Electrochemical impedance spectroscopy remote measurement and transmission method and system for pipeline corrosion

Abstract

The invention relates to a pipeline corrosion-oriented electrochemical impedance spectroscopy remote measurement and transmission method and a pipeline corrosion-oriented electrochemical impedance spectroscopy remote measurement and transmission system. Firstly, a signal excitation module is connected to the input end of a probe of the pipeline corrosion sensor, small-amplitude excitation current signals with different frequencies are input to the pipeline corrosion sensor by controlling the signal excitation module, and then response voltage signals output by the pipeline corrosion sensor are collected by a signal collection module; the excitation signal data and the response signal data are subjected to a traditional impedance calculation method to obtain an electrochemical impedance spectrum, and finally, the obtained electrochemical impedance spectrum data are transmitted to a cloud server through a remote data transmission module. The method solves the problems that a traditional pipeline corrosion electrochemical impedance spectroscopy measurement method is long in single time consumption, heavy and expensive in equipment and incapable of achieving real-time online collection and transmission, has the advantages of being low in cost, mature in application technology, capable of achieving multi-point arrangement and real-time monitoring on the pipeline and the like, and has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of pipeline corrosion detection, and particularly relates to an electrochemical impedance spectroscopy remote measurement and transmission method and system for pipeline corrosion. Background Art

[0002] As of the end of 2022, China has achieved remarkable achievements in long-distance oil and gas transmission pipelines, including international and domestic pipelines, with a total length of more than 180,000 kilometers. To ensure the safe and stable operation of the oil and gas pipeline network, it is necessary to establish a safety status monitoring technology system for risk factors, timely discover potential accident hazards and early accidents through monitoring, conduct early warning and forecasting, and avoid failure behaviors such as oil and gas leakage. Corrosion is one of the main causes of oil and gas pipeline accidents. Corrosion monitoring is an important part of safety status monitoring and an important means to ensure operation safety.

[0003] Regarding the monitoring of pipeline corrosion status, the existing pipeline corrosion monitoring sensors can be generally divided into the following types according to the principle: coupon off - line method, weight loss inspection method, corrosion fracture insurance cable, CUI Corrosometer resistance method. These existing methods are all designed from the perspective of detecting corrosion results and belong to physical inspection methods. They are all off - line detections and have the problem of being unable to provide real - time corrosion detection rates. Moreover, the above - mentioned methods have high costs and are only suitable for installation in key pipeline corrosion risk areas and cannot be deployed at multiple points on long - distance pipelines, resulting in low corrosion detection accuracy. Summary of the Invention

[0004] Aiming at the above - mentioned deficiencies in the prior art, the purpose of the present invention is to provide an electrochemical impedance spectroscopy remote measurement and transmission method and system for pipeline corrosion, mainly used to design and implement a remote measurement and transmission method and system that can be arranged at multiple points on long - distance transmission pipelines and can monitor and collect the electrochemical impedance spectroscopy data of pipeline corrosion probes in real time, so as to achieve precise monitoring of the corrosion status of long - distance transmission pipelines. First, a signal excitation module is connected to the input end of the pipeline corrosion sensor, and a small - amplitude excitation current signal with different frequencies is input to the pipeline corrosion sensor by controlling the signal excitation module. Then, the signal acquisition module is used to collect the response voltage signal output by the pipeline corrosion sensor. The electrochemical impedance spectroscopy is obtained by using the traditional impedance calculation method for the excitation signal data and the response signal data. Then, the obtained electrochemical impedance spectroscopy data is transmitted to the cloud server through the remote data transmission module. Finally, the collected electrochemical impedance spectroscopy data is analyzed and processed on the cloud server to achieve real - time monitoring of the pipeline corrosion situation at that place.

[0005] The technical solution adopted by the present invention to achieve the above purpose: The electrochemical impedance spectroscopy remote measurement and transmission method for pipeline corrosion includes the following steps:

[0006] Generation of small - amplitude excitation signals: By controlling the signal excitation module connected to the input end of the pipeline corrosion sensor, small - amplitude excitation current signals of different frequencies are generated;

[0007] Collection of response signals: The response signal acquisition module collects the response voltage signals generated by the pipeline corrosion sensor excited by the excitation current signal;

[0008] Calculation of impedance spectrum: The main control module calculates the response voltage signals and excitation current signals at different frequencies respectively to obtain the electrochemical complex impedance information at different frequencies, and then combines the electrochemical complex impedance information of all frequencies to form an electrochemical impedance spectrum;

[0009] Remote data transmission: The obtained electrochemical impedance spectrum is transmitted to the cloud server through the remote transmission module.

