A turbine lubrication system and method of controlling the same

Abstract

This invention discloses a turbine lubrication system and its control method. The turbine lubrication system includes a turbine unit, a gearbox, an oil tank, a shaft head pump, an AC lubricating oil pump, an oil cooler, and an oil filter. The turbine unit is connected to the gearbox, and the gearbox is connected to the shaft head pump. The inlet of the shaft head pump is connected to a first pipe extending into the oil tank. The outlet of the shaft head pump is connected to a second pipe extending into the oil tank. A second valve (a three-way pressure reducing valve) is installed on the second pipe. One end of a third pipe is connected to the second valve, and the other end extends to the turbine unit's bearing and the gearbox. An oil cooler and an oil filter are connected in series on the third pipe. The AC lubricating oil pump is located inside the oil tank and is connected to the third pipe via a fourth pipe. The connection point between the fourth and third pipes is located between the second valve and the oil cooler. A fourth valve is installed on the fourth pipe. This invention solves the problems of the AC lubricating oil pump continuously consuming electrical energy and failing to supply oil when the electrical control system malfunctions.

Description

Technical Field

[0001] This invention relates to the field of steam turbines, and in particular to a steam turbine lubrication system and its control method. Background Technology

[0002] The turbine lubrication system supplies lubricating oil to the bearings of the turbine unit to reduce friction, remove heat, and ensure the safe operation of the turbine unit.

[0003] In existing steam turbine lubrication systems, lubricating oil is supplied to the turbine bearings via an AC lubricating oil pump driven by an electric motor. During turbine operation, the electric motor continuously powers the AC lubricating oil pump, consuming a significant amount of electrical energy. Furthermore, when the electric motor's control system malfunctions, the AC lubricating oil pump fails to operate, leading to an interruption in oil supply and impacting the safe operation of the steam turbine.

[0004] Therefore, it is particularly necessary to provide a new turbine lubrication system to solve the problems of the existing AC lubricating oil pump continuously consuming electrical energy and being unable to supply oil when the electronic control system fails. Summary of the Invention

[0005] The purpose of this invention is to provide a turbine lubrication system and its control method to address the aforementioned problems, which can solve the problems in the prior art where the AC lubricating oil pump continuously consumes electrical energy and cannot supply oil when the electrical control system fails.

[0006] The technical solution adopted in this invention is as follows:

[0007] A steam turbine lubrication system includes a steam turbine unit, a gearbox, an oil tank, a shaft head pump, an AC lubrication oil pump, an oil cooler, and an oil filter; the steam turbine unit is connected to the gearbox, and the gearbox is connected to the shaft head pump.

[0008] The inlet end of the shaft pump is connected to a pipe 1, which extends into the oil tank; the outlet end of the shaft pump is connected to a pipe 2, which extends into the oil tank. A valve 2 is provided on the pipe 2, which is a three-way pressure reducing valve.

[0009] One end of pipe three is connected to valve two, and the other end extends to the bearing of the turbine unit and the gearbox respectively. The oil cooler and the oil filter are connected in series on pipe three.

[0010] The AC lubricating oil pump is located inside the oil tank. The AC lubricating oil pump is connected to the pipe three through pipe four. The connection point between pipe four and pipe three is located between valve two and the oil cooler. Valve four is provided on pipe four.

[0011] Furthermore, it also includes an AC starter oil pump and a pressure regulating system;

[0012] The AC starting oil pump is located inside the oil tank. The AC starting oil pump is connected to pipe five. Pipe five is equipped with valve five. Pipe five is connected to pipe six and pipe seven respectively.

[0013] Pipeline 6 connects to the pressure regulating system;

[0014] Pipeline 7 is connected to pipe 1, and valve 7 is provided on pipe 7;

[0015] Pipeline 1 is connected to pipe 9. The connection point between pipe 9 and pipe 1 is located downstream of the connection point between pipe 7 and pipe 1. The connection point between pipe 9 and pipe 1 is close to the shaft pump. Pipeline 9 is equipped with valve 9.

[0016] Pipe 2 is connected to pipe 8. The connection point of pipe 8 is located between the shaft pump and valve 2. Pipe 8 is connected to the pressure regulating system. Pipe 8 is equipped with valve 8.

[0017] Furthermore, a valve is connected between pipe one and pipe two. One end of the valve is connected between the connection point of pipe seven and pipe one and the connection point of pipe nine and pipe one, and the other end is connected between the connection point of pipe eight and pipe two and the shaft pump.

[0018] Furthermore, the outlets of the AC lubricating oil pump, the AC starting oil pump, and the shaft head pump are all equipped with check valves.

[0019] Furthermore, the pressure regulating system includes a high-pressure storage tank, which is connected to pipeline six and pipeline eight.

[0020] The present invention also discloses a control method for a steam turbine lubrication system, including the above-mentioned steam turbine lubrication system, the control method comprising the following steps:

[0021] S1: Before starting the turbine unit, open valve four and start the AC lubricating oil pump. The AC lubricating oil pump draws lubricating oil from the oil tank, sends it through pipeline four to pipeline three, and then sends it to the bearings and gearbox of the turbine unit after being cooled by the oil cooler and filtered by the oil filter.

[0022] S2: Start the AC starting oil pump, open valve five and valve seven, the AC starting oil pump draws lubricating oil from the oil tank and sends it into the pipeline one through the pipeline five and the pipeline seven to fill the pipeline one and the oil inlet of the shaft pump with oil; at the same time, open valve nine on the pipeline nine to expel the air in the pipeline one, and close valve nine after the air is expelled.

[0023] S3: Start the turbine unit. The turbine unit drives the shaft pump to rotate through the gearbox. After the shaft pump reaches the rated speed, the shaft pump draws oil from the oil tank through the first pipeline. The oil is depressurized through the second pipeline and the second valve and then sent to the third pipeline. The oil is then sent to the bearing of the turbine unit and the gearbox through the oil cooler and the oil filter.

[0024] S4: Close valve four to stop the AC lubricating oil pump and the AC starting oil pump, and supply oil to the turbine bearings and the gearbox separately by the shaft head pump.

[0025] Furthermore, in step S3, the process of sending the oil through the second pipeline and the second valve to the third pipeline after pressure reduction specifically includes:

[0026] Obtain the real-time pressure value P2 in the second pipeline and the real-time pressure value P3 in the third pipeline, and calculate the pressure deviation ΔP=P3-P0, where P0 is the preset target oil supply pressure of the turbine unit bearing and the gearbox.

