing online safety monitoring devices (containing strain gauges, acoustic emission, and other contact-based sensors) on the pipelines.

[0004] However, since the pressure pipelines of power plant boilers operate in high-temperature, high-pressure, and high-noise environments, they interfere with the signals of contact sensors, making it impossible to accurately monitor the stress in the pressure pipelines and thus impossible to accurately provide pressure warnings. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for early warning of pressure in power plant boiler pressure pipelines, so as to solve the problem of inaccurate pressure early warning for pressure pipelines.

[0006] To achieve the above objectives, embodiments of the present invention provide a method and system for early warning of pressure in power plant boiler pressure pipelines, comprising:

[0007] An alternating current is applied to the first eddy current detection coil group wound on the pressure pipe of the power plant boiler to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group.

[0008] The obtained normalized impedance response signal amplitude is matched with the pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline; the pre-constructed normalized impedance response signal amplitude-pressure value target curve is used to characterize the mapping relationship between different normalized impedance response signal amplitudes and their corresponding pressure values.

[0009] When the pressure value of the power plant boiler pressure pipeline reaches the preset pressure value, the corresponding generator is controlled to operate at reduced load.

[0010] Optionally, the pre-constructed normalized impedance response signal amplitude-pressure value target curve is determined based on a non-contact pressure pipeline stress detection system; the non-contact pressure pipeline stress detection system includes:

[0011] The second eddy current detection coil group is wound around the normal pressure pipeline and the burst test pressure pipeline;

[0012] An eddy current detector, connected to the second eddy current detection coil group, is used to apply alternating current to the second eddy current detection coil group and to detect the amplitude of the normalized impedance response signal of the second eddy current detection coil group;

[0013] A pressure pump, connected to the burst test pressure pipeline, is used to apply pressure to the burst test pressure pipeline.

[0014] Optionally, the normal pressure pipeline and the burst test pressure pipeline have the same thickness, outer diameter, and material.

[0015] Optionally, the number of turns and the turn spacing of the second eddy current detection coil group wound on the surface of the normal pressure pipeline are the same as the number of turns and the turn spacing of the coil group wound on the surface of the burst test pressure pipeline.

[0016] Optionally, the pre-constructed target curve of normalized impedance response signal amplitude versus pressure value is obtained in the following way:

[0017] The eddy current detector applies an alternating current to the second eddy current detection coil group to initialize the normalized impedance response signal amplitude of the second eddy current detection coil group.

[0018] Pressure is applied to the burst test pressure pipeline by the pressure pump until the maximum pressure value corresponding to the burst test pressure pipeline is reached. The normalized impedance response signal amplitude of the second eddy current detection coil group under different pressures is obtained by the eddy current detector, and a normalized impedance response signal amplitude-pressure value reference curve including different normalized impedance response signal amplitudes and their corresponding pressure values ​​is generated.

[0019] Multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, are obtained from the generated normalized impedance response signal amplitude-pressure value reference curve.

[0020] Based on curve fitting of the acquired target detection points, the pre-constructed normalized impedance response signal amplitude-pressure value target curve is obtained.

[0021] Optionally, initializing the normalized impedance response signal amplitude of the second eddy current detection coil group includes:

[0022] Adjust the eddy current detector so that the normalized response signal amplitude of the second eddy current detection coil group is a preset initial value.

[0023] Optionally, obtaining multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, from the generated normalized impedance response signal amplitude-pressure value reference curve includes:

[0024] The pressure values ​​and their corresponding normalized impedance response signal amplitudes at which the ratio of the pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve to the maximum pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve reaches different preset ratios are identified as target detection points.

[0025] Optionally, the step of obtaining the pre-constructed normalized impedance response signal amplitude-pressure value target curve based on curve fitting of the acquired target detection points includes:

[0026] Establish an initial quadratic curve function that characterizes the mapping relationship between the amplitude of the normalized impedance response signal and its corresponding predicted pressure value;

[0027] The predicted pressure value corresponding to the amplitude of the normalized impedance response signal at each target detection point is calculated by establishing an initial quadratic function curve.

[0028] The sum of squared errors between the calculated predicted pressure value and the corresponding pressure value in the normalized impedance response signal amplitude at the target detection point as shown in the normalized impedance response signal amplitude-pressure value reference curve;

[0029] Using the least squares method, a target fitting function is obtained based on the obtained squares of each error and the initial quadratic function of the curve to characterize the amplitude of different normalized impedance response signals and their corresponding pressure values.

