An architecture of a leakage detection system for a crude oil pipeline and a method for detecting the leakage location

Abstract

The present invention discloses a leakage detection system architecture for a crude oil pipeline and a leakage location detection method, including an upstream station architecture and a downstream station architecture of the pipeline. Among them, an upstream pressure transmitter, a frequency converter of an oil transfer pump, and an upstream flowmeter are respectively arranged at the upstream station of the pipeline. The upstream pressure transmitter, the frequency converter of the oil transfer pump, and the upstream flowmeter are respectively connected to the existing PLC at the upstream station. The downstream pressure transmitter and the downstream flowmeter are respectively arranged at the downstream station of the pipeline. The downstream pressure transmitter and the downstream flowmeter are respectively connected to the existing PLC at the downstream station. The existing PLC at the upstream station and the existing PLC at the downstream station are respectively connected to system components through a communication network in accordance with the Modbus for TCP / IP protocol. The system components can directly collect the data of the existing PLC at the upstream station and the existing PLC at the downstream station.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas transportation, and particularly relates to a leakage detection system architecture for a crude oil transportation pipeline and a leakage location detection method. Background Art

[0002] For traditional leakage detection systems based on the analysis of pressure signals and flow signals, the basic composition of the systems is more or less the same. Among them, the signal acquisition device is a dedicated device of the leakage detection system and the main hardware cost. The signal acquisition device mostly adopts an independent RTU to implement functions such as data acquisition, communication, and GPS time synchronization. The signal acquisition device is responsible for converting the current signal (4~20mA) of the pressure (or flow) transmitter into a digital signal, and transmitting it to the main computer of the monitoring system through communication methods such as Ethernet or serial port. It also receives the synchronization signal of the GPS clock to achieve strict time synchronization of upstream and downstream data packets. However, in the existing system, each pressure transmitter, flowmeter, and oil pump frequency converter needs to be equipped with a signal distributor. Multiple signal distributors are respectively connected to a signal acquisition device, and the signal acquisition device is connected to the system software through a communication network. Due to the high cost of the signal distributor and the signal acquisition device, the overall cost of the leakage detection system is high, which increases the construction cost and the maintenance workload, and is not conducive to popularization and application. At the same time, since the sampling frequency of the signal acquisition device is 100HZ, the sampling frequency is relatively high. However, in actual applications, since the pipeline pressure usually changes relatively slowly during leakage, collecting 10 signals per second can fully meet the needs of leakage detection. Therefore, the existing signal acquisition device causes resource waste, and the excessively high sampling frequency is meaningless. At the same time, due to the limitation of the signal acquisition device in the existing leakage detection system, time asynchronization occurs. In addition, the existing leakage location detection method has a large calculation difficulty and a low accuracy of leakage location prediction. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art, and provide a leakage detection system architecture for a crude oil transportation pipeline and a leakage location detection method, which overcomes the following problems in the prior art: 1. Since multiple signal distributors are respectively connected to a signal acquisition device, and the signal acquisition device is connected to the system software through a communication network, due to the high cost of the signal distributor and the signal acquisition device, the overall cost of the leakage detection system is high, which increases the construction cost and the maintenance workload, and is not conducive to popularization and application; 2. Since the sampling frequency of the signal acquisition device is 100HZ, the sampling frequency is relatively high. However, in actual applications, since the pipeline pressure usually changes relatively slowly during leakage, collecting 10 signals per second can fully meet the needs of leakage detection. Therefore, the existing signal acquisition device causes resource waste; 3. Due to the limitation of the signal acquisition device in the existing leakage detection system, time asynchronization occurs; 4. The existing leakage location detection method has a large calculation difficulty and a low accuracy of leakage location prediction.

[0004] To solve the technical problems, the technical solution of the present invention is: an architecture of a leakage detection system for a crude oil pipeline, including an upstream pipeline site architecture and a downstream pipeline site architecture. The upstream pipeline site architecture includes an upstream pressure transmitter, a frequency converter for the oil transfer pump, an upstream flowmeter, and an existing PLC at the upstream site. The upstream pressure transmitter, the frequency converter for the oil transfer pump, and the upstream flowmeter are respectively arranged at the upstream pipeline site, and are respectively connected to the existing PLC at the upstream site. The downstream site architecture includes a downstream pressure transmitter, a downstream flowmeter, an existing PLC at the downstream site, and system components. The downstream pressure transmitter and the downstream flowmeter are respectively arranged at the downstream pipeline site, and are respectively connected to the existing PLC at the downstream site. The existing PLC at the upstream site and the existing PLC at the downstream site are respectively connected to the system components through a communication network using the Modbus for TCP / IP protocol. The system components can directly collect the data of the existing PLC at the upstream site and the existing PLC at the downstream site.