[0027] When ΔP>ΔP1, the first pressure reduction adjustment strategy is executed; the first pressure reduction adjustment strategy includes increasing the opening of the second valve, so that more oil in the second pipeline flows into the third pipeline through the second valve, until ΔP≤ΔP1;

[0028] When ΔP < -ΔP2, the second pressure reduction adjustment strategy is executed; the second pressure reduction adjustment strategy includes reducing the opening of the second valve to reduce the flow rate of oil in the second pipeline into the third pipeline through the second valve, until ΔP ≥ -ΔP2;

[0029] When -ΔP2≤ΔP≤ΔP1, the current opening degree of valve two remains unchanged;

[0030] Wherein, ΔP is the pressure deviation; P2 is the real-time pressure value in the second pipeline; P3 is the real-time pressure value in the third pipeline; P0 is the preset target oil supply pressure; ΔP1 is the positive pressure deviation threshold, representing the maximum allowable positive value of ΔP; ΔP2 is the absolute value of the negative pressure deviation threshold, representing the minimum allowable negative value of ΔP; both ΔP1 and ΔP2 are positive numbers.

[0031] Furthermore, in step S2, after starting the AC starting oil pump and opening valve five, the process further includes: the AC starting oil pump pre-charging the pressure regulating system via pipeline six; when the pressure in the pressure regulating system reaches a preset pre-charging termination pressure P... pre When this occurs, stop pre-filling the pressure regulating system with oil.

[0032] Furthermore, in step S3, after the shaft pump draws oil from the oil tank through the first pipe, and the oil is depressurized through the second pipe and the second valve before being sent into the third pipe, the process further includes: when the real-time pressure value P2 in the second pipe reaches the preset oil filling start pressure P... c At this time, valve eight is opened, allowing a portion of the oil output from the shaft pump through pipeline two to be transported to the pressure regulating system via pipeline eight and valve eight, thus filling the pressure regulating system with oil; when the pressure in the pressure regulating system reaches the preset oil filling termination pressure P... s At that time, valve eight is closed to stop the oil supply to the pressure regulating system; wherein, P c P is the sum of the minimum operating pressure of the pressure regulating system and the preset safety margin. s This is the maximum operating pressure of the pressure regulating system.

[0033] Furthermore, in step S3, after the shaft pump draws oil from the oil tank through the first pipe, and the oil is depressurized through the second pipe and the second valve before being sent into the third pipe, the process further includes:

[0034] When the real-time pressure value P2 in the second pipeline is lower than the minimum oil supply pressure P required by the turbine bearings and gearbox of the steam turbine unit... min When the pressure is replenished, a pressure replenishment strategy is executed; the pressure replenishment strategy includes opening valve eight, so that the oil in the pressure regulating system is reversely transported to the pipeline two through the pipeline eight to replenish the pressure in the pipeline two;

[0035] When the real-time pressure value P2 in the second pipeline rises back to P min +P h At that time, close valve eight to stop pressurization; where P h This is the preset hysteresis pressure value.

[0036] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0037] Before starting the turbine unit, valve four is opened to start the AC lubricating oil pump. The AC lubricating oil pump draws lubricating oil from the oil tank, sends it through pipeline four to pipeline three, cools it through the oil cooler, filters it through the oil filter, and then sends it to the bearings and gearbox of the turbine unit to ensure the lubrication needs of each bearing of the turbine unit before starting.

[0038] After the turbine unit starts, it drives the shaft head pump to rotate via the gearbox. As the turbine unit's speed increases, the shaft head pump gradually builds up oil pressure. When the shaft head pump reaches its rated speed, it draws oil from the oil tank through pipe one and delivers the oil to valve two via pipe two. Because the output pressure of the shaft head pump at its rated speed is higher than the supply pressure required for bearing lubrication in the turbine unit, valve two is a three-way pressure reducing valve. This valve reduces the pressure of the oil in pipe two and sends it to pipe three, where it passes through the oil cooler and filter before being delivered to the turbine unit's bearings and gearbox. At this point, valve four is closed and the AC lubrication pump is stopped, allowing the shaft head pump to supply oil solely to the turbine unit's bearings and gearbox.

[0039] Since the shaft head pump is mechanically driven by the turbine unit through the gearbox, no additional electric motor is needed to power the AC lubricating oil pump during normal operation of the turbine unit, effectively reducing power consumption. At the same time, since the oil supply of the shaft head pump does not depend on the electric motor and its electrical control system, the risk of oil supply interruption due to electrical control system failure is avoided, improving the safety and reliability of the turbine unit operation. Attached Figure Description

[0040] Figure 1 This is a diagram of the pipeline structure.

[0041] Figure 2 This is a diagram showing the valve locations.

[0042] In the diagram, 1-Pipe 1, 2-Pipe 2, 3-Pipe 3, 4-Pipe 4, 5-Pipe 5, 6-Pipe 6, 7-Pipe 7, 8-Pipe 8, 9-Pipe 9, 101-Valve 1, 102-Valve 2, 104-Valve 4, 105-Valve 5, 107-Valve 7, 108-Valve 8, 109-Valve 9, 1001-Steam turbine unit, 1002-Gearbox, 1003-Shaft pump, 1004-Pressure regulating system, 1005-Oil cooler, 1006-Oil filter, 1007-AC starting oil pump, 1008-AC lubricating oil pump, 1009-Oil tank. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0045] Example 1

[0046] like Figures 1-2 As shown, the present invention discloses a steam turbine lubrication system, including a steam turbine unit 1001, a gearbox 1002, an oil tank 1009, a shaft head pump 1003, an AC lubricating oil pump 1008, an oil cooler 1005, and an oil filter 1006; the steam turbine unit 1001 is connected to the gearbox 1002, and the gearbox 1002 is connected to the shaft head pump 1003;

[0047] The inlet end of the shaft pump 1003 is connected to a pipe 1, which extends into the oil tank 1009; the outlet end of the shaft pump 1003 is connected to a pipe 2, which extends into the oil tank 1009; a valve 2 102 is provided on the pipe 2, which is a three-way pressure reducing valve.

