Heavy gas oil flow velocity online monitoring method

Abstract

The invention discloses a heavy gas oil flow rate on-line monitoring method, and relates to the technical field of flow rate monitoring, and the method comprises the steps: S1, arranging a Doppler flowmeter on a pipeline in a hoop fixing manner, additionally installing a group of Doppler flow rate sensors between a gas relay and an expansion tank, and using an ultrasonic generator as a fixed sound source, the solid particles moving along with the fluid at the same speed move relative to the sound source, and the solid particles reflect incident ultrasonic waves back to the receiver; s2, a flow velocity sensor collects the oil flow velocity in real time and converts the flow velocity value into an electric signal, the electric signal is remotely transmitted to a background data management terminal through a communication module, the management terminal collects the electric signal and converts the electric signal into a flow velocity signal, and the flow velocity signal is displayed on a display device in real time; and S3, according to the Doppler effect and a certain frequency degree difference between incident sound waves and reflected sound waves, through the sound wave frequency shift phenomenon in the fluid, the method has the characteristic of being suitable for the fluid containing solid particles or bubbles.

Description

Technical Field

[0001] The invention relates to the technical field of flow rate detection, in particular to an online monitoring method for heavy gas oil flow rate. Background Art

[0002] When the oil-immersed power transformer leaves the factory, the pipeline structure has been fixed. For online monitoring of the heavy gas flow rate, it is not advisable to damage the original structure. Most of the existing measurement methods are internal insertion measurement, that is, the sensor is installed in the pipeline, which requires changing the structure of the pipeline from the oil pillow to the main transformer, affecting the operation of the gas relay; therefore, external measurement is usually used in measurement, and ultrasonic flowmeter is more suitable to achieve the measurement of heavy gas flow rate.

[0003] Of the two methods of ultrasonic velocity measurement, the time difference method flow meter measures the time, which requires an ultrasonic signal sent from a sensor to cross the pipe and be received by a second sensor, and the upstream and downstream time measurements are compared. Its core is to use the fact that the ultrasonic signal in the fluid propagates fast when it is downstream and slow when it is upstream. By measuring the difference in the time of ultrasonic signal propagation downstream and upstream in the fluid, the fluid velocity is indirectly measured, and then the fluid flow rate can be calculated by the flow velocity.

[0004] Since the ultrasonic signal must cross the pipeline, the fluid must not contain bubbles or solid concentrations. High-frequency sounds will attenuate, and those that are too weak cannot pass through; and if the ultrasonic wave encounters tiny solid particles or bubbles on the propagation path, it will be scattered. Therefore, the time difference method does not work well when measuring fluids containing such things. It is suitable for measuring relatively clean fluids. Therefore, it is necessary to design an online monitoring method for the flow rate of heavy gas oil suitable for fluids containing solid particles and bubbles. Summary of the invention

[0005] The object of the present invention is to provide a method for online monitoring of heavy gas oil flow rate to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a heavy gas oil flow rate online monitoring method, comprising:

[0007] S1. The Doppler flowmeter is fixed on the pipeline by a clamp. A set of Doppler flow velocity sensors is installed between the gas relay and the oil pillow. The ultrasonic generator is a fixed sound source. The solid particles moving at the same speed as the fluid have relative motion with the sound source. The solid particles reflect the incident ultrasonic wave back to the receiver.

[0008] S2. The flow rate sensor collects the oil flow rate in real time and converts the flow rate value into an electrical signal. The electrical signal is transmitted to the background data management terminal through the communication module. The management terminal collects the electrical signal and converts it into a flow rate signal, which is displayed in real time on the display device;

[0009] S3. According to the Doppler effect, there is a certain frequency difference between the incident sound wave and the reflected sound wave. Through the phenomenon of sound wave frequency shift in the fluid, the correlation is established and then the fluid flow rate is calculated.

