CN109469834B - Liquid pipeline leakage detection method, device and system - Google Patents
Liquid pipeline leakage detection method, device and system Download PDFInfo
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Abstract
The embodiment of the specification provides a method, a device and a system for detecting leakage of a liquid pipeline. The method comprises the following steps: selecting a time period of stable operation of a pipeline to be tested from a target time period as a stable time period according to acquired detection data in the target time period, wherein a plurality of computing nodes are arranged on the pipeline to be tested; establishing a characteristic line equation according to the pipeline parameter data of the pipeline to be detected and the detection data in the steady-state time period; calculating the node parameter value of each node at each prediction moment according to the characteristic line equation; determining a threshold value according to the node parameter value; and comparing the detection data in the detection time period with the threshold value, and judging whether the pipeline leaks or not according to the comparison result, wherein the detection time period belongs to the target time period. By using the method, the leakage condition of the pipeline can be judged quickly and accurately, and the reliability of detection is improved.
Description
Technical Field
The embodiment of the specification relates to the field of leakage detection, in particular to a liquid pipeline leakage detection method.
Background
Pipelines are tools that play an important role in transportation in national economy. Maintaining the safe operation of the pipeline and preventing the pipeline production accidents are important work of pipeline industrial production and management departments. The pipeline transportation has the advantages of large transportation volume, small occupied area, easy remote monitoring, low energy consumption, low cost and the like, but pipeline leakage can be caused by factors such as pipeline corrosion, misoperation, artificial damage and the like. Leakage not only causes oil loss and environmental pollution, but also can cause combustion and explosion accidents, so that the pipeline leakage detection technology is more and more attractive to people.
At present, the widely used pipeline leakage detection technology at home and abroad is an empirical method based on artificial neuron networks, statistics or pattern recognition and the like. However, in practical applications, the following problems are present in the prior art:
(1) initial values of model training are all generated randomly, which may cause operation non-convergence;
(2) the sample information being learned may not contain all pipeline fault conditions;
(3) the operation complexity is high and the required time is long.
Disclosure of Invention
An embodiment of the present specification aims to provide a method, an apparatus, and a system for detecting leakage of a liquid pipeline, so as to solve the problems of a large amount of data required for leakage detection, complex calculation, and the like in the prior art, and to realize rapid and accurate detection of leakage of a liquid pipeline.
In order to solve the above technical problem, embodiments of the present application provide a method, an apparatus, and a system for detecting leakage of a liquid pipeline, which are implemented as follows:
a method of fluid line leak detection, comprising:
selecting a time period of stable operation of a pipeline to be tested from a target time period as a stable time period according to acquired detection data in the target time period, wherein a plurality of computing nodes are arranged on the pipeline to be tested;
establishing a characteristic line equation according to the pipeline parameter data of the pipeline to be detected and the detection data in the steady-state time period;
calculating the node parameter value of each node at each prediction moment according to the characteristic line equation;
determining a threshold value according to the node parameter value;
and comparing the detection data in the detection time period with the threshold value, and judging whether the pipeline leaks or not according to the comparison result, wherein the detection time period belongs to the target time period.
A liquid conduit leak detection apparatus comprising:
the steady-state time period determining module is used for selecting a time period of stable operation of the pipeline to be tested from a target time period as the steady-state time period according to the acquired detection data in the target time period, wherein a plurality of computing nodes are arranged on the pipeline to be tested;
the characteristic line equation establishing module is used for establishing a characteristic line equation according to the pipeline parameter data of the pipeline to be detected and the detection data in the steady-state time period;
the node parameter calculation module is used for calculating the node parameter value of each node at each prediction moment according to the characteristic line equation;
a threshold value obtaining module, configured to determine a threshold value according to the node parameter value;
and the leakage judging module is used for comparing the detection data in the detection time period with the threshold value and judging whether the pipeline leaks or not according to the comparison result, wherein the detection time period belongs to the target time period. A liquid conduit leak detection system, comprising:
the upper computer is used for calculating a threshold value according to the acquired detection data in the pipeline and the pipeline parameter data, and comparing the threshold value with the detection data to judge whether leakage occurs or not;
the sensor is used for collecting detection data in the pipeline;
and the lower computer is used for receiving the detection data and directly controlling the sensor.
As can be seen from the above technical solutions provided in the embodiments of the present specification, by determining a stable state of a pipeline, using detection data in a stable operation time period, gradually calculating node parameter values corresponding to each node in the pipeline at each prediction time, mapping the node parameter values to a head end and a tail end to obtain the node parameter values and determining the node parameter values as threshold values, and then comparing the threshold values with the detection data, it can be achieved that whether leakage occurs in the detection pipeline can be accurately and quickly determined.