[0048] One end of pipe 3 is connected to valve 2 102, and the other end extends to the bearing of turbine unit 1001 and gearbox 1002 respectively. Oil cooler 1005 and oil filter 1006 are connected in series on pipe 3.

[0049] The AC lubricating oil pump 1008 is located inside the oil tank 1009. The AC lubricating oil pump 1008 is connected to the pipe 3 via pipe 4. The connection point between pipe 4 and pipe 3 is located between valve 2 102 and the oil cooler 1005. Valve 4 104 is provided on pipe 4.

[0050] Before starting the turbine unit 1001, valve 104 is opened to start the AC lubricating oil pump 1008. The AC lubricating oil pump 1008 draws lubricating oil from the oil tank 1009, sends it through pipeline 4 to pipeline 3, cools it through the oil cooler 1005, filters it through the oil filter 1006, and then sends it to the bearings of the turbine unit 1001 and the gearbox 1002 to ensure the lubrication needs of each bearing of the turbine unit 1001 before starting.

[0051] After the turbine unit 1001 starts, it drives the shaft pump 1003 to rotate via the gearbox 1002. As the turbine unit 1001's rotational speed increases, the shaft pump 1003 gradually builds up oil pressure. When the shaft pump 1003 reaches its rated speed, it draws oil from the oil tank 1009 through pipe 1 and delivers the oil to valve 102 via pipe 2. Since the output pressure of the shaft pump 1003 at its rated speed is higher than the supply pressure required for bearing lubrication in the turbine unit 1001, valve 102 is a three-way pressure reducing valve. It reduces the pressure of the oil in pipe 2 and sends it to pipe 3, then through the oil cooler 1005 and the oil filter 1006 before delivering it to the bearings of the turbine unit 1001 and the gearbox 1002. At this time, valve 4 104 is closed and the AC lubricating oil pump 1008 is stopped, and the shaft head pump 1003 supplies oil to the bearings of the turbine unit 1001 and the gearbox 1002 separately.

[0052] Since the shaft head pump 1003 is mechanically driven by the turbine unit 1001 through the gearbox 1002, no additional electric motor is needed to power the AC lubricating oil pump 1008 during normal operation of the turbine unit 1001, effectively reducing power consumption. At the same time, since the oil supply of the shaft head pump 1003 does not depend on the electric motor and its electrical control system, the risk of oil supply interruption due to electrical control system failure is avoided, improving the safety and reliability of the turbine unit 1001 operation.

[0053] Furthermore, it also includes an AC starter oil pump 1007 and a pressure regulating system 1004;

[0054] The AC starting oil pump 1007 is located inside the oil tank 1009. The AC starting oil pump 1007 is connected to pipe 5. Pipe 5 is equipped with valve 105. Pipe 5 is connected to pipe 6 and pipe 7 respectively.

[0055] Pipeline 6 is connected to the pressure regulating system 1004;

[0056] Pipeline 7 is connected to pipe 1, and valve 7107 is provided on pipe 7;

[0057] Pipe 9 is connected to pipe 1. The connection point of pipe 9 to pipe 1 is located downstream of the connection point of pipe 7 to pipe 1. The connection point of pipe 9 to pipe 1 is close to shaft pump 1003. Valve 109 is provided on pipe 9.

[0058] Pipe 2 is connected to pipe 8. The connection point of pipe 8 is located between the shaft pump 1003 and valve 2 102. Pipe 8 is connected to the pressure regulating system 1004. Pipe 8 is equipped with valve 8 108.

[0059] Before starting the shaft head pump 1003, the AC starting oil pump 1007 is started first. Valve 5 105 and valve 7 107 are opened. The AC starting oil pump 1007 draws lubricating oil from the oil tank 1009 and sends it into the first pipe 1 through the fifth pipe 5 and the seventh pipe 7 to fill the first pipe 1 and the oil inlet of the shaft head pump 1003 with oil. At the same time, valve 9 109 on the ninth pipe 9 is opened. The connection point of the ninth pipe 9 and the first pipe 1 is located downstream of the connection point of the seventh pipe 7 and the first pipe 1 and close to the shaft head pump 1003. The air in the first pipe 1 is discharged through the ninth pipe 9 and valve 9 109 under the push of the oil. When the air is exhausted and the oil reaches the connection point of the ninth pipe 9 and the first pipe 1, valve 9 109 is closed to keep the oil in the first pipe 1, ensuring that the entire pipe section from the connection point of the seventh pipe 7 and the first pipe 1 to the shaft head pump 1003 is filled with oil.

[0060] By filling the oil and venting the air, the air in the pipeline 1 and the oil inlet of the shaft pump 1003 is purged, which avoids cavitation and air intake caused by air intake when the shaft pump 1003 starts up. This protects the shaft pump 1003, extends its service life, and ensures the reliable start-up and operation of the shaft pump 1003.

[0061] After the shaft pump 1003 starts, a portion of the oil output from it through pipe 2 is transported to the pressure regulating system 1004 via pipe 8 and valve 108, providing an oil source for the pressure regulating system 1004. When the pressure in the pressure regulating system 1004 is insufficient, the oil can be reversed through pipe 8 to pipe 2 to increase the pressure in pipe 2.

[0062] Furthermore, a valve 101 is connected between the first pipe 1 and the second pipe 2. One end of the valve 101 is connected between the connection point of the seventh pipe 7 and the first pipe 1 and the connection point of the ninth pipe 9 and the first pipe 1, and the other end is connected between the connection point of the eighth pipe 8 and the second pipe 2 and the shaft head pump 1003.

[0063] When the pressure inside pipe 1 is too high, oil flows from pipe 1 to pipe 2 through valve 101, releasing the pressure inside pipe 1 and balancing the pressure between pipe 1 and pipe 2, thus preventing the shaft pump 1003 from being damaged due to excessive pressure inside pipe 1.

[0064] By installing valve 101 between pipe 1 and pipe 2, the pressure between pipe 1 and pipe 2 is balanced, preventing the oil inlet of shaft pump 1003 from bearing excessive load due to excessive pressure, thus protecting shaft pump 1003 and extending its service life.

[0065] Furthermore, the outlets of the AC lubricating oil pump 1008, the AC starting oil pump 1007, and the shaft head pump 1003 are all equipped with check valves.

[0066] By installing check valves at the outlets of all three pumps, backflow and reverse flow of oil between the pumps are effectively prevented.