[0030] Based on the obtained target fitting function, the pre-constructed normalized impedance response signal amplitude-pressure value target curve is constructed.

[0031] Optionally, the power plant boiler pressure pipeline pressure early warning method further includes:

[0032] Obtain the relative permeability, effective permeability, and outer diameter of the first eddy current detection coil group;

[0033] Using formula (1), the amplitude, relative permeability and effective permeability of the obtained normalized impedance response signal are calculated to obtain the fill factor;

[0034]

[0035] Where η represents the fill factor, and p represents the amplitude of the obtained normalized impedance response signal; u r u represents the relative permeability of the first eddy current detection coil group; eff This represents the effective permeability of the first eddy current detection coil group;

[0036] Using formula (2), the outer diameter of the first eddy current detection coil group and the filling coefficient are calculated to obtain the outer diameter of the power plant boiler pressure pipeline;

[0037]

[0038] Where d represents the outer diameter of the power plant boiler pressure pipe, and D represents the outer diameter of the first eddy current detection coil group.

[0039] A second aspect of the present invention also provides a pressure early warning system for power plant boiler pressure pipelines, comprising:

[0040] The data acquisition module is used to apply alternating current to the first eddy current detection coil group wound on the pressure pipeline of the power plant boiler in order to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group.

[0041] The pressure calculation module is used to match the obtained normalized impedance response signal amplitude with a pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline; the pre-constructed normalized impedance response signal amplitude-pressure value target curve is used to characterize the mapping relationship between different normalized impedance response signal amplitudes and their corresponding pressure values.

[0042] The early warning control module is used to control the corresponding generator to reduce its load when the pressure value of the boiler pressure pipeline of the power plant reaches the preset pressure value.

[0043] In this embodiment, an alternating current is applied to a first eddy current detection coil group wound around a power plant boiler pressure pipeline to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group. The obtained normalized impedance response signal amplitude is matched with a pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline. When the pressure value of the power plant boiler pressure pipeline reaches a preset pressure value, the corresponding generator is controlled to operate with reduced load. This invention is based on non-contact detection of stress in the power plant boiler pressure pipeline, realizing the elimination of direct contact with the power plant boiler pressure pipeline body and avoiding interference in stress detection, thereby enabling accurate pressure early warning for the power plant boiler pressure pipeline.

[0044] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a schematic flowchart of the power plant boiler pressure pipeline pressure early warning method provided in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the non-contact pressure pipeline stress detection system provided in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the structure of the Tabi-type eddy current coil group provided in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of a pre-constructed normalized impedance response signal amplitude-pressure value reference curve provided in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the structure of the power plant boiler pressure pipeline pressure early warning system provided in an embodiment of the present invention.

[0051] Explanation of reference numerals in the attached figures

[0052] 1. Normal pressure pipeline; 2. Burst test pressure pipeline;

[0053] 3. Second eddy current detection coil group; 4. Signal line;

[0054] 5. Eddy current detector; 6. Connecting pipe; 7. Pressure pump. Detailed Implementation

[0055] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0057] In the description of the embodiments of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0058] Before introducing this invention, the inventive concept of this invention will be explained:

[0059] Based on the principle of electromagnetic induction, when a Tabi eddy current coil array carrying alternating current approaches a pressure pipeline, eddy currents are induced in the coil array due to the magnetic field of the coil. The magnitude, phase, and flow pattern of the eddy currents are influenced by factors such as the performance and presence of defects in the pressure pipeline. The reaction magnetic field of the eddy currents then changes the impedance of the Tabi eddy current coil array, thus constructing a normalized impedance response signal amplitude versus pressure value target curve. Therefore, in actual testing, matching the normalized impedance response signal amplitude of the eddy current detection coil array wound around the pressure pipeline with the pre-constructed normalized impedance response signal amplitude versus pressure value target curve allows for the determination of the performance and presence of defects in the tested component. Since the constructed normalized impedance response signal amplitude versus pressure value target curve is built with the eddy current detection coil array wound on the surface of the pressure pipeline without contact with the pipeline, non-contact pressure detection of the pressure pipeline is achieved, avoiding interference from stress detection and enabling accurate pressure warnings for power plant boiler pressure pipelines.

[0060] Reference Figure 1 , Figure 1 This is a flowchart illustrating the pressure early warning method for power plant boiler pressure pipelines provided in an embodiment of the present invention. The method includes the following steps:

[0061] S100, apply alternating current to the first eddy current detection coil group wound on the pressure pipe of the power plant boiler to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group;

[0062] Understandably, an alternating current is applied to the first eddy current detection coil group wound around the pressure pipeline of the power plant boiler using an eddy current detector, and the normalized impedance response signal amplitude of the first eddy current detection coil group is obtained using the eddy current detector. This embodiment of the invention does not specifically limit the type or model of the eddy current detector.