Drawings
In order to more clearly illustrate the embodiments of the present specification or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the specification, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a flow chart of one embodiment of a method of fluid line leak detection according to the present disclosure;
FIG. 2 is a block diagram of one embodiment of a fluid line leak detection apparatus according to the present disclosure;
FIG. 3 is a diagram illustrating a method for partitioning data according to an embodiment of the present disclosure;
FIG. 4 is a schematic diagram illustrating a determination of a steady state time period in accordance with an embodiment of the present disclosure;
FIG. 5 is a schematic diagram illustrating a determination of a steady state time period in accordance with an embodiment of the present disclosure;
FIG. 6 is a diagram illustrating an embodiment of the present disclosure for calculating internal node parameters at a next time;
fig. 7 is a schematic diagram illustrating calculation of parameters of a head-end node at a next time according to an embodiment of the present disclosure;
FIG. 8 is a diagram illustrating an embodiment of the present disclosure for calculating an end node parameter at a next time;
FIG. 9 is a schematic diagram illustrating an embodiment of the present disclosure for calculating a leakage point parameter at a next time;
FIG. 10 is a schematic diagram of a method for determining whether a pipe leaks according to a threshold value according to an embodiment of the present disclosure;
FIG. 11 is a schematic diagram illustrating a method for determining whether a pipe leaks according to a threshold value according to an embodiment of the present disclosure;
FIG. 12 is a block diagram of one embodiment of a fluid line leak detection system according to the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present specification without any creative effort shall fall within the protection scope of the present specification.
An embodiment of a method for detecting a leakage of a liquid pipeline according to the present application is described below with reference to fig. 1. The execution main body of the method is the liquid pipeline leakage detection system provided by the application, and the liquid pipeline leakage detection system comprises a sensor, an alarm, an upper computer and a lower computer. The liquid pipeline leakage detection method comprises the following specific implementation steps:
s100: selecting a time period of stable operation of the pipeline to be tested from the target time period as a stable time period according to the acquired detection data in the target time period, wherein a plurality of computing nodes are arranged on the pipeline to be tested.
Before the step, the method further comprises the following steps:
and (4) SS 101: and collecting data, and filtering the collected pressure data and flow data.
Sensors are arranged in the front end and the tail end 10m of the pipeline to be measured and can be used for collecting pressure and flow information in real time. And meanwhile, collecting the pipeline information such as the length of the pipeline, the inner diameter of the pipeline, the surface roughness and the like as parameters for subsequent calculation.
In actual measurement, the acquired signal contains a large amount of noise and interference components. These noise and interference components are mostly high-frequency signals, while the useful signals are mostly present in the low-frequency range. Therefore, the collected signal data can be separated by means of wavelet filtering and the like, the high-frequency part of the signal data is filtered out, and the signal data is reintegrated with the remaining low-frequency part to finish filtering processing of the pressure data and the flow data.
In order to facilitate the statistics and calculation of data later, a plurality of calculation nodes are arranged on the pipeline at equal intervals according to the size of the space step in advance, and the calculation nodes can be used for calculating the parameter values of the subsequent nodes.
After the pipeline leaks, the leakage point can transmit pressure waves to the head end and the tail end. As the leak progresses, the magnitude of the pressure wave will gradually decay and the conduit will also transition from a steady state to an unsteady state. In the unsteady state, the data used for calculation has uncertainty and cannot be well used for the calculation of the subsequent threshold value, so that the steady operation state of the pipeline needs to be determined first, and the subsequent calculation is performed by using the part of data.
At least a first sub-time period, a second sub-time period and a third sub-time period are selected from target time periods used for selecting detection data, wherein the first sub-time period, the second sub-time period and the third sub-time period have time precedence relations and do not have intersection. Firstly, selecting the detection data in the third sub-time period, calculating an average value, then sequentially comparing the detection data in the third sub-time period with the average value, if the difference value of the detection data and the average value is smaller than a preset fluctuation range, judging that the detection data is normal data, otherwise, judging that the detection data is abnormal data. And if the proportion of the normal data in the third sub-time period to the detection data does not exceed the preset normal data proportion, judging that the third sub-time period is not in a stable state, setting the first sub-time period as a steady-state time period, and otherwise, setting the third sub-time period as the steady-state time period.
In one embodiment, as shown in FIG. 3, when monitoring a pipeline in real time, the data in the region as shown is acquired as data within a target time period. At the current time t0Taking a preset time length t forward as a reference1The data in the time period of (2) are equally divided into a T1 section, a T section and a T0 section in sequence according to the time sequence, and the three sections are also equally divided into A1, B1 and C1 in sequence; A. b, C, respectively; a0, B0, C0 and D0. As described in the above example, the a1, B1 segment is set as the first sub-period, the C1 segment is set as the second sub-period, and the A, B segment is set as the third sub-period. In calculating the initial steady-state value, as shown in fig. 4, data of a detection time period, for example, A, B in the T-segment is extracted, and the average value P of the pressure data in the time period is calculated0Average value Q of sum flow data0Then all the pressure data P in the period of time are reusedjSum flow data QjAnd respectively carrying out comparison with the corresponding data average value, if the absolute value of the difference value of the two is smaller than a preset fluctuation range epsilon, judging that the data is normal data, and otherwise, judging that the data is abnormal data. And finally, counting the proportion of the abnormal data in all the data, if the proportion is smaller than a preset proportion value, judging that the pipeline is in a stable state in the current time period, and determining the time period as the stable time period. Otherwise, as shown in fig. 5, the previous time period is selected as the steady-state time period, for example, the a1 and B1 of the T1 are selected as the steady-state time period.