[0067] Furthermore, the pressure regulating system 1004 includes a high-pressure storage tank, which is connected to the pipeline 6 and the pipeline 8.

[0068] The high-pressure storage tank is connected to pipe 6 and pipe 8. Pipe 6 is connected to the AC starting oil pump 1007 for filling and pressurizing the high-pressure storage tank with oil. Pipe 8 is connected to the shaft pump 1003 for transporting the oil output by the shaft pump 1003 to the high-pressure storage tank for storage. The high-pressure storage tank stores oil for the pressure regulating system 1004. When the pressure in pipe 2 is insufficient, the oil stored in the high-pressure storage tank is reversed and transported to pipe 2 via pipe 8 to quickly replenish the pressure in pipe 2.

[0069] The oil is stored in the high-pressure storage tank, and the energy storage function of the high-pressure storage tank is used to quickly replenish the pressure in pipeline 2 when the pressure is insufficient. Its response speed is faster than the pump start-up pressure replenishment method, which ensures the stability of the oil pressure and the continuity of oil supply in the pressure regulating system 1004 and improves the reliability of the system.

[0070] Example 2

[0071] The present invention also discloses a control method for a steam turbine lubrication system, including the steam turbine lubrication system described in Example 1, wherein the control method includes the following steps:

[0072] S1: Before starting the turbine unit 1001, open valve 4 104 and start the AC lubricating oil pump 1008. The AC lubricating oil pump 1008 draws lubricating oil from the oil tank 1009, sends it through pipeline 4 to pipeline 3, and then sends it to the bearings of the turbine unit 1001 and the gearbox 1002 after being cooled by the oil cooler 1005 and filtered by the oil filter 1006.

[0073] S2: Start the AC starting oil pump 1007, open valve 5 105 and valve 7 107, the AC starting oil pump 1007 draws lubricating oil from the oil tank 1009, and sends it into the pipeline 1 through the pipeline 5 and the pipeline 7 to fill the pipeline 1 and the oil inlet of the shaft pump 1003 with oil; at the same time, open valve 9 109 on the pipeline 9 to expel the air in the pipeline 1, and close valve 9 109 after the air has been expelled.

[0074] S3: Start the turbine unit 1001. The turbine unit 1001 drives the shaft pump 1003 to rotate through the gearbox 1002. After the shaft pump 1003 reaches the rated speed, the shaft pump 1003 draws oil from the oil tank 1009 through the first pipeline 1. After the oil is depressurized through the second pipeline 2 and the second valve 102, it is sent to the third pipeline 3. Then, it is sent to the bearing of the turbine unit 1001 and the gearbox 1002 through the oil cooler 1005 and the oil filter 1006.

[0075] S4: Close valve 4 104 to stop the AC lubricating oil pump 1008 and the AC starting oil pump 1007, and supply oil to the bearings of the turbine unit 1001 and the gearbox 1002 separately by the shaft head pump 1003.

[0076] In step S1, before the turbine unit 1001 is started, valve 4 104 is opened to start the AC lubricating oil pump 1008. The AC lubricating oil pump 1008 draws lubricating oil from the oil tank 1009, sends it through pipeline 4 to pipeline 3, cools it through the oil cooler 1005, filters it through the oil filter 1006, and then sends it to the bearings of the turbine unit 1001 and the gearbox 1002. This ensures the lubrication requirements of each bearing of the turbine unit 1001 before startup and establishes an initial oil film for the safe startup of the turbine unit 1001.

[0077] In step S2, the AC starting oil pump 1007 is started, and valves 5 and 7 are opened. The AC starting oil pump 1007 draws lubricating oil from the oil tank 1009 and sends it into pipe 1 through pipes 5 and 7, filling pipe 1 and the oil inlet of the shaft pump 1003 with oil. At the same time, valve 9 109 on pipe 9 is opened to expel air from pipe 1. After the air is expelled, valve 9 109 is closed. By filling the oil and venting the air, the air in pipe 1 and the oil inlet of the shaft pump 1003 is completely removed, preventing cavitation and air intake caused by air intake during the start-up of the shaft pump 1003, thus ensuring the reliable start-up of the shaft pump 1003.

[0078] In step S3, the turbine unit 1001 is started. The turbine unit 1001 drives the shaft pump 1003 to rotate through the reduction gearbox 1002. After the shaft pump 1003 reaches its rated speed, it draws oil from the oil tank 1009 through pipe 1, reduces the pressure through pipe 2 and valve 2 102, and then sends the oil to pipe 3. The oil then passes through the oil cooler 1005 and oil filter 1006 and is delivered to the bearings of the turbine unit 1001 and the reduction gearbox 1002. After the shaft pump 1003 reaches its rated speed, its output pressure is higher than the supply pressure required for bearing lubrication. Valve 2 102 is a three-way pressure reducing valve, which reduces the pressure of the oil in pipe 2 2 and sends it to pipe 3 3, ensuring that the oil supply pressure meets the lubrication requirements.

[0079] In step S4, valve 4 104 is closed, stopping the AC lubricating oil pump 1008 and the AC starting oil pump 1007. The shaft head pump 1003 then supplies oil solely to the bearings of the turbine unit 1001 and the gearbox 1002. Since the shaft head pump 1003 is mechanically driven by the turbine unit 1001 through the gearbox 1002, no additional electric motor is needed to power the lubricating oil pump during normal operation of the turbine unit 1001, effectively reducing energy consumption. Simultaneously, because the oil supply from the shaft head pump 1003 does not depend on the electric motor and its electrical control system, the risk of oil supply interruption due to electrical control system failure is avoided, improving the safety and reliability of the turbine unit 1001's operation.

[0080] Furthermore, in S2, the air discharge from the pipe 1 specifically includes: the connection point of the pipe 9 and the pipe 1 is located downstream of the connection point of the pipe 7 and the pipe 1 and close to the shaft pump 1003. When filling with oil, the air in the pipe 1 is discharged through the pipe 9 and the valve 9 109 under the push of the oil. When the air is completely discharged and the oil reaches the connection point of the pipe 9 and the pipe 1, the valve 9 109 is closed.

