High-power steam decompression turbine power generation and high-pressure asynchronous power generation grid-connected system

Abstract

A high-power steam decompression turbine power generation high-pressure asynchronous power generation grid-connected system comprises a turbine expansion power generation unit, a steam inlet and outlet unit used for providing a power source for the turbine expansion power generation unit and a high-power high-pressure asynchronous grid-connected unit used for connecting the turbine expansion power generation unit into a plant high-pressure internal network. The high-power high-voltage asynchronous grid-connected unit comprises an automatic reactive power compensation device, a high-voltage circuit breaker I, and an electric parameter sensor I and an electric parameter sensor II which are used for respectively acquiring electric quantity parameters of high-voltage cables at the front end and the rear end of the high-voltage circuit breaker I; the automatic reactive power compensation device is connected to a high-voltage cable at the rear end of the high-voltage circuit breaker I through a high-voltage circuit breaker II; the high-power high-voltage asynchronous grid-connected unit further comprises a high-voltage comprehensive protection unit which is used for collecting signals of the first electric parameter sensor and the second electric parameter sensor so as to control on-off of the first high-voltage circuit breaker and the second high-voltage circuit breaker. The system can quickly and friendly access to a power grid, is simple and convenient to maintain, generates power as much as possible, reduces investment, reduces auxiliary power load, saves energy and reduces consumption.

Description

Technical Field

[0001] The utility model relates to the technical field of steam pressure reducing turbine power generation, and particularly relates to a high-power steam pressure reducing turbine power generation high-voltage asynchronous power generation grid connection system. Background Art

[0002] Steam is widely used as a main energy transfer medium. However, due to the large number of mismatches in steam pressure grades between the supply and use sides, a large amount of steam is depressurized or directly discharged during the production and living processes, resulting in huge waste. With the increasing attention to the utilization of steam pressure reduction, it is an efficient energy-saving technology that turns waste into treasure. With the increasing attention to steam pressure reduction power generation, and at the same time, with the further improvement of steam pressure reduction technology, especially the increasing engineering demand for turbine power generation, and the increasing single-unit power generation capacity. How to quickly and friendly connect the generated electricity to the high-voltage power grid is particularly important. Therefore, the importance of the high-voltage asynchronous power generation grid connection control system in turbine power generation can be imagined. The power generation system requires a reliable and simple structure design, safe and stable operation, can be quickly put into use, simple operation and maintenance requirements, and at the same time generate as much electricity as possible.

[0003] Generally, the grid capacity designed for the plant electricity of production devices is generally limited. Using the general power generation grid connection method has a greater impact on the power grid, and the reactive power of the power grid is limited. If the power factor cannot be well compensated, a series of problems such as the decline in the quality of the power grid will occur. Summary of the Invention

[0004] The purpose of the utility model is to overcome the above-mentioned deficiencies of the prior art, and provide a high-power steam pressure reducing turbine power generation high-voltage asynchronous grid connection control system, which is reliable and simple, has safe and stable operation, can be quickly and friendly connected to the power grid, is simple in operation and maintenance, and at the same time generates as much electricity as possible, reduces investment, reduces the plant electricity load, and saves energy and reduces consumption.

[0005] A high-power steam pressure reducing turbine power generation high-voltage asynchronous power generation grid connection system includes a turbine expansion power generation unit, a steam inlet and outlet unit for providing a power source for the turbine expansion power generation unit, and a high-power high-voltage asynchronous grid connection unit for connecting the turbine expansion power generation unit to the plant high-voltage internal network;

[0006] The steam inlet and outlet unit includes a conveying pipeline for connecting two-stage turbine expanders. One end of the conveying pipeline is the inlet end of high-temperature and high-pressure steam, and the other end is the outlet end. The outlet end is connected to the steam low-pressure pipe network. A steam cut-off valve, a steam regulating valve, and a #1 separator are successively installed on the conveying pipeline between the inlet end and the inlet end of the first-stage turbine expander. A #2 separator is provided on the conveying pipeline between the outlet end of the first-stage turbine expander and the inlet end of the second-stage turbine expander. A second steam regulating valve is installed on the conveying pipeline at the outlet end of the second-stage turbine expander;

[0007] The turbine expansion power generation unit includes a speed reducer. The two input ends of the speed reducer are respectively connected to the first-stage turbine expander and the power input end of the first-stage turbine expander. The output port of the speed reducer is connected to a high-voltage asynchronous motor set to form a transmission system.

