Interlock pump stopping control method for submersible pump displacement over-limit self-protection and application thereof

Abstract

This invention provides a method for interlocking and stopping a submersible pump when its displacement exceeds the limit, and its application, relating to the field of submersible pump control technology in underground water-sealed caverns. The control method involves: collecting head data during submersible pump operation and comparing it with the head data corresponding to the high and low displacement limits on the submersible pump head curve; when the head data during operation is greater than or equal to the head data corresponding to the high displacement limit, the submersible pump is interlocked and stopped; or when the head data during operation is less than or equal to the head data corresponding to the low displacement limit, the submersible pump is interlocked and stopped. This application transforms the displacement over-limit self-protection interlock of the submersible pump into a head over-limit self-protection interlock, effectively alleviating the problems of high investment costs and the inability of existing flow meters to operate stably for long periods due to the need to install large-diameter pipeline flow meters to prevent submersible pump outlet displacement from exceeding the limit.

Description

Technical Field

[0001] This invention relates to the field of submersible pump control technology for underground water-sealed caverns, and in particular to an interlocking pump shutdown control method for self-protection when the submersible pump displacement exceeds the limit, and its application. Background Technology

[0002] Submersible pumps are the main moving equipment in underground water-sealed cavern projects, involving significant investment and complex control. To prevent pump damage caused by excessive pump discharge due to process fluctuations, suppliers typically require flow meters to be installed on the pump outlet pipeline, interlocking to stop the pump when the flow rate is high or low. However, the diameter of submersible pump outlet pipelines is generally very large, ranging from DN400 to DN800, which is expensive. Furthermore, severe vibration in the pump outlet pipeline is detrimental to the long-term operation of the flow meters.

[0003] Therefore, it is both necessary and urgent to research and develop a new interlock control technology for self-protection against excessive displacement of submersible pumps, in order to alleviate the problem that the existing system requires the installation of large-diameter pipeline flow meters to avoid excessive displacement of submersible pump outlets, which results in high investment costs and the inability of the flow meters to be used stably for a long period of time.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The primary objective of this invention is to provide an interlocking pump shutdown control method for submersible pumps that self-protect against exceeding displacement limits, thereby ensuring the safety of submersible pumps in underground water-sealed cavern projects.

[0006] The second objective of this invention is to provide a submersible pump displacement over-limit self-protection interlocking pump shutdown system for implementing the above-mentioned control method.

[0007] The third objective of this invention is to provide a method for controlling the interlocking pump stoppage of a submersible pump with self-protection against excessive displacement, or the application of a submersible pump with self-protection against excessive displacement and interlocking pump stoppage system in underground water-sealed cavern oil storage.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0009] This invention provides a method for interlocking pump shutdown control of a submersible pump with self-protection against over-displacement limits, the control method comprising:

[0010] Head data was collected during the operation of the submersible pump and then compared with the head data corresponding to the high and low limits of the submersible pump displacement on the submersible pump head curve.

[0011] When the head data during the operation of the submersible pump is greater than or equal to the head data corresponding to the high limit of the submersible pump displacement, the submersible pump will be interlocked and stopped.

[0012] Alternatively, when the head data during submersible pump operation is less than or equal to the head data corresponding to the lower limit of submersible pump displacement, the submersible pump will be interlocked and stopped.

[0013] Furthermore, the head data during the operation of the submersible pump is calculated by collecting the pressure values ​​of the oil and gas pipelines in the underground tank, the pressure values ​​of the submersible pump outlet pipeline, and the liquid level data of the underground tank.

[0014] Furthermore, the formula for calculating the head data during the operation of the submersible pump is as follows:

[0015] H=(P2-P1) / ρg-(|h3|+h1)+h2;

[0016] In the formula:

[0017] H is the pump head;

[0018] P1 is the pressure measurement value of the underground tank oil and gas pipeline;

[0019] P2 is the pressure measurement value of the submersible pump outlet pipeline;

[0020] h1 is the liquid level height in the underground tank;

[0021] h2 is the height of the oil outlet pipe from the submersible pump inlet;

[0022] h3 is the height of the submersible pump inlet;

[0023] g is the acceleration due to gravity;

[0024] ρ is the density of the oil in the pump pit.