[0010] The small - amplitude excitation current signals of different frequencies are generated by the digital frequency synthesis chip in the signal excitation module to replace the generation of excitation signals of different frequencies by a frequency divider; by reducing the main frequency of the main control module and inputting a frequency input signal of 0.01 Hz - 1 MHz to the signal excitation module, the digital frequency synthesis chip in the signal excitation module generates a sinusoidal excitation signal of 0.01 Hz - 1 MHz.

[0011] The collection of the response signal includes the following steps:

[0012] Read the pre - set lower limit f L of the measurement frequency of the electrochemical impedance spectrum, the upper limit f H and the number of measurement points, and then equally divide the entire measurement frequency range into M parts according to the number of measurement points, and then start from the lower limit f L of the measurement frequency to sequentially collect the electrochemical impedance spectrum data at each frequency point:

[0013] 1) For the frequency of the current acquisition point, while inputting the excitation signal to the pipeline corrosion sensor, the main control module uses the built - in analog - to - digital converter to collect the excitation current signal i(t) of the excitation signal and store it;

[0014] 2) Control the response signal acquisition module to collect the response signal V(t) of the pipeline corrosion sensor, and the acquisition frequency is selected according to the region where the current frequency is located; when the amplitude of the response voltage signal collected by the response signal acquisition module at the current frequency exceeds more than half of the amplitude of the response voltage signal at the previous frequency point, it is considered that there is a fault in the response signal acquisition at this frequency point, and re - acquisition is performed;

[0015] 3) After collecting the response signal at the current frequency point, record the collected excitation current signal i(t) and response signal V(t) at the current frequency point, then set the excitation frequency f to the next frequency point, and return to step 1);

[0016] The acquisition excitation current signal i(t) and the response signal V(t) at M frequency points are respectively subjected to fast Fourier transform to be converted into frequency domain signals i(ω) and V(ω), and then electrochemical complex impedance data at each frequency point is calculated according to the electrochemical impedance spectrum calculation formula Z(ω) = V(ω) / i(ω) to form electrochemical impedance spectrum data, which is transmitted to the remote data transmission module.

[0017] The acquisition frequency is selected according to the region where the current frequency is located. Different sampling frequencies are used to collect the response voltage signals at different frequencies. The response voltage signal generated by the low-frequency excitation signal is collected with a lower sampling frequency, and the response voltage signal generated by the high-frequency excitation signal is collected with a higher sampling frequency:

[0018] When the response voltage signal is in the range of 0.01 Hz to 1 Hz, the response signal acquisition module collects it at a sampling frequency of 10 Hz;

[0019] When the response voltage signal is in the range of 1 Hz to 100 Hz, the response signal acquisition module collects it at a sampling frequency of 1 kHz;

[0020] When the response voltage signal is in the range of 100 Hz to 10 kHz, the response signal acquisition module collects it at a sampling frequency of 100 kHz;

[0021] When the response voltage signal is in the range of 10 kHz to 1 MHz, the response signal acquisition module collects it at a sampling frequency of 10 MHz.

[0022] The data remote transmission wirelessly transmits the calculated electrochemical impedance spectrum data to the cloud server for storage through the 4G network communication module.

[0023] The remote measurement and transmission system for electrochemical impedance spectrum for pipeline corrosion includes:

[0024] A signal excitation module, which uses a digital frequency synthesis chip and takes the clock signal output by the main control module as input, and is used to input small-amplitude excitation current signals with different frequencies to the pipeline corrosion sensor;

[0025] A response signal acquisition module, which uses an analog-to-digital converter, is used to collect the analog response voltage signal generated by the pipeline corrosion sensor under the excitation of the excitation signal, and perform analog-to-digital conversion, and transmit the digital response voltage signal to the main control module;