[0005] Preferably, the currents of the upstream pressure transmitter, the frequency converter for the oil transfer pump, and the upstream flowmeter are all 4~20mA, and the currents of the downstream pressure transmitter and the downstream flowmeter are all 4~20mA.

[0006] Preferably, the existing PLC at the upstream site stores the collected upstream pressure, upstream flow, and frequency signal of the external transfer pump frequency converter in registers at fixed addresses, and the existing PLC at the downstream site stores the collected downstream pressure and downstream flow in registers at fixed addresses.

[0007] Preferably, the system components include a computer and system software in the computer. The system software has a data reading module, and the data reading module can directly read data from the registers through the Modbus for TCP / IP protocol.

[0008] Preferably, the frequency of the system components collecting data from the existing PLC at the upstream site or the existing PLC at the downstream site is the same as the frequency of the existing PLC at the upstream site or the existing PLC at the downstream site collecting data, and the frequency of the existing PLC at the upstream site or the existing PLC at the downstream site collecting data is 10HZ.

[0009] Preferably, the existing PLC at the upstream site and the existing PLC at the downstream site can both obtain the standard time through the computer of the system components, and then use this time to label each collected data with a time tag, thereby achieving time synchronization.

[0010] Preferably, a method for detecting the leakage position of the architecture of the leakage detection system for a crude oil pipeline as described in any one of the above includes the following steps:

[0011] Step 1) The system components collect the upstream pressure, upstream flow rate, and the frequency signal of the external transmission pump inverter through the established PLC at the upstream station, and collect the downstream pressure and downstream flow rate through the established PLC at the downstream station. At the same time, the system components obtain the standard time, and then use this time to tag each collected data with a time label, thus achieving time synchronization;

[0012] Step 2) Compare the collected upstream pressure and upstream instantaneous flow rate with the downstream pressure and downstream instantaneous flow rate. When the difference between the upstream pressure and the downstream pressure is greater than ΔP, or the difference between the upstream instantaneous flow rate and the downstream instantaneous flow rate is greater than ΔQ, it is determined that there is a leak in the pipeline; when the difference between the upstream pressure and the downstream pressure is less than ΔP, or the difference between the upstream instantaneous flow rate and the downstream instantaneous flow rate is less than ΔQ, it is determined that there is no leak in the pipeline;

[0013] Step 3) When it is determined that there is a leak in the pipeline, the leak point location is calculated through the leak location formula. The leak location formula locates the leak point through the negative pressure wave, and then repairs the leak at the leak point.

[0014] Preferably, the determination method of ΔP is as follows:

[0015] Step 2-1) For a pipeline operating stably, the system components extract a set of upstream pressure data sequences {Pa0, Pa1, Pa2 … Pan} during normal operation of the pipeline, and then extract a set of downstream pressure data sequences {Pb0, Pb1, Pb2 … Pbn}. The data sequences are taken from the data within 24 hours, and the sampling interval is 1 s, thus obtaining the data sequence length n;

[0016] Step 2-2) Calculate the difference between the two sets of data sequences respectively to obtain a set of data sequences of the upstream and downstream pressure differences {Pc0, Pc1, Pc2 … Pcn}; after performing Kalman filtering on this set of data sequences for smoothing and then calculating the mean value, PC is obtained, and this value is the reasonable difference between the upstream and downstream pressures under normal conditions;

[0017] Step 2-3) Multiply PC by the corresponding amplification factor μ to obtain ΔP. The amplification factor μ can be set in the system components, and the range of the amplification factor μ is: 1.05~1.2. The determination method of ΔQ is the same as that of ΔP.

[0018] Preferably, the leak location formula is:

[0019] X

[0020]

[0021] In the formula:

[0022] X-the distance from the release leakage point to the upstream station of the pipeline, m;

[0023] a- propagation speed of negative pressure wave, m / s;

[0024] L-the length of the measured pipeline, m;

[0025] -The time difference between the upstream and downstream pressure transmitters receiving the negative pressure wave;

[0026] v-fluid velocity, m / s.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] (1) The present invention includes a pipeline upstream station architecture and a pipeline downstream station architecture, wherein the upstream pressure transmitter, the oil pump frequency converter and the upstream flow meter are respectively arranged at the upstream station of the pipeline, wherein the upstream pressure transmitter, the oil pump frequency converter and the upstream flow meter are respectively connected to the PLC already built at the upstream station, and the downstream pressure transmitter and the downstream flow meter are respectively arranged at the downstream station of the pipeline, wherein the downstream pressure transmitter and the downstream flow meter are respectively connected to the PLC already built at the downstream station, and the PLC already built at the upstream station and the PLC already built at the downstream station are respectively connected to the system components via the Modbus for TCP / IP protocol communication network. The present invention can directly collect data from the PLC already built at the upstream station and the PLC already built at the downstream station through the system components, thereby reading the signals of each detection instrument, without the need for a signal distributor and a signal acquisition device, thereby reducing the overall cost of the leakage detection system, reducing the construction cost, reducing the maintenance workload, and facilitating promotion and application;

