A steam turbine regulating valve quick closing and oil motor buffer system

Abstract

The present invention relates to a steam turbine regulating valve fast closing and oil motor buffer system, comprising: a regulating valve motion unit, a regulating valve control unit and a regulating valve fast closing unit; the regulating valve motion unit is composed of a valve seat, a valve body, a valve stem, a connecting rod, a valve housing, an oil motor piston, a spring A, a piston rod and an end cover; the valve seat contacts the valve body to form a sealing valve; the valve body is connected to the valve stem, the valve stem is connected to the connecting rod; the connecting rod is connected to the oil motor piston through the piston rod. The beneficial effects of the present invention are: the present invention controls the closing speed of the regulating valve of the steam turbine under different states by judging the closing condition of the regulating valve and the load level of the steam turbine, and can ensure that when the steam turbine is in working conditions such as load rejection and accident shutdown, the impact force of the valve and the hydraulic components in the oil cylinder of the oil motor when the steam turbine regulating valve is quickly closed is reduced without overspeed, thereby extending the service life of the regulating valve and its hydraulic components.

Description

Technical Field

[0001] The invention belongs to the technical field of power station steam turbines, and in particular relates to a steam turbine regulating valve quick closing and oil motor buffer system. Background Art

[0002] Under the general environment of global energy innovation, my country is actively promoting the reform of clean energy structure. In recent years, the installed capacity of new energy represented by photovoltaic and wind power has grown rapidly, but the randomness and intermittent instability of new energy determine that domestic power generation will continue to maintain a structure dominated by thermal power units at this stage. In order to improve the power generation efficiency of thermal power units and control unit emissions, thermal power units are also developing towards higher parameters and higher installed capacity.

[0003] At present, the domestic thermal power generating units in service or newly built are mainly supercritical or ultra-supercritical units, which have the characteristics of high steam parameters and large steam flow. In order to prevent the rotor from overspeeding when the unit is shut down or unloaded, the "Test Guidelines for Steam Turbine Control System" puts forward higher requirements for the valve closing time of large steam turbine units; in the actual unit design process, it is also common to increase the spring preload or use butterfly springs to increase the closing speed of the main steam valve and regulating valve of the steam turbine. However, if the closing speed of the steam turbine regulating valve is too fast, the instantaneous impact force on the main valve and valve seat will be too large, especially when the piston stroke of the oil motor and the valve stem stroke are poorly matched, which may cause damage to the valve body and valve seat; and the damage may cause the valve seat and the surface metal of the valve body to fall off, which brings great risks to the operation of the unit. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a steam turbine regulating valve quick closing and oil motor buffer system.

[0005] The steam turbine regulating valve quick closing and oil motor buffer system comprises a regulating valve motion unit, a regulating valve control unit and a regulating valve quick closing unit;

[0006] The regulating valve motion unit is composed of a valve seat, a valve body, a valve stem, a connecting rod, a valve housing, an oil motor piston, a spring A, a piston rod and an end cover; the valve seat contacts the valve body to form a sealed valve; the valve body is connected to the valve stem, and the valve stem is connected to the connecting rod; the connecting rod is connected to the oil motor piston through the piston rod; the oil motor piston is inserted into the end cover to form a closed chamber; the piston rod is sleeved with a spring A;

[0007] The regulating valve control unit is composed of an oil tank, an oil inlet pipeline, a relief valve C, a servo valve, an oil return pipeline, a cartridge valve, a spring B, a safety oil pipeline, a solenoid valve and a check valve; the oil tank is connected to the relief valve C through the oil inlet pipeline; one outlet of the relief valve C is connected to the servo valve, and the other outlet is connected to the safety oil pipeline; one outlet of the relief valve C connected to the servo valve is connected to the inlet of the lower part of the oil motor piston; the outlet of the lower part of the oil motor piston is connected to the oil return pipeline; one safety oil pipeline is connected to the solenoid valve, a check valve is connected in parallel on the pipeline where the solenoid valve is located, and the other safety oil pipeline is connected to the cartridge valve; a spring B is provided at the bottom of the cartridge valve;