And S200, establishing a characteristic line equation according to the pipeline parameter data of the pipeline to be detected and the detection data in the steady-state time period.
In actual production, the location where the leak occurs is uncertain. For the convenience of calculating the threshold, it is assumed that a leakage occurs in the middle of the pipeline, and the leakage amount is set to a preset value, for example, 1% of the flow rate of the pipeline. Thus, the pressure wave emitted by the leakage point is simultaneously propagated to the head end and the tail end, and the threshold value is convenient to calculate.
Pipe flow equations in pipes mainly comprise differential equations of motion
And continuous differential equation
Wherein V is the average flow velocity of liquid in the pipe, H is pressure data, a is the pressure wave velocity, g is the gravity acceleration, f is the Darcy friction coefficient, D is the pipe inner diameter, t is the time variable, and x is the position variable.
Due to the existence of the secondary friction term, the equation can not be solved by a mathematical calculation method to obtain an analytic solution, so a numerical analysis method is adopted for solving. The characteristic line solution is a common numerical method, the equation is converted by the method to obtain two characteristic lines and a characteristic equation thereof, and the characteristic equation is solved by a finite difference method to obtain the following characteristic line equation:
in the formula (I), the compound is shown in the specification,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPFor the next moment of the internal node pressure parameter, QPThe flow parameter of the internal node at the next moment, A is a pipeThe cross-sectional area of the pipeline, f is the Darcy friction coefficient, deltax is the space step length, which is a parameter value divided according to the pipeline parameter, and D is the inner diameter of the pipeline.
S300: and calculating the node parameter value of each node at each prediction moment according to the characteristic line equation.
The node parameter values mainly comprise a node pressure parameter and a node flow parameter.
For internal nodes except the head and tail end nodes and the leakage point, as shown in fig. 6, the pressure parameter and the flow parameter of the node at the next moment can be obtained according to the characteristic line equation C obtained in step S100+、C-And (4) obtaining. And according to the previous node A point and the next node B point of the node which needs to be obtained currently, obtaining the pressure parameter and the flow parameter corresponding to the next moment, namely the P point, of the current node. In particular, according to the characteristic line equation
And
simultaneous Colebrook-White equation
The internal node pressure parameter and the internal node flow parameter corresponding to the point P are obtained, in the formula,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPIs the internal node pressure parameter, Q, at the next moment of the nodePThe flow parameters of the internal node at the next moment of the node are a pressure wave velocity, g is gravity acceleration, A is the cross section area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the inner diameter of the pipeline, epsilon is the roughness of the surface of the pipeline, R is the surface roughness of the pipelineeIs the reynolds coefficient.
For the head-end node, as shown in fig. 7,only the latter node exists, and the characteristic line equation only includes C-Thus, the parameter value for that point at the next instant is solved simultaneously by means of the pump characteristic equation provided at the head end of the pipeline. According to the characteristic line equation
And pipeline boundary pump characteristic equation HP＝a1+a2QP+a3QP+h0Solving a head end node pressure parameter and a head end node flow parameter, wherein,
HBis a head-end next-to-internal-node pressure parameter, QBAs a head-end next-internal-node flow parameter, HPFor the next moment of head node pressure parameter, QPThe flow parameters of the head end node and the tail end node at the next moment are shown, a is the pressure wave velocity, g is the gravity acceleration, A is the cross section area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the inner diameter of the pipeline, a1Is the head when head-end displacement is equal to 0, a2、a3Are all parameters of the pump characteristic curve, h0The inlet pressure at the head end.
For end nodes, as shown in FIG. 8, where only the previous node exists, the characteristic line equation only includes C+Thus, with the pressure parameter provided by the line end tank, which is typically the boundary condition of a valve plus a constant head buffer tank as shown in FIG. 8, the end tank pressure can be considered unchanged during relatively short leakage transient flows, i.e., the end pressure parameter H0The constant is known, and the parameter value of the point at the next moment is solved accordingly. In particular, according to the characteristic line equation
And
and solving the pressure parameter and the flow parameter of the end node. In the formula (I), the compound is shown in the specification,
HAfor the terminal previous internal node pressure parameter, QAFor the end previous internal node traffic parameter, HPFor the next time end node pressure parameter, QPFor the next time end node flow parameter, H0For the pressure parameter of the outflow tail end, a is the pressure wave velocity, g is the gravity acceleration, A is the cross-sectional area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the inner diameter of the pipe, KLIs the valve coefficient.