[0029] (2) The frequency at which the system components of the present invention collect data from the PLCs already built at the upstream site or the PLCs already built at the downstream site is the same as the frequency at which the PLCs already built at the upstream site or the PLCs already built at the downstream site collect data, wherein the frequency at which the PLCs already built at the upstream site or the PLCs already built at the downstream site collect data is 10 Hz. In practical applications, since pipeline pressure usually changes slowly during a leak, collecting 10 signals per second is sufficient to meet the needs of leak detection, thereby avoiding resource waste and reducing the huge data calculation process of the system components, thereby effectively improving the sensitivity of leak detection;

[0030] (3) The PLCs built at the upstream site and the PLCs built at the downstream site of the present invention obtain the standard time through the computers of the system components, and then use the time to mark each collected data with a time tag, thereby achieving time synchronization and improving the accuracy of leak location detection;

[0031] (4)The architecture of the crude oil pipeline leakage detection system of the present invention is simple and easy to implement, with low operating costs, and is easy to promote and apply in the same type of architecture. At the same time, the leakage location detection method of the present invention locates the leakage through negative pressure waves, with a reasonable calculation method, low calculation difficulty, and high accuracy in predicting the leakage location. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of an architecture of a crude oil pipeline leakage detection system of the present invention;

[0033] Figure 2 Principle diagram of locating the leakage point of negative pressure wave in an architecture of a crude oil pipeline leakage detection system of the present invention.

[0034] 1 - Upstream pressure transmitter, 2 - Frequency converter of oil transfer pump, 3 - Upstream flowmeter, 4 - Existing PLC at upstream station, 5 - Downstream pressure transmitter, 6 - Downstream flowmeter, 7 - Existing PLC at downstream station, 8 - System components. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following describes the specific embodiments of the present invention in conjunction with the embodiments:

[0036] It should be noted that the structures, ratios, sizes, etc. shown in this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0037] At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration, and are not used to limit the scope for the implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope for the implementation of the present invention.

[0038] The system software of the present invention is existing software, named: Pipeline Leakage Detection and Location Client Software, and the data reading module in the system software is any module that can implement data reading.

[0039] Embodiment 1

[0040] As Figure 1As shown in the figure, the present invention discloses an architecture of a leakage detection system for a crude oil transportation pipeline, which includes an upstream site architecture and a downstream site architecture of the pipeline. The upstream site architecture of the pipeline includes an upstream pressure transmitter 1, a variable frequency drive for the oil transfer pump 2, an upstream flowmeter 3, and an existing PLC 4 at the upstream site. The upstream pressure transmitter 1, the variable frequency drive for the oil transfer pump 2, and the upstream flowmeter 3 are respectively arranged at the upstream site of the pipeline. The upstream pressure transmitter 1, the variable frequency drive for the oil transfer pump 2, and the upstream flowmeter 3 are respectively connected to the existing PLC 4 at the upstream site. The downstream site architecture includes a downstream pressure transmitter 5, a downstream flowmeter 6, an existing PLC 7 at the downstream site, and a system component 8. The downstream pressure transmitter 5 and the downstream flowmeter 7 are respectively arranged at the downstream site of the pipeline. The downstream pressure transmitter 5 and the downstream flowmeter 6 are respectively connected to the existing PLC 7 at the downstream site. The existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site are respectively connected to the system component through a communication network using the Modbus for TCP / IP protocol. The system component 8 can directly collect the data of the existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site.

[0041] Embodiment 2

[0042] As Figure 1 As shown in the figure, the present invention discloses an architecture of a leakage detection system for a crude oil transportation pipeline, which includes an upstream site architecture and a downstream site architecture of the pipeline. The upstream site architecture of the pipeline includes an upstream pressure transmitter 1, a variable frequency drive for the oil transfer pump 2, an upstream flowmeter 3, and an existing PLC 4 at the upstream site. The upstream pressure transmitter 1, the variable frequency drive for the oil transfer pump 2, and the upstream flowmeter 3 are respectively arranged at the upstream site of the pipeline. The upstream pressure transmitter 1, the variable frequency drive for the oil transfer pump 2, and the upstream flowmeter 3 are respectively connected to the existing PLC 4 at the upstream site. The downstream site architecture includes a downstream pressure transmitter 5, a downstream flowmeter 6, an existing PLC 7 at the downstream site, and a system component 8. The downstream pressure transmitter 5 and the downstream flowmeter 7 are respectively arranged at the downstream site of the pipeline. The downstream pressure transmitter 5 and the downstream flowmeter 6 are respectively connected to the existing PLC 7 at the downstream site. The existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site are respectively connected to the system component through a communication network using the Modbus for TCP / IP protocol. The system component 8 can directly collect the data of the existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site.