[0008] The regulating valve quick-closing unit is composed of a power sensor, a pressure sensor, a quick-closing card, a pressure relief solenoid valve A, a pressure relief solenoid valve B, a relief valve A, a relief valve B and a stop valve; the pressure relief solenoid valve A and the relief valve A are connected in series and installed on the return oil pipeline, and the pressure relief solenoid valve A is connected to the closed chamber at the bottom of the oil motor piston; the pressure relief solenoid valve B and the relief valve B are connected in series and installed on the return oil pipeline; the pressure relief solenoid valve B is connected to the closed chamber at the bottom of the oil motor piston; a pressure gauge is provided on the pipeline between the pressure relief solenoid valve A and the pressure relief solenoid valve B; stop valves are provided at the outlets of the relief valve A and the relief valve B; the power sensor and the pressure sensor are electrically connected to the input port of the quick-closing card.

[0009] Preferably, the front end of the oil motor piston is a truncated cone-shaped plunger, and the plunger is inserted into the circular hole on the end cover to form a closed chamber.

[0010] Preferably, a slide valve is arranged inside the servo valve; and the solenoid valve is a normally open type.

[0011] Preferably, the branch where the pressure relief solenoid valve A and the overflow valve A are connected in series is connected in parallel with the branch where the pressure relief solenoid valve B and the overflow valve B are connected in series.

[0012] Preferably, the connection relationship between the steam turbine and other control elements is as follows: the steam turbine is divided into three routes, the first route is electrically connected to the distributed control system, the second route is electrically connected to the power sensor, and the third route is electrically connected to the pressure sensor; the power sensor and the pressure sensor are connected in parallel; the distributed control system is electrically connected to the digital electro-hydraulic control system, the trip protection system, the power sensor, the pressure sensor and the quick-closing card; the digital electro-hydraulic control system is electrically connected to the OPC solenoid valve; the trip protection system is electrically connected to the AST solenoid valve; the OPC solenoid valve and the AST solenoid valve are both electrically connected to the oil motor, the oil motor is electrically connected to the regulating valve, and the oil motor is also electrically connected to the buffer chamber; the quick-closing card is electrically connected to the pressure relief solenoid valve A and the pressure relief solenoid valve B; the buffer chamber is electrically connected to the overflow valve A and the overflow valve B; the pressure relief solenoid valve A is connected in series with the overflow valve A, and the pressure relief solenoid valve B is connected in series with the overflow valve B.

[0013] Preferably, the quick-closing card component is a collection controller.

[0014] The working method of the steam turbine regulating valve quick closing and oil motor buffer system comprises the following steps:

[0015] Step 1: The distributed control system sends a closing command to the digital electro-hydraulic control system or the tripping protection system, and at the same time sends the closing command to the quick-closing card;

[0016] Step 2: When the digital electro-hydraulic control system receives the command, the OPC solenoid valve is activated, affecting the safety oil pressure; when the trip protection system receives the command, the AST solenoid valve is activated, the safety oil pressure drops, the cartridge valve opens, the oil return line at the bottom of the oil motor piston is connected, the oil motor piston is closed, and the regulating valve is driven to close;

[0017] Step 3, preset the regulating stage pressure and generator power, and collect the signals of the pressure sensor and the power sensor through the input port of the quick-close card; when the quick-close card receives the instruction, it judges whether the steam turbine is in an emergency shutdown state, a load shedding state or a normal shutdown state according to the closing instruction received by the quick-close card and the unit parameter results measured by the pressure sensor and the power sensor; when the received signal is a normal shutdown signal, the quick-close card does not output the instruction; when the received signal is an abnormal shutdown signal, it judges whether the steam turbine is in a high load state or a low load state by comparing the real-time values ​​of the power signal and the pressure signal with the set values, and responds.

[0018] Preferably, step 3 specifically comprises the following steps:

[0019] Step 3.1: If a manual shutdown command and generator disconnection are received, and the turbine power is less than 15% of the rated power, the result is judged as a normal shutdown, otherwise the unit is judged to be an abnormal shutdown; when the unit is shut down normally, both the pressure relief solenoid valve A and the pressure relief solenoid valve B are closed. If the result is an abnormal shutdown, execute step 3.2;

[0020] Step 3.2: When the unit is abnormally shut down, continue to determine whether the steam turbine is in an emergency shutdown state or a load rejection state, and respond;

