Oil pump switching control system for large unit oil station and large unit oil station

Abstract

This invention provides an oil pump switching control system for a large-scale generator set oil station, and the large-scale generator set oil station itself, belonging to the field of industrial control technology. The oil pump switching control system includes: a first pressure control valve connected to a pipeline between a first lubricating oil pump and a lubricating oil pump outlet safety valve group, used to control the outlet pressure of the first lubricating oil pump; a second pressure control valve connected to a pipeline between a second lubricating oil pump and a lubricating oil pump outlet safety valve group, used to control the outlet pressure of the second lubricating oil pump; and a control module used to control the outlet pressures of the first and second lubricating oil pumps respectively by controlling the opening degrees of the first and second pressure control valves, so that after shutting down either the first or second lubricating oil pump during dual-pump operation, the large-scale generator set oil station operates smoothly.

Description

Technical Field

[0001] This invention relates to the field of industrial control technology, specifically to an oil pump switching control system for a large-scale generator oil station, and the large-scale generator oil station itself. Background Technology

[0002] The PID (Proportion Integration Differentiation) process of conventional large-scale steam turbine-compressor unit oil stations consists of main and auxiliary oil pumps, main and auxiliary pump outlet safety valves, coolers, pump outlet pressure control valves, oil filters, lubricating oil main pressure regulating valves, and related pipelines. Because lubricating oil pumps are typically positive displacement screw pumps, significant fluctuations in pump outlet pressure and the activation of pump outlet safety valves are inevitable during unit operation, especially when auxiliary pumps start automatically or when switching between main and auxiliary pumps. For large centrifugal compressor units driven by steam turbines, low oil pressure can even trigger unit interlock shutdowns, severely impacting the production of the turbine-affiliated units, particularly the stable operation and economic benefits of petrochemical plants. Summary of the Invention

[0003] The purpose of this invention is to provide an oil pump switching control system for large-scale generator oil stations, which can achieve disturbance-free control during the switching operation of main and auxiliary pumps in large-scale generator oil stations.

[0004] To achieve the above objectives, embodiments of the present invention provide an oil pump switching control system for a large-scale generator unit oil station. The large-scale generator unit oil station includes a first lubricating oil pump, a second lubricating oil pump, a lubricating oil pump outlet safety valve group connected to the outlet pipes of the first and second lubricating oil pumps, a lubricating oil pump main control valve group connected to the outlet pipe of the lubricating oil pump outlet safety valve group, and oil pipelines. The oil pump switching control system for the large-scale generator unit oil station includes: a first pressure control valve connected to the pipeline between the first lubricating oil pump and the lubricating oil pump outlet safety valve group, used to control the outlet pressure of the first lubricating oil pump; a second pressure control valve connected to the pipeline between the second lubricating oil pump and the lubricating oil pump outlet safety valve group, used to control the outlet pressure of the second lubricating oil pump; and a control module used to control the outlet pressures of the first and second lubricating oil pumps respectively by controlling the opening degrees of the first and second pressure control valves, so that after shutting down either the first or second lubricating oil pump during dual-pump operation, the large-scale generator unit oil station operates smoothly.

[0005] Optionally, the outlet pressure of one of the first and second lubricating oil pumps can be controlled by one of the pressure control valves, including: when the outlet pressure of the lubricating oil pump is higher than the outlet pressure setting value of the pressure control valve, the pressure control valve opens, and part of the oil generated by the lubricating oil pump flows back through the pressure control valve to reduce the outlet pressure of the lubricating oil pump; when the outlet pressure of the lubricating oil pump is lower than the outlet pressure setting value, the pressure control valve closes to reduce the backflow of oil through the pressure control valve and stabilize the outlet pressure of the lubricating oil pump.

[0006] Optionally, the step of controlling the outlet pressures of the first and second lubricating oil pumps by controlling the opening degrees of the first and second pressure control valves, respectively, so that the large unit oil station can operate smoothly after shutting down either the first or second lubricating oil pump during dual-pump operation, includes: when it is necessary to shut down the first lubricating oil pump and start the second lubricating oil pump, controlling the second pressure control valve to open at a first preset speed until it is fully open, wherein the initial state of the first and second pressure control valves is closed; controlling the second lubricating oil pump to start; controlling the opening degrees of the first and second pressure control valves so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve group; controlling the first lubricating oil pump to stop; and controlling the operating mode of the first and second pressure control valves to be automatic control mode.

[0007] Optionally, when the second pressure control valve is opened at a first preset speed, the control module is further configured to: acquire the lubricating oil pump outlet pressure; acquire the outlet pressure of the lubricating oil pump main control valve group; and when the decrease in the lubricating oil pump outlet pressure or the lubricating oil pump main control valve group is greater than a first preset threshold, control the second pressure control valve to close at the first preset speed until the lubricating oil pump outlet pressure and the lubricating oil pump main control valve group return to normal values.