[0081] In step S2, the connection point between pipe 9 and pipe 1 is located downstream of the connection point between pipe 7 and pipe 1 and close to the shaft head pump 1003. When the AC starter oil pump 1007 fills pipe 1 with oil, the air in pipe 1 is discharged through pipe 9 and valve 9 109 under the push of the oil. Since the connection point between pipe 9 and pipe 1 is close to the shaft head pump 1003, valve 9 109 is closed when the air is exhausted and the oil reaches the connection point, ensuring that the entire pipe section from the connection point between pipe 7 and pipe 1 to the shaft head pump 1003 is filled with oil.

[0082] By setting the connection point of the pipe 9 near the shaft pump 1003, air is ensured to be discharged from the end of the pipe 1, avoiding residual air at the oil inlet of the shaft pump 1003. This effectively prevents cavitation and air intake caused by air intake when the shaft pump 1003 starts up, ensuring reliable start-up and operation of the shaft pump 1003.

[0083] Furthermore, in step S3, the process of sending the oil through the second pipeline 2 and the second valve 102 to the third pipeline 3 after pressure reduction specifically includes:

[0084] Obtain the real-time pressure value P2 in the second pipeline 2 and the real-time pressure value P3 in the third pipeline 3, and calculate the pressure deviation ΔP=P3-P0, where P0 is the preset target oil supply pressure of the bearing of the turbine unit 1001 and the gearbox 1002.

[0085] When ΔP>ΔP1, the first pressure reduction adjustment strategy is executed; the first pressure reduction adjustment strategy includes increasing the opening of the valve 2 102, so that more oil in the pipeline 2 flows into the pipeline 3 through the valve 2 102, until ΔP≤ΔP1;

[0086] When ΔP < -ΔP2, the second pressure reduction adjustment strategy is executed; the second pressure reduction adjustment strategy includes reducing the opening of the valve 102 to reduce the flow rate of oil in the pipeline 2 into the pipeline 3 through the valve 102, until ΔP ≥ -ΔP2;

[0087] When -ΔP2≤ΔP≤ΔP1, the current opening degree of valve 102 remains unchanged;

[0088] Wherein, ΔP is the pressure deviation; P2 is the real-time pressure value in pipeline 2; P3 is the real-time pressure value in pipeline 3; P0 is the preset target oil supply pressure; ΔP1 is the positive pressure deviation threshold, representing the maximum allowable positive value of ΔP; ΔP2 is the absolute value of the negative pressure deviation threshold, representing the minimum allowable negative value of ΔP; ΔP1 and ΔP2 are both positive numbers.

[0089] When ΔP > ΔP1, it indicates that the actual oil supply pressure in pipeline 3 is higher than the preset target oil supply pressure and the positive deviation exceeds the allowable range. The first pressure reduction adjustment strategy is then executed, increasing the opening of valve 2 102 to allow more oil from pipeline 2 2 to flow into pipeline 3, increasing the pressure-reduced oil flow rate and lowering the pressure in pipeline 3 until ΔP ≤ ΔP1. This strategy effectively reduces the pressure in pipeline 3 by increasing the opening of valve 2 102, bringing the actual oil supply pressure back to the preset target range.

[0090] When ΔP < -ΔP2, it indicates that the actual oil supply pressure in pipeline 3 is lower than the preset target oil supply pressure and the negative deviation exceeds the allowable range. A second pressure reduction adjustment strategy is then implemented, reducing the opening of valve 2 102 to decrease the flow rate of oil from pipeline 2 2 into pipeline 3 via valve 2 102, thereby increasing the pressure in pipeline 3 until ΔP ≥ -ΔP2. This strategy effectively increases the pressure in pipeline 3 by reducing the opening of valve 2 102, bringing the actual oil supply pressure back to the preset target range.

[0091] When -ΔP2≤ΔP≤ΔP1, it means that the deviation between the actual oil supply pressure in the pipeline 3 and the preset target oil supply pressure is within the allowable range, and the current opening of the valve 2 102 remains unchanged to maintain the stability of the current oil supply pressure.

[0092] By acquiring pressure values ​​in real time and calculating deviations, different adjustment strategies are executed according to the three intervals where ΔP is located, achieving closed-loop control of the opening degree of valve 102. This ensures that the actual oil supply pressure in pipeline 3 is always maintained within the preset target range, avoiding problems such as bearing damage or seal failure due to excessively high oil supply pressure, and insufficient lubrication due to excessively low oil supply pressure. This guarantees the safety and reliability of bearing lubrication in turbine unit 1001.

[0093] Furthermore, the first pressure reduction adjustment strategy specifically includes: the opening adjustment amount of the valve 102 is determined according to the following formula:

[0094]

[0095] Wherein, ΔK is the opening adjustment amount of valve 102, Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the differential coefficient, τ is the time integral variable, and t is the time variable;

[0096] express The derivative with respect to time t;

[0097] when When ΔK is positive, it indicates an increase in the opening degree of valve 102; when When ΔK is negative, it indicates a reduction in the opening degree of valve 102.

[0098] In the first pressure reduction adjustment strategy, the opening adjustment amount of valve 2 102 is determined according to the above formula.

[0099] Among them, the proportion term An immediate adjustment is generated based on the current deviation; the larger the deviation, the larger the adjustment, thus improving the system's response speed. (Integral term) Historical deviations are accumulated to eliminate steady-state errors, ensuring that the pressure within pipeline 3 converges precisely to the preset target value during long-term operation; differential term Adjustments are generated based on the rate of change of the deviation, the trend of deviation change is predicted, and actions are taken in advance before the deviation expands further, thus suppressing pressure fluctuations and overshoot and improving system stability.

[0100] when When ΔK is positive, it indicates that the opening of valve 102 is increased, allowing more oil in pipe 2 to flow into pipe 3 through valve 102, thus reducing the pressure in pipe 3; when When ΔK is negative, it indicates that the opening of valve 102 is reduced, the flow rate of oil in pipe 2 through valve 102 into pipe 3 is reduced, and the pressure in pipe 3 is increased.

[0101] The opening adjustment of valve 102 is calculated using the above formula. The formula integrates the adjustment effects of proportional, integral, and derivative terms, so that the actual oil supply pressure in pipeline 3 converges quickly, accurately, and stably to the preset target range, avoiding the impact of oil supply pressure fluctuations on bearing lubrication and ensuring the oil supply stability of the turbine unit 1001 bearings during startup and operation.