[0021] Step 3.2.1, if the steam turbine is in a load rejection state, compare the measured values ​​of the pressure sensor and the power sensor with the preset values; if the steam turbine power is >50% of the rated power, and the regulating stage pressure measured by the pressure sensor is >60% of the rated pressure, open the pressure relief solenoid valve A, otherwise open the pressure relief solenoid valve B; when the OPC solenoid valve is reset, the pressure relief solenoid valve A and the pressure relief solenoid valve B are reset;

[0022] Step 3.2.2, if the steam turbine is in an emergency shutdown state, compare the measured values ​​of the pressure sensor and the power sensor with the preset values; if the steam turbine power is >50% of the rated power, and the regulating stage pressure is >60% of the rated pressure, open the pressure relief solenoid valve A, otherwise open the pressure relief solenoid valve B, and the pressure relief solenoid valve A and the pressure relief solenoid valve B will not be reset;

[0023] Step 3.3, determine whether the steam turbine is in a high load state or a low load state, and respond: set the overflow pressure of overflow valve A to P1, and set the overflow pressure of overflow valve B to P2; when the steam turbine has an accident trip or load shedding under high load, the pressure relief solenoid valve A opens, and the overflow pressure P1 of overflow valve A is set according to the set closing time of the turbine control valve; when the steam turbine has an accident trip or load shedding under low load, the pressure relief solenoid valve B opens, and the overflow pressure P2 of overflow valve B is adjusted upward by a certain amount with reference to the set value of P1.

[0024] The beneficial effects of the present invention are as follows: the present invention controls the closing speed of the regulating valve of the steam turbine under different conditions by judging the closing conditions of the regulating valve and the load level of the steam turbine, thereby ensuring that when the steam turbine is in working conditions such as load shedding and accident shutdown, the impact force on the valve and the hydraulic components in the oil cylinder of the oil motor when the regulating valve of the steam turbine is quickly closed is reduced without overspeeding, thereby extending the service life of the regulating valve and its hydraulic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the connection relationship diagram of the turbine control valve speed closing and the oil motor buffer system;

[0026] Figure 2 It is a schematic diagram of the turbine control valve quick closing and oil motor buffer system;

[0027] Figure 3 It is the working flow chart of the turbine control valve quick closing and oil motor buffer system.

[0028] Description of reference numerals:

[0029] Valve seat 001, valve body 002, valve stem 003, connecting rod 004, valve housing 005, oil motor piston 006, spring A007, piston rod 008, end cover 009, oil inlet pipeline 010, oil return pipeline 011, safety oil pipeline 012, cartridge valve 013, spring B014, pressure relief solenoid valve A015, pressure gauge 016, pressure relief solenoid valve B017, overflow valve A018, overflow valve B019, stop valve 020, solenoid valve 021, check valve 022, servo valve 023, oil tank 024, overflow valve C025, distributed control system 101, digital electro-hydraulic control system 102, trip protection system 103, OPC solenoid valve 104, AST solenoid valve 105, pressure sensor 106, power sensor 107. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0031] Embodiment 1

[0032] Embodiment 1 of the present application provides a Figure 1 and Figure 2 The steam turbine regulating valve quick closing and oil motor buffer system shown includes a regulating valve motion unit, a regulating valve control unit and a regulating valve quick closing unit;

[0033] The regulating valve motion unit is composed of valve seat 001, valve body 002, valve stem 003, connecting rod 004, valve housing 005, oil motor piston 006, spring A007, piston rod 008 and end cover 009; valve seat 001 contacts valve body 002 to form a sealed valve; valve body 002 is connected to valve stem 003, and valve stem 003 is connected to connecting rod 004; connecting rod 004 is connected to oil motor piston 006 through piston rod 008; oil motor piston 006 is inserted into end cover 009 to form a closed chamber; spring A007 is sleeved on piston rod 008; the front end of oil motor piston 006 is a truncated cone plunger, and the plunger is inserted into the round hole on end cover 009 to form a closed chamber;