[0008] Optionally, controlling the opening of the first pressure control valve and the second pressure control valve to make the outlet pressure of the first lubricating oil pump lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve assembly includes: controlling the second pressure control valve to close at a second preset speed, so that the outlet pressure of the second lubricating oil pump is lower than the outlet pressure of the lubricating oil pump by a first preset value; controlling the second pressure control valve to close at a third preset speed until it is fully closed.

[0009] Optionally, the step of controlling the outlet pressures of the first and second lubricating oil pumps by controlling the opening degrees of the first and second pressure control valves, respectively, so that the large unit oil station can operate smoothly after stopping either the first or second lubricating oil pump during dual-pump operation, includes: when the first and second lubricating oil pumps are running simultaneously and the first lubricating oil pump needs to be stopped, controlling the opening degrees of the first and second pressure control valves so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve group; controlling the first lubricating oil pump to stop; and controlling the operating mode of the first and second pressure control valves to automatic control mode.

[0010] Optionally, controlling the opening of the first pressure control valve and the second pressure control valve to make the outlet pressure of the first lubricating oil pump lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve assembly includes: if the state of the second pressure control valve is not fully closed, controlling the second pressure control valve to close at a third preset speed until it is fully closed.

[0011] Optionally, when the second pressure control valve is closed at a third preset speed, the control module is further configured to: acquire the lubricating oil pump outlet pressure; when the lubricating oil pump outlet pressure rises above a second preset threshold and the first pressure control valve is fully open, control the second pressure control valve to open at the third preset speed until the lubricating oil pump outlet pressure drops to a normal value.

[0012] Optionally, controlling the opening degree of the first pressure control valve and the second pressure control valve to make the outlet pressure of the first lubricating oil pump lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve group further includes: controlling the first pressure control valve to open at the third preset speed, so that the outlet pressure of the first lubricating oil pump is lower than the lubricating oil pump outlet pressure by a second preset value; and controlling the first pressure control valve to open at the fourth preset speed until it is fully open.

[0013] Optionally, when the first pressure control valve is opened at the third preset speed, the control module is further configured to: when the lubricating oil pump outlet pressure drops by more than the second preset threshold, control the first pressure control valve to close at the third preset speed until the lubricating oil pump outlet pressure returns to the normal value.

[0014] Optionally, controlling the operating mode of the first pressure control valve and the second pressure control valve to be in automatic control mode includes: when the outlet pressure of the second lubricating oil pump is lower than the initial set value of the second pressure control valve, controlling the operating mode of the second pressure control valve to be in automatic control mode; and controlling the operating mode of the first pressure control valve to be in automatic control mode.

[0015] This invention also provides a large-scale generator oil station, wherein the large-scale generator oil station is equipped with the oil pump switching control system described in any of the above-mentioned embodiments.

[0016] Through the above technical solution, the oil pump switching control system for large-scale unit oil stations provided by the embodiments of the present invention can realize the disturbance-free automatic switching of the main and auxiliary lubricating oil pumps in large-scale unit oil stations. Specifically, pressure control valves (i.e., first pressure control valve PV1 and second pressure control valve PV2) can be added to the outlet pipes of the main and auxiliary lubricating oil pumps (i.e., the first lubricating oil pump R1 and the second lubricating oil pump R2), respectively. By reasonably setting the outlet pressure setpoints of the main and auxiliary pressure control valves through the DCS, the outlet pressure of the main and auxiliary pumps can be precisely controlled to achieve smooth switching of oil pumps.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 This is a schematic diagram of the structure of the oil pump switching control system for a large-scale generator oil station provided in an embodiment of the present invention;

[0020] Figure 2 Example diagram of PID control for generator unit oil station;

[0021] Figure 3 This is a schematic diagram illustrating the trends of main and auxiliary pump currents and lubricating oil pump outlet pressure during pump switching. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0023] Figure 1 This is a schematic diagram of the oil pump switching control system for a large-scale generator oil station provided in an embodiment of the present invention. Please refer to it. Figure 1The large-scale unit oil station may include a first lubricating oil pump R1, a second lubricating oil pump R2, a lubricating oil pump outlet safety valve group PV3 connected to the outlet pipes of the first lubricating oil pump R1 and the second lubricating oil pump R2, a lubricating oil pump main control valve group PV4 connected to the outlet pipe of the lubricating oil pump outlet safety valve group PV3, and oil pipelines. The oil pump switching control system for the large-scale unit oil station may include: a first pressure control valve PV1, connected to the pipeline between the first lubricating oil pump R1 and the lubricating oil pump outlet safety valve group PV3, for controlling the first lubricating oil pump R1. The outlet pressure of oil pump R1; the second pressure control valve PV2, connected to the pipeline between the second lubricating oil pump R2 and the lubricating oil pump outlet safety valve group PV3, is used to control the outlet pressure of the second lubricating oil pump R2; the control module (not shown in the figure) is used to control the outlet pressure of the first lubricating oil pump R1 and the second lubricating oil pump R2 respectively by controlling the opening degree of the first pressure control valve PV1 and the second pressure control valve PV2, so that after the first lubricating oil pump or the second lubricating oil pump is stopped when the dual lubricating oil pumps are running, the large unit oil station operates smoothly.