[0008] The high-power high-voltage asynchronous grid-connection unit includes an automatic reactive power compensation device, a first high-voltage circuit breaker connected to the high-voltage cable between the in-plant high-voltage internal network and the high-voltage asynchronous motor set, a first electrical parameter sensor and a second electrical parameter sensor for respectively collecting the electrical quantity parameters of the high-voltage cable before and after the first high-voltage circuit breaker.

[0009] The automatic reactive power compensation device is connected to the high-voltage cable at the rear end of the first high-voltage circuit breaker through a second high-voltage circuit breaker.

[0010] The high-power high-voltage asynchronous grid-connection unit further includes a high-voltage comprehensive protection unit for collecting the signals of the first electrical parameter sensor and the second electrical parameter sensor and then controlling the on-off of the first high-voltage circuit breaker and the second high-voltage circuit breaker.

[0011] The turbine expansion power generation unit further includes a lubricating oil circulation system for providing lubricating grease for the speed reducer and the high-voltage asynchronous motor set. The lubricating oil circulation system includes a lubricating oil tank. The oil outlet pipe led out from the outlet end of the lubricating oil tank is divided into two branch pipes after passing through a lubricating oil pump and a cooler, and respectively leads into the oil inlet of the speed reducer and the high-voltage asynchronous motor set. The return oil pipes led out from the oil outlet of the speed reducer and the high-voltage asynchronous motor set are communicated with the oil inlet of the lubricating oil tank.

[0012] A first oil supply pressure regulating valve is installed on the branch pipe between the lubricating oil tank and the outlet end of the lubricating oil pump. A second oil supply pressure regulating valve and a fifth pressure transmitter are installed at the oil inlet end of the high-voltage asynchronous motor set, and a fourth pressure transmitter is installed at the oil inlet end of the speed reducer.

[0013] Temperature transmitters for measuring the temperature of the motor bearings and temperature transmitters for detecting the stator temperature of the motors are provided on each high-voltage asynchronous motor of the high-voltage asynchronous motor set.

[0014] Level transmitters for measuring the liquid level in the corresponding separators are installed on both the 1# separator and the 2# separator. Drain pipes are connected to the lower ends of the 1# separator and the 2# separator, and drain valves are installed on the drain pipes.

[0015] There is a first temperature transmitter and a first pressure transmitter on the conveying pipeline between the 1# separator and the first-stage turbine expander. There is a second pressure transmitter and a second temperature transmitter on the conveying pipeline between the first-stage turbine expander and the 2# separator. There is a third pressure transmitter and a third temperature transmitter on the conveying pipeline between the second-stage turbine expander and the second steam regulating valve. There is a sixth pressure transmitter on the conveying pipeline connected to the other end of the second steam regulating valve.

[0016] A speed transmitter one, a vibration transmitter one, an axial displacement transmitter and a temperature transmitter four are provided on the speed reducer.

[0017] It also includes a control unit that can monitor signals of each liquid level transmitter, temperature transmitter one, pressure transmitter one, pressure transmitter two, temperature transmitter two, pressure transmitter three, temperature transmitter three, speed transmitter one, vibration transmitter one, axial displacement transmitter, temperature transmitter four, temperature transmitter five, temperature transmitter six, pressure transmitter four, pressure transmitter five, high-voltage comprehensive protection unit and pressure transmitter six signals, and then correspondingly controls the opening degrees of the steam cut-off valve, steam regulating valve, steam regulating valve two, oil supply pressure regulating valve one, oil supply pressure regulating valve two and each drain valve, and controls the start / stop of the speed reducer, lubricating oil pump and high-voltage asynchronous motor.

[0018] The control unit includes a PLC controller and a human-machine interface connected to the output end of the PLC controller.

[0019] The steam cut-off valve, steam regulating valve, steam regulating valve two, oil supply pressure regulating valve one, oil supply pressure regulating valve two and each drain valve are pneumatic valves.