[0025] This invention provides a submersible pump displacement over-limit self-protection interlocking pump shutdown system for implementing the above control method, comprising:

[0026] A shaft, pipes installed inside a shaft, an underground cavern installed at the bottom of a shaft, and a shaft sealing plug used to isolate the underground cavern;

[0027] The pipes inside the shaft include oil outlet pipes and oil and gas pipes;

[0028] A pump pit is set at the bottom of the shaft, and a submersible oil pump is installed inside the pump pit. The submersible oil pump is connected to the oil outlet pipeline and has a pump suction inlet.

[0029] The submersible pump displacement over-limit self-protection interlocking pump shutdown system also includes detection instruments for detecting oil and gas pressure and liquid level.

[0030] Furthermore, the detection instrument includes a pressure transmitter and a level transmitter.

[0031] Furthermore, the pressure transmitter includes:

[0032] The pressure transmitter for underground tank oil and gas pipelines is referred to as the first pressure transmitter.

[0033] And, the submersible pump outlet pipeline pressure transmitter, denoted as the second pressure transmitter.

[0034] Furthermore, the level transmitter includes:

[0035] A level transmitter for detecting the liquid level in underground underground tanks and the distance between the tank bottom and the liquid level.

[0036] Furthermore, the submersible pump displacement over-limit self-protection interlocking pump shutdown system also includes a controller;

[0037] The controller is used to collect oil and gas pressure and liquid level information transmitted by the detection instrument, and calculate the head data during the operation of the submersible pump; then, according to the above control method, the self-protection interlocking pump is stopped when the submersible pump displacement exceeds the limit.

[0038] The above-mentioned submersible pump displacement over-limit self-protection interlocking pump stop control method, or submersible pump displacement over-limit self-protection interlocking pump stop system, provided by the present invention, is applied in underground water-sealed cavern oil storage.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] This invention provides a submersible pump displacement over-limit self-protection interlocking pump shutdown control method. The method includes: collecting head data during submersible pump operation, and then comparing it with the head data corresponding to the high and low displacement limits on the submersible pump head curve; when the head data during operation is greater than or equal to the head data corresponding to the high displacement limit, the submersible pump is interlocked and stopped; or when the head data during operation is less than or equal to the head data corresponding to the low displacement limit, the submersible pump is interlocked and stopped. In long-term production practice, the applicant has found that the submersible pump displacement and head often show a corresponding relationship during operation, as seen on the submersible pump head curve. Therefore, this application transforms the submersible pump's displacement over-limit self-protection interlock into a head over-limit self-protection interlock. That is, by using the high and low limits of the submersible pump's displacement on the head curve, the corresponding high and low limits of the submersible pump's head are obtained. Then, when the submersible pump's head is greater than or equal to the high limit and less than or equal to the low limit, the submersible pump is interlocked to stop. This effectively alleviates the problem that existing methods require the installation of large-diameter pipeline flow meters to avoid exceeding the submersible pump's outlet displacement limit, which results in high investment costs and the inability of the flow meters to be used stably for a long time.

[0041] The submersible pump over-displacement self-protection interlocking pump shutdown system provided by this invention includes: a vertical shaft, pipes installed inside the vertical shaft, an underground storage tank installed at the bottom of the vertical shaft, and a vertical shaft sealing plug for isolating the underground storage tank; wherein, the pipes inside the vertical shaft include an oil outlet pipe and an oil and gas pipe; a pump pit is provided at the bottom of the vertical shaft, and a submersible pump is installed inside the pump pit, the submersible pump being connected to the oil outlet pipe; the submersible pump over-displacement self-protection interlocking pump shutdown system also includes detection instruments for detecting oil and gas pressure and liquid level. The above-mentioned submersible pump over-displacement self-protection interlocking pump shutdown system, through the installed detection instruments, can detect the oil and gas pressure and liquid level of the storage tank in real time, providing an equipment foundation for the self-protection interlocking pump shutdown control of submersible pump over-displacement.