For a leak, as shown in fig. 9, the flow parameters at the two ends of the leak are different, and the values of the flow parameters in the characteristic line equation about the leak are not consistent, and are QPAnd QP'. In general, the difference between the two is the leakage of the pipeline, i.e. QP＝QP' + q. Thus, according to the characteristic line equation
And
simultaneous equation QP＝QP' + q and
calculating the pressure parameter and the flow parameter of the leakage point, wherein,
HApressure parameter of internal node before the leak point, HBAs a parameter of internal node pressure, Q, after the leakAAs a previous internal node flow parameter of the leak, QBAs a parameter of the internal node flow behind the leak, HPFor the pressure parameter of the leak point at the next moment, QPFor the next moment of revealing the flow parameter, Q, before the dew pointPIs the next momentPost-leak flow parameter, H0The parameter is the external pressure parameter of the leakage point pipe, a is the pressure wave velocity, g is the gravity acceleration, A is the cross section area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the internal diameter of the pipe, CVIs the flow rate coefficient.
By combining the method for solving the node flow parameter and the pressure parameter in the pipeline, the node pressure parameter and the node flow parameter corresponding to each node in the grid shown in fig. 6 at any moment can be obtained in turn.
S400: and determining a threshold value according to the node parameter value.
Correspondingly, according to the node pressure parameter and the node flow parameter of each node at each moment obtained in step S300, a corresponding pressure threshold and a corresponding flow threshold are determined.
Under the general condition, the normal speed centrifugal pump can be connected to the head end of pipeline for pipeline end pressure change is showing inadequately when taking place to leak, and the constant voltage liquid level jar can be connected to the pipeline end simultaneously, causes the head end flow variation obvious inadequately easily. Therefore, to ensure the validity of the threshold setting, the head end pressure parameter and the tail end flow parameter are selected as the threshold determination criteria.
According to the pressure parameters and the flow parameters of each node at each time point calculated in step S300, in the grid shown in fig. 6, from the node corresponding to the leakage point at time point 0, the nodes corresponding to the leakage point on the vertical axis where the head end and the tail end are located are determined by extending the node in the upward-leftward oblique direction and the upward-rightward oblique direction, the pressure parameter at the time point corresponding to the head end at the node is used as the pressure threshold, and the flow parameter at the time point corresponding to the tail end at the node is used as the flow threshold.
S500: and comparing the detection data in the detection time period with the threshold value, and judging whether the pipeline leaks or not according to the comparison result, wherein the detection time period belongs to the target time period.
And at least selecting a fourth sub-time period and a fifth sub-time period from the detection time periods. The fourth sub-period and the fifth sub-period have a time-sequential relationship with the first sub-period, the second sub-period and the third sub-period in step S100, and there are no intersecting portions between the fourth sub-period and the fifth sub-period. And if the detected data in the fourth sub-time period are all smaller than the flow threshold value and the pressure threshold value, judging that the pipeline leaks at the moment. If the part of the detection data in the fourth sub-time period is smaller than the flow threshold and the pressure threshold, respectively comparing the data in the fifth sub-time period with the pressure threshold and the flow threshold, and if all the detection data in the fifth sub-time period is smaller than the pressure threshold and the flow threshold, judging that the pipeline leaks at the moment. Otherwise, judging that the pipeline is not leaked.
As shown in fig. 10, for the division of the detection time period according to the embodiment in step S100, the segment C is taken as the fourth sub-time period, and the segment a0 is taken as the fifth sub-time period. Comparing the detection data in the fourth sub-period with the flow threshold and the pressure threshold, respectively. And if all the flow data in the period of time are smaller than the flow threshold value, judging that the pipeline leaks. As shown in fig. 11, if the detected data portion in the fourth sub-period is smaller than the threshold value according to the above-described determination method, the data in the fifth sub-period is extracted and compared with the flow rate threshold value and the pressure threshold value. If all the flow data in the period of time are smaller than the flow threshold value, or all the pressure data in the period of time are smaller than the pressure threshold value, judging that the pipeline leaks at the moment, or else, judging that the pipeline is normal at the moment.
The method can further comprise the following steps:
SS 501: and if the pipeline to be detected leaks, determining the specific position of the leakage according to the propagation speed of the pressure wave, the length of the pipeline and the time difference of the pressure wave reaching the head end and the tail end.
In the step of detecting the pipeline leakage, a threshold step detection method based on a model method is adopted, the coverage area is wide, aiming at the result, a negative pressure wave method is adopted to realize the positioning of the leakage position, the positioning of the specific leakage position can be realized simply and accurately, and the leakage signal can be captured accurately and effectively.