[0024] In this process, a Distributed Control System (DCS) is used as the control module, and its control program is configured.

[0025] Preferably, the outlet pressure of one of the first lubricating oil pumps R1 and R2 is controlled by one of the first pressure control valve PV1 and the second pressure control valve PV2, including: when the outlet pressure of the lubricating oil pump is higher than the outlet pressure setting value of the pressure control valve, the pressure control valve opens, and part of the oil generated by the lubricating oil pump flows back through the pressure control valve to reduce the outlet pressure of the lubricating oil pump; when the outlet pressure of the lubricating oil pump is lower than the outlet pressure setting value, the pressure control valve closes to reduce the backflow of oil through the pressure control valve and stabilize the outlet pressure of the lubricating oil pump.

[0026] In a conventional large-scale unit oil station (e.g., a large turbine-compressor oil station), the lubrication oil station mainly consists of a lubrication oil tank, a first lubrication oil pump (e.g., main lubrication oil pump R1), a second lubrication oil pump (e.g., auxiliary lubrication oil pump R2), a lubrication oil pump inlet valve, a lubrication oil pump inlet filter, a lubrication oil pump outlet safety valve assembly PV3, a dual lubrication oil cooler, a pump outlet pressure control valve, a dual lubrication oil filter, a lubrication oil main control valve assembly PV4, and oil pipelines. Lubrication oil is pressurized from the lubrication oil tank by the main (R1) and / or auxiliary (R2) lubrication oil pumps, then cooled to the normal supply temperature by the oil cooler. The lubrication oil is then controlled at a set value by the lubrication oil pump outlet safety valve assembly PV3 (pump outlet main pressure P3). When the pump outlet main pressure exceeds the set value, PV3 is opened, allowing some oil to return to the lubrication oil tank, thereby maintaining the pump outlet main pressure at the set value. However, if PV3 is not opened in time or the amount of lubricating oil returned to the tank after opening is insufficient, the pump outlet main pipe pressure (P3) will continue to rise. When it exceeds the set value of PV3, it will cause the pump outlet safety valve to trip, and the pump outlet pressure will drop sharply, even falling to the interlock action value, thus causing the unit to shut down due to interlock. This phenomenon is particularly prominent when the auxiliary pump starts automatically or when both pumps are running. Furthermore, when the pump outlet main pipe pressure (P3) is lower than the set value, PV3 can be closed to reduce the amount of lubricating oil returning to the tank and maintain the main pipe pressure (P3) stable.

[0027] This invention optimizes large-scale generator oil stations (e.g., large turbine-compressor oil stations) through an oil pump switching control system. Pressure control valves PV1 and PV2 (for connection details, please refer to [reference needed]) are added to the outlet pipes of the first lubricating oil pump (e.g., main lubricating oil pump R1) and the second lubricating oil pump (e.g., auxiliary lubricating oil pump R2) respectively. Figure 1 (Red line section). After being pressurized by the main (R1) and auxiliary (R2) lubricating oil pumps, the lubricating oil first passes through pressure control valves PV1 and PV2 respectively to control its outlet pressure before flowing into the main pipe. By reasonably setting the outlet pressure setpoints of pressure control valves PV1 and PV2, the outlet pressure P1 of the main lubricating oil pump (R1) and the outlet pressure P2 of the auxiliary lubricating oil pump (R2) can be precisely controlled during the pump switching process. When the auxiliary lubricating oil pump R2 starts and enters dual-pump operation, the outlet pressure of the main lubricating oil pump (R1) can be reduced by gradually increasing the opening of the first pressure control valve until the outlet pressure of the main lubricating oil pump (R1) is lower than the pump outlet main pipe pressure P3 (i.e., the lubricating oil pump outlet pressure). At this time, the main lubricating oil pump (R1) can automatically and smoothly switch out of the system, thereby reducing the impact of the auxiliary lubricating oil pump R2 or the dual-pump operation on the pump outlet main pipe pressure. This achieves the purpose of non-disruptive switching of lubricating oil pumps in large unit oil stations.

[0028] The following section will describe in detail the process of precisely controlling the outlet pressure P1 of the main lubricating oil pump (R1) and the outlet pressure P2 of the auxiliary lubricating oil pump (R2) during the oil pump switching process by reasonably setting the outlet pressure set values ​​of pressure control valves PV1 and PV2.