[0063] The types of the first eddy current detection coil group include, but are not limited to: self-inductive, self-comparing, and other-comparing. A self-inductive eddy current detection coil group consists of one set of coils wound around a power plant boiler pressure pipe. A self-comparing eddy current detection coil group consists of two sets of closely spaced coils wound around a power plant boiler pressure pipe. An other-comparing eddy current detection coil group consists of one set of coils wound around two pressure pipes. This invention does not specifically limit the type of eddy current detection coil group.

[0064] Understandably, since the magnitude and amplitude of alternating current change periodically, and the flow of alternating current is accompanied by a changing magnetic field, the changing magnetic field will generate eddy currents in ferromagnetic materials. Therefore, only by applying alternating current to the first eddy current detection coil group wound on the pressure pipe of the power plant boiler can the normalized impedance response signal amplitude of the first eddy current detection coil group be obtained; applying direct current to the first eddy current detection coil group wound on the pressure pipe of the power plant boiler will not yield the normalized impedance response signal amplitude of the first eddy current detection coil group.

[0065] The normalized impedance response signal amplitude refers to the change in impedance signal amplitude caused by the eddy current detection coil due to the effects of parameters such as lift-off effect, fill factor, and conductivity when a pressure pipeline expands or deforms.

[0066] S200, the obtained normalized impedance response signal amplitude is matched with the pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline; the pre-constructed normalized impedance response signal amplitude-pressure value target curve is used to characterize the mapping relationship between different normalized impedance response signal amplitudes and their corresponding pressure values.

[0067] The pre-constructed target curve of normalized impedance response signal amplitude-pressure value is used to characterize the mapping relationship between different normalized impedance response signal amplitudes and their corresponding pressure values. It is constructed based on the pressure in the pressure pipeline obtained using eddy current detection technology and its corresponding amplitude. The specific construction process of the target curve of normalized impedance response signal amplitude-pressure value will be explained in detail later and will not be repeated here.

[0068] S300: When the pressure value of the power plant boiler pressure pipeline reaches the preset pressure value, the corresponding generator is controlled to reduce the load.

[0069] In one embodiment, when the pressure value of the power plant boiler pressure pipeline reaches a preset pressure value, an alarm signal is generated and uploaded to the corresponding generator control system to control the corresponding generator to operate at reduced load.

[0070] In one embodiment, an alarm signal can be uploaded to the corresponding generator control system via an eddy current detector.

[0071] It should be noted that when the generator needs to increase its load, the boiler will release a large amount of steam. When a large amount of steam passes through the power plant boiler pressure pipeline, the stress on the power plant boiler pressure pipeline will increase. Therefore, when the pressure value of the power plant boiler pressure pipeline reaches the preset pressure value, in order to ensure that the power plant boiler pressure pipeline is not damaged, it is necessary to control the generator to reduce its load.

[0072] In this embodiment, an alternating current is applied to a first eddy current detection coil group wound around a power plant boiler pressure pipeline to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group. The obtained normalized impedance response signal amplitude is matched with a pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline. When the pressure value of the power plant boiler pressure pipeline reaches a preset pressure value, the corresponding generator is controlled to operate with reduced load. This invention is based on non-contact detection of stress in the power plant boiler pressure pipeline, realizing the elimination of direct contact with the power plant boiler pressure pipeline body and avoiding interference in stress detection, thereby enabling accurate pressure early warning for the power plant boiler pressure pipeline.

[0073] Optionally, refer to Figure 2 The pre-constructed normalized impedance response signal amplitude-pressure value target curve is determined based on a non-contact pressure pipeline stress detection system. The non-contact pressure pipeline stress detection system includes: a second eddy current detection coil group 3, wound around the normal pressure pipeline 1 and the burst test pressure pipeline 2; an eddy current detector 5, connected to the second eddy current detection coil group 3, used to apply alternating current to the second eddy current detection coil group 3 and to detect the normalized impedance response signal amplitude of the second eddy current detection coil group 3; and a pressure pump 7, connected to the burst test pressure pipeline 2, used to apply pressure to the burst test pressure pipeline 2.

[0074] It should be noted that this implementation utilizes eddy current testing technology to achieve non-contact, non-destructive testing of pressure pipelines.