[0043] Preferably, the currents of the upstream pressure transmitter 1, the variable frequency drive for the oil transfer pump 2, and the upstream flowmeter 3 are all 4 - 20 mA, and the currents of the downstream pressure transmitter 5 and the downstream flowmeter 6 are all 4 - 20 mA.

[0044] Embodiment 3

[0045] As Figure 1As shown in the figure, the present invention discloses an architecture of a leakage detection system for a crude oil transportation pipeline, which includes an upstream site architecture and a downstream site architecture of the pipeline. The upstream site architecture of the pipeline includes an upstream pressure transmitter 1, a frequency converter of an oil transmission pump 2, an upstream flowmeter 3, and an existing PLC 4 at the upstream site. The upstream pressure transmitter 1, the frequency converter of the oil transmission pump 2, and the upstream flowmeter 3 are respectively arranged at the upstream site of the pipeline. The upstream pressure transmitter 1, the frequency converter of the oil transmission pump 2, and the upstream flowmeter 3 are respectively connected to the existing PLC 4 at the upstream site. The downstream site architecture includes a downstream pressure transmitter 5, a downstream flowmeter 6, an existing PLC 7 at the downstream site, and a system component 8. The downstream pressure transmitter 5 and the downstream flowmeter 7 are respectively arranged at the downstream site of the pipeline. The downstream pressure transmitter 5 and the downstream flowmeter 6 are respectively connected to the existing PLC 7 at the downstream site. The existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site are respectively connected to the system component through a communication network in accordance with the Modbus for TCP / IP protocol. The system component 8 can directly collect the data of the existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site.

[0046] Preferably, the currents of the upstream pressure transmitter 1, the frequency converter of the oil transmission pump 2, and the upstream flowmeter 3 are all 4 - 20 mA, and the currents of the downstream pressure transmitter 5 and the downstream flowmeter 6 are all 4 - 20 mA.

[0047] Preferably, the existing PLC 4 at the upstream site stores the collected upstream pressure, upstream flow, and frequency signals of the external transmission pump converter in registers at fixed addresses (such as 40051, 40052, 40053), and the existing PLC 7 at the downstream site stores the collected downstream pressure and downstream flow in registers at fixed addresses (such as 40051, 40052).

[0048] Embodiment 4

[0049] Such as Figure 1As shown in the figure, the present invention discloses an architecture of an oil - pipeline leakage detection system, which includes an upstream - site architecture and a downstream - site architecture of the pipeline. The upstream - site architecture of the pipeline includes an upstream pressure transmitter 1, an oil - transfer pump frequency converter 2, an upstream flowmeter 3, and an existing PLC 4 at the upstream site. Among them, the upstream pressure transmitter 1, the oil - transfer pump frequency converter 2, and the upstream flowmeter 3 are respectively arranged at the upstream site of the pipeline, and the upstream pressure transmitter 1, the oil - transfer pump frequency converter 2, and the upstream flowmeter 3 are respectively connected to the existing PLC 4 at the upstream site. The downstream - site architecture includes a downstream pressure transmitter 5, a downstream flowmeter 6, an existing PLC 7 at the downstream site, and a system component 8. Among them, the downstream pressure transmitter 5 and the downstream flowmeter 7 are respectively arranged at the downstream site of the pipeline, and the downstream pressure transmitter 5 and the downstream flowmeter 6 are respectively connected to the existing PLC 7 at the downstream site. The existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site are respectively connected to the system component 8 through a communication network in accordance with the Modbus for TCP / IP protocol. The system component 8 can directly collect the data of the existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site.

[0050] Preferably, the currents of the upstream pressure transmitter 1, the oil - transfer pump frequency converter 2, and the upstream flowmeter 3 are all 4 - 20 mA, and the currents of the downstream pressure transmitter 5 and the downstream flowmeter 6 are all 4 - 20 mA.

[0051] Preferably, the existing PLC 4 at the upstream site stores the collected upstream pressure, upstream flow, and the frequency signal of the external - transfer pump frequency converter in registers with fixed addresses (such as 40051, 40052, 40053), and the existing PLC 7 at the downstream site stores the collected downstream pressure and downstream flow in registers with fixed addresses (such as 40051, 40052).

[0052] Preferably, the system component 8 includes a computer and system software in the computer. The system software has a data - reading module, and the data - reading module can directly read data from the registers through the Modbus for TCP / IP protocol.