[0029] Preferably, the step of controlling the outlet pressures of the first and second lubricating oil pumps by controlling the opening degrees of the first and second pressure control valves, respectively, so that the large unit oil station can operate smoothly after stopping either the first or second lubricating oil pump during dual-pump operation, may include the following steps S11-S15:

[0030] S11, when it is necessary to stop the first lubricating oil pump and start the second lubricating oil pump, control the second pressure control valve to open at a first preset speed until it is fully open, wherein the initial state of the first pressure control valve is the closed state and the initial state of the second pressure control valve is the closed state.

[0031] Before step S11, the one-way valve of the second lubricating oil pump R2 can be manually checked for internal leakage; the outlet pressure setting values ​​of pressure control valves PV1, PV2, lubricating oil pump outlet safety valve group PV3, and lubricating oil pump main pipe control valve group PV4 can also be preset.

[0032] For example, the outlet pressure setting value for PV1 is 0.6 MPa; the outlet pressure setting value for PV2 is 0.6 MPa; the outlet pressure setting value for PV3 is 0.5 MPa; and the outlet pressure setting value for PV4 is 0.4 MPa. In actual implementation, the outlet pressure setting values ​​for PV1, PV2, PV3, and PV4 should be preset and adjusted according to the characteristics of each unit. The setting values ​​in this embodiment are for illustration only.

[0033] Taking the control of the outlet pressure of the first lubricating oil pump R1 by controlling the first pressure control valve PV1 as an example, when the outlet pressure P1 of R1 is greater than 0.6 MPa, PV1 will automatically open (or its opening speed can be controlled by the control module), so that part of the lubricating oil generated by R1 flows back to the oil tank through PV1, thereby reducing the outlet pressure P1 of R1; while when the outlet pressure P1 of R1 is lower than 0.6 MPa, PV1 can automatically close (or its closing speed can be controlled by the control module), so as to reduce the backflow of lubricating oil through PV1 and stabilize the outlet pressure P1 of R1.

[0034] Before switching the first lubricating oil pump R1 and the second lubricating oil pump R2, the first pressure control valve PV1 is initially closed, that is, the opening degree of PV1 is 0%; the second pressure control valve PV2 is initially closed, that is, the opening degree of PV2 is 0%.

[0035] In step S11, PV2 is controlled to open, while the opening degree of PV1 remains at 0%. The second pressure control valve is controlled to open at a first preset speed until it is fully open.

[0036] Taking the first preset speed of 10% per second when PV2 is fully open as an example, PV2 is opened at a speed of 10% / second until the opening of PV2 is 100%.

[0037] Preferably, when the second pressure control valve is opened at a first preset speed, the control module is further configured to: acquire the lubricating oil pump outlet pressure; acquire the outlet pressure of the lubricating oil pump main control valve group; and when the decrease in the lubricating oil pump outlet pressure or the lubricating oil pump main control valve group is greater than a first preset threshold, control the second pressure control valve to close at the first preset speed until the lubricating oil pump outlet pressure and the lubricating oil pump main control valve group return to normal values.

[0038] Continuing with the example above, during the opening of PV2, the control module monitors the lubricating oil pump outlet pressure P3 and the lubricating oil pump main control valve group PV4 outlet pressure P4 in real time. If P3 or P4 drops by more than 10% of its original value (a first preset threshold), the opening stops, and the valve closes at the same rate (e.g., 10% per second of PV2 fully open) until P3 and P4 return to their normal values, and the cause is investigated. During the opening process of PV2, it is necessary to prevent internal leakage in its one-way valve from causing a rapid drop in P3 and P4. Depending on the actual situation, the drop should be set to not exceed the first preset threshold, for example, 10% of PV3 and PV4 fully open.

[0039] S12, control the second lubricating oil pump to start.

[0040] Following the example above, start R2. At this time, the opening degree of PV1 is 0%, and the opening degree of PV2 is 100%.

[0041] S13, control the opening degree of the first pressure control valve and the second pressure control valve so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve group.

[0042] Preferably, step S13 may include: controlling the second pressure control valve to close at a second preset speed, so that the outlet pressure of the second lubricating oil pump is lower than the outlet pressure of the lubricating oil pump by a first preset value; controlling the second pressure control valve to close at a third preset speed until it is fully closed.

[0043] For example, at a second preset speed of 5% per second that PV2 is fully open, PV2 is closed, causing the outlet pressure P2 of the second lubricating oil pump R2 to be lower than the outlet pressure P3 of the lubricating oil pump by a first preset value (e.g., approximately 0.10 MPa). At this time, the opening degree of PV1 is 0%.

[0044] Next, at a third preset speed of 1% per second for PV2 to fully open, PV2 is continuously closed until it is fully closed. At this point, PV1 can automatically open.

[0045] First, PV2 is opened at the second preset speed, which is only to slightly speed up the opening of PV2 (i.e., the second preset speed is greater than the third preset speed); then, PV2 is opened at the third preset speed to reduce the impact on the main oil pressure when connected to the grid (R1 and R2 are running at the same time); therefore, PV2 can also be opened at the third preset speed throughout the process, for example, at a speed of 1% / second, until PV2 is completely closed.