[0075] It should be noted that the type of the second eddy current detection coil group 3 in this embodiment is described using the Tabi type eddy current coil group as an example. The following descriptions will all use the Tabi type eddy current coil group and will not be repeated. Other types of eddy current detection coil groups are also applicable to this invention.

[0076] Eddy current testing is a non-contact, non-destructive testing method that utilizes the electromagnetic effect of eddy currents induced in conductive materials by an alternating magnetic field to evaluate the workpiece under inspection. Eddy current testing is based on the principle of electromagnetic induction. When the outer diameter of the pressure pipe inside the eddy current testing coil changes, it affects parameters such as the lift-off effect, fill factor, and conductivity of the eddy current testing coil assembly, causing a change in the normalized impedance signal of the eddy current testing coil. Conversely, if the pressure pipe expands or deforms, it affects the gap size between the pressure pipe and the eddy current testing coil, thus altering the lift-off effect. Therefore, by collecting data on the changes in the impedance signal generated by the lift-off effect, we can determine the changes in the outer diameter of the pressure pipe.

[0077] Lift-off refers to the gap between the eddy current detection coil and the pressure pipeline.

[0078] The fill factor describes the degree of coupling between the eddy current detection coil assembly and the pressure pipe. The relationship between the fill factor and the outer diameter of the eddy current detection coil assembly and the outer diameter of the pressure pipe is expressed as follows:

[0079] η=d 2 / D 2 Where D represents the outer diameter of the eddy current detection coil group, and d represents the outer diameter of the pressure pipe.

[0080] Z / Z0=1-η+η×μ r ×μ eff Where Z / Z0 represents the normalized impedance response signal amplitude; η represents the fill factor; μ r μ represents relative permeability. eff This represents the effective permeability.

[0081] Normal pressure pipeline 1 is used to simulate a pressure pipeline that does not undergo significant expansion or deformation under normal working conditions.

[0082] The burst test pressure pipeline 2 is used to simulate a pressure pipeline that undergoes significant expansion, deformation, and ultimately burst failure.

[0083] The embodiments of the present invention do not specifically limit the type and model of the pressure pump 7.

[0084] Eddy current detector 5 is an instrument that uses the property of conductive materials generating eddy currents in an alternating magnetic field to detect changes in the superimposed magnetic field of conductive materials in order to characterize material defects.

[0085] In one embodiment, the second eddy current detection coil group 3 can be connected to the eddy current detector 5 via the signal line 4.

[0086] In one embodiment, the burst test pressure pipeline 2 can be connected to the pressure pump 7 via the connecting pipe 6.

[0087] In this embodiment, since the eddy current response characteristics of the normal pressure pipeline 1 and the pressure pipeline with reduced wall thickness, reduced hardness, expansion and deformation are different, the pressure pump 7 is used to apply pressure to the burst test pressure pipeline 2 to simulate the pressure on the pressure pipeline, and the normalized impedance response signal amplitude of the second eddy current detection coil group 3 is detected by the eddy current detector 5, so as to obtain the relationship between the pressure value of the pressure pipeline and the corresponding normalized impedance response signal amplitude, that is, to construct the target curve of normalized impedance response signal amplitude-pressure value.

[0088] Optionally, refer to Figure 3 The thickness, outer diameter, and material of the normal pressure pipeline 1 and the burst test pressure pipeline 2 are the same.

[0089] In this embodiment, the thickness, outer diameter, and material of the normal pressure pipeline 1 and the burst test pressure pipeline 2 are configured to be the same, which ensures the reliability of the test results and enables the accurate construction of the normalized impedance response signal amplitude-pressure value target curve.

[0090] Optionally, referring to 3, the number of turns and the turn spacing of the second eddy current detection coil group 3 wound on the surface of the normal pressure pipeline 1 are the same as the number of turns and the turn spacing of the second eddy current detection coil group 3 wound on the surface of the burst test pressure pipeline 2.

[0091] In this embodiment, a second eddy current detection coil group 3 with the same number of turns and turn pitch is wound on the surfaces of the burst test pressure pipeline 2 and the normal pressure pipeline 1, which ensures the reliability of the test results and enables the accurate construction of the normalized impedance response signal amplitude-pressure value target curve.