[0010] According to the above technical solution, in S3, specifically:

[0011] When sound waves propagate in a fluid, they move toward the sound wave generator at a fluid velocity v. At this time, the liquid is the receiver of the sound waves, and receives sound waves with a frequency of f1. f0 is the initial sound wave frequency of the sound source, and the calculation formula is: Where c is the speed of light and θ is the incident angle of the sound wave;

[0012] When the sound waves with a frequency of f1 received by the fluid particles are transmitted to the receiver, the frequency of the sound waves at this time is:

[0013] Therefore, there is a frequency difference between the sound wave receiver and the generator, namely the Doppler frequency shift, which is calculated as: In this way, the flow velocity v of the fluid in the pipeline can be measured.

[0014] According to the above technical solution, it also includes analyzing the flow rate and temperature of oil in multiple transformer pipelines in the substation;

[0015] S4. Count and evaluate the optimal oil flow rate of the transformer pipeline in the substation, as well as the optimal oil temperature of the substation, mark and distinguish each transformer pipeline in the substation, and derive the inherent safety of each transformer pipeline;

[0016] S5. During operation, the transformer pipeline information collected on site is compared with the optimal oil flow rate and optimal oil temperature of the substation to determine whether they meet the requirements, control the operation status and detect damage in a timely manner;

[0017] S6. Count the working status information during the operation process, obtain the oil flow rate and oil temperature of the current transformer pipeline, and decide what response method to adopt under the current working state of the transformer pipeline;

[0018] S7. According to the safety of the transformer pipeline itself in the transformer pipeline, the frequency of participation in monitoring is set for each transformer pipeline of the substation.

[0019] According to the above technical solution, in S4, the calculation method of the optimal oil flow rate and the optimal oil temperature of the transformer pipeline of the substation is as follows: first, the optimal flow rates of each transformer pipeline in the substation are counted as (U1, U2, ..., U i}, and then calculate the overall optimal oil flow rate ∑U of the substation i, read the optimal oil temperature of each transformer pipeline, the optimal oil temperature monitored by each transformer pipeline is {w1, w2, ..., w i}, where i is the number of transformer pipes, and the overall optimal oil temperature is ∑w i .

[0020] According to the above technical solution, in S5, the specific method for obtaining the oil flow rate and oil temperature of the current transformer pipeline is:

[0021] S5-1. As long as the transformer pipeline is detected to be in working state, the transformer pipeline that is already in working state under the current operating condition is monitored and determined at fixed time intervals T. Let the number of transformer pipelines that are already in working state be k, then the overall oil flow rate of the transformer pipeline is ∑U k , the overall oil temperature of the transformer pipeline is ∑w k The optimal index of oil flow rate and oil temperature of the substation is X = μ∑U i +δ∑w i ;

[0022] S5-2. The current operating status indicators of the transformer pipeline are: Here, μ is the weight coefficient of oil velocity in the risk index, and δ is the weight coefficient of oil temperature in the risk index.

[0023] According to the above technical solution, in S5, the specific method for determining the response method adopted by the transformer pipeline under the current working state is:

[0024] S5-2, when Y≤X, the current working state of the substation is in a safe state, and regular monitoring of oil temperature, flow rate, and dielectric strength parameters continues to be performed to ensure that the substation equipment operates within the normal range;

[0025] S5-3. When Y>X, the current working state of the substation is in a dangerous state, and an emergency shutdown is immediately performed to prevent the accident from expanding.

[0026] According to the above technical solution, in S4, the method for determining the self-safety of the transformer pipeline in the transformer pipeline is:

[0027] S4-1. The hazard index of a transformer pipeline in a substation and the oil flow rate U of the transformer pipeline itself i and the oil temperature W of the transformer pipeline itself i Related, specifically the danger index of transformer pipeline Z = μU i +δW i ;

[0028] The specific method for setting the frequency of participation monitoring is:

[0029] S4-2. The more dangerous the transformer pipeline is, the more frequently it needs to be monitored. Since the entire transformer pipeline is monitored at a fixed time unit T, the transformer pipeline interval

[0030] nT time units are monitored, and Where τ is the conversion coefficient between the danger index of the transformer pipeline and the monitoring interval time unit.