[0053] Embodiment 5

[0054] As Figure 1As shown in the figure, the present invention discloses an architecture of a leakage detection system for a crude oil transportation pipeline, which includes an upstream site architecture and a downstream site architecture of the pipeline. The upstream site architecture includes an upstream pressure transmitter 1, an oil pump frequency converter 2, an upstream flowmeter 3, and an existing PLC 4 at the upstream site. The upstream pressure transmitter 1, the oil pump frequency converter 2, and the upstream flowmeter 3 are respectively arranged at the upstream site of the pipeline. The upstream pressure transmitter 1, the oil pump frequency converter 2, and the upstream flowmeter 3 are respectively connected to the existing PLC 4 at the upstream site. The downstream site architecture includes a downstream pressure transmitter 5, a downstream flowmeter 6, an existing PLC 7 at the downstream site, and a system component 8. The downstream pressure transmitter 5 and the downstream flowmeter 7 are respectively arranged at the downstream site of the pipeline. The downstream pressure transmitter 5 and the downstream flowmeter 6 are respectively connected to the existing PLC 7 at the downstream site. The existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site are respectively connected to the system component through a communication network using the Modbus for TCP / IP protocol. The system component 8 can directly collect the data of the existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site.

[0055] Preferably, the currents of the upstream pressure transmitter 1, the oil pump frequency converter 2, and the upstream flowmeter 3 are all 4 - 20 mA, and the currents of the downstream pressure transmitter 5 and the downstream flowmeter 6 are all 4 - 20 mA.

[0056] Preferably, the existing PLC 4 at the upstream site stores the collected upstream pressure, upstream flow, and external pump frequency converter frequency signals in registers at fixed addresses (such as 40051, 40052, 40053), and the existing PLC 7 at the downstream site stores the collected downstream pressure and downstream flow in registers at fixed addresses (such as 40051, 40052).

[0057] Preferably, the system component 8 includes a computer and system software in the computer. The system software has a data reading module, and the data reading module can directly read data from the registers through the Modbus for TCP / IP protocol.

[0058] Preferably, the frequency of the system component 8 collecting the data of the existing PLC 4 at the upstream site or the existing PLC 7 at the downstream site is the same as the frequency of the existing PLC 4 at the upstream site or the existing PLC 7 at the downstream site collecting data, and the frequency of the existing PLC 4 at the upstream site or the existing PLC 7 at the downstream site collecting data is 10 HZ.

[0059] Preferably, the existing PLC 4 at the upstream site and the existing PLC 7 at the downstream site can both obtain the standard time through the computer of the system component 8, and then use this time to label each collected data with a time tag, thereby achieving time synchronization.

[0060] Example 6

[0061] As Figure 1 shown, the present invention discloses an architecture of a leakage detection system for a crude oil transportation pipeline, including an upstream pipeline station architecture and a downstream pipeline station architecture. The upstream pipeline station architecture includes an upstream pressure transmitter 1, a fuel transfer pump frequency converter 2, an upstream flowmeter 3, and an existing PLC 4 at the upstream station. The upstream pressure transmitter 1, the fuel transfer pump frequency converter 2, and the upstream flowmeter 3 are respectively arranged at the upstream pipeline station, and the upstream pressure transmitter 1, the fuel transfer pump frequency converter 2, and the upstream flowmeter 3 are respectively connected to the existing PLC 4 at the upstream station. The downstream station architecture includes a downstream pressure transmitter 5, a downstream flowmeter 6, an existing PLC 7 at the downstream station, and a system component 8. The downstream pressure transmitter 5 and the downstream flowmeter 7 are respectively arranged at the downstream pipeline station, and the downstream pressure transmitter 5 and the downstream flowmeter 6 are respectively connected to the existing PLC 7 at the downstream station. The existing PLC 4 at the upstream station and the existing PLC 7 at the downstream station are respectively connected to the system component through a communication network in accordance with the Modbus for TCP / IP protocol. The system component 8 can directly collect the data of the existing PLC 4 at the upstream station and the existing PLC 7 at the downstream station.

[0062] Preferably, the currents of the upstream pressure transmitter 1, the fuel transfer pump frequency converter 2, and the upstream flowmeter 3 are all 4 - 20 mA, and the currents of the downstream pressure transmitter 5 and the downstream flowmeter 6 are all 4 - 20 mA.

[0063] Preferably, the existing PLC 4 at the upstream station stores the collected upstream pressure, upstream flow, and external transmission pump frequency converter frequency signals in registers at fixed addresses (such as 40051, 40052, 40053), and the existing PLC 7 at the downstream station stores the collected downstream pressure and downstream flow in registers at fixed addresses (such as 40051, 40052).

[0064] Preferably, the system component 8 includes a computer and system software in the computer. The system software is provided with a data reading module, and the data reading module can directly read data from the register through the Modbus for TCP / IP protocol.

[0065] Preferably, the frequency at which the system component 8 collects the data of the existing PLC 4 at the upstream station or the existing PLC 7 at the downstream station is the same as the frequency at which the existing PLC 4 at the upstream station or the existing PLC 7 at the downstream station collects data, and the frequency at which the existing PLC 4 at the upstream station or the existing PLC 7 at the downstream station collects data is 10 HZ.