In particular, a formula may be utilized
And calculating the leakage position, wherein X is the leakage position, L is the length of the pipeline, a is the propagation speed of the pressure wave in the pipeline, and delta t is the time difference of the pressure wave propagating to the head end and the tail end. Wherein a can utilize a formula
And calculating, wherein K is a fluid volume elastic coefficient and represents the characteristic that the liquid volume changes due to the change of the external pressure, rho represents the fluid density, E represents the elastic modulus of the pipe, D represents the inner diameter of the pipeline, E represents the thickness of the pipe wall, and C represents a correction coefficient related to the constraint condition of the pipeline.
In the following, an embodiment of the liquid pipe leakage detection apparatus of the present application is described, and as shown in fig. 2, the liquid pipe leakage detection apparatus includes:
the steady-state time period determining module 210 is configured to select a time period of stable operation of the pipeline to be tested from a target time period as a steady-state time period according to acquired detection data in the target time period, where the pipeline to be tested is provided with a plurality of computing nodes;
a characteristic line equation establishing module 220, configured to establish a characteristic line equation according to the pipeline parameter data of the pipeline to be tested and the detection data in the steady-state time period;
a node parameter value calculating module 230, configured to calculate a node parameter value of each node at each prediction time according to the characteristic line equation;
a threshold obtaining module 240, configured to determine a threshold according to the node parameter value;
and a leakage judging module 250, configured to compare the detection data in a detection time period with the threshold, and judge whether the pipeline leaks according to a comparison result, where the detection time period belongs to the target time period.
In one embodiment, the fluid line leak detection apparatus further comprises:
the data filtering module 250: the device is used for acquiring data and filtering the acquired pressure data and flow data.
The steady state time period determination module 210 includes:
sub-period molecular dividing unit 211: the time slot selection device is used for selecting at least a first sub-time slot, a second sub-time slot and a third sub-time slot from the target time slot;
average parameter value operator unit 212: extracting detection data in the third sub-time period, and calculating the average value of the detection values in the time period; abnormal data judgment subunit 213: the data processing device is used for sequentially comparing the detection data in the third sub-time period with the average value of the detection values, if the difference value between the detection data and the average value does not exceed a preset fluctuation range, judging the data to be normal data, and otherwise, judging the data to be abnormal data;
the steady state time period determination subunit 214: and the controller is used for judging that the third sub-time period is not in a stable operation state when the proportion of the normal data in the detection data does not exceed the preset normal data proportion, setting the first sub-time period as a steady-state time period, and otherwise, setting the third sub-time period as the steady-state time period.
The characteristic line equation establishing module 220 includes:
differential equation establishment subunit 221: is used for establishing a motion differential equation according to the pressure data, the average flow velocity of liquid in the pipe, the pressure wave velocity and the inner diameter of the pipe
And continuous differential equation
In the formula, V is the average flow velocity of liquid in the pipe, H is pressure data, a is the pressure wave velocity, g is the gravity acceleration, f is the Darcy friction coefficient, D is the inner diameter of the pipe, t is a time variable, and x is a position variable;
the characteristic line equation establishing subunit 222: for converting the differential equation of motion and the differential equation of continuity into an equation of characteristic line
And
in the formula (I), the compound is shown in the specification,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPAs internal node pressure parameter, QPThe flow parameters of the internal nodes are represented, A is the cross-sectional area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, and D is the inner diameter of the pipeline.
The node pressure parameters comprise internal node pressure parameters, head end node pressure parameters, tail end node pressure parameters and leakage point pressure parameters, and the node flow parameters comprise internal node flow parameters, head end node flow parameters, tail end node flow parameters and leakage point flow parameters; the node parameter value calculating module 230 includes:
an internal node parameter calculation subunit 231 for calculating the internal node parameters according to the characteristic line equation
And
simultaneous equations
Calculating the internal node pressure parameter and the internal node flow parameter, wherein,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPAs internal node pressure parameter, QPIs an internal node flow parameter, a is a pressure wave velocity, g is a gravity acceleration, A is a cross section area of the pipeline, f is a Darcy friction coefficient, Deltax is a space step length, D is an inner diameter of the pipeline, epsilon is a surface roughness of the pipeline, ReIs the Reynolds coefficient;
head-end node parameter calculation subunit 232: for equation based on characteristic line
And pipeline boundary pump characteristic equation HP＝a1+a2QP+a3QP+h0Solving head end node pressure parameters and head end node flow parameters according to characteristic line equations
And
solving for the end node pressure parameter and the end node flow parameter, wherein,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPAs internal node pressure parameter, QPAs internal node traffic parameters, H0For the pressure parameter of the outflow tail end, a is the pressure wave velocity, g is the gravity acceleration, A is the cross-sectional area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the inner diameter of the pipeline, a1Is the head when head-end displacement is equal to 0, a2、a3Are all parameters of the head end characteristic curve, h0Inlet pressure at head end, KLIs the valve coefficient.