[0042] The submersible pump displacement over-limit self-protection interlocking pump stop control method or submersible pump displacement over-limit self-protection interlocking pump stop system provided by the present invention can be widely used in the process of oil storage in underground water-sealed caverns. Attached Figure Description

[0043] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the submersible pump displacement over-limit self-protection interlocking pump shutdown system provided in Embodiment 1 of the present invention.

[0045] Icons: 1-Submersible pump; 2-Pump inlet; 3-Underground tank; 4-Sealing plug; 5-Shaft; 6-Oil outlet pipeline; 7-Oil and gas pipeline; 8-First pressure transmitter; 9-Second pressure transmitter; 10-Level transmitter; 11-Surface. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] According to one aspect of the present invention, a method for interlocking pump shutdown control of a submersible pump with self-protection against over-displacement limits is provided, the control method comprising:

[0048] Head data was collected during the operation of submersible pump 1, and then compared with the head data corresponding to the high and low displacement limits of submersible pump 1 on the head curve of submersible pump 1.

[0049] When the head data during the operation of submersible pump 1 is greater than or equal to the head data corresponding to the high displacement limit of submersible pump 1, submersible pump 1 will be interlocked and stopped.

[0050] Alternatively, when the head data during the operation of submersible pump 1 is less than or equal to the head data corresponding to the lower limit of the displacement of submersible pump 1, submersible pump 1 shall be interlocked and stopped.

[0051] The present invention provides a method for interlocking pump shutdown control of submersible pump 1 with self-protection against over-displacement limits. This control method includes: collecting head data during the operation of submersible pump 1, and then comparing it with the head data corresponding to the high and low displacement limits of submersible pump 1 on the submersible pump 1 head curve; when the head data during the operation of submersible pump 1 is greater than or equal to the head data corresponding to the high displacement limit of submersible pump 1, interlocking to stop submersible pump 1; or when the head data during the operation of submersible pump 1 is less than or equal to the head data corresponding to the low displacement limit of submersible pump 1, interlocking to stop submersible pump 1. In long-term production practice, the applicant has found that, from the head curve of submersible pump 1, the displacement and head of submersible pump 1 often show a corresponding relationship during operation. Therefore, in this application, the displacement over-limit self-protection interlock of submersible pump 1 is transformed into the head over-limit self-protection interlock. That is, the high limit and low limit of the displacement of submersible pump 1 are obtained on the head curve by using the high limit and low limit of the displacement of submersible pump 1. Then, when the head of submersible pump 1 is greater than or equal to the high limit and less than or equal to the low limit, the submersible pump 1 is interlocked to stop. This effectively alleviates the problem that the existing method of installing a large-diameter pipeline flow meter to avoid the outlet displacement of submersible pump 1 from exceeding the limit is expensive and the flow meter cannot be used stably for a long time.

[0052] In a preferred embodiment of the present invention, the head data of the submersible pump 1 during operation is calculated by collecting the pressure values ​​of the oil and gas pipeline of the underground tank 3, the pressure values ​​of the outlet pipeline of the submersible pump 1, and the liquid level height data of the underground tank 3.

[0053] As a preferred embodiment, this application utilizes the level gauge, oil pipeline 6 pressure transmitter, and oil and gas pipeline 7 pressure transmitter already installed in the underground water-sealed cavern to calculate the head over-limit self-protection interlock control of submersible pump 1 through a formula, thereby realizing its displacement over-limit self-protection interlock control. No new equipment needs to be added; the existing equipment can be used to realize the submersible pump 1 displacement over-limit self-protection interlocking pump stop control, which has the advantage of strong economy.