[0026] The main control module, which uses an embedded processor, is used to collect small-amplitude excitation current signals output by the signal excitation module at different frequencies through the internal analog-to-digital converter of the embedded processor, and then, together with the response voltage signal sent by the response signal collection module, obtain the electrochemical impedance spectrum of the pipeline corrosion sensor according to the electrochemical impedance calculation formula, and transmit the electrochemical impedance spectrum to the remote data transmission module;

[0027] The remote data transmission module, which uses a 4G transmission module, is used to transmit the electrochemical impedance spectrum transmitted by the main control module to the cloud server in a wireless transmission form;

[0028] The signal excitation module uses a digital frequency synthesis chip to replace the frequency divider to generate small-amplitude excitation current signals at different frequencies.

[0029] The main control module performs the following steps:

[0030] Read the preset lower limit f of the electrochemical impedance spectrum measurement frequency L and upper limit f H of the measurement, as well as the number of measurement points, and then equally divide the entire measurement frequency range into M parts according to the number of measurement points, and then start from the lower limit f of the measurement frequency L Perform data acquisition on the electrochemical impedance spectrum data of each frequency point in turn:

[0031] 1) Then, according to the frequency of the current acquisition point, control the signal excitation module to generate an excitation signal. While inputting the excitation signal into the pipeline corrosion sensor, the main control module uses the built-in analog-to-digital converter to collect the excitation current signal i(t) of the excitation signal and store it;

[0032] 2) Control the response signal collection module to collect the response signal V(t) of the pipeline corrosion sensor, and the acquisition frequency is selected according to the area where the current frequency is located; when the amplitude of the response voltage signal of the current frequency collected by the response signal collection module exceeds half of the amplitude of the response voltage signal of the previous frequency point, it is considered that a failure occurs in the response signal acquisition of this frequency point, and re-acquisition is performed;

[0033] 3) After collecting the response signal of the current frequency point, record the collected excitation current signal i(t) and response signal V(t) of the current frequency point, and then set the excitation frequency f to the next frequency point, and return to step 1);

[0034] Perform fast Fourier transform on the collected excitation current signals i(t) and response signals V(t) of M frequency points respectively to convert them into frequency domain signals i(w) and V(w), and then calculate the electrochemical complex impedance data of each frequency point according to the electrochemical impedance spectrum calculation formula Z(ω) = V(ω) / i(ω) to form electrochemical impedance spectrum data, and transmit it to the remote data transmission module.

[0035] The present invention relates to a remote measurement and transmission method and system for electrochemical impedance spectroscopy for pipeline corrosion. It has the following advantages:

[0036] 1. Fast measurement speed. In the method of the present invention, an excitation signal of different frequencies is generated by a control signal excitation module and input into a pipeline corrosion sensor, and then a response signal acquisition module acquires the response signal of the corrosion sensor. Electrochemical impedance spectroscopy data is obtained by using an electrochemical impedance calculation method. Compared with the traditional electrochemical impedance spectroscopy analysis station, the measurement time is significantly shortened, so that online monitoring of the pipeline corrosion state can be realized.

[0037] 2. Lightweight and easy to deploy on-site. The electrochemical impedance spectroscopy remote measurement system in the method of the present invention is more portable than the heavy traditional electrochemical impedance spectroscopy analysis station. In addition, compared with the method of transmitting and collecting data through cables in the electrochemical impedance spectroscopy analysis station, this method uses wireless transmission, eliminating the layout of transmission cables during on-site application, providing a basis for the application of this system in long-distance transportation pipelines.

[0038] 3. Low cost and easy to implement. The embedded processor, 16-bit analog-to-digital conversion chip, digital frequency synthesis chip, 4G communication module and supporting standard peripheral hardware circuits selected in the method of the present invention have been widely used in the fields of industrial control and intelligent detection. Therefore, the overall hardware development workload is relatively small, and the hardware cost is also relatively low. In addition, the small-amplitude excitation signal generation technology, remote data transmission technology, and electrochemical impedance spectroscopy measurement technology adopted in the present invention are all mature application technologies, and the software development difficulty of the system is relatively low.