Leak point parameter calculation subunit 233: for equation based on characteristic line
And
simultaneous equation QP＝QP' + q and
calculating the pressure parameter and the flow parameter of the leakage point, wherein,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPFor the pressure parameter of the leak node, QPFor leakage of the flow parameter before dew point, QP' is the post-leak flow parameter, H0The parameter is the external pressure parameter of the leakage point pipe, a is the pressure wave velocity, g is the gravity acceleration, A is the cross section area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the internal diameter of the pipe, CVIs the flow rate coefficient.
The threshold obtaining module 240 includes:
and a threshold determination subunit 241, configured to obtain, according to the node pressure parameter and the node flow parameter, a head-end node pressure parameter corresponding to a moment when the leak point is mapped to the head end as a pressure threshold, and obtain a tail-end node flow parameter corresponding to a moment when the leak point is mapped to the tail end as a flow threshold.
The leakage determining module 250 includes:
a determining subunit 251, configured to select at least a fourth sub-period and a fifth sub-period from the target period; and comparing the detection data in the fourth sub-time period with the threshold, if the detection data in the fourth sub-time period are all smaller than the threshold, judging that the detection pipeline leaks, if only part of the detection data in the fourth sub-time period is smaller than the threshold, comparing the detection data in the fifth sub-time period with the threshold, if the detection data in the fifth sub-time period are all smaller than the threshold, judging that the pipeline leaks at the moment, and otherwise, judging that the pipeline does not leak.
The liquid pipeline leakage detection device further comprises:
leak location module 270: and when the pipeline to be detected is judged to leak, determining the specific position of the leaking according to the propagation speed of the pressure wave, the length of the pipeline and the time difference of the pressure wave reaching the head end and the tail end.
The following describes a liquid pipeline leakage detection device of the present application. As shown in fig. 12, the apparatus includes:
the sensor is arranged in the range of 10m between the head end and the tail end of the pipeline and is used for acquiring detection data such as temperature data, pressure data and the like of the head end and the tail end of the pipeline in real time;
the alarm is used for sending an alarm signal to remind after receiving a pipeline leakage signal;
the lower computer is used for directly controlling the sensor and the alarm;
and the upper computer is used for calculating a threshold value according to the acquired detection data and the acquired pipeline parameter data in the pipeline and comparing the threshold value with the detection data to judge whether leakage occurs or not.
In the application, the device is mainly used for collecting pipeline data and judging whether the pipeline leaks or not, and meanwhile, the alarm for the leakage condition is realized.
In the 90 s of the 20 th century, improvements in a technology could clearly distinguish between improvements in hardware (e.g., improvements in circuit structures such as diodes, transistors, switches, etc.) and improvements in software (improvements in process flow). However, as technology advances, many of today's process flow improvements have been seen as direct improvements in hardware circuit architecture. Designers almost always obtain the corresponding hardware circuit structure by programming an improved method flow into the hardware circuit. Thus, it cannot be said that an improvement in the process flow cannot be realized by hardware physical modules. For example, a Programmable Logic Device (PLD), such as a Field Programmable Gate Array (FPGA), is an integrated circuit whose Logic functions are determined by programming the Device by a user. A digital system is "integrated" on a PLD by the designer's own programming without requiring the chip manufacturer to design and fabricate a dedicated integrated circuit chip 2. Furthermore, nowadays, instead of manually making an integrated Circuit chip, such Programming is often implemented by "logic compiler" software, which is similar to a software compiler used in program development and writing, but the original code before compiling is also written by a specific Programming Language, which is called Hardware Description Language (HDL), and HDL is not only one but many, such as abel (advanced Boolean Expression Language), ahdl (alternate Language Description Language), traffic, pl (core unified Programming Language), HDCal, JHDL (Java Hardware Description Language), langue, Lola, HDL, laspam, hardsradware (Hardware Description Language), vhjhd (Hardware Description Language), and vhigh-Language, which are currently used in most popular applications. It will also be apparent to those skilled in the art that hardware circuitry that implements the logical method flows can be readily obtained by merely slightly programming the method flows into an integrated circuit using the hardware description languages described above.
The systems, devices, modules or units illustrated in the above embodiments may be implemented by a computer chip or an entity, or by a product with certain functions. One typical implementation device is a computer. In particular, the computer may be, for example, a personal computer, a laptop computer, a cellular telephone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.
From the above description of the embodiments, it is clear to those skilled in the art that the present specification can be implemented by software plus a necessary general hardware platform. Based on such understanding, the technical solutions of the present specification may be essentially or partially implemented in the form of software products, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and include instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments of the present specification.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The description is operational with numerous general purpose or special purpose computing system environments or configurations. For example: personal computers, server computers, hand-held or portable devices, tablet-type devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
This description may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
While the specification has been described with examples, those skilled in the art will appreciate that there are numerous variations and permutations of the specification that do not depart from the spirit of the specification, and it is intended that the appended claims include such variations and modifications that do not depart from the spirit of the specification.