[0020] The utility model drives a two-stage turbine expander through steam, drags the high-voltage asynchronous motor to reach a higher speed, triggers the start of the high-voltage motor according to the set speed condition, shortens the start-up time of the high-voltage asynchronous motor, enables the motor to be smoothly and shocklessly connected to the power grid, configures an automatic reactive power compensation device, and automatically improves the power factor of the high-voltage internal network of the power plant. Adopting the high-voltage asynchronous grid-connected power generation method, it has a simple structure, a small motor generating current, less line loss, a small cable current-carrying cross-sectional area, less cable investment, and is convenient for adapting to a system with a larger single-machine capacity. Description of the Drawings

[0021] Figure 1 It is a structural schematic diagram of the utility model;

[0022] In the figure: 1. Steam inlet and outlet unit; 2. Control unit; 3. Turbine expansion power generation unit; 4. High-power high-voltage asynchronous grid connection unit; 5. Steam cut-off valve; 6. Steam regulating valve; 7. 1# separator; 8. Level transmitter 1; 9. Temperature transmitter 1; 10. Pressure transmitter 1; 11. First-stage turbine expander; 12. Pressure transmitter 2; 13. Temperature transmitter 2; 14. 2# separator; 15. Level transmitter 2; 16. Second-stage turbine expander; 17. Pressure transmitter 3; 18. Temperature transmitter 3; 19. Steam regulating valve 2; 20. Reducer; 21. Speed transmitter 1; 22. Vibration transmitter 1; 23. Axial displacement transmitter; 24. Temperature transmitter 4; 25. Coupling; 26. High-voltage asynchronous motor; 27. Temperature transmitter 5; 28. Temperature transmitter 6; 29. Lubricating oil tank; 30. Lubricating oil pump; 31. Cooler; 32. Pressure transmitter 4; 33. Oil supply pressure regulating valve 1; 34. Pressure transmitter 5; 35. Oil supply pressure regulating valve 2; 36. High-voltage comprehensive protection unit; 37. Electrical parameter sensor 1; 38. High-voltage circuit breaker 1; 39. Automatic reactive power compensation device; 40. High-voltage circuit breaker 2; 41. Electrical parameter sensor 2; 42. Factory high-voltage internal network; 43. Human-machine interface; 44. PLC controller; 45. Drain valve 1; 46. Pressure transmitter 6; 47. Drain valve 2. Detailed implementation manners

[0023] Now, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings. This drawing is a simplified schematic diagram, which only illustrates the basic structure of the present utility model in a schematic manner.

[0024] As Figure 1, A high-power steam pressure-reducing turbine power generation high-voltage asynchronous grid-connection system, comprising a steam inlet and outlet unit 1, a steam turbine expansion power generation unit 3, a control unit 2, and a high-power high-voltage asynchronous grid-connection unit 4. The steam inlet and outlet unit 1 includes a steam cut-off valve 5, a steam regulating valve 6, a 1# separator 7, and a 2# separator 14. The conveying pipeline passes through the steam cut-off valve 5, the steam regulating valve 6, and then through the 1# separator 7 for steam-water separation. A liquid level transmitter 8 is provided on the 1# separator 7. A temperature transmitter 9 and a pressure transmitter 10 are provided on the outlet pipeline of the 1# separator 7, and then it is connected to the inlet of the first-stage turbine expander 11. A temperature transmitter 13 and a pressure transmitter 12 are provided on the outlet conveying pipeline of the first-stage turbine expander 11, and then it is connected to the inlet of the 2# separator 14. After steam-water separation by the 2# separator 14, the outlet of the 2# separator 14 is connected to the inlet of the second-stage turbine expander 16 through a conveying pipeline. A temperature transmitter 18 and a pressure transmitter 17 are provided on the conveying pipeline at the outlet end of the second-stage turbine expander 16, and it is connected to the inlet of the steam regulating valve 19 through a conveying pipeline. The outlet of the steam regulating valve 19 is connected to the steam low-pressure pipe network through a conveying pipeline, and a pressure transmitter 46 is provided on the conveying pipeline at the outlet end of the steam regulating valve 19; A liquid level transmitter 15 is provided on the 2# separator 14;

