Natural gas pipeline wireless heat tracing system based on photovoltaic power supply

Abstract

The embodiment of the specification provides a natural gas pipeline wireless heat tracing system based on photovoltaic power supply, wherein the method comprises the following steps: a distributed photovoltaic array is used for receiving solar energy by using a plurality of photovoltaic power generation panels and converting the solar energy into a plurality of groups of electric energy; a current combiner box is connected with the distributed photovoltaic array and is used for current combination of the plurality of groups of electric energy; a direct-current power distribution cabinet is connected with the current combiner box and is used for current equalization and voltage equalization adjustment of the current after combination; an inverter is connected with the direct-current power distribution cabinet and is used for converting direct-current electric energy into high-frequency alternating-current electric energy which can be wirelessly transmitted by a pipeline coil; an infinite heat tracing structure is connected with the inverter and is used for rectifying the alternating-current high-frequency electric energy into direct-current electric energy to provide energy for heat generation; and a data acquisition and control system is connected with the infinite heat tracing structure and is used for data acquisition from the infinite heat tracing structure and control of the infinite heat tracing structure.

Description

TECHNICAL FIELD

[0001] The present document relates to the technical field of electricity, and particularly relates to a natural gas pipeline wireless heat tracing system based on photovoltaic power supply. BACKGROUND

[0002] At present, the temperature of the pipeline needs to be regulated during the natural gas pipeline transportation process to ensure smooth transportation of natural gas. Most natural gas stations use electric heat tracing to regulate the temperature. Common electric heat tracing systems mainly include three categories: electric heat tape heat tracing, cable heat tracing and skin effect heat tracing. The heat tracing pipeline is laid in the natural gas pipeline, and the data is transmitted to the control end through the temperature sensor to ensure that the temperature in the pipeline meets the demand. However, the electric heat tracing system currently used in the natural gas pipeline has three major problems: (1) The electric heat tracing system consumes a large amount of energy, especially in the winter in the north, which often needs to run for 24 hours, and the power consumption is extremely large, which not only causes a large burden on the local power grid system, but also does not meet the basic national policy of carbon neutralization and carbon peak in China. (2) The heating line of the traditional electric heat tracing system is directly connected with the power supply, and strong explosion-proof and insulation need to be designed to avoid natural gas fire or explosion. (3) The heating pipeline of the cable heat tracing and the skin effect heat tracing in the traditional heat tracing system is laid as a whole under the insulation layer, which leads to the need to replace the whole pipeline when a certain section of the pipeline fails, and the whole pipeline cannot achieve local temperature control of the pipeline. Therefore, the traditional electric heat tracing system used in the natural gas pipeline has serious energy waste, high maintenance cost and low temperature control precision, and does not meet the development needs of future natural gas stations. SUMMARY

[0003] The purpose of the present application is to provide a natural gas pipeline wireless heat tracing system based on photovoltaic power supply, which aims to solve the above problems in the prior art.

[0004] The present application provides a natural gas pipeline wireless heat tracing system based on photovoltaic power supply, comprising:

[0005] A distributed photovoltaic array is used to receive solar energy and convert it into multiple groups of electric energy by using multiple groups of photovoltaic panels.

[0006] A current combiner box is connected with the distributed photovoltaic array and is used to combine the multiple groups of electric energy.

[0007] A direct current distribution cabinet is connected with the current combiner box and is used to regulate the current after current combination.

[0008] An inverter is connected with the direct current distribution cabinet and is used to convert direct current into high-frequency alternating current that can be wirelessly transmitted by the pipeline coil.

[0009] An infinite heat tracing structure is connected with the inverter and is used to rectify the alternating high-frequency current into direct current to provide heat generation energy.

[0010] a data acquisition and control system connected with the infinite heat tracing structure, for data acquisition from the infinite heat tracing structure and control of the infinite heat tracing structure;

[0011] The pipeline outside is provided with a pipeline outside coil L composed of a square and a solenoid p The pipeline inside is provided with a pipeline inside coil L of a solenoid s .