[0092] Optionally, the pre-constructed target curve of normalized impedance response signal amplitude versus pressure value is obtained in the following way:

[0093] S210, apply alternating current to the second eddy current detection coil group 3 through the eddy current detector 5 to initialize the normalized impedance response signal amplitude of the second eddy current detection coil group 3;

[0094] Understandably, to compensate for system errors and ensure the accuracy of the test experiment, it is necessary to initialize the normalized impedance response signal amplitude of the second eddy current detection coil group 3. This can be achieved by adjusting the eddy current detector 5 so that the normalized response signal amplitude of the second eddy current detection coil group 3 is at a preset initial value, thus avoiding system errors.

[0095] In one implementation, initializing the normalized impedance response signal amplitude of the second eddy current detection coil group 3 can be done by adjusting the normalized impedance response signal amplitude of the second eddy current detection coil group 3 to zero, or by adjusting the normalized impedance response signal amplitude of the second eddy current detection coil group 3 to a preset value. This embodiment does not specifically limit this.

[0096] S220, pressure is applied to the burst test pressure pipeline 2 by the pressure pump 7 until the maximum pressure value corresponding to the burst test pressure pipeline 2 is reached. The normalized impedance response signal amplitude of the second eddy current detection coil group 3 under different pressures is obtained by the eddy current detector 5, and a reference curve of normalized impedance response signal amplitude-pressure value including different normalized impedance response signal amplitudes and their corresponding pressure values ​​is generated.

[0097] Specifically, the outer diameter of the burst test pressure pipe 2 continuously increases under the action of increasing internal pressure, and the sample tube will undergo expansion, deformation, and eventually burst leakage. Therefore, pressure is applied to the burst test pressure pipe 2 through the connecting pipe 6 using the pressure pump 7, and the pressure is increased until the burst test pressure pipe 2 ruptures (that is, the maximum pressure value corresponding to the burst test pressure pipe 2 is reached). Since the change in outer diameter will bring about a change in the eddy current response signal, the normalized impedance response signal amplitude of the burst test pressure pipe 2 is continuously collected by the eddy current detector 5 during this process, thereby constructing a signal such as... Figure 4 The normalized impedance response signal amplitude versus pressure value reference curve is shown.

[0098] S230: Obtain multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, from the generated normalized impedance response signal amplitude-pressure value reference curve;

[0099] S240, based on curve fitting of the acquired target detection points, obtains the pre-constructed normalized impedance response signal amplitude-pressure value target curve.

[0100] It should be noted that the normalized impedance response signal amplitude-pressure value reference curve can only express the relationship between the pressure value of the pressure pipeline and its corresponding normalized response signal amplitude in a limited or approximate way. In order to express the relationship between the pressure value of the pressure pipeline and its corresponding normalized response signal amplitude under any circumstances, it is necessary to perform curve fitting on the detection points on the normalized impedance response signal amplitude-pressure value reference curve to obtain the target curve of normalized impedance response signal amplitude-pressure value.

[0101] It should be noted that curve fitting methods include, but are not limited to, least squares method, spline interpolation, and polynomial fitting.

[0102] In this embodiment, as the outer diameter of the burst test pressure pipe 2 continuously increases under the action of increasing internal pressure, the sample tube will undergo expansion, deformation, and eventually burst leakage. The change in outer diameter will cause a change in the eddy current response signal. Therefore, the pressure pump 7 applies pressure to the burst test pressure pipe 2 through the connecting pipe 6 until the maximum pressure value corresponding to the burst test pressure pipe 2 is reached. The eddy current detector 5 acquires the normalized impedance response signal amplitude of the second eddy current detection coil group 3 under different pressures, thereby constructing a... Figure 4 The normalized impedance response signal amplitude-pressure value reference curve is shown. Finally, multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, are obtained from the generated normalized impedance response signal amplitude-pressure value reference curve. Based on the obtained target detection points, curve fitting is performed to obtain the pre-constructed normalized impedance response signal amplitude-pressure value target curve. This allows the normalized impedance response signal amplitude of the eddy current detection coil wound on the pressure pipeline of the power plant boiler at any time to be matched directly according to the normalized impedance response signal amplitude-pressure value target curve in subsequent practical applications, thereby obtaining the pressure value of the power plant boiler pressure pipeline.

[0103] Optionally, step S230 may further include:

[0104] The pressure values ​​and their corresponding normalized impedance response signal amplitudes at which the ratio of the pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve to the maximum pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve reaches different preset ratios are identified as target detection points.

[0105] For ease of understanding, please refer to the following: Figure 4 For example:

[0106] like Figure 4 As shown, Figure 4 The curve includes four points: the ratio of pressure value to maximum pressure of 25%, 50%, 75%, and 100%, and the corresponding normalized impedance response signal amplitudes of X1, X2, X3, and X4. These four points are used as target detection points.