[0102] Furthermore, the second pressure reduction adjustment strategy specifically includes: the adjustment amount of the valve 102 opening is determined according to the following formula:

[0103]

[0104] Wherein, ΔK is the opening adjustment amount of valve 102, Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the differential coefficient, τ is the time integral variable, and t is the time variable;

[0105] express The derivative with respect to time t;

[0106] when When ΔK is negative, it indicates a reduction in the opening degree of valve 102; when When ΔK is positive, it indicates that the opening degree of valve 102 is increased.

[0107] In the second pressure reduction adjustment strategy, the opening adjustment amount of valve 102 is determined according to the above formula.

[0108] Among them, the proportion term An immediate adjustment is generated based on the current deviation; the larger the deviation, the larger the adjustment, thus improving the system's response speed. (Integral term) Historical deviations are accumulated to eliminate steady-state errors, ensuring that the pressure within pipeline 3 converges precisely to the preset target value during long-term operation; differential term Adjustments are generated based on the rate of change of the deviation, the trend of deviation change is predicted, and actions are taken in advance before the deviation expands further, thus suppressing pressure fluctuations and overshoot and improving system stability.

[0109] when When ΔK is negative, it indicates a reduction in the opening of valve 102, reducing the flow rate of oil from pipe 2 into pipe 3 via valve 102, and increasing the pressure within pipe 3; when When ΔK is positive, it means that the opening of valve 102 is increased, so that more oil in pipe 2 flows into pipe 3 through valve 102, thereby reducing the pressure in pipe 3.

[0110] The opening adjustment of valve 102 is calculated using the above formula. The formula integrates the adjustment effects of proportional, integral, and derivative terms, so that the actual oil supply pressure in pipeline 3 rises quickly, accurately, and stably to the preset target range, avoiding the problem of insufficient lubrication caused by excessively low oil supply pressure, and ensuring the oil supply stability of the turbine unit 1001 bearings during startup and operation.

[0111] Furthermore, in step S2, after starting the AC starting oil pump 1007 and opening valve 105, the process further includes: the AC starting oil pump 1007 pre-charging oil into the pressure regulating system 1004 via pipeline 6; when the pressure in the pressure regulating system 1004 reaches a preset pre-charging termination pressure P... pre When this occurs, stop pre-charging oil into the pressure regulating system 1004.

[0112] In step S2, after starting the AC starting oil pump 1007 and opening valve 105, the AC starting oil pump 1007 pre-charges the pressure regulating system 1004 with oil via pipeline 6. When the pressure in the pressure regulating system 1004 reaches the preset pre-charge termination pressure P... pre When this occurs, the pre-filling of oil into the pressure regulating system 1004 is stopped. Through pre-filling, the pressure regulating system 1004 establishes an initial pressure reserve before the shaft head pump 1003 is started, providing initial conditions for the subsequent oil filling of the pressure regulating system 1004 by the shaft head pump 1003 and the reverse oil replenishment of the pressure regulating system 1004.

[0113] By establishing initial pressure through pre-filling oil, the pressure regulating system 1004 ensures that it has a certain oil pressure reserve before the shaft head pump 1003 starts. This avoids the oil filling delay caused by the low initial pressure when the shaft head pump 1003 fills the pressure regulating system 1004 after starting, and ensures that the pressure regulating system 1004 can quickly respond to the oil filling demand after the shaft head pump 1003 starts, thus improving the system's response speed.

[0114] Furthermore, in step S3, after the shaft pump 1003 draws oil from the oil tank 1009 through the first pipe 1, and after the oil is depressurized through the second pipe 2 and the second valve 102 and then sent into the third pipe 3, the process further includes: when the real-time pressure value P2 in the second pipe 2 reaches the preset oil filling start pressure P... c When valve 8 108 is opened, a portion of the oil output from the shaft pump 1003 through the pipeline 2 is transported to the pressure regulating system 1004 via the pipeline 8 8 and valve 8 108 to fill the pressure regulating system 1004 with oil; when the pressure in the pressure regulating system 1004 reaches the preset oil filling termination pressure P s At that time, valve 8108 is closed to stop the oil supply to the pressure regulating system 1004; wherein, P c P is the sum of the minimum operating pressure of the pressure regulating system 1004 and the preset safety margin. s This is the maximum operating pressure of the pressure regulating system 1004.

[0115] Because of P c The minimum operating pressure of the pressure regulating system 1004 is the sum of the preset safety margin and the minimum operating pressure of the system. When P2 reaches P... c At this time, the shaft pump 1003 has sufficient oil pressure to fill the pressure regulating system 1004, ensuring pressure balance between oil supply and filling, and preventing the bearing oil supply from being affected by the pressure drop in the pipeline 2 due to oil filling. When the pressure in the pressure regulating system 1004 reaches the preset oil filling termination pressure P... s When this happens, close valve 8 108 to stop filling the pressure regulating system 1004 with oil, preventing the pressure regulating system 1004 from being overcharged and causing excessive pressure that could damage the components.

[0116] By achieving P at P2 c When valve 8108 is opened, oil is added and the pressure regulating system 1004 reaches P. s When valve 8 108 is closed, the pressure of the pressure regulating system 1004 is automatically maintained, ensuring that the pressure regulating system 1004 has the ability to provide reverse pressure to the pipeline 2 at any time, thereby improving the reliability and response speed of the system.

[0117] Furthermore, in step S3, after the shaft pump 1003 draws oil from the oil tank 1009 through the first pipe 1, and after the oil is depressurized through the second pipe 2 and the second valve 102 and then sent into the third pipe 3, it further includes:

[0118] When the real-time pressure value P2 in the pipeline 2 is lower than the minimum oil supply pressure P required by the bearings of the turbine unit 1001 and the gearbox 1002 min When the pressure is replenished, a pressure replenishment strategy is executed; the pressure replenishment strategy includes opening valve 8 108, so that the oil in the pressure regulating system 1004 is reversely transported to the pipeline 2 via the pipeline 8 to replenish the pressure in the pipeline 2;

[0119] When the real-time pressure value P2 in the second pipeline 2 rises back to P min +P h At that time, close valve 8108 to stop pressurization; where P h This is the preset hysteresis pressure value.