[0039] 4. High real-time corrosion detection accuracy. The digital frequency synthesis chip adopted in the present invention can generate a sine excitation signal of 0.01 Hz - 1 MHz. The generated excitation signal has good quality, and the controlled frequency fineness is higher. For the excitation signals of different frequencies generated by a frequency divider, the frequency band is narrow and the quality of the excitation signal is poor, which will cause obvious jitter in the generated response signal and reduce the acquisition accuracy of electrochemical impedance spectroscopy data. In addition, the present invention adopts different sampling frequencies for the response voltage signals of different frequencies. The response voltage signal generated by a low-frequency excitation signal is collected with a lower sampling frequency, and the response voltage signal generated by a high-frequency excitation signal is collected with a higher sampling frequency, which can improve the single-time electrochemical impedance spectroscopy data acquisition speed and the overall acquisition efficiency while ensuring the data acquisition accuracy. Description of the Drawings

[0040] Figure 1 is a block diagram of an implementation example of the remote measurement and transmission method and system for electrochemical impedance spectroscopy for pipeline corrosion in the method of the present invention;

[0041] Figure 2 It is a schematic flow diagram of the electrochemical impedance spectroscopy remote measurement and transmission method for pipeline corrosion in the method of the present invention;

[0042] Figure 3 It is a graph of the electrochemical impedance spectroscopy measured in the implementation example of the method of the present invention. Specific implementation manners

[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings and implementation examples.

[0044] An electrochemical impedance spectroscopy remote measurement and transmission method for pipeline corrosion, which is used to monitor and collect the electrochemical impedance spectroscopy data of pipeline corrosion probes in real time and remotely transmit them, so as to achieve accurate monitoring of the corrosion state of long-distance transmission pipelines, and includes the following steps:

[0045] Generation of small-amplitude excitation signals, and different-frequency small-amplitude excitation current signals are generated by controlling the signal excitation module connected to the input end of the pipeline corrosion sensor;

[0046] Collection of response signals, the response signal collection module is connected to the output end of the pipeline corrosion sensor, and the response voltage signal generated by the pipeline corrosion sensor under the excitation of the excitation signal is collected;

[0047] Calculation of impedance spectroscopy, the response voltage signals at different frequencies are respectively calculated with the excitation current signals to obtain the electrochemical complex impedance information at different frequencies, and then the electrochemical complex impedance information at all frequencies is combined to form an electrochemical impedance spectroscopy;

[0048] Remote data transmission, the calculated electrochemical impedance spectroscopy data is transmitted to the cloud server through the remote transmission module.

[0049] The generation of the small-amplitude excitation signal is to control the digital frequency synthesis chip by the controller to generate small-amplitude sine excitation signals of different frequencies and input them to the input end of the pipeline corrosion sensor. Compared with generating excitation signals of different frequencies through a frequency divider, the generated small-amplitude sine excitation signal has a wider frequency band.

[0050] The generation of the small-amplitude excitation signal is to input an extremely low-frequency input signal to the signal excitation module by reducing the main frequency of the controller, so that the digital frequency synthesis chip in the excitation module generates a sine excitation signal with a minimum of 0.01 Hz.

[0051] For the collection of the response signals, different sampling frequencies are used to collect the response voltage signals at different frequencies. The response voltage signals generated by low-frequency excitation signals are collected with a lower sampling frequency, and the response voltage signals generated by high-frequency excitation signals are collected with a higher sampling frequency, so as to reduce the signal collection time while ensuring the collection accuracy of the response signals.

[0052] The response signal acquisition has an acquisition error correction mechanism. Since the complex impedance at each frequency in the electrochemical impedance spectrum of the pipeline corrosion sensor changes continuously in terms of mechanism, when the amplitude of the response voltage signal at the current frequency collected by the signal acquisition module exceeds half of the amplitude of the response voltage signal at the previous frequency point, it is considered that there is a fault in the response signal acquisition at this frequency point, and the acquisition is restarted.

[0053] The impedance spectrum calculation is that the controller calculates according to the electrochemical impedance spectrum calculation formula, calculates the response voltage signal and the excitation current signal at different frequencies respectively, obtains the electrochemical complex impedance information at different frequencies, and then combines the electrochemical complex impedance information at all frequencies to form an electrochemical impedance spectrum.

[0054] The data remote transmission is to wirelessly transmit the electrochemical impedance spectrum data calculated by the controller to the cloud server for storage through the 4G network communication module.

