Auxiliary braking method for steam turbine

Abstract

The invention provides an auxiliary braking method for a steam turbine, which adopts an auxiliary braking device for the steam turbine. A rotor magnetic part is arranged at one end of a rotor of the steam turbine, and a motor coil which can be combined with the rotor magnetic part to generate current is correspondingly arranged; therefore, energy generated by idle running of the rotor can be converted into current and transferred during braking of the steam turbine, the braking time of the steam turbine is greatly shortened, the temperature of components of the steam turbine in the braking process is reduced, and the service life of the steam turbine is prolonged. The auxiliary braking method for the steam turbine can be widely applied to various conditions that vibration of the steam turbine becomes larger and larger, a lubricating oil tank is on fire and needs to be extinguished, axial displacement of the steam turbine collides with a film or lubricating oil supply is abnormal, and the application prospect is wide.

Description

[0001] This invention is a divisional application of the invention patent application with Chinese national application number 202210064127.4, application date January 20, 2022, and invention name “A steam turbine auxiliary braking device and auxiliary braking method”. Technical Field

[0002] The invention relates to the technical field of steam turbine braking, and in particular to a steam turbine auxiliary braking method. Background Art

[0003] The current emergency shutdown operation mode of steam turbines is: when a system failure requires emergency shutdown, the shutdown solenoid valve is remotely controlled to operate, the safety oil pressure is released, the steam valve is closed, and then the vacuum is destroyed for emergency shutdown. However, the unit runaway time is still very long and the braking efficiency is relatively low. At the same time, if the safety oil pressure cannot be released due to oil line blockage, mechanical jamming, etc., the turbine braking failure is likely to occur. In severe cases, it may even cause a turbine runaway accident, which seriously affects the safety and reliability of the turbine equipment operation. Therefore, in response to this problem, it is urgent to develop a braking mechanism that can provide auxiliary emergency braking operations for turbine braking operations, so as to achieve the purpose of improving the safety and reliability of steam turbine equipment operation.

[0004] CN207920675U discloses a novel auxiliary forced shutdown device for steam turbines, which specifically includes: when the steam turbine needs to perform braking operation, the control circuit drives the brake drive mechanism to operate, so as to make the brake shoe contact with the friction disk, and achieve the purpose of braking operation on the steam turbine through friction force. When performing braking operation, the temperature of the brake shoe and the pressure between the brake shoe and the friction disk are detected by the pressure sensor and the temperature sensor, and the detected temperature and pressure parameters are used as the braking force control parameters, and then the control system adjusts the braking force output by the brake drive mechanism, and adjusts the distance between the brake shoe and the friction disk, so as to achieve the purpose of adjusting the braking force. However, the auxiliary forced shutdown device enhances the braking effect by increasing the friction force, and cannot avoid the problem of the bearing shell burning due to the increase of temperature, and it is difficult to start the auxiliary forced shutdown device by itself, and the circuit failure is easy to occur in an emergency.

[0005] It can be seen from this that the existing auxiliary braking system is still difficult to solve the problem of excessive bearing temperature damage caused by turbine idling. In actual production processes, when the turbine vibration becomes more and more severe, the lubricating oil tank catches fire and needs to be extinguished, the turbine axial displacement hits the membrane, or the lubricating oil supply is abnormal, the turbine needs to be shut down in time to avoid the accident from expanding and the bearing and other components being damaged due to excessive temperature.

[0006] Therefore, there is an urgent need to develop a steam turbine auxiliary braking device and method. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a steam turbine auxiliary braking device and an auxiliary braking method. The steam turbine auxiliary braking device and the auxiliary braking method can be widely used in various situations such as the increasingly large vibration of the steam turbine, the fire in the lubricating oil tank that needs to be extinguished, the axial displacement of the steam turbine hitting the membrane, or the abnormal lubricating oil supply. They can achieve emergency braking and avoid further expansion of accidents, and have broad application prospects.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a steam turbine auxiliary braking device, the steam turbine auxiliary braking device comprising:

[0010] A rotor magnetic part arranged at one end of a rotor in a steam turbine; the NS pole pointing line of the rotor magnetic part is perpendicular to the axial center line of the rotor;

[0011] A motor coil is arranged outside the rotor magnetic part and has a gap between the motor coil and the rotor magnetic part; the motor coil is arranged coaxially with the rotor magnetic part;

[0012] An electric conversion device disposed in a closed circuit formed by the motor coil;

[0013] A hydraulic cylinder system connected to the motor coil; a movable part of the hydraulic cylinder system is connected to the motor coil, the movable part of the hydraulic cylinder system is connected to an elastic part arranged away from the steam turbine, and one end of the hydraulic cylinder system is connected to the original oil supply pipeline.

[0014] The steam turbine auxiliary braking device provided by the present invention can not only transfer the energy generated by the rotor idling during braking to avoid damage to the steam turbine components due to overheating by arranging a motor coil, a rotor magnetic part and an electric conversion device, but also can react to the steam turbine to increase the braking effect and achieve a rapid braking effect. In the event of an emergency, the steam turbine can be braked urgently to avoid further expansion of the accident.

[0015] The motor coil of the present invention can cooperate with the rotor magnetic part to form a motor working circuit, output current, and transmit it to the electric conversion device for energy conversion.

[0016] The movable parts of the hydraulic cylinder system are connected to the motor coil, so that the energy generated by the rotor idling during the braking of the steam turbine can be utilized. When braking is required, the original oil supply pipeline of the steam turbine is first disconnected, and the oil supply pressure is fed back to the hydraulic cylinder through a simple mechanical structure. When the oil supply pressure is lost in the hydraulic cylinder, the elastic part can restore its natural length, so that the movable parts can be pushed to move close to the magnetic part of the rotor, and then the motor coil is driven to move close to the magnetic part of the rotor to convert kinetic energy into electrical energy, and the electrical energy is transferred through the electrical conversion device. Since the energy of the rotor can be transferred in time, the braking time is greatly reduced, and since the energy is transferred in time instead of increasing friction, the problem of reduced life caused by the increase in temperature of components such as bearings is also avoided.

[0017] The present invention has no special limitation on the structure of the rotor magnetic part, and any magnetic rotor conventionally used by those skilled in the art may be used.

[0018] Preferably, the rotor magnetic portion is located at an end of the steam turbine away from the generator.

[0019] Preferably, a permanent magnet is disposed inside the rotor magnetic part.

[0020] Preferably, the length of the rotor is greater than that of the original steam turbine rotor, and the length of the rotor is longer than that of the original steam turbine rotor by the distance of the rotor magnetic part. Preferably, the above design avoids affecting the original steam turbine.

[0021] Preferably, the elastic member can realize the positioning of the motor coil reliably and accurately.

[0022] Preferably, the electrical conversion means comprises a resistive heating element.

[0023] Preferably, the resistance heating component comprises a resistor. Preferably, the resistor has a characteristic that the resistance value increases with the increase of temperature, such as a thermistor, and the material is preferably a metal material, such as tungsten, copper, etc.

[0024] Preferably, the resistance heating component is arranged in the water tank.

[0025] Preferably, the effective water storage capacity of the water tank can consume at least 1.2 times the mechanical energy of the rotor rotation.

[0026] Preferably, the water tank is grounded. Further preferably, the generated voltage is harmful to the human body.

[0027] Preferably, the turbine auxiliary braking device also includes a liquid level gauge, a thermometer, a water conveying device, etc. arranged in the water tank.

[0028] Preferably, the steam turbine auxiliary braking device further comprises a start-stop component;

[0029] Preferably, the start-stop component includes a flow control component provided on the original oil supply pipeline.

[0030] The start and stop components of the turbine auxiliary braking device described in the present invention are directly controlled by a mechanical flow control component. When the flow control component is closed and the original oil supply pipeline is disconnected, the pressure in the hydraulic cylinder system is lost, so that the elastic part recovers its natural length. When the flow control component is opened, there is oil pressure in the hydraulic cylinder system, the elastic part is compressed, the motor coil is away from the rotor magnetic part, and no current potential is generated.