[0054] It should be noted that interlocking refers to a control system that uses a series of interlocking devices in electrical equipment or systems to ensure the safe and reliable operation of the equipment or system. In this application, interlocking refers to calculating the head by collecting data from the level gauge in the underground water-sealed cavern, the pressure transmitter of the oil outlet pipeline 6, and the pressure transmitter of the oil and gas pipeline 7. Using the high and low limits of the submersible pump 1's displacement, corresponding to the high and low limits of the submersible pump 1's head on the head curve, the displacement over-limit self-protection interlock of submersible pump 1 is converted into a head over-limit self-protection interlock. When the head of submersible pump 1 is greater than or equal to the high limit and less than or equal to the low limit, submersible pump 1 is shut down.

[0055] In a preferred embodiment of the present invention, the formula for calculating the head data of the submersible pump 1 during operation is as follows:

[0056] H=(P2-P1) / ρg-(|h3|+h1)+h2;

[0057] In the formula:

[0058] H represents the pump head, measured in meters (m).

[0059] P1 is the pressure measurement value of the oil and gas pipeline in underground tank 3, in Pa;

[0060] P2 is the pressure measurement value of the outlet pipeline of submersible pump 1, in Pa;

[0061] h1 is the liquid level height of underground tank 3, which is the measured value (absolute elevation value, which is negative) at the liquid level transmitter 10, in meters;

[0062] h2 is the height of the oil outlet pipe 6 from the suction inlet of the submersible pump 1, in meters, and is the basic data for the specific project.

[0063] h3 is the height of the suction inlet of submersible pump 1 (absolute elevation value, which is negative), in meters, and is the basic data for specific projects;

[0064] g is the acceleration due to gravity;

[0065] ρ is the density of the oil in the pump pit.

[0066] According to one aspect of the present invention, a submersible pump 1 displacement over-limit self-protection interlocking pump shutdown system for implementing the above-described control method comprises:

[0067] Shaft 5, pipes installed inside shaft 5, underground cavern 3 installed at the bottom of shaft 5, and sealing plug 4 for isolating underground cavern 3;

[0068] The pipes inside shaft 5 include oil outlet pipe 6 and oil and gas pipe 7;

[0069] A pump pit is provided at the bottom of the vertical shaft 5, and a submersible oil pump 1 is installed inside the pump pit. The submersible oil pump 1 is connected to the oil outlet pipe 6, and the submersible oil pump 1 is provided with a pump suction port 2.

[0070] The submersible pump 1 displacement over-limit self-protection interlocking pump stop system also includes detection instruments for detecting oil and gas pressure and liquid level.

[0071] The submersible pump 1 displacement over-limit self-protection interlocking pump shutdown system provided by this invention includes: a vertical shaft 5, pipes installed inside the vertical shaft 5, an underground tank 3 installed at the bottom of the vertical shaft 5, and a sealing plug 4 for isolating the underground tank 3; wherein, the pipes inside the vertical shaft 5 include an oil outlet pipe 6 and an oil and gas pipe 7; a pump pit is provided at the bottom of the vertical shaft 5, and a submersible pump 1 is installed inside the pump pit, the submersible pump 1 being connected to the oil outlet pipe 6; the submersible pump 1 displacement over-limit self-protection interlocking pump shutdown system also includes a detection instrument for detecting oil and gas pressure and liquid level. The above-mentioned submersible pump 1 displacement over-limit self-protection interlocking pump shutdown system, through the installed detection instrument, can detect the oil and gas pressure and liquid level of the underground tank in real time, providing an equipment foundation for the self-protection interlocking pump shutdown control of the submersible pump 1 displacement over-limit.

[0072] In a preferred embodiment of the present invention, the detection instrument includes a pressure transmitter and a level transmitter 10.

[0073] In the preferred embodiment described above, the pressure transmitter includes:

[0074] The pressure transmitter for the oil and gas pipeline in underground tank 3 is designated as the first pressure transmitter 8.

[0075] The pressure transmitter in the outlet pipeline of submersible pump 1 is designated as the second pressure transmitter 9.