[0107] Optionally, step S240 may further include:

[0108] S241, establish an initial quadratic curve function that characterizes the mapping relationship between the amplitude of the normalized impedance response signal and its corresponding predicted pressure value;

[0109] S242, calculate the predicted pressure value corresponding to the normalized impedance response signal amplitude at each target detection point by using the established initial curve quadratic function;

[0110] S243, the sum of squared errors between the calculated predicted pressure value and the corresponding pressure value in the normalized impedance response signal amplitude-pressure value reference curve at the corresponding target detection point;

[0111] S244, using the least squares method, based on the obtained error squares and the initial quadratic function of the curve, the target fitting function characterizing the amplitude of different normalized impedance response signals and their corresponding pressure values ​​is obtained.

[0112] S245. Based on the obtained target fitting function, construct the pre-constructed normalized impedance response signal amplitude-pressure value target curve.

[0113] The following explains the function fitting process:

[0114] First, we define an initial quadratic function P = a(X) that characterizes the mapping relationship between the amplitude of the normalized impedance response signal and its corresponding predicted pressure value. 2 +b(X)+c; where, P: pressure value of the burst test pressure pipeline, MPa; X: normalized impedance amplitude, dB; a, b are the second and first power coefficients of the equation X to be fitted, respectively, and c is a constant.

[0115] When X are X1, X2, X3, and X4 respectively, P = a(X) 2 +b(X)+c can be used to obtain the corresponding predicted values ​​P1, P2, P3, and P4, resulting in 4 target detection points.

[0116] Since P = a(X) 2 +b(X)+c is an approximate relationship, so there will be a certain error (S) between the predicted value and the actual value. i S can be expressed by the following formula: i =P i -P i′ , i = 1, 2, 3, 4, where P i Take X for X i The actual value at time; P i′ Take X for X i The predicted value at that time.

[0117] Let the sum of squared errors be S(a, b, c), and the formula for the sum of squared errors is:

[0118]

[0119] Using the least squares method and the four sets of data collected above, we can calculate the partial derivatives of S with respect to a, b, and c, and set them to zero. This allows us to obtain the values ​​of a, b, and c, which can then be substituted into P = a(X). 2 In +b(X)+c, the target fitting function is obtained.

[0120] In this embodiment, since the normalized impedance response signal amplitude-pressure value reference curve can only express the relationship between the pressure value of the pressure pipeline and the corresponding normalized response signal amplitude in a limited or approximate way, curve fitting is performed on the detection points on the normalized impedance response signal amplitude-pressure value reference curve to obtain the normalized impedance response signal amplitude-pressure value target curve, thereby enabling the expression of the relationship between the pressure value of the pressure pipeline and the corresponding normalized response signal amplitude under any circumstances.

[0121] Optionally, the pressure early warning method for power plant boiler pressure pipelines also includes:

[0122] S400, obtain the relative permeability, effective permeability and outer diameter of the first eddy current detection coil group;

[0123] S500, using formula (1), calculate the amplitude, relative permeability and effective permeability of the obtained normalized impedance response signal to obtain the fill factor;

[0124]

[0125] Where η represents the fill factor, and p represents the amplitude of the obtained normalized impedance response signal; u r u represents the relative permeability of the first eddy current detection coil group; eff This represents the effective permeability of the first eddy current detection coil group;

[0126] S600, using formula (2), the outer diameter and filling coefficient of the first eddy current detection coil group are calculated to obtain the outer diameter of the power plant boiler pressure pipeline;

[0127]

[0128] Where d represents the outer diameter of the power plant boiler pressure pipe, and D represents the outer diameter of the first eddy current detection coil group.

[0129] Based on the aforementioned relationship between the filling coefficient and the outer diameter of the eddy current detection coil group and the outer diameter of the pressure pipe, therefore p = 1 - η + η × μ r ×μ eff By performing the inverse operation, we can obtain... Let η = d 2 / D 2 By performing the inverse operation, we can obtain...

[0130] Specifically, the normalized impedance response signal amplitude of the first eddy current detection coil group is substituted into formula (1) to calculate the filling coefficient. Then, the filling coefficient is substituted into (2) to calculate the outer diameter of the power plant boiler pressure pipeline.

[0131] In this embodiment, by using formulas (1) and (2), the outer diameter of the power plant boiler pressure pipeline can be calculated, thereby quantifying the specific situation of the expansion and deformation of the power plant boiler pressure pipeline.