[0046] The first preset speed, second preset speed, third preset speed, and first preset value mentioned above are all set according to actual conditions. The values ​​used in this embodiment of the invention are for illustrative purposes only.

[0047] Preferably, when the second pressure control valve is closed at a third preset speed, the control module is further configured to: acquire the lubricating oil pump outlet pressure; when the lubricating oil pump outlet pressure rises above a second preset threshold and the first pressure control valve is fully open, control the second pressure control valve to open at the third preset speed until the lubricating oil pump outlet pressure drops to a normal value.

[0048] Following the example above, when PV2 is closed at a third preset speed (e.g., 1% / second), the control module monitors the lubricating oil pump outlet pressure P3 and PV1 in real time. If P3 rises above the second preset threshold (e.g., 10%) and PV1 is fully open, the closure of PV2 is paused, and the valve is opened at the same rate (third preset speed, e.g., 1% / second) until P3 returns to the normal value, and the cause is checked.

[0049] Preferably, step S13 may further include: controlling the first pressure control valve to open at the third preset speed, so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure of the lubricating oil pump by a second preset value; controlling the first pressure control valve to open at the fourth preset speed until it is fully open.

[0050] Continuing with the example above, PV2 is controlled to close at a third preset speed of 1% per second until it is fully closed (opening degree is 0%). At this point, PV1 can open automatically. If the opening degree of PV1 is not 100%, PV1 needs to be controlled to open. For example, PV1 can be controlled to open at a third preset speed (1% / second) until the outlet pressure P1 of the first lubricating oil pump R1 is lower than the outlet pressure P3 of the lubricating oil pump by a second preset value (e.g., about 0.05 MPa). Then, PV1 is controlled to open at a fourth preset speed (e.g., 5% / second) until it is fully open.

[0051] The fourth preset speed and the second preset value mentioned above are all set according to actual conditions, and the values ​​in this embodiment are only for illustration.

[0052] More preferably, when the first pressure control valve is opened at the third preset speed, the control module can also be used to: when the lubricating oil pump outlet pressure drops by more than the second preset threshold, control the first pressure control valve to close at the third preset speed until the lubricating oil pump outlet pressure returns to the normal value.

[0053] Continuing with the example above, when PV1 is opened at 1% / second, the control module monitors the lubricating oil pump outlet pressure P3 in real time. If the pressure drops beyond the second preset threshold (e.g., 10% of the PV3 setting), PV1 is stopped from opening and closed at the same rate (the third preset speed, 1% / second) until P3 returns to its normal value, and the cause is investigated. During the PV1 opening process, it is necessary to prevent the possibility that the second lubricating oil pump R2 may actually have insufficient displacement.

[0054] S14, control the first lubricating oil pump to stop.

[0055] The first lubricating oil pump R1 has switched out of operating mode.

[0056] S15, the operating mode of the first pressure control valve and the second pressure control valve is set to automatic control mode.

[0057] Preferably, step S15 may include: when the outlet pressure of the second lubricating oil pump is lower than the initial set value of the second pressure control valve, controlling the operating mode of the second pressure control valve to be automatic control mode; and controlling the operating mode of the first pressure control valve to be automatic control mode.

[0058] For example, when the first lubricating oil pump R1 switches out of operation and the second lubricating oil pump R2 starts working, the opening degree of PV2 is 0%, and the opening degree of PV1 is 100%. The system checks if the outlet pressure P2 of the second lubricating oil pump R2 is lower than the outlet pressure setting value of PV2 (e.g., 0.6 MPa). If so, PV2 is switched to automatic control mode, and PV2 is first completely closed (opening degree 0%). If not, the program is paused to find the cause. As mentioned earlier, the outlet pressure setting value of PV2 (0.6 MPa) is higher than the outlet pressure setting value of PV3 (0.5 MPa), and the outlet pressure P2 of the second lubricating oil pump R2 differs from the lubricating oil pump outlet pressure P3 only by the pressure drop in the pipeline and oil cooler. Therefore, PV2 will remain fully closed. PV1 is then switched to automatic control mode.

[0059] The following table 1 provides a simple summary of the process of stopping the first lubricating oil pump R1 and starting the second lubricating oil pump R2 by controlling the first pressure control valve PV1 and the second pressure control valve PV2:

[0060] Table 1

[0061]

[0062]

[0063] Among them, "automatic control" means that the working mode of PV1 and PV2 is automatic control mode, while "non-automatic control" means that PV1 and PV2 are controlled by the control module.

[0064] This invention also provides a method for controlling the outlet pressures of the first and second lubricating oil pumps when both pumps are running simultaneously and the first pump needs to be shut down. This is achieved by controlling the opening of the first and second pressure control valves to ensure stable operation of the large-scale unit oil station after shutting down either the first or second lubricating oil pump during dual-pump operation. This method includes the following steps S21-S23:

[0065] Step S21: When the first lubricating oil pump and the second lubricating oil pump are running simultaneously and the first lubricating oil pump needs to be stopped, control the opening degree of the first pressure control valve and the second pressure control valve so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve group.