[0076] In a preferred embodiment of the present invention, the level transmitter 10 includes:

[0077] A level transmitter 10 is used to detect the distance between the liquid level in the underground tank 3 and the bottom of the tank, wherein the bottom of the tank is located on the ground surface 11.

[0078] In a preferred embodiment of the present invention, the submersible pump 1 displacement over-limit self-protection interlocking pump stop system further includes a controller;

[0079] The controller is used to collect oil and gas pressure and liquid level information transmitted by the detection instrument and calculate the head data of the submersible pump 1 during operation; then, according to the above control method, the submersible pump 1 is automatically stopped due to over-displacement.

[0080] According to one aspect of the present invention, the above-mentioned submersible pump 1 displacement over-limit self-protection interlocking pump stop control method, or submersible pump 1 displacement over-limit self-protection interlocking pump stop system, is applied in underground water-sealed cavern oil storage.

[0081] The submersible pump 1 displacement over-limit self-protection interlocking pump stop control method or submersible pump 1 displacement over-limit self-protection interlocking pump stop system provided by the present invention can be widely used in the process of oil storage in underground water-sealed caverns.

[0082] The technical solution of the present invention will be further described below with reference to the embodiments.

[0083] Example 1

[0084] Figure 1 This is a schematic diagram of the submersible pump 1 displacement over-limit self-protection interlocking pump stop system provided in this embodiment. Figure 1 h2 is the height of the oil outlet pipe 6 from the suction inlet of the submersible pump 1; Figure 1 In the figure, hx is the sum of the height (absolute value) of the suction inlet of submersible pump 1 and the liquid level height of underground tank 3.

[0085] See Figure 1 A self-protection interlocking pump shutdown system for submersible pumps with over-displacement limits, comprising:

[0086] Shaft 5, pipes installed inside shaft 5, underground cavern 3 installed at the bottom of shaft 5, and sealing plug 4 for isolating underground cavern 3;

[0087] The pipes inside shaft 5 include oil outlet pipe 6 and oil and gas pipe 7;

[0088] A pump pit is set at the bottom of the vertical shaft 5, and a submersible oil pump 1 is installed inside the pump pit. The submersible oil pump 1 is connected to the oil outlet pipe 6.

[0089] The submersible pump 1 displacement over-limit self-protection interlocking pump stop system also includes detection instruments for detecting oil and gas pressure and liquid level.

[0090] Furthermore, the detection instrument includes:

[0091] The first pressure transmitter 8 is used to record the pressure of the oil and gas pipeline in the underground tank 3.

[0092] The second pressure transmitter 9 is used to record the pressure in the outlet pipe of the submersible pump 1.

[0093] The level transmitter 10 is used to record the distance between the liquid level of the underground tank 3 and the bottom of the tank, which is located on the ground surface 11.

[0094] A method for interlocking pump shutdown control of a submersible pump with self-protection against over-displacement limits, the control method comprising:

[0095] Head data was collected during the operation of submersible pump 1, and then compared with the head data corresponding to the high and low displacement limits of submersible pump 1 on the head curve of submersible pump 1.

[0096] When the head data during the operation of submersible pump 1 is greater than or equal to the head data corresponding to the high displacement limit of submersible pump 1, submersible pump 1 will be interlocked and stopped.

[0097] Alternatively, when the head data during the operation of submersible pump 1 is less than or equal to the head data corresponding to the lower limit of the displacement of submersible pump 1, submersible pump 1 shall be interlocked and stopped.

[0098] The specific working process of the interlocked pump stop control method for self-protection when the displacement of submersible pump 1 exceeds the limit in this application is as follows:

[0099] (1) From the head curve of submersible pump 1, the head limit corresponding to its displacement high limit Q1 is H1, and the head limit corresponding to its displacement low limit Q2 is H2.

[0100] (2) During the operation of submersible pump 1, the oil and gas pressure and liquid level are detected using testing instruments. Specifically:

[0101] The first pressure transmitter 8 detects the pressure of the oil and gas pipeline in the underground tank 3.