[0031] The present invention has no special restrictions on the flow control component, and any flow control component known to those skilled in the art that can be used to control flow can be used. The flow control component preferably retains a mechanical switch, and further preferably is connected to an electrical circuit while retaining the mechanical switch to achieve electrical control.

[0032] Preferably, the turbine auxiliary braking device further comprises a limiting component, and the motor coil is provided with a position switch in the deactivated position and the working position respectively.

[0033] The present invention preferably provides a position switch at the coil deactivation position and the working position respectively, so as to display the mechanical position of the coil on the display component.

[0034] Preferably, the turbine auxiliary braking device also includes a display component connected to the position switch by a signal.

[0035] Preferably, the display component comprises a DCS display.

[0036] Preferably, the natural length of the elastic member is 1.1 to 1.2 times the distance between the inactive position and the working position of the motor coil, for example, it can be 1.1 times, 1.11 times, 1.12 times, 1.13 times, 1.14 times, 1.15 times, 1.16 times, 1.17 times, 1.18 times or 1.2 times, etc.

[0037] The present invention preferably controls the natural length of the elastic member within the above range, which is beneficial for accurately controlling the motor coil in the inactive position and the working position.

[0038] Preferably, the elastic coefficient of the elastic member is the ratio of the distance between the inactive position and the working position to the oil supply pressure of the original oil supply pipeline.

[0039] Preferably, the motor coil forms a closed circuit via a cable.

[0040] Preferably, a voltage transformer is connected to the motor coil.

[0041] Preferably, the motor coil and the hydraulic cylinder are arranged in parallel up and down.

[0042] Preferably, the hydraulic cylinder is fixed on the steam turbine via a bracket.

[0043] In a second aspect, the present invention provides a steam turbine auxiliary braking method, which is performed using the steam turbine auxiliary braking device described in the first aspect.

[0044] The steam turbine auxiliary braking method provided by the present invention is carried out by adopting the steam turbine auxiliary braking device described in the first aspect. It can be used for protecting steam turbine components during normal steam turbine braking, and is particularly suitable for emergency situations such as when the vibration of the steam turbine becomes increasingly larger, the lubricating oil tank catches fire and needs to be extinguished, the axial displacement of the steam turbine hits the membrane, or the lubricating oil supply is abnormal. It can quickly brake and reduce the risk of accidents.

[0045] Preferably, when the steam turbine needs to be braked, the original oil supply pipeline is closed, the oil supply pressure in the hydraulic cylinder system gradually decreases, the elastic part gradually pushes the movable part toward the magnetic part of the rotor, and drives the motor coil toward the magnetic part of the rotor, and transfers from the inactive position to the working position; the motor coil generates current under the rotation of the rotor, and the current realizes energy conversion through the electric conversion device, so as to brake the steam turbine quickly and smoothly.

[0046] It can be seen from the above steps that the turbine auxiliary braking method provided by the present invention only needs to control the flow control component of the lubricating oil to achieve automatic protection and auxiliary braking of the turbine when the turbine needs to be braked, and can start the turbine auxiliary braking device for auxiliary braking in the form of a mechanical structure, avoiding the situation where the electric starting equipment line fails, and the system does not require external input of kinetic energy or power supply, and is a passive system with high reliability.

[0047] Preferably, the electric current is passed through the resistance heating element to convert the electrical energy into thermal energy, preferably into the thermal energy of water vapor.

[0048] The present invention does not impose any special limitation on the use of the heat energy generated by the water vapor, which can be supplied externally or used by the system.

[0049] Preferably, when the steam turbine is started, the motor coil is manually moved from the working position to the deactivated position.