[0132] Reference Figure 5 , Figure 5 This is a schematic diagram of the structure of the power plant boiler pressure pipeline pressure early warning system provided in an embodiment of the present invention.

[0133] Based on the same inventive concept, this invention also provides a power plant boiler pressure pipeline pressure early warning system 200, comprising:

[0134] Data acquisition module 210 is used to apply alternating current to the first eddy current detection coil group wound on the pressure pipeline of the power plant boiler in order to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group.

[0135] The pressure calculation module 220 is used to match the obtained normalized impedance response signal amplitude with the pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline; the pre-constructed normalized impedance response signal amplitude-pressure value target curve is used to characterize the mapping relationship between different normalized impedance response signal amplitudes and their corresponding pressure values.

[0136] The early warning control module 230 is used to control the corresponding generator to reduce load operation when the pressure value of the power plant boiler pressure pipeline reaches the preset pressure value.

[0137] It should be understood that this device corresponds to the aforementioned power plant boiler pressure pipeline pressure early warning method embodiment and is capable of performing the various steps involved in the above method embodiment. The specific functions of this device can be found in the description above, and detailed descriptions are omitted here to avoid repetition. The device includes at least one software functional module that can be stored in memory or embedded in the device's operating system (OS) in the form of software or firmware.

[0138] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0139] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0140] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0141] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0142] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0143] In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0144] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0145] The above are merely embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for early warning of pressure in power plant boiler pressure pipelines, characterized in that, include: An alternating current is applied to the first eddy current detection coil group wound on the pressure pipe of the power plant boiler to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group. The obtained normalized impedance response signal amplitude is matched with the pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline; the pre-constructed normalized impedance response signal amplitude-pressure value target curve is used to characterize the mapping relationship between different normalized impedance response signal amplitudes and their corresponding pressure values. When the pressure value of the power plant boiler pressure pipeline reaches the preset pressure value, the corresponding generator is controlled to operate at reduced load. The pre-constructed normalized impedance response signal amplitude-pressure value target curve is determined based on a non-contact pressure pipeline stress detection system; the non-contact pressure pipeline stress detection system includes: The second eddy current detection coil group is wound around the normal pressure pipeline and the burst test pressure pipeline; An eddy current detector, connected to the second eddy current detection coil group, is used to apply alternating current to the second eddy current detection coil group and to detect the amplitude of the normalized impedance response signal of the second eddy current detection coil group; A pressure pump, connected to the burst test pressure pipeline, is used to apply pressure to the burst test pressure pipeline; The pre-constructed target curve of normalized impedance response signal amplitude versus pressure value is obtained in the following way: The eddy current detector applies an alternating current to the second eddy current detection coil group to initialize the normalized impedance response signal amplitude of the second eddy current detection coil group. Pressure is applied to the burst test pressure pipeline by the pressure pump until the maximum pressure value corresponding to the burst test pressure pipeline is reached. The normalized impedance response signal amplitude of the second eddy current detection coil group under different pressures is obtained by the eddy current detector, and a normalized impedance response signal amplitude-pressure value reference curve including different normalized impedance response signal amplitudes and their corresponding pressure values ​​is generated. Multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, are obtained from the generated normalized impedance response signal amplitude-pressure value reference curve. Based on curve fitting of the acquired target detection points, the pre-constructed normalized impedance response signal amplitude-pressure value target curve is obtained; The process of obtaining multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, from the generated normalized impedance response signal amplitude-pressure value reference curve includes: The pressure value and its corresponding normalized impedance response signal amplitude are determined as target detection points when the ratio of the pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve to the maximum pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve reaches different preset ratios; among which, the different preset ratios include: 25%, 50%, 75% and 100%.

2. The power plant boiler pressure pipeline pressure early warning method according to claim 1, characterized in that, The thickness, outer diameter, and material of the normal pressure pipeline and the burst test pressure pipeline are the same.

3. The power plant boiler pressure pipeline pressure early warning method according to claim 1, characterized in that, The number of turns and the turn spacing of the second eddy current detection coil group wound on the surface of the normal pressure pipeline are the same as those of the coil group wound on the surface of the burst test pressure pipeline.

4. The power plant boiler pressure pipeline pressure early warning method according to claim 1, characterized in that, The initialization of the normalized impedance response signal amplitude of the second eddy current detection coil group includes: Adjust the eddy current detector so that the normalized response signal amplitude of the second eddy current detection coil group is a preset initial value.