[0066] Before step S21, a comprehensive on-site inspection can be conducted and the pump R1 to be shut down can be determined. The outlet pressure settings of pressure control valves PV1 and PV2, lubricating oil pump outlet safety valve group PV3, and lubricating oil pump main pipe control valve group PV4 can also be preset.

[0067] For example, the outlet pressure setting value for PV1 is 0.6 MPa; the outlet pressure setting value for PV2 is 0.6 MPa; the outlet pressure setting value for PV3 is 0.5 MPa; and the outlet pressure setting value for PV4 is 0.4 MPa. In actual implementation, the outlet pressure setting values ​​for PV1, PV2, PV3, and PV4 should be preset and adjusted according to the characteristics of each unit. The setting values ​​in this embodiment are for illustration only.

[0068] It should be noted that there are the same terms in steps S21-S23 as in steps S11-S15, such as the third preset speed and the second preset threshold. These terms are only used to distinguish the same type of terms in steps S21-S23 and do not need to be the same as the values ​​in steps S11-S15.

[0069] Before shutting down the first lubricating oil pump R1, the first pressure control valve PV1 and the second pressure control valve PV2 operate in automatic control mode.

[0070] Preferably, step S21 may include: if the second pressure control valve is not fully closed, controlling the second pressure control valve to close at a third preset speed until it is fully closed.

[0071] For example, if PV2 is not fully closed, control PV2 to close at a third preset speed (e.g., 1% / second) until the opening is 0%.

[0072] Preferably, when the second pressure control valve is closed at a third preset speed, the control module can also be used to: obtain the lubricating oil pump outlet pressure; when the lubricating oil pump outlet pressure rises above a second preset threshold and the first pressure control valve is fully open, control the second pressure control valve to open at the third preset speed until the lubricating oil pump outlet pressure drops to a normal value.

[0073] Following the example above, when PV2 is closed at a third preset speed (e.g., 1% / second), the control module monitors the lubricating oil pump outlet pressure P3 and PV1 in real time. If P3 rises above the second preset threshold (e.g., 10%) and PV1 is fully open, the closure of PV2 is paused, and the valve is opened at the same rate (third preset speed, e.g., 1% / second) until P3 returns to the normal value, and the cause is checked.

[0074] Preferably, step S21 may further include: controlling the first pressure control valve to open at the third preset speed, so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure of the lubricating oil pump by a second preset value; controlling the first pressure control valve to open at the fourth preset speed until it is fully open.

[0075] Continuing with the example above, PV2 is controlled to close at a third preset speed of 1% per second until it is fully closed (opening degree is 0%). At this point, PV1 can open automatically. If the opening degree of PV1 is not 100%, PV1 needs to be controlled to open. For example, PV1 can be controlled to open at a third preset speed (1% / second) until the outlet pressure P1 of the first lubricating oil pump R1 is lower than the outlet pressure P3 of the lubricating oil pump by a second preset value (e.g., about 0.05 MPa). Then, PV1 is controlled to open at a fourth preset speed (e.g., 5% / second) until it is fully open.

[0076] More preferably, when the first pressure control valve is opened at the third preset speed, the control module can also be used to: when the lubricating oil pump outlet pressure drops by more than the second preset threshold, control the first pressure control valve to close at the third preset speed until the lubricating oil pump outlet pressure returns to the normal value.

[0077] Continuing with the example above, when PV1 is opened at 1% / second, the control module monitors the lubricating oil pump outlet pressure P3 in real time. If the pressure drops beyond the second preset threshold (e.g., 10% of the PV3 setting), PV1 is stopped from opening and closed at the same rate (the third preset speed, 1% / second) until P3 returns to its normal value, and the cause is investigated. During the PV1 opening process, it is necessary to prevent the possibility that the second lubricating oil pump R2 may actually have insufficient displacement.

[0078] Step S22: Control the first lubricating oil pump to stop.

[0079] The first lubricating oil pump R1 has switched out of operating mode.

[0080] Step S23: Control the working mode of the first pressure control valve and the second pressure control valve to automatic control mode.

[0081] Preferably, step S23 may include: when the outlet pressure of the second lubricating oil pump is lower than the initial set value of the second pressure control valve, controlling the working mode of the second pressure control valve to be automatic control mode; and controlling the working mode of the first pressure control valve to be automatic control mode.