[0102] The second pressure transmitter 9 detects the pressure in the outlet pipeline of the submersible pump 1.

[0103] The level transmitter 10 detects the distance between the liquid level of the underground tank 3 and the bottom of the tank, which is located on the ground surface 11.

[0104] (3) Substitute the values ​​obtained in step (2) into the following formula to calculate the real-time head data H of the submersible pump 1 during operation.

[0105] The formula for calculating the head data of the submersible pump 1 during operation is as follows:

[0106] H=(P2-P1) / ρg-(|h3|+h1)+h2;

[0107] In the formula:

[0108] H represents the pump head, measured in meters (m).

[0109] P1 is the pressure measurement value of the oil and gas pipeline in underground tank 3, in Pa;

[0110] P2 is the pressure measurement value of the outlet pipeline of submersible pump 1, in Pa;

[0111] h1 is the liquid level height of underground tank 3, which is the measured value (absolute elevation value, which is negative) at the liquid level transmitter 10, in meters;

[0112] h2 is the height of the oil outlet pipe 6 from the suction inlet of the submersible pump 1, in meters, and is the basic data for the specific project.

[0113] h3 is the height of the suction inlet of submersible pump 1 (absolute elevation value, which is negative), in meters, and is the basic data for specific projects;

[0114] g is the acceleration due to gravity;

[0115] ρ is the density of the oil in the pump pit.

[0116] (4) Compare the actual head data H obtained in step (3) with H1 and H2 in step (1). When H≥H1 or H≤H2, interlock and stop the submersible pump 1.

[0117] Application Example 1

[0118] The submersible pump 1 displacement over-limit self-protection interlocking pump stop control method and device system in Embodiment 1 of this application were applied to the Huangdao underground water-sealed cavern. After more than 3 years of practical operation, it was found that the pump interlocking scheme based on this technology works well in application.

[0119] Taking one submersible oil pump 1 as an example in the underground water-sealed cavern of Huangdao: (one):

[0121] The real-time head designation for submersible pump 1P-0301-07 during operation is H-1123, and its specific formula is as follows:

[0122] H-1123=[(PT-1103)×10 6 -(PT-1105)×10 3 ] / (880×9.81)-[|-56|+(LT-1103)]+155.62

[0123] in:

[0124] PT-1103 is a pressure transmitter for the outlet pipeline of pump P-0301-07. Its measurement value in this project is in MPa.

[0125] PT-1105 is a pressure transmitter for the oil and gas pipeline in underground tank 3. Its measurement value in this project is in kPa.

[0126] The height of the suction inlet of submersible pump 1 is -56m, which is the absolute elevation (engineering foundation data);

[0127] LT-1103 is the level transmitter 10 for underground tank 3. Its measurement value in this project is in meters (m) and is expressed as a negative value (absolute elevation), with the bottom of the tank at -50m (basic engineering data, absolute elevation) as the base point.

[0128] For example, when the oil level in the tank is 0 meters from the bottom, the LT-1103 reading on the controller is -50m; when the oil level is 10 meters from the bottom, the LT-1103 reading on the controller is -40m; and when the oil level is 15.4 meters from the bottom, the LT-1103 reading on the controller is -34.6m.

[0129] The distance between the oil outlet pipe 6 and the suction inlet of the submersible pump 1 is 155.62m (basic engineering data);

[0130] Gravitational acceleration: 9.81;

[0131] Oil density 880 kg / m³ 3 . (two):

[0133] Based on the relationship between pump displacement and head, the head curve shows that when the real-time head H-1123 during the operation of submersible pump 1 is ≥208m or H-1123≤157m, submersible pump 1P-0301-07 will be interlocked and stopped.