[0050] Preferably, when the steam turbine operates normally, the voltage transformer detects that the motor coil voltage is 0.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] (1) The steam turbine auxiliary brake device provided by the present invention is relatively simple, the system is independent, and basically maintenance-free. For daily operation, it only needs to monitor the coil voltage and the water level of the water tank;

[0053] (2) The turbine auxiliary brake device provided by the present invention can shorten the idling time from 40 to 90 minutes to 20 to 30 seconds when braking the turbine. The friction heat generated between the bearing and the journal is limited, and the temperature rise is limited, which prevents the bearing burning accident. At the same time, it avoids the phenomenon of dynamic and static friction caused by the change of the dynamic and static clearance of the unit after the bearing is burned. It can avoid the dynamic and static friction, large vibration, component shedding and large shaft bending caused by the burning of the bearing, and greatly reduce the probability of the accident expansion;

[0054] (3) The steam turbine auxiliary braking method provided by the present invention can be widely applied to various situations where the vibration of the steam turbine becomes increasingly larger, the lubricating oil tank catches fire and needs to be extinguished, the axial displacement of the steam turbine hits the membrane, or the lubricating oil supply is abnormal. It can realize emergency braking, and the temperature of the steam turbine components during the braking process is ≤95°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic diagram of the steam turbine auxiliary braking device provided in Example 1 of the present invention.

[0056] In the figure: 1. rotor magnetic part; 2. motor coil; 3. resistor; 4. hydraulic cylinder system; 41. movable part; 42. elastic part; 43. bracket; 5. water tank; 61. off position switch; 62. working position switch; 101. original oil supply pipeline; 102. steam turbine; 103. generator. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0058] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0059] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0060] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0061] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0062] Example 1

[0063] This embodiment provides a steam turbine auxiliary braking device, such as Figure 1 As shown, the steam turbine auxiliary braking device comprises:

[0064] A rotor magnetic part 1 is arranged at an end of the rotor of the steam turbine 102 away from the generator 103; the NS pole pointing line of the rotor magnetic part 1 is perpendicular to the axial center line of the rotor;

[0065] A motor coil 2 is arranged outside the rotor magnetic part 1 and has a gap between the motor coil 2 and the rotor magnetic part 1; the motor coil 2 is arranged coaxially with the rotor magnetic part 1;

[0066] An electric conversion device arranged in the closed circuit formed by the motor coil 2;

[0067] A hydraulic cylinder system 4 connected to the motor coil 2; a movable part 41 of the hydraulic cylinder system 4 is connected to the motor coil 2, and the movable part 41 of the hydraulic cylinder system 4 is connected to an elastic part 42 disposed away from the steam turbine 102, and one end of the hydraulic cylinder system 4 is connected to the original oil supply pipeline. The motor coil 2 can cooperate with the rotor magnetic part 1 to form a motor working circuit, output current, and transmit it to the electric conversion device for energy conversion.

[0068] The movable part 41 of the hydraulic cylinder system 4 is connected to the motor coil 2, so that the energy generated by the rotor idling when the steam turbine 102 is braked can be utilized. When braking is required, the original oil supply pipeline of the steam turbine 102 is first disconnected, and the oil supply pressure is fed back to the hydraulic cylinder through a simple mechanical structure. When the oil supply pressure is lost in the hydraulic cylinder, the elastic part 42 can restore its natural length, so that the movable part 41 can be pushed to move close to the rotor magnetic part 1, and then the motor coil 2 is driven to move close to the rotor magnetic part 1 to convert kinetic energy into electrical energy, and the electrical energy is transferred through the electrical conversion device. There is no special limitation on the structure of the rotor magnetic part 1, and a magnetic rotor conventionally used by technicians in this field can be used.

[0069] The rotor magnetic part 1 is located at one end of the steam turbine 102 away from the generator 103. A permanent magnet is arranged inside the rotor magnetic part 1. The length of the rotor is greater than the length of the original steam turbine 102 rotor, and the length of the rotor is longer than the length of the original steam turbine 102 rotor by the distance of the rotor magnetic part 1.

[0070] The elastic member 42 can reliably and accurately realize the positioning of the motor coil 2. The electric conversion device includes a resistor 3 heating component. The resistor 3 heating component includes a resistor 3.