[0120] Since the pressure regulating system 1004 has been pre-filled with oil during the startup phase and filled with oil by the shaft head pump 1003 during normal operation, it stores high-pressure oil. When P2 is lower than P... min It can immediately reverse the pressure, and its response speed is faster than the pump's start-up pressure replenishment method, ensuring uninterrupted oil supply. When the real-time pressure value P2 in the pipeline 2 rises back to P... min +P h When this happens, valve 8108 is closed to stop pressure replenishment. This is achieved by setting the hysteresis pressure value P. h To avoid P2 in P min Nearby fluctuations caused valve 8108 to open and close frequently, improving the system's stability.

[0121] By P2 being lower than P min The pressure replenishment strategy is implemented in a timely manner to ensure that the pressure in the pipeline 2 is always maintained above the minimum oil supply pressure, thereby avoiding dry friction damage caused by insufficient bearing lubrication due to excessively low oil supply pressure, and improving the safety and reliability of the turbine unit 1001 operation.

[0122] Furthermore, the pressure replenishment strategy specifically includes: the flow rate Q of the pressure regulating system 1004 replenishing the pressure of the second pipeline 2 is determined according to the following formula:

[0123]

[0124] Where Q is the flow rate of the pressure regulating system 1004 supplying pressure to the pipeline 2, C is the flow coefficient, A is the effective flow area of ​​valve 8 108, and P t P1 is the real-time pressure within the pressure regulating system 1004, P2 is the real-time pressure within the pipeline 2, and ρ is the density of the lubricating oil.

[0125] When P t -P2>ΔP t When P is increased, the opening of valve 8108 is increased to improve the pressure compensation flow; t -P2≤ΔP t At this time, reduce the opening of valve 8108 to reduce the pressure compensation flow; where ΔP t This is the preset differential pressure threshold.

[0126] The above formula reflects the relationship between the pressure compensation flow rate Q and the pressure difference P. t -The square root of P2 is directly proportional: when P t When P2 is large, the pressure compensation flow rate increases; when P t When -P2 is small, the pressure compensation flow rate decreases.

[0127] By monitoring P t The real-time pressure difference between P1 and P2, when P t -P2>ΔP t When the pressure difference is large, increase the opening of valve 8108 to increase the pressure compensation flow, so that the pressure in pipeline 2 can quickly recover; when P t -P2≤ΔP t When the pressure difference is small, reduce the opening of valve 8108 to reduce the pressure compensation flow and prevent excessive pressure compensation.

[0128] By adjusting the opening of the differential pressure regulating valve 8108 in real time, precise control of the pressure replenishment flow rate is achieved, avoiding the problems of insufficient pressure replenishment leading to continuously low pressure in pipeline 2 and excessive pressure replenishment leading to pressure overshoot. This ensures a smooth recovery of pressure in pipeline 2 and improves the accuracy and stability of the pressure replenishment strategy.

[0129] Furthermore, in step S3, after the shaft pump 1003 draws oil from the oil tank 1009 through the first pipe 1, and after the oil is depressurized through the second pipe 2 and the second valve 102 and then sent into the third pipe 3, the method further includes: acquiring the real-time pressure value P1 in the first pipe 1; when P1 exceeds the preset maximum allowable pressure P of the first pipe 1... 1max When this occurs, a pressure relief strategy is executed; the pressure relief strategy includes opening valve 101, allowing oil to flow from pipeline 1 to pipeline 2 through valve 101, releasing the pressure in pipeline 1 until P1 ≤ P 1max -P h1 When valve 101 is closed, P h1 This is the preset hysteresis pressure value.

[0130] By setting the hysteresis pressure value P h1 To avoid P 1max Nearby fluctuations caused valve 101 to open and close frequently, improving the system's stability.

[0131] By exceeding P1 1max The pressure relief strategy is implemented in a timely manner to ensure that the pressure in the pipeline 1 is always maintained within the safe range that the oil inlet of the shaft pump 1003 can withstand. This avoids damage to the shaft pump 1003 due to excessive load caused by excessive pressure in the pipeline 1, thus protecting the shaft pump 1003 and extending its service life.

[0132] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A steam turbine lubrication system, comprising a steam turbine unit (1001), a gearbox (1002), an oil tank (1009), a shaft pump (1003), an AC lubrication oil pump (1008), an oil cooler (1005), and an oil filter (1006); characterized in that, The steam turbine unit (1001) is connected to the gearbox (1002), and the gearbox (1002) is connected to the shaft head pump (1003); The inlet end of the shaft pump (1003) is connected to a pipe (1), which extends into the oil tank (1009); the outlet end of the shaft pump (1003) is connected to a pipe (2), which extends into the oil tank (1009); a valve (102) is provided on the pipe (2), which is a three-way pressure reducing valve. One end of the pipe (3) is connected to the valve (102), and the other end extends to the bearing of the turbine unit (1001) and the gearbox (1002), respectively. The oil cooler (1005) and the oil filter (1006) are connected in series on the pipe (3). The AC lubricating oil pump (1008) is located inside the oil tank (1009). The AC lubricating oil pump (1008) is connected to the pipe three (3) through pipe four (4). The connection point between pipe four (4) and pipe three (3) is located between valve two (102) and the oil cooler (1005). Valve four (104) is provided on pipe four (4).

2. The turbine lubrication system according to claim 1, characterized in that, It also includes an AC starter oil pump (1007) and a pressure regulating system (1004). The AC starting oil pump (1007) is located inside the oil tank (1009). The AC starting oil pump (1007) is connected to pipe five (5). Pipe five (5) is equipped with valve five (105). Pipe five (5) is connected to pipe six (6) and pipe seven (7) respectively. Pipeline 6 (6) is connected to the pressure regulating system (1004). The seventh pipe (7) is connected to the first pipe (1), and the seventh pipe (7) is equipped with a valve (107). Pipeline 9 (9) is connected to Pipeline 1 (1). The connection point of Pipeline 9 (9) and Pipeline 1 (1) is located downstream of the connection point of Pipeline 7 (7) and Pipeline 1 (1). The connection point of Pipeline 9 (9) and Pipeline 1 (1) is close to the shaft pump (1003). Pipeline 9 (9) is equipped with valve 9 (109). Pipeline 2 (2) is connected to pipe 8 (8). The connection point of pipe 8 (8) is located between the shaft pump (1003) and valve 2 (102). Pipeline 8 (8) is connected to the pressure regulating system (1004). Valve 8 (108) is provided on pipe 8 (8).