[0134] At this point, in the controller:

[0135] (1) If the level transmitter 10LT-1103 is -35m, PT-1103 is 0.2MPa, and PT-1105 is 50kPa:

[0136] H-1123=[0.2×10 6 -50×10 3 ] / (880×9.81)-[|-56|-35]+155.62=152m;

[0137] In the above formula, H-1123 is 152m. Since 152m < 157m, the interlocking pump stop command P-0301-07 is issued.

[0138] (2) If the level transmitter 10LT-1103 is -30m, PT-1103 is 0.25MPa, and PT-1105 is 0kPa:

[0139] H-1123=[0.25×10 6 -0] / (880×9.81)-[|-56|-30]+155.62=158.58m;

[0140] In the above formula, H-1123 is 158.58m. Since 157m < 158.58m < 208m, the pump operates normally and is not interlocked.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A kind of submersible pump displacement over-limit self-preservation interlock pump control method, it is characterized in that, The control method includes: Head data was collected during the operation of the submersible pump and then compared with the head data corresponding to the high and low limits of the submersible pump displacement on the submersible pump head curve. When the head data during the operation of the submersible pump is greater than or equal to the head data corresponding to the high limit of the submersible pump displacement, the submersible pump will be interlocked and stopped. Alternatively, when the head data during submersible pump operation is less than or equal to the head data corresponding to the lower limit of submersible pump displacement, the submersible pump will be interlocked and stopped. The head data during the operation of the submersible pump is obtained by collecting the pressure values ​​of the oil and gas pipelines in the underground tank, the pressure values ​​of the submersible pump outlet pipeline, and the liquid level height data of the underground tank, and then calculating them. The formula for calculating the head data during the operation of the submersible pump is as follows: H=(P2-P1) / ρg-(|h3|+h1)+h2; In the formula: H is the pump head; P1 is the pressure measurement value of the underground tank oil and gas pipeline; P2 is the pressure measurement value of the submersible pump outlet pipeline; h1 is the liquid level height in the underground tank; h2 is the height of the oil outlet pipe from the submersible pump inlet; h3 is the height of the submersible pump inlet; g is the acceleration due to gravity; ρ is the density of the oil in the pump pit.

2. A system for implementing the control method of claim 1, wherein the system comprises a pump displacement over-limit self-protection interlocking pump stopping system, characterized in that, include: A shaft, pipes installed inside the shaft, an underground cavern installed at the bottom of the shaft, and a sealing plug used to isolate the underground cavern; The pipes inside the shaft include oil outlet pipes and oil and gas pipes; A pump pit is set at the bottom of the shaft, and a submersible oil pump is installed inside the pump pit. The submersible oil pump is connected to the oil outlet pipeline and is equipped with a pump suction inlet. The submersible pump displacement over-limit self-protection interlocking pump stop system also includes detection instruments and controllers for detecting oil and gas pressure and liquid level; The controller is used to collect oil and gas pressure and liquid level information transmitted by the detection instrument, and calculate the head data during the operation of the submersible pump; then, according to the control method, the self-protection interlocking of the submersible pump to stop when the pump displacement exceeds the limit is realized.

3. The submersible pump displacement over-limit self-protection interlocking pump shutdown system according to claim 2, characterized in that, The detection instruments include pressure transmitters and level transmitters.

4. The submersible pump displacement over-limit self-protection interlocking pump shutdown system according to claim 3, characterized in that, The pressure transmitter includes: The pressure transmitter for underground tank oil and gas pipelines is referred to as the first pressure transmitter. And, the submersible pump outlet pipeline pressure transmitter, denoted as the second pressure transmitter.

5. The submersible pump displacement over-limit self-protection interlocking pump shutdown system according to claim 3, characterized in that, The level transmitter includes: A level transmitter for detecting the distance between the liquid level and the bottom of an underground tank.

6. The application of the submersible pump displacement over-limit self-protection interlocking pump stop control method as described in claim 1 in underground water-sealed cavern oil storage.

7. The application of the submersible pump displacement over-limit self-protection interlocking pump stop system according to any one of claims 2 to 5 in underground water-sealed cavern oil storage.

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