Claims (12)
1. A method of detecting a leak in a fluid line, comprising:
selecting a time period of stable operation of a pipeline to be tested from a target time period as a stable time period according to acquired detection data in the target time period, wherein a plurality of computing nodes are arranged on the pipeline to be tested;
establishing a characteristic line equation according to the pipeline parameter data of the pipeline to be detected and the detection data in the steady-state time period;
calculating the node parameter values of the plurality of calculation nodes at each prediction moment according to the characteristic line equation;
determining a threshold value according to the node parameter value; the threshold values comprise a pressure threshold value and a flow threshold value; the determining a threshold value according to the node parameter value includes: according to the node parameter values, acquiring a head end node pressure parameter corresponding to the moment when the leakage point is mapped to the head end as a pressure threshold value, and acquiring a tail end node flow parameter corresponding to the moment when the leakage point is mapped to the tail end as a flow threshold value;
and comparing the detection data in the detection time period with the threshold value, and judging whether the pipeline leaks or not according to the comparison result, wherein the detection time period belongs to the target time period.
2. The method of claim 1, wherein selecting a time period of stable operation of the pipeline to be tested from the target time period as a steady-state time period according to the acquired detection data in the target time period comprises:
selecting at least a first sub-time period, a second sub-time period and a third sub-time period from the target time period;
extracting detection data in a third sub-time period, and calculating the average value of detection values in the third sub-time period;
comparing the detection data in the third sub-time period with the average value of the detection values in sequence, if the difference value between the detection data and the average value does not exceed a preset fluctuation range, judging the data to be normal data, and otherwise, judging the data to be abnormal data;
and if the proportion of the normal data in the third sub-time period to the detection data does not exceed the preset normal data proportion, judging that the third sub-time period is not in a stable operation state, setting the first sub-time period as a steady-state time period, and otherwise, setting the third sub-time period as a steady-state time period.
3. The method of claim 1, wherein establishing a characteristic line equation based on the pipe parameter data of the pipe under test and the detection data during the steady state time period comprises:
establishing a motion differential equation according to pressure data, flow data and pipeline parameter data in the detection data
And continuous differential equation
In the formula, V is the average flow velocity of liquid in the pipe, H is pressure data, a is the pressure wave velocity, g is the gravity acceleration, f is the Darcy friction coefficient, D is the inner diameter of the pipe, t is a time variable, and x is a position variable;
converting the differential equation of motion and the differential equation of continuity into an equation of characteristic line
And
in the formula (I), the compound is shown in the specification,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPIs insidePartial node pressure parameter, QPThe flow parameters of the internal nodes are represented, A is the cross-sectional area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, and D is the inner diameter of the pipeline.
4. The method of claim 1, wherein the node parameter values include internal node pressure parameters and internal node flow parameters, and the calculating node parameter values of each node in the pipe to be measured at each time according to the characteristic line equation includes:
according to the characteristic line equation
And
simultaneous equations
The internal node pressure parameter and the internal node flow parameter corresponding to the node at the next moment are obtained, in the formula,
HAis the previous internal node pressure parameter, HBFor the latter internal node pressure parameter, QAFor the previous internal node traffic parameter, QBFor the latter internal node traffic parameter, HPIs the internal node pressure parameter, Q, at the next moment of the nodePThe flow parameters of the internal node at the next moment of the node are a pressure wave velocity, g is gravity acceleration, A is the cross section area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the inner diameter of the pipeline, epsilon is the roughness of the surface of the pipeline, R is the surface roughness of the pipelineeIs the reynolds coefficient.
5. The method of claim 1, wherein the node parameter values include a head-end node pressure parameter, a tail-end node pressure parameter, a head-end node flow parameter, a tail-end node flow parameter, and wherein calculating the node parameter value for each node at each time based on the characteristic line equation comprises:
according to the characteristic line equation
And pipeline boundary pump characteristic equation HP＝a1+a2QP+a3QP+h0Solving head end node pressure parameters and head end node flow parameters according to the characteristic line equation
And
solving for the end node pressure parameter and the end node flow parameter, wherein,
HAis the terminal previous internal node pressure parameter, HBIs a head-end next-to-internal-node pressure parameter, QAFor the end previous internal node traffic parameter, QBAs a head-end next-internal-node flow parameter, HPFor the pressure parameter of the head and tail end nodes at the next time, QPFor the next time-point head-end node flow parameter, H0For the pressure parameter of the outflow tail end, a is the pressure wave velocity, g is the gravity acceleration, A is the cross-sectional area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the inner diameter of the pipeline, a1Is the head when head-end displacement is equal to 0, a2、a3Are all parameters of the head end characteristic curve, h0Inlet pressure at head end, KLIs the valve coefficient.