[0031] According to the above technical solution, in S2, when a damaged transformer pipeline is found, the transformer pipeline is adjusted from an operating state to a suspended operation state, and is removed from the current transformer pipelines until the transformer pipeline resumes normal operation.

[0032] Compared with the prior art, the beneficial effect achieved by the present invention is that the present invention adopts the Doppler method to monitor the heavy gas flow rate of the oil-immersed power transformer online. The Doppler method works by utilizing the characteristic of ultrasonic wave scattering. Compared with the time difference method, it is more suitable for measuring fluids containing solid particles or bubbles and will not affect the flow rate action value of the transformer gas relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 It is a schematic diagram of the flow rate monitoring principle of the present invention;

[0035] Figure 2 It is a schematic diagram of the flow rate monitoring installation of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] See also Figure 1 and Figure 2 The present invention provides a technical solution: a method for online monitoring of heavy gas oil flow rate, comprising:

[0038] S1. The Doppler flowmeter is fixed on the pipeline by a clamp. A set of Doppler flow velocity sensors is installed between the gas relay and the oil pillow. The ultrasonic generator is a fixed sound source. The solid particles moving at the same speed as the fluid have relative motion with the sound source. The solid particles reflect the incident ultrasonic wave back to the receiver.

[0039] S2. The flow rate sensor collects the oil flow rate in real time and converts the flow rate value into an electrical signal. The electrical signal is transmitted to the background data management terminal through the communication module. The management terminal collects the electrical signal and converts it into a flow rate signal, which is displayed in real time on the display device;

[0040] S3. According to the Doppler effect, there is a certain frequency difference between the incident sound wave and the reflected sound wave. Through the phenomenon of sound wave frequency shift in the fluid, the correlation is established and then the fluid flow rate is calculated;

[0041] In S3, specifically:

[0042] When sound waves propagate in a fluid, they move toward the sound wave generator at a fluid velocity v. At this time, the liquid is the receiver of the sound waves, and receives sound waves with a frequency of f1. f0 is the initial sound wave frequency of the sound source, and the calculation formula is: Where c is the speed of light and θ is the incident angle of the sound wave;

[0043] When the sound waves with a frequency of f1 received by the fluid particles are transmitted to the receiver, the frequency of the sound waves at this time is:

[0044] Therefore, there is a frequency difference between the sound wave receiver and the generator, namely the Doppler frequency shift, which is calculated as: Thus, the flow velocity V of the fluid in the pipeline can be measured;

[0045] It also includes analyzing the flow rate and temperature of oil in the pipes of multiple transformers in the substation;

[0046] S4. Count and evaluate the optimal oil flow rate of the transformer pipeline in the substation, as well as the optimal oil temperature of the substation, mark and distinguish each transformer pipeline in the substation, and derive the inherent safety of each transformer pipeline;

[0047] S5. During operation, the transformer pipeline information collected on site is compared with the optimal oil flow rate and optimal oil temperature of the substation to determine whether they meet the requirements, control the operation status and detect damage in a timely manner;

[0048] S6. Count the working status information during the operation process, obtain the oil flow rate and oil temperature of the current transformer pipeline, and decide what response method to adopt under the current working state of the transformer pipeline;

[0049] S7. According to the safety of the transformer pipeline itself in the transformer pipeline, the frequency of participation in monitoring is set for each transformer pipeline of the substation;

[0050] In S4, the calculation method of the optimal oil flow rate and the optimal oil temperature of the transformer pipeline of the substation is as follows: first, the optimal flow rates of each transformer pipeline in the substation are counted as {U1, U2, ..., U i}, and then calculate the overall optimal oil flow rate ∑U of the substation i , read the optimal oil temperature of each transformer pipeline, the optimal oil temperature monitored by each transformer pipeline is {w1, w2, ..., w i}, where i is the number of transformer pipes, and the overall optimal oil temperature is ∑w i ;