[0082] For example, when the first lubricating oil pump R1 switches out of operation and the second lubricating oil pump R2 starts working, the opening degree of PV2 is 0%, and the opening degree of PV1 is 100%. The system checks if the outlet pressure P2 of the second lubricating oil pump R2 is lower than the outlet pressure setting value of PV2 (e.g., 0.6 MPa). If so, PV2 is switched to automatic control mode, and PV2 is first completely closed (opening degree 0%). If not, the program is paused to find the cause. As mentioned earlier, the outlet pressure setting value of PV2 (0.6 MPa) is higher than the outlet pressure setting value of PV3 (0.5 MPa), and the outlet pressure P2 of the second lubricating oil pump R2 differs from the lubricating oil pump outlet pressure P3 only by the pressure drop in the pipeline and oil cooler. Therefore, PV2 will remain fully closed. PV1 is then switched to automatic control mode.

[0083] Based on the example in Table 2 below, the process of stopping the first lubricating oil pump R1 by controlling the first pressure control valve PV1 and the second pressure control valve PV2 when the first lubricating oil pump R1 is running simultaneously and needs to be stopped is as follows:

[0084] Table 2

[0085]

[0086]

[0087] Among them, "automatic control" means that the working mode of PV1 and PV2 is automatic control mode, while "non-automatic control" means that PV1 and PV2 are controlled by the control module.

[0088] This invention also provides a large-scale generator oil station, which includes the above-mentioned oil pump switching control system for large-scale generator oil stations.

[0089] The technical content and effects of the large-scale generator oil station provided in this embodiment of the invention are similar to those of the oil pump switching control system used in large-scale generator oil stations, and will not be repeated here.

[0090] Accordingly, the oil pump switching control system for large-scale unit oil stations provided in this embodiment of the invention can achieve seamless automatic switching between the main and auxiliary lubricating oil pumps in large-scale unit oil stations. Specifically, pressure control valves (i.e., first pressure control valve PV1 and second pressure control valve PV2) can be added to the outlet pipes of the main and auxiliary lubricating oil pumps (i.e., the first lubricating oil pump R1 and the second lubricating oil pump R2), respectively. By reasonably setting the outlet pressure setpoints of the main and auxiliary pressure control valves through the DCS, the outlet pressure of the main and auxiliary pumps can be precisely controlled to achieve smooth switching of oil pumps. Furthermore, while simplifying the oil pump switching operation, it can completely avoid unplanned shutdowns of large-scale units caused by large oil pressure fluctuations during oil pump switching, which is of profound significance for the long-term safe and stable operation of continuous production units such as petrochemical plants. Further, through this oil pump switching control system for large-scale unit oil stations, the oil pressure fluctuation of the lubricating oil pump outlet pressure P3 can be small (e.g., less than 10%) during the oil pump switching process, and there is no drop in oil pressure when any one of the pumps is shut down, thereby achieving a seamless oil pump switching effect.

[0091] Figure 2 ,and Figure 3 This is a schematic diagram illustrating an application example of an embodiment of the present invention. Wherein, Figure 2 Example diagram of PID control for unit oil station; Figure 3 This diagram illustrates the trends of main and auxiliary pump currents and lubricating oil pump outlet pressure during pump switching. The green line represents the historical trend of the pump outlet main pipe pressure (PI25003), while the blue and yellow lines represent the operating currents of the main and auxiliary pumps, respectively. Please refer to this diagram. Figure 2 , 3 During the switching process, the oil pressure increase was less than 10% when both pumps were running, and there was no drop in oil pressure when one of them was shut down, achieving the expected goal.

[0092] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0093] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0094] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0095] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0096] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0097] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0098] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0099] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0100] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A pump switching control system for a large-scale generator oil station, the large-scale generator oil station comprising a first lubricating oil pump, a second lubricating oil pump, a lubricating oil pump outlet safety valve group connected to the outlet pipes of the first lubricating oil pump and the second lubricating oil pump, a lubricating oil pump main control valve group connected to the outlet pipe of the lubricating oil pump outlet safety valve group, and oil pipelines, characterized in that, The oil pump switching control system for large-scale unit oil stations includes: The first pressure control valve is connected to the pipeline between the first lubricating oil pump and the lubricating oil pump outlet safety valve group. It is used to control the outlet pressure of the first lubricating oil pump. When the first pressure control valve is opened, part of the lubricating oil generated by the first lubricating oil pump flows back to the oil tank through the first pressure control valve. The second pressure control valve is connected to the pipeline between the second lubricating oil pump and the lubricating oil pump outlet safety valve group. It is used to control the outlet pressure of the second lubricating oil pump. When the second pressure control valve is open, part of the lubricating oil generated by the second lubricating oil pump flows back to the oil tank through the second pressure control valve. The control module is used to control the outlet pressure of the first lubricating oil pump and the second lubricating oil pump respectively by controlling the opening degree of the first pressure control valve and the second pressure control valve, so that when the dual-pump operation is running, the large unit oil station operates smoothly after the first lubricating oil pump or the second lubricating oil pump is stopped. This includes: When it is necessary to stop the first lubricating oil pump and start the second lubricating oil pump, the second pressure control valve is controlled to open at a first preset speed until it is fully open. The initial state of the first pressure control valve is closed, and the initial state of the second pressure control valve is closed. Control the start of the second lubricating oil pump; Control the opening degree of the first pressure control valve and the second pressure control valve so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve group; Control the first lubricating oil pump to stop; The operating mode of the first pressure control valve and the second pressure control valve is set to automatic control mode. The step of controlling the opening degrees of the first pressure control valve and the second pressure control valve to make the outlet pressure of the first lubricating oil pump lower than the outlet pressure set value of the lubricating oil pump outlet safety valve assembly includes: The second pressure control valve is controlled to close at a second preset speed, so that the outlet pressure of the second lubricating oil pump is lower than the outlet pressure of the lubricating oil pump by a first preset value; The second pressure control valve is controlled to close at a third preset speed until it is fully closed. The first pressure control valve is controlled to open at the third preset speed, so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure of the lubricating oil pump by a second preset value. The first pressure control valve is controlled to open at a fourth preset speed until it is fully open.