[0071] The resistor 3 heating component is arranged in a water tank 5. The effective water storage capacity of the water tank 5 can consume at least 1.2 times the mechanical energy of the rotor rotation. The water tank 5 is grounded. The turbine auxiliary braking device also includes a liquid level meter, a thermometer and a water conveying device arranged in the water tank 5.

[0072] The steam turbine auxiliary brake device also includes a start-stop component; the start-stop component includes a flow control component arranged on the original oil supply pipeline. The flow control component is preferably a mechanical switch.

[0073] The turbine auxiliary brake device also includes a limit component. The motor coil 2 is provided with position switches at the deactivated position and the working position, namely, a deactivated position switch 61 and a working position switch 62, which can display the mechanical position of the coil on the display component.

[0074] The steam turbine auxiliary brake device also includes a display component connected to the position switch by a signal. The display component includes a DCS display.

[0075] The natural length of the elastic member 42 is 1.0 times the distance between the inactive position and the working position of the motor coil 2. The elastic coefficient of the elastic member 42 is the ratio of the distance between the inactive position and the working position to the oil supply pressure of the original oil supply pipeline 101.

[0076] The motor coil 2 forms a closed circuit through a cable. The motor coil 2 is connected to a voltage transformer. The motor coil 2 is arranged in parallel with the hydraulic cylinder. The hydraulic cylinder is fixed on the steam turbine 102 through a bracket 43.

[0077] In this embodiment, the elastic member 42 is preferably a spring, and the movable member 41 is preferably a piston or a movable rod.

[0078] This embodiment also provides a method for performing steam turbine auxiliary braking using the above steam turbine auxiliary braking device, the method comprising:

[0079] When the steam turbine 102 needs to be braked, the original oil supply pipeline is closed, the oil supply pressure in the hydraulic cylinder system 4 is gradually reduced, the elastic member 42 gradually pushes the movable member 41 to approach the rotor magnetic part 1, and drives the motor coil 2 to approach the rotor magnetic part 1, and moves from the inactive position to the working position; the motor coil 2 generates current under the rotation of the rotor, and the current converts electrical energy into thermal energy through the resistor 3 heating component, so as to brake the steam turbine 102 quickly and smoothly. When the steam turbine 102 is started, the motor coil 2 is manually moved from the working position to the inactive position, and the voltage transformer detects that the voltage of the motor coil 2 is 0 when monitoring and ensuring the normal operation of the steam turbine 102.

[0080] In this embodiment, when various situations occur, such as the vibration of the steam turbine becomes increasingly severe, the lubricating oil tank catches fire and needs to be extinguished, the axial displacement of the steam turbine hits the membrane, or the lubricating oil supply is abnormal, the original oil supply pipeline is cut off, the energy idling during the braking process of the steam turbine is transferred in time, and the generator is reversed and decoupled, thereby shortening the braking time. The rotor idling time is shortened to 20-30s, and the maximum temperature of the bearing during the idling process can be reduced to below 95°C.

[0081] Example 2

[0082] The present invention provides a steam turbine auxiliary braking device, which is different from Example 1 in that a control circuit is added on the basis of Example 1, a flow control component adopts an electromagnetic valve, the power supply is taken to the safety section, and when the power is lost, the coil is pushed to the working position, the oil circuit is controlled to be on and off, and then the position of the motor coil is controlled, and logical judgment and manual operation functions are added.

[0083] This embodiment also provides a method for performing steam turbine auxiliary braking using the above steam turbine auxiliary braking device, the method comprising:

[0084] When the steam turbine needs to be braked, the original oil supply pipeline is closed by using the logic judgment and manual operation function, the oil supply pressure in the hydraulic cylinder system gradually decreases, the elastic part gradually pushes the movable part closer to the magnetic part of the rotor, and drives the motor coil closer to the magnetic part of the rotor, and moves from the inactive position to the working position; the motor coil generates current under the rotation of the rotor, and the current converts electrical energy into thermal energy through the resistance heating component to brake the steam turbine quickly and smoothly. When the steam turbine is started, the motor coil is manually moved from the working position to the inactive position, and the voltage transformer detects that the voltage of the motor coil is 0 when monitoring and ensuring the normal operation of the steam turbine.