[0025] The turbine expander power generation unit 3 includes two turbine expanders. The shaft power output ends of the two turbine expanders are connected to the two input ends of the speed reducer 20. The output end of the speed reducer 20 is connected to the input end of the diaphragm coupling 25. The output end of the diaphragm coupling 25 is connected to the input end of the high-voltage asynchronous motor 26. The turbine expander and the high-voltage asynchronous motor 26 form a shaft power transmission system through the speed reducer 20; A lubricating oil circulation system is provided between the speed reducer 20 and the high-voltage asynchronous motor 26, including a lubricating oil supply pump and a lubricating oil cooler. The lubricating oil circulation system includes a lubricating oil tank 29. The oil outlet pipe led out from the outlet end of the lubricating oil tank 29 is divided into two branch pipes after passing through the lubricating oil pump 30 and the cooler 31, and respectively enters the oil inlets of the speed reducer 15 and the high-voltage asynchronous motor 26. The return oil pipes led out from the oil outlets of the speed reducer 15 and the high-voltage asynchronous motor 26 are connected to the oil inlet of the lubricating oil tank 29. A fuel supply pressure regulating valve 33 is installed on the branch pipe between the lubricating oil tank 29 and the outlet end of the lubricating oil pump 30. A fuel supply pressure regulating valve 35 and a pressure transmitter 5 are installed at the oil inlet end of the high-voltage asynchronous motor 26. A pressure transmitter 4 is installed at the oil inlet end of the speed reducer 15. A speed transmitter 21, a vibration transmitter 22, a shaft displacement transmitter 23, and a temperature transmitter 24 are provided on the speed reducer 20. A temperature transmitter 27 for measuring the temperature of the motor bearing and a temperature transmitter 28 for detecting the temperature of the motor stator are provided on the high-voltage asynchronous motor 26. The power output end of the high-voltage asynchronous motor 26 is connected to the power input end of the high-power high-voltage asynchronous grid-connection unit 4. The power output end of the high-power high-voltage asynchronous grid-connection unit 4 is connected to the plant high-voltage internal network 42.

[0026] The high-power high-voltage asynchronous grid-connection unit 4 includes a high-voltage three-phase asynchronous motor group composed of more than one high-voltage three-phase asynchronous motor 26, a first high-voltage circuit breaker 38 connected to the electrical output end of the high-voltage three-phase asynchronous motor group, a first electrical parameter sensor 37 and a second electrical parameter sensor 41 for respectively collecting the electrical quantity parameters of the high-voltage cables before and after the first high-voltage circuit breaker 38. The automatic reactive power compensation device 39 is connected to the high-voltage cable at the rear end of the first high-voltage circuit breaker 38 through a second high-voltage circuit breaker 40. The high-power high-voltage asynchronous grid-connection unit 4 further includes a high-voltage comprehensive protection unit 36 for collecting the signals of the first electrical parameter sensor 37 and the second electrical parameter sensor 41 and then controlling the on / off of the first high-voltage circuit breaker 38 and the second high-voltage circuit breaker 40. The first high-voltage circuit breaker 38, the second electrical parameter sensor 47 and the automatic reactive power compensation device 39 are connected to the high-voltage comprehensive protection unit 36.

[0027] The control unit 2 includes a PLC controller 44 and a human-machine interface 43. The steam inlet / outlet unit 1, the turbine expansion power generation unit 3, and the high-power high-voltage asynchronous grid-connection unit 4 are respectively connected to the control unit 2. The control unit 2 controls the start-up grid-connection power generation, stop, and emergency stop of the entire steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connection system. The level transmitter 1 8, the level transmitter 2 15, the temperature transmitter 1 9, the pressure transmitter 1 10, the pressure transmitter 2 12, the temperature transmitter 2 13, the pressure transmitter 3 17, the temperature transmitter 3 18, the rotational speed transmitter 1 21, the vibration transmitter 1 22, the axial displacement transmitter 23, the temperature transmitter 4 24, the temperature transmitter 5 27, the temperature transmitter 6 28, the pressure transmitter 4 32, the pressure transmitter 5 34, the high-voltage comprehensive protection unit 36, and the pressure transmitter 6 46 are connected to the input ports of the PLC controller. The steam cut-off valve 5, the steam regulating valve 6, the steam regulating valve 2 19, the oil supply pressure regulating valve 1 33, the oil supply pressure regulating valve 2 35, the drain valve, the speed reducer 20, the lubricating oil pump 30, and the high-voltage asynchronous motor 26 are connected to the output ports of the PLC controller. The high-voltage comprehensive protection unit 36 and the human-machine interface 43 are connected to the input / output ports of the PLC controller. Collecting the signals of the level transmitter 1 8, the level transmitter 2 15, the temperature transmitter 1 9, the pressure transmitter 1 10, the pressure transmitter 2 12, the temperature transmitter 2 13, the pressure transmitter 3 17, the temperature transmitter 3 18, the rotational speed transmitter 1 21, the vibration transmitter 1 22, the axial displacement transmitter 23, the temperature transmitter 4 24, the temperature transmitter 5 27, the temperature transmitter 6 28, the pressure transmitter 4 32, the pressure transmitter 5 34, the high-voltage comprehensive protection unit 36, and the pressure transmitter 6 46 by the PLC controller, and controlling the steam cut-off valve 5, the steam regulating valve 6, the steam regulating valve 2 19, the oil supply pressure regulating valve 1 33, the oil supply pressure regulating valve 2 35, the drain valve, the speed reducer 20, the lubricating oil pump 30, and the high-voltage asynchronous motor 26 are prior arts and will not be elaborated in this embodiment. The signal intercommunication between the PLC controller and the high-voltage comprehensive protection unit 36 and the human-machine interface 43 is a prior art and will not be elaborated in this embodiment.