5. The power plant boiler pressure pipeline pressure early warning method according to claim 1, characterized in that, The step of obtaining the pre-constructed normalized impedance response signal amplitude-pressure value target curve based on curve fitting of the acquired target detection points includes: Establish an initial quadratic curve function that characterizes the mapping relationship between the amplitude of the normalized impedance response signal and its corresponding predicted pressure value; The predicted pressure value corresponding to the amplitude of the normalized impedance response signal at each target detection point is calculated by establishing an initial quadratic function curve. The sum of squared errors between the calculated predicted pressure value and the corresponding pressure value in the normalized impedance response signal amplitude at the target detection point as shown in the normalized impedance response signal amplitude-pressure value reference curve; Using the least squares method, a target fitting function characterizing the amplitude of different normalized impedance response signals and their corresponding pressure values ​​is obtained based on the obtained sum of squared errors and the initial quadratic function of the curve. Based on the obtained target fitting function, the pre-constructed normalized impedance response signal amplitude-pressure value target curve is constructed.

6. The power plant boiler pressure pipeline pressure early warning method according to claim 1, characterized in that, The method further includes: Obtain the relative permeability, effective permeability, and outer diameter of the first eddy current detection coil group; Using formula (1), the amplitude, relative permeability and effective permeability of the obtained normalized impedance response signal are calculated to obtain the fill factor; （1）； in, Indicates the fill factor. This represents the amplitude of the normalized impedance response signal obtained. This represents the relative permeability of the first eddy current detection coil group; This represents the effective permeability of the first eddy current detection coil group; Using formula (2), the outer diameter of the first eddy current detection coil group and the filling coefficient are calculated to obtain the outer diameter of the power plant boiler pressure pipeline; （2）； in, This indicates the outer diameter of the pressure pipes in the power plant boiler. This indicates the outer diameter of the first eddy current detection coil group.

7. A pressure early warning system for power plant boiler pressure pipelines, characterized in that, include: The data acquisition module is used to apply alternating current to the first eddy current detection coil group wound on the pressure pipeline of the power plant boiler in order to obtain the normalized impedance response signal amplitude of the first eddy current detection coil group. The pressure calculation module is used to match the obtained normalized impedance response signal amplitude with a pre-constructed normalized impedance response signal amplitude-pressure value target curve to determine the pressure value of the power plant boiler pressure pipeline; the pre-constructed normalized impedance response signal amplitude-pressure value target curve is used to characterize the mapping relationship between different normalized impedance response signal amplitudes and their corresponding pressure values. The early warning control module is used to control the corresponding generator to reduce its load when the pressure value of the power plant boiler pressure pipeline reaches the preset pressure value. The pre-constructed normalized impedance response signal amplitude-pressure value target curve is determined based on a non-contact pressure pipeline stress detection system; the non-contact pressure pipeline stress detection system includes: The second eddy current detection coil group is wound around the normal pressure pipeline and the burst test pressure pipeline; An eddy current detector, connected to the second eddy current detection coil group, is used to apply alternating current to the second eddy current detection coil group and to detect the amplitude of the normalized impedance response signal of the second eddy current detection coil group; A pressure pump, connected to the burst test pressure pipeline, is used to apply pressure to the burst test pressure pipeline; The pre-constructed target curve of normalized impedance response signal amplitude versus pressure value is obtained in the following way: The eddy current detector applies an alternating current to the second eddy current detection coil group to initialize the normalized impedance response signal amplitude of the second eddy current detection coil group. Pressure is applied to the burst test pressure pipeline by the pressure pump until the maximum pressure value corresponding to the burst test pressure pipeline is reached. The normalized impedance response signal amplitude of the second eddy current detection coil group under different pressures is obtained by the eddy current detector, and a normalized impedance response signal amplitude-pressure value reference curve including different normalized impedance response signal amplitudes and their corresponding pressure values ​​is generated. Multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, are obtained from the generated normalized impedance response signal amplitude-pressure value reference curve. Based on curve fitting of the acquired target detection points, the pre-constructed normalized impedance response signal amplitude-pressure value target curve is obtained; The process of obtaining multiple target detection points, including the normalized impedance response signal amplitude and its corresponding pressure value, from the generated normalized impedance response signal amplitude-pressure value reference curve includes: The pressure value and its corresponding normalized impedance response signal amplitude are determined as target detection points when the ratio of the pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve to the maximum pressure value in the generated normalized impedance response signal amplitude-pressure value reference curve reaches different preset ratios; among which, the different preset ratios include: 25%, 50%, 75% and 100%.

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