[0034] The regulating valve control unit is composed of an oil tank 024, an oil inlet pipeline 010, a relief valve C025, a servo valve 023, an oil return pipeline 011, a cartridge valve 013, a spring B014, a safety oil pipeline 012, a solenoid valve 021 and a check valve 022; the oil tank 024 is connected to the relief valve C025 through the oil inlet pipeline 010; one outlet of the relief valve C025 is connected to the servo valve 023, and the other outlet is connected to the safety oil pipeline 012; the relief valve C025 is connected to the oil tank 024, and the oil tank 024 is connected to the oil return pipeline 011, a plug valve 013, a spring B014, a safety oil pipeline 012, a solenoid valve 021 and a check valve 022; the oil tank 024 is connected to the relief valve C025 through the oil inlet pipeline 010; one outlet of the relief valve C025 is connected to the servo valve 023, and the other outlet is connected to the safety oil pipeline 012; the relief valve C025 is connected to the oil tank 024, and the oil return pipeline 011 is connected to the oil tank 024. One path connected to the servo valve 023 is connected to the inlet at the bottom of the oil motor piston 006; the outlet at the bottom of the oil motor piston 006 is connected to the oil return pipeline 011; one path of the safety oil pipeline 012 is connected to the solenoid valve 021, and a one-way valve 022 is connected in parallel on the pipeline where the solenoid valve 021 is located; the other path of the safety oil pipeline 012 is connected to the cartridge valve 013; a spring B014 is provided at the bottom of the cartridge valve 013; a slide valve is provided inside the servo valve 023; the solenoid valve 021 is a normally open type;

[0035] The regulating valve quick-closing unit is composed of a power sensor 107, a pressure sensor 106, a quick-closing card, a pressure relief solenoid valve A015, a pressure relief solenoid valve B017, an overflow valve A018, an overflow valve B019 and a stop valve 020; the pressure relief solenoid valve A015 and the overflow valve A018 are connected in series and installed on the oil return pipeline 011, and the pressure relief solenoid valve A015 is connected to the closed chamber at the bottom of the oil motor piston 006; the pressure relief solenoid valve B017 and the overflow valve B019 are connected in series and installed on the oil return pipeline 011; the pressure relief solenoid valve B017 is connected to the closed chamber at the bottom of the oil motor piston 006; the pressure relief solenoid valve A015 A pressure gauge 016 is provided on the pipeline between the pressure relief solenoid valve A015 and the pressure relief solenoid valve B017 to detect whether there is leakage in the pipeline where the speed-closing unit is located during normal operation; a stop valve 020 is provided at the outlet of the relief valve A018 and the relief valve B019 to ensure the system isolation during the maintenance of the speed-closing unit; the power sensor 107 and the pressure sensor 106 are electrically connected to the input port of the speed-closing card; the branch where the pressure relief solenoid valve A015 and the relief valve A018 are connected in series is connected in parallel with the branch where the pressure relief solenoid valve B017 and the relief valve B019 are connected in series; the speed-closing card is an acquisition controller with high-speed acquisition, storage and high-speed computing functions;

[0036] The steam turbine is divided into three paths, the first path is electrically connected to the distributed control system 101, the second path is electrically connected to the power sensor 107, and the third path is electrically connected to the pressure sensor 106; the power sensor 107 and the pressure sensor 106 are connected in parallel; the distributed control system 101 is electrically connected to the digital electro-hydraulic control system 102, the trip protection system 103, the power sensor 107, the pressure sensor 106 and the fast-closing card; the digital electro-hydraulic control system 102 is electrically connected to the OPC solenoid valve 104; the trip protection system 103 is electrically connected to the AST solenoid valve 105; the OPC solenoid valve 104 and the AST solenoid valve 105 are both electrically connected to the oil motor, the oil motor is electrically connected to the regulating valve, and the oil motor is also electrically connected to the buffer chamber; the fast-closing card is electrically connected to the pressure relief solenoid valve A015 and the pressure relief solenoid valve B017; the buffer chamber is electrically connected to the overflow valve A018 and the overflow valve B019; the pressure relief solenoid valve A015 is connected in series with the overflow valve A018, and the pressure relief solenoid valve B017 is connected in series with the overflow valve B019.