[0066] Preferably, both the established PLC 4 at the upstream station and the established PLC 7 at the downstream station can obtain the standard time through the computer of the system component 8, and then use this time to tag each collected data with a time label, thereby achieving time synchronization.

[0067] Preferably, a method for detecting the leakage position of the crude oil pipeline leakage detection system architecture as described in any one of the above, includes the following steps:

[0068] Step 1) The system component collects the upstream pressure, upstream flow rate, and frequency signal of the external transmission pump inverter through the established PLC at the upstream station, collects the downstream pressure and downstream flow rate through the established PLC at the downstream station, and simultaneously obtains the standard time through the system component, and then uses this time to tag each collected data with a time label, thereby achieving time synchronization;

[0069] Step 2) Compare the collected upstream pressure and upstream instantaneous flow rate with the downstream pressure and downstream instantaneous flow rate. When the difference between the upstream pressure and the downstream pressure is greater than ΔP, or the difference between the upstream instantaneous flow rate and the downstream instantaneous flow rate is greater than ΔQ, it is determined that there is a leakage in the pipeline; when the difference between the upstream pressure and the downstream pressure is less than ΔP, or the difference between the upstream instantaneous flow rate and the downstream instantaneous flow rate is less than ΔQ, it is determined that there is no leakage in the pipeline;

[0070] Step 3) When it is determined that there is a leakage in the pipeline, calculate the leakage point position through the leakage position formula, where the leakage position formula is used to locate the leakage point through the negative pressure wave, and then repair the leakage point.

[0071] Preferably, the determination method of ΔP is as follows:

[0072] Step 2-1) For a pipeline running smoothly, the system component extracts a set of upstream pressure data sequences {Pa0, Pa1, Pa2 … Pan} during normal operation of the pipeline, and then extracts a set of downstream pressure data sequences {Pb0, Pb1, Pb2 … Pbn}. The data sequences are taken from the data within 24 hours, and the sampling interval is 1 s, thereby obtaining the data sequence length n;

[0073] Step 2-2) Calculate the difference between the two sets of data sequences respectively to obtain a set of data sequences of the upstream and downstream pressure differences {Pc0, Pc1, Pc2 … Pcn}; perform Kalman filtering on this set of data sequences for smoothing processing and then calculate the mean value to obtain PC, and this value is the reasonable difference between the upstream and downstream pressures under normal conditions;

[0074] Step 2-3) Multiply PC by the corresponding amplification factor μ to obtain ΔP. The amplification factor μ can be set in the system component, where the range of the amplification factor μ is: 1.05~1.2. The determination method of ΔQ is the same as that of ΔP.

[0075] Preferably, the leakage position formula is as follows:

[0076] X

[0077]

[0078] In the formula:

[0079] X - the leakage point from the upstream station of the pipeline, m;

[0080] a - the propagation speed of the negative pressure wave, m / s;

[0081] L - the length of the measured pipeline, m;

[0082] - the time difference between the upstream pressure transmitter and the downstream pressure transmitter receiving the negative pressure wave;

[0083] v - the fluid flow velocity, m / s.

[0084] Example 7

[0085] Select a pipeline to be tested. This pipeline is the oil gathering pipeline from Station A to Transfer and Water Injection Station B. The pipeline specification is L245N - Φ89×4.0, with a length of 10.0 km, an external transmission pressure of 3.0 MPa. Install an upstream pressure transmitter 1, a frequency converter 2 for the oil transfer pump, an upstream flowmeter 3, and the existing PLC 4 at the upstream station at Station A. Install a downstream pressure transmitter 5, a downstream flowmeter 6, a system component 8, and the existing PLC 7 at the downstream station at Station B. And install the leakage detection system software in the system component 8. Read the pipeline head pressure, flow rate, the operating status and frequency of the oil transfer pump at Station A from the corresponding registers of the existing PLC 4 at the upstream station at Station A through the communication network using the Modbus for TCP / IP protocol, with a sampling frequency of 10HZ; read the pipeline end pressure and flow rate from the corresponding registers of the existing PLC 7 at the downstream station at Station B, with a sampling frequency of 10HZ.

[0086] After running for a period of time, it is found that the difference ΔP between the upstream pressure and the downstream pressure is greater than 0.01MP, predicting that there is a leakage in the transportation pipeline. Calculate the leakage point position through the leakage position formula. Calculated by subtracting the time stamps of the head and end pressure signals read by the system software during leakage:

[0087] X

[0088]

[0089] Where L is 10.0km, a is 1100m / s, The calculated time is 0.25s, and X is 5137.5m, which means that a leakage point occurs 5137.5m away from the upstream station of the pipeline, and the leakage point needs to be repaired in time.