[0051] In S5, the specific method for obtaining the oil flow rate and oil temperature of the current transformer pipeline is:

[0052] S5-1. As long as the transformer pipeline is detected to be in working state, the transformer pipeline that is already in working state under the current operating condition is monitored and determined at fixed time intervals T. Let the number of transformer pipelines that are already in working state be k, then the overall oil flow rate of the transformer pipeline is ∑U k , the overall oil temperature of the transformer pipeline is ∑w k The optimal index of oil flow rate and oil temperature of the substation is X = μ∑U i +δ∑w i ;

[0053] S5-2. The current operating status indicators of the transformer pipeline are: In the equation, μ is the weight coefficient of oil velocity in the risk index, and δ is the weight coefficient of oil temperature in the risk index;

[0054] In S5, the specific method for determining the response method adopted by the transformer pipeline under the current working state is:

[0055] S5-2, when Y≤X, the current working state of the substation is in a safe state, and regular monitoring of oil temperature, flow rate, and dielectric strength parameters continues to be performed to ensure that the substation equipment operates within the normal range;

[0056] S5-3, when Y>X, the current working state of the substation is in a dangerous state, and an emergency shutdown is immediately carried out to prevent the accident from expanding;

[0057] In S4, the method for determining the inherent safety of the transformer pipeline in the transformer pipeline is:

[0058] S4-1. The hazard index of a transformer pipeline in a substation and the oil flow rate U of the transformer pipeline itself i and the oil temperature W of the transformer pipeline itself i Related, specifically the danger index of transformer pipeline Z = μU i +δW i ;

[0059] The specific method for setting the frequency of participation monitoring is:

[0060] S4-2. The more dangerous the transformer pipeline is, the more frequently it needs to be monitored. Since the entire transformer pipeline is monitored at a fixed time unit T, the transformer pipeline is monitored at an interval of nT time units, and Where τ is the conversion factor between the danger index of the transformer pipeline and the monitoring interval time unit;

[0061] In S2, when a damaged transformer pipeline is found, the transformer pipeline is adjusted from an operating state to a suspended operation state, and is removed from the current transformer pipelines until the transformer pipeline resumes normal operation.

[0062] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0063] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for online monitoring of heavy gas oil flow rate, characterized in that: include: S1. The Doppler flowmeter is fixed on the pipeline by a clamp. A set of Doppler flow velocity sensors is installed between the gas relay and the oil pillow. The ultrasonic generator is a fixed sound source. The solid particles moving at the same speed as the fluid have relative motion with the sound source. The solid particles reflect the incident ultrasonic wave back to the receiver. S2. The flow rate sensor collects the oil flow rate in real time and converts the flow rate value into an electrical signal. The electrical signal is transmitted to the background data management terminal through the communication module. The management terminal collects the electrical signal and converts it into a flow rate signal, which is displayed in real time on the display device; S3. According to the Doppler effect, there is a certain frequency difference between the incident sound wave and the reflected sound wave. Through the phenomenon of sound wave frequency shift in the fluid, the correlation is established and then the fluid flow rate is calculated.

2. The method for online monitoring of heavy gas oil flow rate according to claim 1, characterized in that: In the S3, specifically: When sound waves propagate in a fluid, they move toward the sound wave generator at a fluid velocity v. At this time, the liquid is the receiver of the sound waves, and receives sound waves with a frequency of f1. f0 is the initial sound wave frequency of the sound source, and the calculation formula is: Where c is the speed of light and θ is the incident angle of the sound wave; When the sound waves with a frequency of f1 received by the fluid particles are transmitted to the receiver, the frequency of the sound waves at this time is: Therefore, there is a frequency difference between the sound wave receiver and the generator, namely the Doppler frequency shift, which is calculated as: In this way, the flow velocity v of the fluid in the pipeline can be measured.