[0037] Embodiment 2

[0038] Based on the first embodiment, the second embodiment of the present application provides an embodiment such as Figure 3 The working method of the turbine regulating valve quick closing and oil motor buffer system shown in the figure:

[0039] Step 1: The closing of the steam turbine regulating valve is achieved through the cooperation of the DCS, DEH, ETS and the regulating valve fast closing unit. The distributed control system 101 sends a closing command to the digital electro-hydraulic control system 102 or the tripping protection system 103, and sends the closing command to the fast closing card at the same time;

[0040] Step 2, when the digital electro-hydraulic control system 102 receives the command, the OPC solenoid valve 104 is activated, affecting the safety oil pressure; when the trip protection system 103 receives the command, the AST solenoid valve 105 is activated, the safety oil pressure drops, the cartridge valve 013 is opened, the oil return line 011 at the lower part of the oil motor piston 006 is connected, the oil motor piston 006 is closed and drives the regulating valve to close; the power oil in the oil tank 024 enters the relief valve C025 through the oil inlet line 010; the power oil in the way connected between the relief valve C025 and the servo valve 023 enters the oil motor through the inlet at the lower part of the oil motor piston 006 under the control of the servo valve 023, and enters the oil return line 011 through the outlet at the upper part of the oil motor piston 006; the servo valve 023 adjusts the position of the internal slide valve according to the received electrical signal to inlet or return oil. Oil; the oil inlet and oil return of the closed chamber are controlled by the movement of the oil motor piston 006: after the truncated cone-shaped plunger on the oil motor piston 006 enters the circular hole on the end cover 009, the flow area of ​​the circular hole is reduced, the oil return rate of the power oil decreases, and the power oil pressure at the lower part of the oil motor piston 006 increases. The movement of the oil motor piston 006 drives the piston rod 008 to move up and down, and then drives the connecting rod 004 to move; the movement of the connecting rod 004 drives the valve stem 003 to move up and down; the closing speed of the piston rod 008 decreases; when the plunger completely enters the circular hole, the plunger cooperates with the circular hole to form a closed chamber filled with power oil at the lower end of the oil motor piston 006; the power oil pressure at the lower part of the oil motor piston 006 further increases, and the closing speed of the piston rod 008 further decreases until the movement of the oil motor piston 006 stops completely;

[0041] Step 3, preset the regulating stage pressure and generator power, and collect the signals of the pressure sensor 106 and the power sensor 107 through the input port of the quick-close card; when the quick-close card receives the instruction, according to the closing instruction received by the quick-close card, combined with the unit parameter results measured by the pressure sensor 106 and the power sensor 107, determine whether the steam turbine is in an emergency shutdown state, a load rejection state or a normal shutdown state; when the received signal is a normal shutdown signal, the quick-close card does not output the instruction; when the received signal is an abnormal shutdown signal, by comparing the real-time value of the power signal and the pressure signal with the set value, determine whether the steam turbine is in a high load state or a low load state, and respond;

[0042] Step 3.1, if a manual shutdown command and generator disconnection are received, and the turbine power is less than 15% of the rated power, the judgment result is a normal shutdown, otherwise the unit is judged to be an abnormal shutdown; when the unit is shut down normally, the pressure relief solenoid valve A015 and the pressure relief solenoid valve B017 are both closed to increase the buffering effect of the oil motor and reduce the impact and wear during normal shutdown; when the unit is operating normally, the return oil side of the safety oil pipeline 012 is cut off to ensure the pressure of the safety oil pipeline, the cartridge valve 013 is in a closed state under the combined force of the spring preload, the power oil pressure and the safety oil pressure, and the return oil pipeline 011 at the bottom of the oil motor piston 006 is cut off; when the return oil of the safety oil pipeline 012 is connected, the safety oil pressure drops, the cartridge valve 013 opens under the power oil pressure, and the return oil pipeline 011 at the bottom of the oil motor piston 006 is connected; if the judgment result is an abnormal shutdown, execute step 3.2;

[0043] Step 3.2: When the unit is abnormally shut down, continue to determine whether the steam turbine is in an emergency shutdown state or a load rejection state, and respond;

[0044] Step 3.2.1, if the steam turbine is in a load rejection state, the measured values ​​of the pressure sensor 106 and the power sensor 107 are compared with the preset values; if the steam turbine power is greater than 50% of the rated power, and the regulating stage pressure measured by the pressure sensor is greater than 60% of the rated pressure, the pressure relief solenoid valve A015 is opened, otherwise the pressure relief solenoid valve B017 is opened; when the OPC solenoid valve is reset, the pressure relief solenoid valve A015 and the pressure relief solenoid valve B017 are reset, so that the oil return of the lower oil chamber of the oil motor piston is blocked;