[0090] The working principle of the present invention is as follows:

[0091] The present invention includes an upstream site architecture and a downstream site architecture of the pipeline. An upstream pressure transmitter, an oil pump frequency converter, and an upstream flow meter are respectively arranged at the upstream site of the pipeline. The installation method is the conventional installation method of existing instruments, and the system is used to detect the pressure value, flow value, and oil pump frequency conversion frequency, etc. at the upstream site of the pipeline. The upstream pressure transmitter, the oil pump frequency converter, and the upstream flow meter are respectively connected to a PLC already built at the upstream site. The downstream pressure transmitter and the downstream flow meter are respectively arranged at the downstream site of the pipeline. The installation method is the conventional installation method of existing instruments, and the system is used to detect the pressure value, flow value, etc. at the downstream site of the pipeline. The downstream pressure transmitter and the downstream flow meter are respectively connected to a PLC already built at the downstream site. The PLC already built at the upstream site and the PLC already built at the downstream site are respectively connected to system components via a Modbus for TCP / IP protocol communication network. The system components can directly collect data from registers with fixed addresses of the PLC already built at the upstream site and the PLC already built at the downstream site, thereby reading signals from various detection instruments. No signal distributor or signal acquisition device is required, thereby reducing the overall cost of the leak detection system, reducing construction costs, reducing maintenance workload, and facilitating promotion and application.

[0092] The system components of the present invention include a computer and system software in the computer, wherein the system software is a leak detection system software. The leak detection system software analyzes the collected data to determine the pipeline leakage and locate the leak point. The specific implementation process is as follows:

[0093] like Figure 2 As shown, the length of the measured pipeline is L (m), the fluid flow rate is v (m / s), and the propagation speed of the negative pressure wave in the pipe at point X, which is the distance from the upstream end of the pipeline, is a. X (m / s), when a leak occurs at a distance of X meters from the upstream station of the pipeline, the time it takes for the negative pressure wave to reach the upstream station of the pipeline from the leak point is t1(s), and the time it takes to reach the end of the downstream station of the pipeline is t2(s), then we can get:

[0094] (1-1)

[0095] (1-2)

[0096] For this oil pipeline, the propagation speed of the negative pressure wave method takes a fixed value, which is considered to be above 1100 m / s in this application. The value of the fluid velocity V is about 2.5 m / s. Therefore, the flow velocity v of the crude oil in the pipeline can be ignored relative to the wave velocity of the negative pressure wave. The time difference between the upstream pressure transmitter and the downstream pressure transmitter receiving the negative pressure wave , substituting into (1-1) and (1-2) and simplifying, we get:

[0097] (1-3)

[0098] X (1-4)

[0099] X (1-5)

[0100] Equation (1-5) is the location of the leakage point. Among the three dependent variables, the pipeline length L is known, can be calculated by subtracting the timestamps of the pressure signals at the head and tail ends read by the software during leakage. Taking the negative pressure wave velocity as 1100 m / s and substituting it into the calculation, the leakage point location can be obtained.

[0101] The frequency of the system components of the present invention collecting data from the existing PLC at the upstream station or the existing PLC at the downstream station is the same as the frequency of the existing PLC at the upstream station or the existing PLC at the downstream station collecting data. The frequency of the existing PLC at the upstream station or the existing PLC at the downstream station collecting data is 10 HZ. In actual applications, since the pipeline pressure usually changes relatively slowly during leakage, collecting 10 signals per second can fully meet the needs of leakage detection, avoiding resource waste and reducing the operation process of huge data of the system components. This effectively improves the sensitivity of leakage detection.

[0102] The existing PLC at the upstream station and the existing PLC at the downstream station of the present invention obtain the standard time through the computer of the system components, and then use this time to label each collected data with a time tag, thereby achieving time synchronization and improving the accuracy of leakage location detection.

[0103] The leakage detection system architecture of the present invention for crude oil pipelines has a simple structure, is easy to implement, has a low operation cost, and is easy to promote and apply in the same type of architecture. At the same time, the leakage location detection method of the present invention locates the leakage through the negative pressure wave, has a reasonable calculation method, low calculation difficulty, and high accuracy of leakage location prediction.

[0104] The present invention provides a topological structure and an implementation method for a new leakage detection system of crude oil pipelines, which makes full use of the existing facilities of stations and pipelines, simplifies signal acquisition, and greatly reduces the construction cost and maintenance workload of the leakage detection system.

[0105] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those of ordinary skill in the art.

[0106] Many other changes and modifications can be made without departing from the concept and scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments, and the scope of the present invention is defined by the appended claims. The components and structures not described in detail in this embodiment are well-known components and common structures or common means in this industry, and will not be described one by one here.