[0055] An electrochemical impedance spectrum remote measurement and transmission system for pipeline corrosion includes the following parts:

[0056] Signal excitation module: With a digital frequency synthesis chip as the core unit, taking the clock signal output by the main control module as the input, and outputting small-amplitude sine excitation signals with different frequencies to the output end of the pipeline corrosion sensor;

[0057] Response signal acquisition module: With an analog-to-digital converter as the core unit, collecting the analog response voltage signal generated by the pipeline corrosion sensor under the excitation of the excitation signal, and converting the analog response voltage signal into a digital signal and transmitting it to the main control module;

[0058] Main control module: With an embedded processor as the core unit, using the 16-bit analog-to-digital converter inside the embedded processor to collect the small-amplitude sine signals output by the signal excitation module at different frequencies, and then combining with the response voltage digital signal transmitted by the response signal acquisition module, calculating the electrochemical impedance spectrum of the pipeline corrosion sensor according to the traditional electrochemical impedance calculation formula, and transmitting the electrochemical impedance data to the remote data transmission module;

[0059] Remote data transmission module: With a 4G transmission module as the core unit, transmitting the electrochemical impedance spectrum data transmitted by the main control module to the cloud server in a wireless transmission form;

[0060] Figure 1It is a specific application example of an electrochemical impedance spectroscopy remote measurement and transmission system for pipeline corrosion; the system takes the main control module as the core, controls the signal excitation module to generate a sine excitation signal with a frequency range of 0.01 Hz to 1 MHz to excite the pipeline corrosion sensor probe, and collects the small-amplitude sine excitation signal generated by the signal excitation module. Then, the main control module controls the response signal acquisition module to collect the response signal generated by the pipeline corrosion sensor probe; then the main control module calculates the electrochemical impedance spectroscopy information of the pipeline corrosion sensor probe according to the electrochemical impedance spectroscopy calculation formula, and finally wirelessly transmits it to the cloud server through the 4G network communication module for storage. The following combines the actual acquisition and transmission process to specifically introduce each functional module, and combines each functional module to introduce in detail the specific process of remote measurement and transmission of electrochemical impedance spectroscopy for pipeline corrosion in the method of the present invention.

[0061] Signal excitation module: The signal excitation module is mainly responsible for generating excitation signals with different frequencies input to the pipeline corrosion sensor probe. The traditional excitation signal generation method is to continuously divide the fundamental wave signal by a frequency divider to generate signals with different frequencies, but the excitation signals generated by this method have a narrow frequency band and poor amplitude quality of the excitation signals. In this method, the main control module controls the digital frequency synthesis chip to generate small-amplitude sine excitation signals with different frequencies, and the generated excitation signals have good quality and higher frequency fineness in control. In addition, the frequency of the excitation signal generated by the digital frequency synthesis chip is positively correlated with the input signal frequency generated by the control module. However, when the main control module is operating normally, the main control module cannot generate ultra-low frequency signals. Therefore, this method adjusts the working mode of the main control module through software, that is, reduces the working frequency of the main control module when ultra-low frequency excitation signals need to be generated, so that the signal excitation module generates low-frequency signals with a frequency range of 0.01 Hz to 1 Hz. Among them, the digital frequency synthesis chip selects the AD9382 chip of ADI Company.

[0062] Response signal acquisition module: The response signal acquisition module is mainly responsible for acquiring the analog response voltage signal generated by the pipeline corrosion sensor under the excitation of the excitation signal, and converting the analog response voltage signal into a digital signal and transmitting it to the main control module. Since the frequency of the response signal generated by the pipeline corrosion sensor under excitation is the same as that of the excitation signal generated by the signal excitation module, the response signal acquisition module needs to acquire a wide range of frequency response signals from 0.01 Hz to 1 MHz. If the same acquisition frequency is used according to the traditional acquisition method, it will lead to too long sampling time in the low-frequency acquisition stage and low acquisition accuracy in the high-frequency acquisition stage. Therefore, this method adopts a segmented acquisition method, that is, in the range of 0.01 Hz - 1 Hz, the response signal acquisition module acquires the response signal at a sampling frequency of 10 Hz; in the range of 1 Hz - 100 Hz, the response signal acquisition module acquires the response signal at a sampling frequency of 1 KHz; in the range of 100 Hz - 10 KHz, the response signal acquisition module acquires the response signal at a sampling frequency of 100 KHz; in the range of 10 KHz - 1 MHz, the response signal acquisition module acquires the response signal at a sampling frequency of 10 MHz. By using a lower sampling frequency to acquire low-frequency response signals and a higher sampling frequency to acquire high-frequency response signals, this method can effectively reduce the overall sampling time while ensuring the acquisition accuracy of each frequency band.