[0045] Step 3.2.2, if the steam turbine is in an emergency shutdown state, compare the measured values ​​of the pressure sensor 106 and the power sensor 107 with the preset values; if the steam turbine power is greater than 50% of the rated power, and the regulating stage pressure is greater than 60% of the rated pressure, open the pressure relief solenoid valve A015, otherwise open the pressure relief solenoid valve B017, and the pressure relief solenoid valve A015 and the pressure relief solenoid valve B017 are not reset;

[0046] Step 3.3, determine whether the steam turbine is in a high load state or a low load state, and respond: set the overflow pressure of the overflow valve A018 to P1, and set the overflow pressure of the overflow valve B019 to P2; when the steam turbine has an accident trip or load shedding under high load, the pressure relief solenoid valve A015 opens, and the overflow pressure P1 of the overflow valve A018 is set according to the set closing time of the turbine control valve to ensure that the control valve closes quickly and suppresses the turbine speed from rising; when the steam turbine has an accident trip or load shedding under low load, the pressure relief solenoid valve B017 opens, and the overflow pressure P2 of the overflow valve B019 is adjusted upward by a certain amount (1.5 times of P1) with reference to the set value of P1, taking into account the speed closing of the control valve and the buffering of the oil motor.

[0047] For the unit, the rotor rise rate is different for different steam parameters and flow rates. Under low load conditions, the closing rate of the unit's regulating valve at the end can be appropriately reduced to reduce the damage caused by impact.

Claims

1. A working method for a steam turbine regulating valve quick closing and oil motor buffer system, characterized in that: A steam turbine regulating valve quick closing and oil motor buffer system comprises a regulating valve motion unit, a regulating valve control unit and a regulating valve quick closing unit; the regulating valve motion unit comprises a valve seat (001), a valve body (002), a valve stem (003), a connecting rod (004), a valve housing (005), an oil motor piston (006), a spring A (007), a piston rod (008) and an end cover (009); the valve seat (001) contacts the valve body (002) to form a sealed valve; the valve body (002) is connected to the valve stem (003), and the valve stem (003) is connected to the connecting rod (004); the connecting rod (004) is connected to the oil motor piston (006) through the piston rod (008); the oil motor piston (006) is inserted into the end cover (009) to form A closed chamber; a spring A (007) is sleeved on the piston rod (008); the regulating valve control unit is composed of an oil tank (024), an oil inlet pipeline (010), a relief valve C (025), a servo valve (023), an oil return pipeline (011), a cartridge valve (013), a spring B (014), a safety oil pipeline (012), a solenoid valve (021) and a check valve (022); the oil tank (024) is connected to the relief valve C (025) through the oil inlet pipeline (010); one outlet of the relief valve C (025) is connected to the servo valve (023), and the other outlet is connected to the safety oil pipeline (012); one outlet of the relief valve C (025) connected to the servo valve (023) is connected to the oil motor piston (006) The inlet at the bottom of the oil motor piston (006) is connected to the oil return pipeline (011); one path of the safety oil pipeline (012) is connected to the solenoid valve (021), a one-way valve (022) is connected in parallel to the pipeline where the solenoid valve (021) is located, and the other path of the safety oil pipeline (012) is connected to the cartridge valve (013); a spring B (014) is provided at the bottom of the cartridge valve (013), when the safety oil pressure drops, the cartridge valve (013) opens, and the oil return pipeline (011) at the bottom of the oil motor piston (006) is connected; the regulating valve quick closing unit is composed of a power sensor (107), a pressure sensor (106), a quick closing card, a pressure relief solenoid valve A (015), a pressure relief solenoid valve B (017), and a relief valve A (018). ), a relief valve B (019) and a stop valve (020); a pressure relief solenoid valve A (015) and a relief valve A (018) are connected in series and then installed on the oil return pipeline (011); the pressure relief solenoid valve A (015) is connected to a sealed chamber at the bottom of the oil motor piston (006); a pressure relief solenoid valve B (017) and a relief valve B (019) are connected in series and then installed on the oil return pipeline (011); the pressure relief solenoid valve B (017) is connected to a sealed chamber at the bottom of the oil motor piston (006); a pressure gauge (016) is provided on the pipeline between the pressure relief solenoid valve A (015) and the pressure relief solenoid valve B (017); stop valves (020) are provided at the outlets of the relief valve A (018) and the relief valve B (019);The power sensor (107) and the pressure sensor (106) are electrically connected to the input port of the quick-closing card component. The steam turbine is divided into three paths, the first path is electrically connected to the distributed control system (101), the second path is electrically connected to the power sensor (107), and the third path is electrically connected to the pressure sensor (106); the power sensor (107) and the pressure sensor (106) are connected in parallel to measure the parameter results of the steam turbine unit and determine whether the steam turbine is in an emergency shutdown state, a load rejection state, or a normal shutdown state; the working method of the steam turbine regulating valve quick closing and oil motor buffer system comprises the following steps:; Step 1, the distributed control system (101) sends a closing instruction to the digital electro-hydraulic control system (102) or the tripping protection system (103), and at the same time sends the closing instruction to the fast-closing card component; Step 2: When the digital electro-hydraulic control system (102) receives the command, the OPC solenoid valve (104) is activated, affecting the safety oil pressure; when the trip protection system (103) receives the command, the AST solenoid valve (105) is activated, the safety oil pressure drops, the cartridge valve (013) opens, the oil return line (011) below the oil motor piston (006) is connected, the oil motor piston (006) is closed and drives the regulating valve to close; Step 3, preset the regulating stage pressure and the generator power, and collect the signals of the pressure sensor (106) and the power sensor (107) through the input port of the quick-close card; when the quick-close card receives the instruction, according to the closing instruction received by the quick-close card, combined with the unit parameter results measured by the pressure sensor (106) and the power sensor (107), determine whether the steam turbine is in an emergency shutdown state, a load rejection state or a normal shutdown state; when the received signal is a normal shutdown signal, the quick-close card does not output the instruction; when the received signal is an abnormal shutdown signal, by comparing the real-time values ​​of the power signal and the pressure signal with the set values, determine whether the steam turbine is in a high-load state or a low-load state, and respond.