6. The method of claim 1, wherein the node parameter values include a leak point pressure parameter, a leak point flow parameter, and wherein calculating the node parameter value for each node at each time based on the characteristic line equation comprises:
according to the characteristic line equation
And
simultaneous equation QP＝QP' + q and
calculating the pressure parameter and the flow parameter of the leakage point, wherein,
HApressure parameter of internal node before the leak point, HBAs a parameter of internal node pressure, Q, after the leakAAs a previous internal node flow parameter of the leak, QBAs a parameter of the internal node flow behind the leak, HPFor the pressure parameter of the leak point at the next moment, QPFor the next moment of revealing the flow parameter, Q, before the dew pointP' is the post-leak flow parameter at the next time, H0The parameter is the external pressure parameter of the leakage point pipe, a is the pressure wave velocity, g is the gravity acceleration, A is the cross section area of the pipeline, f is the Darcy friction coefficient, Deltax is the space step length, D is the internal diameter of the pipe, CVIs the flow rate coefficient.
7. The method of claim 1, wherein comparing the detection data in the detection time period with the threshold value and determining whether the pipeline leaks according to the comparison result comprises:
selecting at least a fourth sub-time period and a fifth sub-time period from the target time period; and comparing the detection data in the fourth sub-time period with the threshold, if all the detection data in the fourth sub-time period is smaller than the threshold, judging that the detection pipeline leaks, if only part of the detection data in the fourth sub-time period is smaller than the threshold, comparing the detection data in the fifth sub-time period with the threshold, if all the detection data in the fifth sub-time period is smaller than the threshold, judging that the pipeline leaks at the moment, and otherwise, judging that the pipeline does not leak.
8. The method of claim 1, further comprising:
and if the pipeline to be detected leaks, determining the specific position of the leakage according to the propagation speed of the pressure wave, the length of the pipeline and the time difference of the pressure wave reaching the head end and the tail end.
9. A liquid conduit leak detection apparatus comprising:
the steady-state time period determining module is used for selecting a time period of stable operation of the pipeline to be tested from a target time period as the steady-state time period according to the acquired detection data in the target time period, wherein a plurality of computing nodes are arranged on the pipeline to be tested;
the characteristic line equation establishing module is used for establishing a characteristic line equation according to the pipeline parameter data of the pipeline to be detected and the detection data in the steady-state time period;
the node parameter value calculation module is used for calculating the node parameter values of the plurality of calculation nodes at each prediction moment according to the characteristic line equation;
a threshold value obtaining module, configured to determine a threshold value according to the node parameter value; the threshold values comprise a pressure threshold value and a flow threshold value; the determining a threshold value according to the node parameter value includes: according to the node parameter values, acquiring a head end node pressure parameter corresponding to the moment when the leakage point is mapped to the head end as a pressure threshold value, and acquiring a tail end node flow parameter corresponding to the moment when the leakage point is mapped to the tail end as a flow threshold value;
and the leakage judging module is used for comparing the detection data in the detection time period with the threshold value and judging whether the pipeline leaks or not according to the comparison result, wherein the detection time period belongs to the target time period.
10. The apparatus of claim 9, further comprising:
and the leakage point positioning module is used for determining the specific position of leakage according to the pressure wave propagation speed, the length of the pipeline and the time difference of the pressure wave reaching the head end and the tail end under the condition of judging the leakage of the pipeline to be detected.
11. A liquid conduit leak detection system, comprising:
the system comprises an upper computer, a pipeline to be detected and a control unit, wherein the upper computer is used for selecting a time period of stable operation of the pipeline to be detected from a target time period as a stable time period according to acquired detection data in the target time period, and a plurality of computing nodes are arranged on the pipeline to be detected; establishing a characteristic line equation according to the pipeline parameter data of the pipeline to be detected and the detection data in the steady-state time period; calculating the node parameter values of the plurality of calculation nodes at each prediction moment according to the characteristic line equation; calculating a threshold value according to the acquired detection data in the pipeline and the pipeline parameter data, and comparing the threshold value with the detection data to judge whether leakage occurs or not; the threshold values comprise a pressure threshold value and a flow threshold value; the threshold value is obtained according to the following mode: according to the node parameter values, acquiring a head end node pressure parameter corresponding to the moment when the leakage point is mapped to the head end as a pressure threshold value, and acquiring a tail end node flow parameter corresponding to the moment when the leakage point is mapped to the tail end as a flow threshold value;
the sensor is used for collecting detection data in the pipeline;
and the lower computer is used for receiving the detection data and directly controlling the sensor.
12. The system of claim 11, further comprising:
and the alarm is used for giving an alarm after receiving the information that the pipeline leaks.
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