Claims

1. A leakage location detection method for a crude oil pipeline leakage detection system architecture, characterized in that a crude oil pipeline leakage detection system architecture is adopted, wherein the system architecture includes a pipeline upstream site architecture and a pipeline downstream site architecture, wherein the pipeline upstream site architecture includes an upstream pressure transmitter, an oil pump frequency converter, an upstream flow meter and a PLC already built at the upstream site, wherein the upstream pressure transmitter, the oil pump frequency converter and the upstream flow meter are respectively arranged at the upstream site of the pipeline, wherein the upstream pressure transmitter, the oil pump frequency converter and the upstream flow meter are respectively connected to the PLC already built at the upstream site, and the downstream site architecture includes a downstream pressure transmitter, a downstream flow meter, a PLC already built at the downstream site and system components, wherein the downstream pressure transmitter and the downstream flow meter are respectively arranged at the downstream site of the pipeline, wherein the downstream pressure transmitter and the downstream flow meter are respectively connected to the PLC already built at the downstream site, wherein the PLC already built at the upstream site and the PLC already built at the downstream site are respectively communicated via a communication network using Modbus for TCP. / IP protocol is used to connect system components, where the system components can directly collect data from the existing PLCs at upstream sites and downstream sites; the frequency at which the system components collect data from the existing PLCs at upstream sites or downstream sites is the same as the frequency at which the existing PLCs at upstream sites or downstream sites collect data; the current of the upstream pressure transmitter, oil pump frequency converter, and upstream flow meter are all 4-20mA, where the current of the downstream pressure transmitter and downstream flow meter are both 4-20mA; the existing PLC at the upstream site stores the collected upstream pressure, upstream flow, and external pump frequency converter frequency signals in a register with a fixed address, where the existing PLC at the downstream site stores the collected downstream pressure and downstream flow in a register with a fixed address; both the existing PLC at the upstream site and the existing PLC at the downstream site can obtain standard time through the system component's computer, and then use this time to time-tag each collected data, thereby achieving time synchronization; The leakage location detection method of the crude oil pipeline leakage detection system architecture includes the following steps: Step 1) The system components collect upstream pressure, upstream flow, and the frequency signal of the output pump inverter through the PLC installed at the upstream site. The system components also collect downstream pressure and flow through the PLC installed at the downstream site. At the same time, the system components obtain the standard time and then use this time to time-tag each collected data, thus achieving time synchronization. Step 2) Compare the collected upstream pressure and upstream instantaneous flow rate with the downstream pressure and downstream instantaneous flow rate. When the difference between the upstream pressure and the downstream pressure is greater than ΔP, or the difference between the upstream instantaneous flow rate and the downstream instantaneous flow rate is greater than ΔQ, it is determined that there is a leak in the transmission pipeline. When the difference between the upstream pressure and the downstream pressure is less than ΔP, or the difference between the upstream instantaneous flow rate and the downstream instantaneous flow rate is less than ΔQ, it is determined that there is no leak in the transmission pipeline. Step 3) When a leak is determined in the pipeline, the leak point is located using the leak location formula. The leak location formula uses a negative pressure wave to locate the leak point, and then the leak point is repaired. The method for determining ΔP is as follows: Step 2-1) For a pipeline operating smoothly, the system component extracts a set of upstream pressure data sequences {Pa0, Pa1, Pa2…Pan} during normal operation of the pipeline, and then extracts a set of downstream pressure data sequences {Pb0, Pb1, Pb2…Pbn}. The data sequences are collected within 24 hours with a sampling interval of 1 second, thereby obtaining the data sequence length n; Step 2-2) Calculate the difference between the two data series to obtain a data series of upstream and downstream pressure differences {Pc0, Pc1, Pc2…Pcn}; apply Kalman filtering to this data series to smooth it and then calculate the average to obtain PC, which is the reasonable difference between upstream and downstream pressures under normal conditions; Steps 2-3) Multiply PC by the corresponding amplification factor μ to obtain ΔP. The amplification factor μ can be set in the system components. The range of the amplification factor μ is: 1.05-1.2, the method for determining ΔQ is the same as the method for determining ΔP.

2. The method for detecting a leak position of a crude oil pipeline leak detection system according to claim 1, characterized in that: The system components include a computer and system software in the computer, wherein the system software is provided with a data reading module, wherein the data reading module can directly read data from a register through the Modbus for TCP / IP protocol.

3. The method for detecting a leak position of a crude oil pipeline leak detection system according to claim 1, characterized in that: The frequency of data collection by the PLC built at the upstream site or the PLC built at the downstream site is 10HZ.

4. The method for detecting a leak position of a crude oil pipeline leak detection system according to claim 1, characterized in that: The leak location formula is: Where: X-the distance from the release leakage point to the upstream station of the pipeline, m; a- propagation speed of negative pressure wave, m / s; L-the length of the measured pipeline, m; -The time difference between the upstream and downstream pressure transmitters receiving the negative pressure wave; v-fluid velocity, m / s.

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