[0012] The natural gas pipeline wireless heat tracing system based on photovoltaic power supply of the embodiment of the application uses a new type of clean solar energy to provide a power source for the natural gas pipeline heat tracing system, and improves the cleanliness of the system; a new type of wireless heat tracing structure is applied to realize electrical isolation between the electric heat tracing pipeline and the power supply, and improve the reliability of the system; meanwhile, the multi-section wireless heat tracing structure is used to realize intelligent regulation and control of the temperature of the natural gas pipeline, improve the temperature precision of the system, and the multi-section structure is also replaced, thereby reducing the difficulty of system maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the one or more embodiments of the present specification or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present specification, and other drawings can also be obtained by those skilled in the art without creative labor.

[0014] Figure 1 is a schematic diagram of the natural gas pipeline wireless heat tracing system based on photovoltaic power supply of the embodiment of the application;

[0015] Figure 2 is a schematic diagram of a traditional electric heat tracing structure for comparison of the embodiment of the application;

[0016] Figure 3 is a schematic diagram of a wireless electric heat tracing structure of the embodiment of the application;

[0017] Figure 4 is a plan view of the pipeline outside and inside coils of the wireless electric heat tracing structure of the embodiment of the application;

[0018] Figure 5 is a sectional view of the pipeline outside and inside coils of the wireless electric heat tracing structure of the embodiment of the application;

[0019] Figure 6 is a schematic diagram of a simplified circuit of a single-section coil of the wireless electric heat tracing structure of the embodiment of the application;

[0020] Figure 7 is a schematic diagram of a simplified circuit of a single-section coil of the wireless electric heat tracing structure of the embodiment of the application;

[0021] Figure 8 is a pipeline internal coil L of an embodiment of the present application s and a resonance capacitor C s Equivalent circuit schematic diagram equivalent to the pipeline external coil;

[0022] Figure 9 is a temperature partition control block diagram of an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order for those skilled in the art to better understand the technical solutions in one or more embodiments of the present specification, the technical solutions in one or more embodiments of the present specification will be described clearly and completely in conjunction with the drawings in one or more embodiments of the present specification. Obviously, the described embodiments are only a part of the embodiments of the present specification, not all. Based on one or more embodiments of the present specification, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present document.

[0024] According to an embodiment of the present application, a natural gas pipeline wireless heat tracing system based on photovoltaic power supply is provided, Figure 1 is a schematic diagram of a natural gas pipeline wireless heat tracing system based on photovoltaic power supply of an embodiment of the present application, as Figure 1 shown, the natural gas pipeline wireless heat tracing system based on photovoltaic power supply according to an embodiment of the present application specifically comprises:

[0025] The distributed photovoltaic array 10 is used to receive solar energy and convert it into multiple sets of electrical energy using multiple sets of photovoltaic panels.

[0026] The bus box 20 is connected with the distributed photovoltaic array and is used to converge multiple sets of electrical energy.

[0027] The direct current distribution cabinet 30 is connected with the bus box and is used to regulate the current after convergence, current and voltage.

[0028] The inverter 40 is connected with the direct current distribution cabinet and is used to convert direct current into high-frequency alternating current that can be wirelessly transmitted by the pipeline coil.

[0029] The infinite heat tracing structure 50 is connected with the inverter and is used to rectify the alternating high-frequency current into direct current to provide energy for heat generation. The infinite heat tracing structure 50 specifically comprises:

[0030] The transmitting end compensation network, the pipeline and the receiving end resonance network, wherein the transmitting end compensation network comprises: an inductor L p0 and a capacitor C p and a pipeline external coil L p, for forming high-frequency resonant current, the receiving end resonant network specifically comprises: a pipeline internal coil L s and a capacitor C s , for making current i s fully resonant after receiving energy from coil L s , and for rectifying alternating high-frequency current into direct current by uncontrolled rectifier tube to provide energy for heat generation. The pipeline outside is provided with a pipeline external coil L p composed of square and solenoid type mixed together, and the pipeline inside is provided with a pipeline internal coil L s composed of solenoid type. The relationship among magnetic flux, magnetic resistance and coupling coefficient of the mixed coil composed of square coil and solenoid is formula 1:

[0031]

[0032] Wherein, magnetic flux Φ = F / R, air magnetic resistance R = l / (μ0S), l represents air gap length, S represents effective air cross-sectional area, and μ0 represents air permeability, coupling coefficient k represents the ratio of mutual coupling magnetic flux to total magnetic flux, and F represents coupling mechanism magnetic motive force.