[0085] In this embodiment, when the vibration of the steam turbine is large and the vibration is still beyond the limit after shutdown, the control instruction can be triggered to move the coil to the working position and stop the shaft system as soon as possible, thereby reducing the degree of dynamic and static friction and collision. When the bearing temperature continues to rise and the axial displacement continues to increase after the steam turbine overspeeds or the unit trips, rapid braking can be considered through this set of devices to reduce the degree of equipment damage.

[0086] This embodiment combines the advantages of circuit control and manual mechanical control, and can better realize daily monitoring and rapid braking when the device fails. It can transfer the energy of idling during the braking process of the steam turbine in time and perform reverse power decoupling of the generator, thereby shortening the braking time. The rotor idling time is shortened to 20-30s, and the maximum temperature of the bearing during idling can be reduced to below 95°C.

[0087] To sum up, the turbine auxiliary braking device and turbine auxiliary braking method provided by the present invention can be applied to steam turbines in thermal power plants and nuclear power plants, and are also suitable for gas turbines in gas power plants. They can effectively make up for the lack of braking assistance in existing steam turbines and have a wide range of uses.

[0088] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A steam turbine auxiliary braking method, characterized in that: The steam turbine auxiliary braking method is performed by using the following device, which comprises: A rotor magnetic part arranged at one end of a rotor in a steam turbine; the NS pole pointing line of the rotor magnetic part is perpendicular to the axial center line of the rotor; A motor coil is arranged outside the rotor magnetic part and has a gap between the motor coil and the rotor magnetic part; the motor coil is arranged coaxially with the rotor magnetic part; An electric conversion device disposed in a closed circuit formed by the motor coil; A hydraulic cylinder system connected to the motor coil; a movable part of the hydraulic cylinder system is connected to the motor coil, the movable part of the hydraulic cylinder system is connected to an elastic part arranged away from the steam turbine, and one end of the hydraulic cylinder system is connected to the original oil supply pipeline; The steam turbine auxiliary brake device also includes a start-stop component; the start-stop component includes a flow control component for controlling the lubricating oil provided on the original oil supply pipeline; The steam turbine auxiliary braking method comprises: When the steam turbine needs to be braked, the original oil supply pipeline is closed, the oil supply pressure in the hydraulic cylinder system gradually decreases, the elastic part gradually pushes the movable part closer to the magnetic part of the rotor, and drives the motor coil closer to the magnetic part of the rotor, and transfers from the inactive position to the working position; the motor coil generates current under the rotation of the rotor, and the current realizes energy conversion through the electric conversion device, so as to brake the steam turbine quickly and smoothly.

2. The steam turbine auxiliary braking method according to claim 1, characterized in that: The device also includes the following: The electric conversion device comprises a resistance heating component; preferably, the resistance heating component is arranged in the water tank; The flow control component is a mechanical switch; The steam turbine auxiliary brake device also includes a limit component, and the motor coil is provided with a position switch at the deactivation position and the working position respectively; The natural length of the elastic member is 1.1 to 1.2 times the distance between the inactive position and the working position of the motor coil; The elastic coefficient of the elastic member is the ratio of the distance between the inactive position and the working position to the oil supply pressure of the original oil supply pipeline; The motor coil forms a closed circuit through the cable; The motor coil is connected with a voltage transformer.

3. The steam turbine auxiliary braking method according to claim 1, characterized in that: The current passes through the resistive heating element to convert electrical energy into thermal energy.

4. The steam turbine auxiliary braking method according to claim 3, characterized in that: The current passes through the resistive heating element to convert electrical energy into thermal energy of water vapor.

5. The steam turbine auxiliary braking method according to claim 1, characterized in that: When the steam turbine is started, the motor coil is manually moved from the working position to the deactivated position.

6. The steam turbine auxiliary braking method according to claim 1, characterized in that: When the steam turbine operates normally, the voltage transformer detects that the motor coil voltage is 0.

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