2. The working method of the steam turbine regulating valve quick closing and oil motor buffer system according to claim 1 is characterized in that: Step 3 specifically includes the following steps: Step 3.1: If a manual shutdown command and generator disconnection are received, and the turbine power is less than 15% of the rated power, the unit is judged to be shut down normally, otherwise the unit is judged to be shut down abnormally; when the unit is shut down normally, the pressure relief solenoid valve A (015) and the pressure relief solenoid valve B (017) are both closed. If the judgment result is an abnormal shutdown, execute step 3.2; Step 3.2: When the unit is abnormally shut down, continue to determine whether the steam turbine is in an emergency shutdown state or a load rejection state, and respond; Step 3.2.1, if the steam turbine is in a load rejection state, the measured values ​​of the pressure sensor (106) and the power sensor (107) are compared with the preset values; if the steam turbine power is greater than 50% of the rated power, and the regulating stage pressure measured by the pressure sensor is greater than 60% of the rated pressure, the pressure relief solenoid valve A (015) is opened, otherwise the pressure relief solenoid valve B (017) is opened; when the OPC solenoid valve is reset, the pressure relief solenoid valve A (015) and the pressure relief solenoid valve B (017) are reset; Step 3.2.2, if the steam turbine is in an emergency shutdown state, compare the measured values ​​of the pressure sensor (106) and the power sensor (107) with the preset values; if the steam turbine power is greater than 50% of the rated power, and the regulating stage pressure is greater than 60% of the rated pressure, open the pressure relief solenoid valve A (015), otherwise open the pressure relief solenoid valve B (017), and the pressure relief solenoid valve A (015) and the pressure relief solenoid valve B (017) are not reset; Step 3.3, determine whether the steam turbine is in a high load state or a low load state, and respond: set the overflow pressure of the overflow valve A (018) to P1, and set the overflow pressure of the overflow valve B (019) to P2; when the steam turbine has an accident trip or load shedding under the high load state, the pressure relief solenoid valve A (015) opens, and the overflow pressure P1 of the overflow valve A (018) is set according to the set closing time of the turbine control valve; when the steam turbine has an accident trip or load shedding under the low load state, the pressure relief solenoid valve B (017) opens, and the overflow pressure P2 of the overflow valve B (019) is adjusted upward by a certain amount with reference to the set value of P1.

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