[0028] Usage process:

[0029] Confirmation of the rotation direction of the turboexpander power generation unit 1: First, manually disconnect the high-voltage asynchronous motor 26 from the speed reducer 20. The high-voltage asynchronous motor 26 is connected to the power input end of the high-voltage asynchronous grid connection unit 4 through a high-voltage cable. The high-power high-voltage asynchronous grid connection unit 4 is connected to the plant high-voltage internal network 42. Click on the human-machine interface 43 to send a signal to the high-power high-voltage asynchronous grid connection unit 4 to control the high-voltage asynchronous motor 26 to judge the rotation direction of the high-voltage asynchronous motor 26 and the rotation direction of the shaft connected to the coupling 25 of the speed reducer 20. If they are the same, they can be coupled. If they are not the same, the phase sequence of the high-voltage cable connected to the high-voltage asynchronous motor 26 must be adjusted. This high-voltage cable connects the high-voltage asynchronous motor 26 and the high-power high-voltage asynchronous grid connection unit 4 and has three phases. Adjusting the phase sequence means swapping two of the three phases at the high-voltage cable end. Only after the phase sequence is adjusted can the rotation directions be the same.

[0030] The control unit 2 turns on the lubricating oil supply oil pump 30 of the speed reducer 20 of the turbine expander power generation unit 3 to extract the lubricating oil in the oil tank 29. By adjusting the opening of the first oil supply pressure regulating valve 33, the measured value of the fourth pressure transmitter 32 is ensured to meet the requirements. By adjusting the opening of the second oil supply pressure regulating valve 35, the measured value of the fifth pressure transmitter 34 is ensured to meet the requirements. The cooling water of the cooler 31 is turned on to cool the lubricating oil in a timely manner. When the control unit 2 determines that the first speed measurement transmitter 21, vibration measurement transmitter 22, axial displacement transmitter 23, fourth temperature transmitter 24 for measuring the bearing temperature of the speed reducer, fifth temperature transmitter 27 for measuring the bearing temperature of the motor, and sixth temperature transmitter 28 for measuring the stator temperature of the motor do not exceed the interlock set value, and there is no trip signal in the high-power high-voltage asynchronous grid-connection unit 4, and the measured values of the fourth pressure transmitter 32 and the fifth pressure transmitter 34 are not lower than the interlock set value, the steam decompression turbine power generation high-voltage asynchronous power generation grid-connection system is normally reset through the control unit 2. The steam cut-off valve 5 is fully opened, the first steam regulating valve 6 is fully closed, and the second steam regulating valve 19 is fully closed. The opening of the steam regulating valve 6 is gradually increased through the control unit 2, and the steam enters the 1# separator 7 to separate the liquid water. When the first level transmitter 8 of the 1# separator 7 measures that the liquid level is higher than the alarm value, the control unit 2 issues a high liquid level alarm for the 1# separator. When the first level transmitter 8 of the 1# separator 7 measures that the liquid level is higher than the liquid discharge set value, the control unit 2 issues a liquid discharge signal to the first liquid discharge valve 45 for liquid discharge. The gas phase enters the first-stage turbine expander 11, expands, and then enters the 2# separator 15 to separate the liquid water. When the second level transmitter 15 of the 2# separator 14 measures that the liquid level is higher than the alarm value, the control unit 2 issues a high liquid level alarm for the 2# separator 14. When the second level transmitter 15 of the 2# separator 14 measures that the liquid level is higher than the liquid discharge set value, the control unit 2 issues a liquid discharge signal to the second liquid discharge valve 47 for liquid discharge. The gas phase enters the second-stage turbine expander 16 to continue expanding. The expanded steam enters the low-pressure steam pipe network through the second steam regulating valve 19. During this process, the opening of the second steam regulating valve 19 is controlled through the control unit 2 to make the measured value of the third pressure transmitter 17 ≥ the measured value of the sixth pressure transmitter 46. When this condition is met, the second steam regulating valve 19 is fully opened to increase the steam volume of the first-stage turbine expander 11. The steam volume gradually increases, and the rotational speeds of the first-stage turbine expander 11 and the second-stage turbine expander 16 gradually increase. When the measured value of the speed transmitter 21 of the first-stage turbine expander 11 (the high-speed shafts of the turbine expander and the speed reducer are connected together) reaches the range of 95% - 99% of the rated speed of the first-stage turbine expander 11, the control unit 2 sends a signal to the high-voltage comprehensive