[0063] Remote data transmission module: The remote data transmission module is mainly responsible for remotely transmitting the electrochemical impedance spectroscopy data of the pipeline corrosion sensor transmitted by the main control module to a remote server. The core of the remote data transmission module is a 4G wireless transmission module. The data transmitted by the main control module forms a message according to the wireless network transmission protocol and is transmitted to the server deployed in the cloud through the 4G network. Using this method can effectively solve the problem of laying the acquisition and transmission optical cable for the pipeline corrosion sensor of long-distance transmission pipelines, making it possible to realize real-time online monitoring of the corrosion of long-distance transmission pipelines.

[0064] Main control module: The main control module is the core of the entire remote measurement and transmission method and system for the electrochemical impedance spectroscopy of pipeline corrosion, and is responsible for controlling the signal excitation module, the response signal acquisition module, and the remote data transmission module to complete the measurement and transmission function of the electrochemical impedance spectroscopy of the pipeline corrosion sensor probe. In this implementation example, the embedded processor of the main control module selects the STM32F431 model embedded microprocessor of STMicroelectronics. This model of processor has the advantages of powerful performance, stable and mature, and wide application in the industrial control field. Moreover, this model of processor supports many peripheral device interfaces, meeting the interface requirements of other modules of the entire system. The following combines Figure 2 A schematic diagram of the process of a remote measurement and transmission method for the electrochemical impedance spectroscopy of pipeline corrosion to specifically introduce how the main control module controls other functional modules to realize the remote measurement and transmission of the electrochemical impedance spectroscopy of the pipeline corrosion sensor probe.

[0065] First, the main control module reads the preset lower limit, upper limit, and number of measurement points of the electrochemical impedance spectroscopy measurement frequency. In this embodiment, the lower limit f of the electrochemical impedance spectroscopy measurement frequency L = 0.01 Hz, the upper limit f of the electrochemical impedance spectroscopy measurement frequency H = 1 MHz, and the number of measurement points is 51. Then, the entire measurement frequency range is equally divided into 50 parts according to the number of measurement points. Then, data acquisition of the electrochemical impedance spectroscopy data for each frequency point is sequentially performed starting from the lower limit of the measurement frequency. Then, according to the frequency of the current acquisition point, the main control module controls the signal excitation module to generate an excitation signal. While inputting the excitation signal into the pipeline corrosion sensor, the internal embedded processor STM32F431 of the main control module uses the internally built 16-bit high-precision analog-to-digital converter to collect the current signal i(t) of the excitation signal. Since the 16-bit high-precision analog-to-digital converter inside STM32F431 is a voltage-type analog-to-digital converter and the output is a voltage signal, the main control module converts the voltage signal collected by the 16-bit high-precision analog-to-digital converter into the current signal i(t) for storage. Next, the main control module controls the 16-bit high-precision analog-to-digital converter of the response signal acquisition module to collect the response signal V(t) of the pipeline corrosion sensor. The acquisition frequency is selected according to the region where the current frequency is located. Since the complex impedance at each frequency in the electrochemical impedance spectroscopy of the pipeline corrosion sensor changes continuously in principle, when the amplitude of the response voltage signal at the current frequency collected by the response signal acquisition module exceeds half of the amplitude of the response voltage signal at the previous frequency point, it is considered that a failure occurs in the response signal acquisition at this frequency point, and re-acquisition is performed. When the response signal at the current frequency point is successfully and accurately acquired, the collected excitation signal i(t) and response signal V(t) at the current frequency point are recorded. Then, the excitation frequency f is set to the next frequency point, and the above operations are repeated.