[0033] In addition, the infinite heat tracing structure 50 adopts a multi-section coil structure.

[0034] A data acquisition and control system 60 is connected with the infinite heat tracing structure, for collecting data from the infinite heat tracing structure and controlling the infinite heat tracing structure.

[0035] The data acquisition and control system 60 is specifically used for independently regulating the current of each coil of the infinite heat tracing structure, and performing regional temperature control.

[0036] The data acquisition and control system 60 is specifically used for: acquiring the temperature data, comparing the temperature data with a preset temperature value, and adjusting the voltage value induced by the pipeline internal coil by high-frequency inverter regulated output bus voltage according to the comparison result, so as to realize the adjustment of pipeline internal energy.

[0037] The data acquisition and control system 60 is specifically used for:

[0038] The voltage value U s induced by the pipeline internal coil is determined according to formula 2:

[0039]

[0040] Wherein, M is mutual inductance of pipeline outside coil and pipeline inside coil, ω represents angular frequency, I p represents pipeline outside coil current, L p0 represents pipeline outside coil inductance, U inv is inverter regulated output bus voltage.

[0041] The above technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0042] The novel electric heat tracing system structure provided by the embodiments of the present application is powered by photovoltaic new energy, photovoltaic adopts a distributed system, and makes full use of the spatial position of the natural gas station to realize maximum power output and energy saving and emission reduction. The novel electric heat tracing system adopts a wireless heat conduction structure, utilizes the electromagnetic induction principle between coils to realize energy transmission, and specifically for circular pipelines, a mixed coil composed of solenoid coils and square coils is laid outside the natural gas pipeline, the electric energy generated by photovoltaic is connected to the mixed coil, a uniform spatial magnetic field is generated in all directions, solenoid coils are laid inside the pipeline, the spatial magnetic field can be received, the magnetic field is converted into electric energy to generate heat, energy is transmitted in a non-contact form, and the contact between the power supply and the natural gas is eliminated from the source, and the safety is improved. Meanwhile, the coils inside and outside the pipeline are composed of multiple segments, the temperature of each region of the pipeline can be detected at any time, the voltage felt inside the pipeline is changed by controlling the current of each segment of the coil outside the pipeline, and the heat generated by each segment of the coil is changed, so that the temperature of the pipeline is adjusted in different regions. The electric heat tracing structure composed of multiple segments of coils also facilitates later maintenance, and the segment of the coil that needs to be replaced and maintained can be replaced and maintained without the need for overall replacement.

[0043] Figure 2 is a schematic diagram of a traditional electric heat tracing structure for comparison of the embodiments of the present application, Figure 3 is a schematic diagram of a wireless electric heat tracing structure of the embodiments of the present application, Figure 4 is a plan view of the coils outside and inside the pipeline of the wireless electric heat tracing structure of the embodiments of the present application, Figure 5 is a sectional view of the coils outside and inside the pipeline of the wireless electric heat tracing structure of the embodiments of the present application, Figure 6 is a schematic diagram of a simplified circuit of a single segment of the coil of the wireless electric heat tracing structure of the embodiments of the present application, as shown in Figure 1 、 3 -6:

[0044] The distributed photovoltaic array is the source of energy of the whole system, a plurality of photovoltaic panels receive solar energy, the solar energy is input into a direct current distribution cabinet through a bus box, the direct current distribution cabinet adjusts the current to be uniform and uniform in voltage, and then inputs the current into a high-frequency inverter, the high-frequency inverter converts the direct current into high-frequency alternating current which can be wirelessly transmitted to the pipeline coil. The inductance L p0 and Cp L p The compensation network of the transmitting end forms a high-frequency resonant current, and by reasonably designing the pipeline external coil composed of a square and a solenoid type and the solenoid type pipeline internal coil, the inherent resonant frequencies are made the same, so that the energy transmission is realized. The pipeline internal coil L s After receiving the energy, the current i s L s The receiving end resonant network composed of C s is fully resonated, and finally the uncontrolled rectifier tube rectifies the alternating high-frequency current into a direct current, thereby providing energy for heat generation.

[0045] wherein, Figure 5 The coil shape of the wireless heat tracing system is shown, and since the natural gas pipeline is circular, the electromagnetic field distribution at the circular arc needs to be considered. Since the energy exchange between the pipeline external coil and the internal coil is realized through the space magnetic field, the coil shape must be optimized to ensure uniform distribution of the space magnetic field. Therefore, the pipeline external coil is composed of a square coil and a solenoid coil, so that the magnetic field distribution area is increased, Figure 7 is a simplified circuit schematic diagram of a single coil of the wireless heat tracing structure of the embodiment of the present application, as shown in Figure 7 The magnetic lines are divided into self-coupling areas and mutual coupling areas, the magnetic lines in the self-coupling areas are directly closed to the pipeline external coil without passing through the pipeline internal coil, and the magnetic lines in the mutual coupling areas are closed to the pipeline external coil after passing through the pipeline internal coil. More mutual magnetic flux in the pipeline external coil and the internal coil helps to improve the coupling performance. Reducing the fluctuation of the mutual magnetic flux with the offset can improve the offset adaptability. R s is the magnetic resistance of the self-coupling area, R m is the magnetic resistance of the mutual coupling area, Φ s is the magnetic flux of the self-coupling area, Φ m is the magnetic flux of the mutual coupling area, and F1 is the magnetic motive force. Since the permeability of the ferrite core is large, the magnetic resistance can be ignored, and at this time, the relationship between the magnetic flux, the magnetic resistance and the coupling coefficient of the mixed coil composed of the square coil and the solenoid is formula (1). The magnetic flux Φ = F / R, the air magnetic resistance R = l / (μ0S). l represents the air gap length, S represents the effective air cross-sectional area, and μ0 represents the air permeability. The coupling coefficient can be represented as the ratio of the mutual coupling magnetic flux to the total magnetic flux.

[0046]

[0047] The lower the coupling coefficient is, the greater the energy in the coil is when transmitting the same power, and the low coupling coefficient will cause the energy of the resonant cavity inside and outside the pipeline to be too high, thereby causing a safety hazard, therefore, in the application of the natural gas pipeline, the mixed coil composed of the square coil and the solenoid is used outside the pipeline, and the solenoid coil is used inside the pipeline, so that the coupling coefficient of the wireless heat tracing structure is improved.

[0048] The electric heat tracing system of the embodiment of the application adopts a multi-section coil structure, the current of each section of coil is independently controlled, the regional temperature control is realized, and the independent control principle is specifically analyzed as follows. Figure 6 The internal coil L of the pipeline s and the resonant capacitor C s are equivalent to the external coil of the pipeline, as shown in Figure 8 .

[0049]

[0050] Let The transconductance gain g m of the equivalent topology can be obtained.

[0051]

[0052] When the external coil of the pipeline and the internal coil are completely resonant, the condition is met, that is, α = 1 and β = -1.

[0053] g m(full-tuned) = I P / U inv = Z L1 -1 (4)

[0054] As long as β = -1, the equivalent topology has a constant current characteristic.