2. The oil pump switching control system for large-scale generator oil stations according to claim 1, characterized in that, By controlling the outlet pressure of one of the first and second lubricating oil pumps through one of the pressure control valves, the following steps are taken: When the outlet pressure of the lubricating oil pump is higher than the outlet pressure setting value of the pressure control valve, the pressure control valve opens, and part of the oil generated by the lubricating oil pump flows back through the pressure control valve to reduce the outlet pressure of the lubricating oil pump. When the outlet pressure of the lubricating oil pump is lower than the set outlet pressure value, the pressure control valve closes to reduce oil backflow through the pressure control valve and stabilize the outlet pressure of the lubricating oil pump.

3. The oil pump switching control system for large-scale generator oil stations according to claim 1, characterized in that, When the control module controls the second pressure control valve to open at a first preset speed, it is further configured to: Obtain the lubricating oil pump outlet pressure, wherein the lubricating oil pump outlet pressure is the pump outlet main pipe pressure; Obtain the outlet pressure of the lubricating oil pump main control valve assembly; When the drop in the outlet pressure of the lubricating oil pump or the outlet pressure of the lubricating oil pump main control valve group exceeds a first preset threshold, the second pressure control valve is controlled to close at the first preset speed until the outlet pressure of the lubricating oil pump and the outlet pressure of the lubricating oil pump main control valve group return to normal values.

4. The oil pump switching control system for large-scale generator oil stations according to claim 1, characterized in that, The step of controlling the outlet pressures of the first and second lubricating oil pumps by controlling the opening degrees of the first and second pressure control valves, respectively, so that when the dual-pump operation is in operation, the first or second lubricating oil pump stops, and the large unit oil station operates smoothly, includes: When the first lubricating oil pump and the second lubricating oil pump are running simultaneously and the first lubricating oil pump needs to be stopped, the opening degree of the first pressure control valve and the second pressure control valve is controlled so that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure setting value of the lubricating oil pump outlet safety valve group. Control the first lubricating oil pump to stop; The operating mode for controlling the first pressure control valve and the second pressure control valve is automatic control mode.

5. The oil pump switching control system for large-scale generator oil stations according to claim 4, characterized in that, Controlling the opening degrees of the first pressure control valve and the second pressure control valve to ensure that the outlet pressure of the first lubricating oil pump is lower than the outlet pressure set value of the lubricating oil pump outlet safety valve assembly includes: If the second pressure control valve is not fully closed, control the second pressure control valve to close at a third preset speed until it is fully closed.

6. The oil pump switching control system for large-scale generator oil stations according to claim 1 or 5, characterized in that, When controlling the second pressure control valve to close at a third preset speed, the control module is further configured to: Obtain the lubricating oil pump outlet pressure, wherein the lubricating oil pump outlet pressure is the pump outlet main pipe pressure; When the outlet pressure of the lubricating oil pump rises above the second preset threshold and the first pressure control valve is fully open, the second pressure control valve is controlled to open at the third preset speed until the outlet pressure of the lubricating oil pump drops to the normal value.

7. The oil pump switching control system for large-scale generator oil stations according to claim 6, characterized in that, When the first pressure control valve is opened at the third preset speed, the control module is further configured to: When the outlet pressure of the lubricating oil pump drops by more than the second preset threshold, the first pressure control valve is controlled to close at the third preset speed until the outlet pressure of the lubricating oil pump returns to the normal value.

8. The oil pump switching control system for large-scale generator oil stations according to claim 1, characterized in that, The automatic control mode for controlling the operation of the first pressure control valve and the second pressure control valve includes: When the outlet pressure of the second lubricating oil pump is lower than the initial setting value of the second pressure control valve, the operating mode of the second pressure control valve is controlled to be automatic control mode. The operating mode of the first pressure control valve is set to automatic control mode.

9. A large-scale generator set oil station, characterized in that, The large-scale generator oil station includes the oil pump switching control system for large-scale generator oil stations as described in any one of claims 1-8.

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