[0066] Next, the collected excitation signal i(t) and response signal V(t) at each frequency point are respectively subjected to fast Fourier transform to be converted into frequency-domain signals i(ω) and V(ω). Then, according to the electrochemical impedance spectroscopy calculation formula Z(ω) = V(ω) / i(ω), where Z(ω) represents impedance, the electrochemical complex impedance data at each frequency point is calculated. Finally, the electrochemical impedance spectroscopy data of the collected pipeline corrosion sensor is transmitted to the cloud server in a wireless transmission manner through the remote data transmission module. Figure 3 is the electrochemical impedance spectroscopy curve obtained based on the electrochemical impedance spectroscopy data of the pipeline corrosion sensor read from the cloud server database. The abscissa is the real part data of the electrochemical complex impedance of the pipeline corrosion sensor, and the ordinate is the imaginary part data of the electrochemical complex impedance of the pipeline corrosion sensor. The shape of the electrochemical impedance spectroscopy curve in the figure is very close to the theoretical electrochemical impedance spectroscopy curve of the pipeline corrosion sensor.

Claims

1. A remote measurement and transmission method of electrochemical impedance spectroscopy for pipeline corrosion, characterized in that: The following steps are involved: Small amplitude excitation signal generation: small amplitude excitation current signals of different frequencies are generated by controlling the signal excitation module connected to the input end of the pipeline corrosion sensor; Response signal acquisition: The response signal acquisition module is used to acquire the response voltage signal generated by the pipeline corrosion sensor after being stimulated by the excitation current signal; Impedance spectrum calculation: The main control module calculates the response voltage signal and the excitation current signal at different frequencies respectively to obtain the electrochemical complex impedance information at different frequencies, and then combines the electrochemical complex impedance information of all frequencies to form an electrochemical impedance spectrum; Remote data transmission: The obtained electrochemical impedance spectrum is transmitted to the cloud server through the remote transmission module.

2. The electrochemical impedance spectroscopy remote measurement and transmission method for pipeline corrosion according to claim 1 is characterized in that: The small-amplitude excitation current signals of different frequencies are generated by a digital frequency synthesis chip in the signal excitation module to replace the excitation signals of different frequencies generated by a frequency divider; by reducing the main frequency of the main control module, a 0.01Hz to 1MHz frequency input signal is input to the signal excitation module, so that the digital frequency synthesis chip in the signal excitation module generates a 0.01Hz to 1MHz sinusoidal excitation signal.

3. The electrochemical impedance spectroscopy remote measurement and transmission method for pipeline corrosion according to claim 1 is characterized in that: The response signal collection comprises the following steps: Read the preset lower limit of the electrochemical impedance spectroscopy measurement frequency f L , measurement upper limit f H And the number of measurement points, then divide the entire measurement frequency range into M parts in equal proportion according to the number of measurement points, and then start from the measurement frequency lower limit f L The electrochemical impedance spectroscopy data of each frequency point are collected in turn: 1) For the frequency of the current acquisition point, while inputting the excitation signal to the pipeline corrosion sensor, the main control module uses the internal analog-to-digital converter to collect and store the excitation current signal i(t) of the excitation signal; 2) Control the response signal acquisition module to acquire the response signal V(t) of the pipeline corrosion sensor, and the acquisition frequency is selected according to the area where the current frequency is located; when the response signal acquisition module acquires that the amplitude of the response voltage signal of the current frequency exceeds the amplitude of the response voltage signal of the previous frequency point by more than half, it is considered that the response signal acquisition of the frequency point has a fault, and the acquisition is performed again; 3) After collecting the response signal at the current frequency point, record the collected excitation current signal i(t) and the response signal V(t) at the current frequency point, then set the excitation frequency f to the next frequency point, and return to step 1); The collected excitation current signal i(t) and response signal V(t) at M frequency points are respectively converted into frequency domain signals i(w) and V(w) by fast Fourier transform. Then, the electrochemical complex impedance data of each frequency point is calculated according to the electrochemical impedance spectrum calculation formula Z(ω)=V(ω)i(ω) to form electrochemical impedance spectrum data, and transmitted to the remote data transmission module.