[0055] g m(half-tuned) = I P / V inv = αZ L1 -1 = Z LP0 -1 (5)

[0056] When the mutual inductance between the external coil of the pipeline and the internal coil of the pipeline is M, the induced voltage of the internal coil of the pipeline can be expressed as

[0057]

[0058] The regional temperature control of the wireless heat tracing system is shown in Figure 9 , and Figure 9 is a temperature zoning control block diagram of the embodiment of the application, Figure 9Three-section coils are used to realize wireless heating function, and the three-section coils are for three regions, each region is provided with a temperature monitoring point, the monitored temperature data are fed back to the upper computer, compared with the required temperature given value of each region, the bus voltage U of the high-frequency inverter is adjusted to adjust the voltage value of the coil in the pipeline, as shown in formula (6), and then the energy in the pipeline is adjusted. inv The control ideas of each region are same, so that the temperature partition control of the wireless heat tracing system is realized.

[0059] The natural gas pipeline wireless heat tracing system based on photovoltaic power supply utilizes photovoltaic power supply, does not need power grid power supply, and reduces the urban power burden; the mixed coil is laid outside the pipeline, and the solenoid coil is laid in the pipeline heat preservation layer, contactless power transmission is realized, the isolation of natural gas and power supply can be guaranteed, and the safety of the electric heat tracing system is improved; the laying of the multi-section coil can realize the regional regulation of the temperature in the pipeline, and the temperature regulation accuracy is enhanced.

[0060] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wireless heat tracing system for natural gas pipelines based on photovoltaic power supply, characterized in that, include: Distributed photovoltaic arrays are used to receive solar energy using multiple sets of photovoltaic panels and convert it into multiple sets of electrical energy. The combiner box, connected to the distributed photovoltaic array, is used to combine multiple groups of electrical energy. A DC distribution cabinet, connected to the combiner box, is used to regulate the current and voltage after the current is combined. An inverter, connected to the DC distribution cabinet, is used to convert DC power into high-frequency AC power that can wirelessly transmit energy via a coil. A wireless heat tracing structure, connected to the inverter, is used to rectify AC high-frequency electricity into DC electricity to provide energy for heat generation; wherein, the wireless heat tracing structure specifically includes: The transmitter compensation network, the conduit, and the receiver resonant network, wherein the transmitter compensation network includes: an inductor L p0 and capacitor C p With the external coil L of the pipeline p The receiving end resonant network, used to generate a high-frequency resonant current, specifically includes: an internal coil L of the pipe. s and capacitor C s , used by coil L s After receiving energy, the current i s Full resonance occurs when the uncontrolled rectifier diodes rectify the high-frequency AC power into DC power, providing energy for heat generation. A data acquisition and control system, connected to the wireless heat tracing structure, is used to acquire data from the wireless heat tracing structure and control the wireless heat tracing structure. The pipe is externally fitted with an external coil L composed of a hybrid square and solenoid shape. p The pipe is equipped with a solenoid-type internal coil L. s .

2. The system according to claim 1, characterized in that, The wireless heat tracing structure adopts a multi-segment coil structure.

3. The system according to claim 1, characterized in that, The data acquisition and control system is specifically used to: independently adjust the current of each coil segment of the wireless heat tracing structure to perform regional temperature control.

4. The system according to claim 2, characterized in that, The multi-segment coil structure is a 3-segment coil structure.

5. The system according to claim 4, characterized in that, A temperature monitoring point is set in the area corresponding to the multi-segment coil structure. The temperature monitoring point is used to send the detected temperature data to the data acquisition and control system.

6. The system according to claim 5, characterized in that, The data acquisition and control system is specifically used to: acquire the temperature data, compare the temperature data with a preset temperature value, and, based on the comparison result, adjust the output bus voltage through a high-frequency inverter to adjust the voltage value induced by the coil inside the pipeline, thereby achieving energy regulation inside the pipeline.

7. The system according to claim 6, characterized in that, The data acquisition and control system is specifically used for: The voltage U induced by the coil inside the pipe is determined according to Formula 2. s : Where M is the mutual inductance between the outer coil and the inner coil of the pipe, ω represents the angular frequency, and I... p L represents the current in the external coil of the pipe. p0 U represents the inductance of the external coil of the pipe. inv To regulate the output bus voltage of the inverter.

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