3. The method for online monitoring of heavy gas oil flow rate according to claim 2, characterized in that: It also includes analyzing the flow rate and temperature of oil in the pipes of multiple transformers in the substation; S4. Count and evaluate the optimal oil flow rate of the transformer pipeline in the substation, as well as the optimal oil temperature of the substation, mark and distinguish each transformer pipeline in the substation, and derive the inherent safety of each transformer pipeline; S5. During operation, the transformer pipeline information collected on site is compared with the optimal oil flow rate and optimal oil temperature of the substation to determine whether they meet the requirements, control the operation status and detect damage in a timely manner; S6. Count the working status information during the operation process, obtain the oil flow rate and oil temperature of the current transformer pipeline, and decide what response method to adopt under the current working state of the transformer pipeline; S7. According to the safety of the transformer pipeline itself in the transformer pipeline, the frequency of participation in monitoring is set for each transformer pipeline of the substation.

4. The method for online monitoring of heavy gas oil flow rate according to claim 3, characterized in that: In S4, the calculation method of the optimal oil flow rate and the optimal oil temperature of the transformer pipeline of the substation is as follows: first, the optimal flow rates of each transformer pipeline in the substation are counted as {U1, U2, ..., U i }, and then calculate the overall optimal oil flow rate ∑U of the substation i , read the optimal oil temperature of each transformer pipeline, the optimal oil temperature monitored by each transformer pipeline is {w1, w2, ..., w i }, where i is the number of transformer pipes, and the overall optimal oil temperature is ∑w i .

5. The method for online monitoring of heavy gas oil flow rate according to claim 4, characterized in that: In S5, the specific method for obtaining the oil flow rate and oil temperature of the current transformer pipeline is: S5-1. As long as the transformer pipeline is detected to be in working state, the transformer pipeline that is already in working state under the current operating condition is monitored and determined at fixed time intervals T. Let the number of transformer pipelines that are already in working state be k, then the overall oil flow rate of the transformer pipeline is ∑U k , the overall oil temperature of the transformer pipeline is ∑w k The optimal index of oil flow rate and oil temperature of the substation is X = μ∑U i +δ∑w i ; S5-2. The current operating status indicators of the transformer pipeline are: Where μ is the weight coefficient of oil flow rate in the risk index, and δ is the weight coefficient of oil temperature in the risk index.

6. The method for online monitoring of heavy gas oil flow rate according to claim 5, characterized in that: In S5, the specific method for determining the response method adopted by the transformer pipeline under the current working state is: S5-2, when Y≤X, the current working state of the substation is in a safe state, and regular monitoring of oil temperature, flow rate, and dielectric strength parameters continues to be performed to ensure that the substation equipment operates within the normal range; S5-3. When Y>X, the current working state of the substation is in a dangerous state, and an emergency shutdown is immediately performed to prevent the accident from expanding.

7. The method for online monitoring of heavy gas oil flow rate according to claim 6, characterized in that: In S4, the method for determining the self-safety of the transformer pipeline in the transformer pipeline is: S4-1. The hazard index of a transformer pipeline in a substation and the oil flow rate U of the transformer pipeline itself i and the oil temperature W of the transformer pipeline itself i Related, specifically the danger index of transformer pipeline Z = μU i +δW i ; The specific method for setting the frequency of participation monitoring is: S4-2. The more dangerous the transformer pipeline is, the more frequently it needs to be monitored. Since the entire transformer pipeline is monitored at a fixed time unit T, the transformer pipeline is monitored at an interval of nT time units, and Where τ is the conversion coefficient between the danger index of the transformer pipeline and the monitoring interval time unit.

8. The method for online monitoring of heavy gas oil flow rate according to claim 7, characterized in that: In S2, when a damaged transformer pipeline is found, the transformer pipeline is adjusted from an operating state to a suspended operation state, and is removed from the current transformer pipelines until the transformer pipeline resumes normal operation.

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