3. The turbine lubrication system according to claim 2, characterized in that, A valve (101) is connected between the first pipe (1) and the second pipe (2). One end of the valve (101) is connected between the connection point of the seventh pipe (7) and the first pipe (1) and the connection point of the ninth pipe (9) and the first pipe (1), and the other end is connected between the connection point of the eighth pipe (8) and the second pipe (2) and the shaft pump (1003).

4. The turbine lubrication system according to claim 2, characterized in that, The outlets of the AC lubricating oil pump (1008), the AC starting oil pump (1007), and the shaft head pump (1003) are all equipped with one-way valves.

5. The turbine lubrication system according to claim 2, characterized in that, The pressure regulating system (1004) includes a high-pressure storage tank, which is connected to the sixth pipe (6) and the eighth pipe (8).

6. A control method for a steam turbine lubrication system, comprising the steam turbine lubrication system according to any one of claims 1 to 5, characterized in that, The control method includes the following steps: S1: Before starting the turbine unit (1001), open valve four (104) and start the AC lubricating oil pump (1008). The AC lubricating oil pump (1008) draws lubricating oil from the oil tank (1009), sends it through the pipeline four (4) into the pipeline three (3), and then sends it to the bearings of the turbine unit (1001) and the gearbox (1002) after being cooled by the oil cooler (1005) and filtered by the oil filter (1006). S2: Start the AC starting oil pump (1007), open valve five (105) and valve seven (107), the AC starting oil pump (1007) draws lubricating oil from the oil tank (1009), and sends it into the pipeline one (1) through the pipeline five (5) and the pipeline seven (7) to fill the pipeline one (1) and the oil inlet of the shaft pump (1003) with oil; at the same time, open valve nine (109) on the pipeline nine (9) to discharge the air in the pipeline one (1), and close valve nine (109) after the air is discharged. S3: Start the turbine unit (1001). The turbine unit (1001) drives the shaft pump (1003) to rotate through the gearbox (1002). After the shaft pump (1003) reaches the rated speed, the shaft pump (1003) draws oil from the oil tank (1009) through the first pipeline (1). After the oil is depressurized through the second pipeline (2) and the second valve (102), it is sent to the third pipeline (3). Then, it is sent to the bearing of the turbine unit (1001) and the gearbox (1002) through the oil cooler (1005) and the oil filter (1006). S4: Close valve four (104), stop the AC lubricating oil pump (1008) and the AC starting oil pump (1007), and supply oil to the bearings of the turbine unit (1001) and the gearbox (1002) separately by the shaft head pump (1003).

7. The control method according to claim 6, characterized in that, In step S3, the process of sending oil into the third pipeline (3) after depressurization via the second pipeline (2) and the second valve (102) specifically includes: Obtain the real-time pressure value P2 in the second pipeline (2) and the real-time pressure value P3 in the third pipeline (3), and calculate the pressure deviation ΔP=P3-P0, where P0 is the preset target oil supply pressure of the bearing of the turbine unit (1001) and the gearbox (1002); When ΔP>ΔP1, the first pressure reduction adjustment strategy is executed; the first pressure reduction adjustment strategy includes increasing the opening of the valve two (102) so that more oil in the pipeline two (2) flows into the pipeline three (3) through the valve two (102) until ΔP≤ΔP1; When ΔP < -ΔP2, the second pressure reduction adjustment strategy is executed; the second pressure reduction adjustment strategy includes reducing the opening of the valve two (102) to reduce the flow rate of oil in the pipeline two (2) into the pipeline three (3) through the valve two (102) until ΔP ≥ -ΔP2; When -ΔP2≤ΔP≤ΔP1, the current opening degree of valve 2 (102) remains unchanged; Wherein, ΔP is the pressure deviation; P2 is the real-time pressure value in the second pipeline (2); P3 is the real-time pressure value in the third pipeline (3); P0 is the preset target oil supply pressure; ΔP1 is the positive pressure deviation threshold, representing the positive maximum allowable value of ΔP; ΔP2 is the absolute value of the negative pressure deviation threshold, representing the negative minimum allowable value of ΔP; ΔP1 and ΔP2 are both positive numbers.

8. The control method according to claim 6, characterized in that, In step S2, after starting the AC starting oil pump (1007) and opening valve five (105), the process further includes: the AC starting oil pump (1007) pre-charging oil into the pressure regulating system (1004) via the pipeline six (6), and when the pressure in the pressure regulating system (1004) reaches the preset pre-charging termination pressure P. pre When this occurs, stop pre-filling the pressure regulating system (1004) with oil.

9. The control method according to claim 6, characterized in that, In step S3, the shaft pump (1003) draws oil from the oil tank (1009) through the first pipe (1), and after the oil is depressurized through the second pipe (2) and the second valve (102) and sent into the third pipe (3), the process further includes: when the real-time pressure value P2 in the second pipe (2) reaches the preset oil filling start pressure P c At this time, valve eight (108) is opened, so that a portion of the oil output by the shaft pump (1003) through the pipeline two (2) is transported to the pressure regulating system (1004) through the pipeline eight (8) and valve eight (108) to fill the pressure regulating system (1004) with oil; when the pressure in the pressure regulating system (1004) reaches the preset oil filling termination pressure P s At that time, valve eight (108) is closed to stop the oil supply to the pressure regulating system (1004); wherein, P c P is the sum of the minimum operating pressure of the pressure regulating system (1004) and the preset safety margin. s The maximum operating pressure of the pressure regulating system (1004) is given.

10. The control method according to claim 6, characterized in that, In S3, the shaft pump (1003) draws oil from the oil tank (1009) through the first pipe (1), and after the oil is depressurized through the second pipe (2) and the second valve (102) and sent into the third pipe (3), it further includes: When the real-time pressure value P2 in the second pipeline (2) is lower than the minimum oil supply pressure P required by the bearings of the turbine unit (1001) and the gearbox (1002), min At that time, a pressure replenishment strategy is executed; the pressure replenishment strategy includes opening valve eight (108) to allow the oil in the pressure regulating system (1004) to be reversely transported to the pipeline two (2) through the pipeline eight (8) to replenish the pressure in the pipeline two (2); When the real-time pressure value P2 in the second pipe (2) rises back to P min +P h At that time, close valve eight (108) to stop pressurization; where P h This is the preset hysteresis pressure value.

Images