4. The electrochemical impedance spectroscopy remote measurement and transmission method for pipeline corrosion according to claim 3 is characterized in that: The acquisition frequency is selected according to the region where the current frequency is located. Different sampling frequencies are used for acquisition of response voltage signals of different frequencies. The response voltage signal generated by the low-frequency excitation signal adopts a lower sampling frequency for data acquisition, and the response voltage signal generated by the high-frequency excitation signal adopts a higher sampling frequency for data acquisition: The response voltage signal is in the range of 0.01Hz to 1Hz, and the response signal acquisition module uses a sampling frequency of 10Hz for acquisition; The response voltage signal is in the range of 1Hz to 100Hz, and the response signal acquisition module uses a 1KHz sampling frequency for acquisition; The response voltage signal is in the range of 100Hz to 10KHz, and the response signal acquisition module uses a sampling frequency of 100KHz for acquisition; The response voltage signal is in the range of 10KHz to 1MHz, and the response signal acquisition module uses a 10MHz sampling frequency for acquisition.

5. The electrochemical impedance spectroscopy remote measurement and transmission method for pipeline corrosion according to claim 1 is characterized in that: The data remote transmission wirelessly transmits the calculated electrochemical impedance spectroscopy data to a cloud server via a 4G network communication module for storage.

6. The electrochemical impedance spectroscopy remote measurement and transmission system for pipeline corrosion is characterized by: include: The signal excitation module uses a digital frequency synthesis chip and takes the clock signal output by the main control module as input to input small-amplitude excitation current signals of different frequencies to the pipeline corrosion sensor; The response signal acquisition module uses an analog-to-digital converter to collect the analog response voltage signal generated by the pipeline corrosion sensor after being stimulated by the excitation signal, and performs analog-to-digital conversion to transmit the digital response voltage signal to the main control module; The main control module uses an embedded processor to collect the small-amplitude excitation current signal output by the signal excitation module at different frequencies through the internal analog-to-digital converter of the embedded processor, and then obtain the electrochemical impedance spectrum of the pipeline corrosion sensor according to the electrochemical impedance calculation formula by combining it with the response voltage signal sent by the response signal acquisition module, and transmit the electrochemical impedance spectrum to the remote data transmission module; The remote data transmission module adopts a 4G transmission module to transmit the electrochemical impedance spectrum transmitted by the main control module to the cloud server via wireless transmission.

7. The electrochemical impedance spectroscopy remote measurement and transmission system for pipeline corrosion according to claim 6 is characterized in that: The signal excitation module adopts a digital frequency synthesis chip to replace the frequency divider to generate small amplitude excitation current signals with different frequencies.

8. The electrochemical impedance spectroscopy remote measurement and transmission system for pipeline corrosion according to claim 6 is characterized in that: The main control module performs the following steps: Read the preset lower limit of the electrochemical impedance spectroscopy measurement frequency f L , measurement upper limit f H And the number of measurement points, then divide the entire measurement frequency range into M parts in equal proportion according to the number of measurement points, and then start from the measurement frequency lower limit f L The electrochemical impedance spectroscopy data of each frequency point are collected in turn: 1) Then, according to the frequency of the current acquisition point, the control signal excitation module generates an excitation signal. While the excitation signal is input to the pipeline corrosion sensor, the main control module uses the internal analog-to-digital converter to collect and store the excitation current signal i(t) of the excitation signal; 2) Control the response signal acquisition module to acquire the response signal V(t) of the pipeline corrosion sensor, and the acquisition frequency is selected according to the area where the current frequency is located; when the response signal acquisition module acquires that the amplitude of the response voltage signal of the current frequency exceeds the amplitude of the response voltage signal of the previous frequency point by more than half, it is considered that the response signal acquisition of the frequency point has a fault, and the acquisition is performed again; 3) After collecting the response signal at the current frequency point, record the collected excitation current signal i(t) and the response signal V(t) at the current frequency point, then set the excitation frequency f to the next frequency point, and return to step 1); The collected excitation current signal i(t) and response signal V(t) at M frequency points are respectively converted into frequency domain signals i(w) and V(w) by fast Fourier transform. Then, the electrochemical complex impedance data of each frequency point is calculated according to the electrochemical impedance spectrum calculation formula Z(ω)=V(ω)i(ω) to form electrochemical impedance spectrum data, and transmitted to the remote data transmission module.

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