protection unit 36,Close the high-voltage circuit breaker 40 through the high-voltage comprehensive protection unit 36, and at the same time start the automatic reactive power compensation device 39 to work. After the automatic reactive power compensation device 29 works normally, the control unit 2 issues a command to start the high-power high-voltage asynchronous grid-connection unit 4. The high-voltage motor comprehensive protection of the high-power high-voltage asynchronous grid-connection unit issues a command to close the high-voltage grid-connection circuit breaker 38. After reaching the rated speed of the high-voltage asynchronous motor, the start-up and grid-connection process is completed. Then continue to open the steam regulating valve 6 to the fully open position. When the speed of the high-voltage asynchronous motor 26 exceeds the synchronous speed of 3000 r / min and is in the power generation state until the maximum power is generated, during this process, the automatic reactive power compensation device 39 adjusts the power factor to 0.93 automatically by collecting the data of the electrical parameter measurement transmitter 41. At the same time, the control unit 2 monitors the pressure transmitter 10, temperature transmitter 9, pressure transmitter 13, temperature transmitter 12, temperature transmitter 18, and pressure transmitter 17 of the turbine expansion power generation unit 3, and monitors the speed transmitter 21, vibration transmitter 22, shaft displacement transmitter 23, temperature transmitter 24, pressure transmitter 32, pressure transmitter 34, temperature transmitter 27, temperature transmitter 28, separator liquid level 8, and separator liquid level 15 of the speed reducer 20. The high-voltage motor comprehensive protection 36 in the high-power high-voltage asynchronous grid-connection unit 4 monitors the electrical parameter measurement transmitter 37. When a fault occurs, the control unit 2 quickly controls the steam cut-off valve 5 to be fully closed, the steam regulating valve 6 to be fully closed, and the steam regulating valve 19 to be fully closed. At the same time, the high-voltage circuit breaker 38 of the high-power high-voltage asynchronous grid-connection unit is opened, the high-voltage asynchronous motor 26 is disconnected from the plant high-voltage internal network 42, the automatic reactive power compensation device 39 stops working, and the high-voltage circuit breaker 41 is opened.,

Claims

1. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system, characterized in that: It includes a turbine expansion power generation unit (3), a steam inlet and outlet unit (1) for providing a power source for the turbine expansion power generation unit (3), and a high-power high-voltage asynchronous grid connection unit (4) for connecting the turbine expansion power generation unit (3) to the plant high-voltage internal network (42); The steam inlet and outlet unit (1) includes a conveying pipeline for connecting two-stage turbine expanders. One end of the conveying pipeline is the inlet end of high-temperature and high-pressure steam, and the other end is the outlet end. The outlet end is connected to the steam low-pressure pipe network. A steam cut-off valve (5), a steam regulating valve (6), and a 1# separator (7) are successively installed on the conveying pipeline between the inlet end and the inlet end of the first-stage turbine expander (11). A 2# separator (14) is provided on the conveying pipeline between the outlet end of the first-stage turbine expander (11) and the inlet end of the second-stage turbine expander (16). A second steam regulating valve (19) is installed on the conveying pipeline at the outlet end of the second-stage turbine expander (16); The turbine expansion power generation unit (3) includes a speed reducer (20). The two input ends of the speed reducer (20) are respectively connected to the first-stage turbine expander (11) and the power input end of the first-stage turbine expander (11). The output port of the speed reducer (20) is connected to a high-voltage asynchronous motor set to form a transmission system; The high-power high-voltage asynchronous grid connection unit (4) includes an automatic reactive power compensation device (39), a first high-voltage circuit breaker (38) connected to the high-voltage cable between the plant high-voltage internal network (42) and the high-voltage asynchronous motor set, a first electrical parameter sensor (37) and a second electrical parameter sensor (41) for respectively collecting the electrical quantity parameters of the high-voltage cables before and after the first high-voltage circuit breaker (38); The automatic reactive power compensation device (39) is connected to the high-voltage cable at the rear end of the first high-voltage circuit breaker (38) via a second high-voltage circuit breaker (40); The high-power high-voltage asynchronous grid connection unit (4) further includes a high-voltage comprehensive protection unit (36) for collecting the signals of the first electrical parameter sensor (37) and the second electrical parameter sensor (41) and then controlling the on-off of the first high-voltage circuit breaker ((38)) and the second high-voltage circuit breaker (40).

2. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 1, characterized in that: The turbine expansion power generation unit (3) further includes a lubricating oil circulation system for providing lubricating grease for the speed reducer (20) and the high-voltage asynchronous motor set. The lubricating oil circulation system includes a lubricating oil tank (29). The oil outlet pipe led out from the outlet end of the lubricating oil tank (29) is divided into two branch pipes after passing through a lubricating oil pump (30) and a cooler (31), and respectively leads into the oil inlet ports of the speed reducer (20) and the high-voltage asynchronous motor set. The return oil pipes led out from the oil outlet ports of the speed reducer (20) and the high-voltage asynchronous motor set are communicated with the oil inlet port of the lubricating oil tank (29).

3. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 2, characterized in that: A first oil supply pressure regulating valve (33) is installed on the branch pipe between the lubricating oil tank (29) and the outlet end of the lubricating oil pump (30). A second oil supply pressure regulating valve (35) and a fifth pressure transmitter are installed at the oil inlet end of the high-voltage asynchronous motor set. A fourth pressure transmitter (32) is installed at the oil inlet end of the speed reducer (20).

4. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to any one of claims 1-3, characterized in that: Temperature transmitters five (27) for measuring the temperature of the motor bearings and temperature transmitters six (28) for detecting the temperature of the motor stator are provided on each high-voltage asynchronous motor (26) of the high-voltage asynchronous motor set.

5. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 4, characterized in that: Level transmitters for measuring the liquid levels in the corresponding separators are installed on both the 1# separator (7) and the 2# separator (14). Drain pipes are connected to the lower ends of the 1# separator (7) and the 2# separator (14), and drain valves are installed on the drain pipes.

6. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 1 or 4, characterized in that: There are a temperature transmitter one (9) and a pressure transmitter one (10) on the pipeline between the 1# separator (7) and the first-stage turbine expander (11). There are a pressure transmitter two (12) and a temperature transmitter two (13) on the pipeline between the first-stage turbine expander (11) and the 2# separator (14). There are a pressure transmitter three (17) and a temperature transmitter three (18) on the pipeline between the second-stage turbine expander (16) and the steam control valve two (19). There is a pressure transmitter six (46) on the pipeline connected to the other end of the steam control valve two (19).

7. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 6, characterized in that: A speed transmitter one (21), a vibration transmitter one (22), an axial displacement transmitter (23), and a temperature transmitter four (24) are installed on the speed reducer (20).

8. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 7, characterized in that: It also includes a control unit (2) that can monitor the signals of each level transmitter, temperature transmitter one (9), pressure transmitter one (10), pressure transmitter two (12), temperature transmitter two (13), pressure transmitter three (17), temperature transmitter three (18), speed transmitter one (21), vibration transmitter one (22), axial displacement transmitter (23), temperature transmitter four (24), temperature transmitter five (27), temperature transmitter six (28), pressure transmitter four (32), pressure transmitter five (34), high-voltage comprehensive protection unit (36), and pressure transmitter six (46), and then correspondingly control the opening degrees of the steam cut-off valve (5), steam control valve (6), steam control valve two (19), oil supply pressure control valve one (33), oil supply pressure control valve two (35), and each drain valve, and control the start / stop of the speed reducer (20), lubricating oil pump (30), and high-voltage asynchronous motor (26).

9. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 8, characterized in that: The control unit (2) includes a PLC controller (44) and a human-machine interface (43) connected to the output end of the PLC controller.

10. A high-power steam pressure-reducing turbine power generation high-voltage asynchronous power generation grid-connected system according to claim 8 or 9, characterized in that: The steam cut-off valve (5), steam control valve (6), steam control valve two (19), oil supply pressure control valve one (33), oil supply pressure control valve two (35), and each drain valve are pneumatic valves.

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