Small steam turbine barring gear capable of preventing reverse rotation and control method of small steam turbine barring gear

Abstract

The invention provides a small steam turbine turning gear capable of preventing reverse rotation and a control method of the small steam turbine turning gear, relates to the technical field of small steam turbine turning gear devices, and realizes accurate control of the running state of the turning gear through signal acquisition, formation of a signal loop, driving of an intermediate relay and dynamic monitoring of a DCS (Distributed Control System) upper computer. The core logic lies in that through serial connection of signals and judgment of a loop, reliability and safety of the barring driving device in a normal operation state are guaranteed, meanwhile, shutdown measures are taken rapidly under abnormal conditions, and equipment damage is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of small steam turbine cranking devices, and in particular to a small steam turbine cranking device that prevents reverse rotation and a control method thereof. Background Art

[0002] Small steam turbines are widely used in thermal power plants and are one of the key equipment in thermal power generating units. During the shutdown of the generating unit, due to the uneven cooling inside the unit, especially the cooling difference between the upper and lower parts of the cylinder and the rotor, the rotor will bend after it stops rotating. In order to avoid this thermal bending and prevent the rotor from rubbing against the static parts during restart, which will cause vibration beyond the allowable range, a turning device is needed to prevent the rotor from bending. The function of the turning device is to keep the rotor rotating during the shutdown of the generating unit, maintain uniform cooling of the rotor, and effectively prevent the rotor from bending.

[0003] Take the WK63 / 71 small steam turbine as an example. The turbine is equipped with a turning device, and a switch for detecting 2JK is installed at the connection between its reducer and the turning machine. However, the control system has the following main problems: 1. Signal independence problem: In the existing control mode, the cranking signal and the inverter operation signal are completely independent. When the motor reverses, the 2JK cannot detect the engagement signal, resulting in no cranking signal feedback to the DCS host computer. At this time, the DCS system cannot issue a shutdown command. If the machine is not shut down in time, the machine will be damaged or the turbine rotor will be bent.

[0004] 2. Monitoring and operation issues: Since the cranking signal and the inverter operation signal are independent of each other, the monitoring operation interface is cumbersome, and operators are prone to ignore or misjudge. When the DCS host computer does not receive the cranking signal, the monitoring operator cannot promptly detect equipment abnormalities or signal loss, and thus fails to take shutdown operations in time, resulting in serious equipment damage and accidents. Summary of the invention

[0005] The main purpose of the present invention is to provide a small steam turbine turning gear that can prevent reverse rotation and effectively solve the problems in the background technology.

[0006] A conveying mechanism is provided above the steam turbine, a feed pipe is provided on one side of the conveying mechanism, a turning gear connecting device is provided on one side of the steam turbine, a turning gear driving device is provided on one side of the turning gear connecting device, the turning gear driving device is electrically connected to a turning gear control cabinet, a connecting wire is provided at one end of the turning gear control cabinet, and one end of the connecting wire is connected to a motor terminal box; A reducer is provided below the turning gear driving device, a driving shaft is provided on the top of the reducer, a ball screw is provided at one end of the driving shaft, and one end of the ball screw is connected to the rotor.

[0007] Furthermore, the turning gear connecting device is connected to the turning gear driving device via a flange, and the flange is provided with a plurality of evenly distributed bolt holes, and the diameter of the bolt holes is 12 mm.

[0008] Furthermore, a universal coupling is provided on the top of the reducer of the turning gear driving device, and the universal coupling is connected to the driving shaft.

[0009] Furthermore, the motor of the turning gear driving device is a three-phase asynchronous motor with a power of 75kW and a voltage level of 380V. The motor is coaxially connected to the reducer through a mounting flange.

[0010] A small steam turbine turning gear to prevent reverse rotation and a control method thereof, the specific steps are as follows: Step S1: Collect 2JK and inverter operation signals, 2JK and the inverter operation signal are connected in series to form a signal loop, and drive the intermediate relay KA5; Step S2: The intermediate relay KA5 feeds back the cranking operation signal to the DCS host computer; Step S3: DCS determines the turning gear operation status according to the KA5 feedback signal; Step S4: When the signal loop is disconnected, KA5 disconnects the cranking operation signal, and the DCS host computer issues a stop command to stop the operation of the cranking drive device; Step S5: When the signal loop is closed normally, KA5 maintains continuous feedback of the cranking operation signal.

[0011] Furthermore, in step S1: The 2JK is collected by a limit switch installed on the turning gear connection device, and the limit switch is fixedly connected to the small steam turbine rotor through a flange; The cranking signal collected by 2JK is fed back to the cranking control cabinet and connected in series with the inverter operation signal to form a signal loop in the control cabinet to drive the intermediate relay KA5.

[0012] Furthermore, in step S2: The KA5 is used to feed back the cranking operation signal to the DCS host computer through the cranking control cabinet; The KA5 is connected to the signal processing module in the turning gear control cabinet through electrical contacts, and the signal processing module has a redundant design; The turning gear control cabinet is connected to the DCS host computer through a dedicated communication port.

[0013] Furthermore, in step S3: The DCS host computer determines the turning gear operation status according to the feedback signal from KA5; During the judgment process, the DCS host computer collects the current sensor data on the turning gear drive device in real time to assist in judging whether the turning gear drive device is working properly.

[0014] Furthermore, in step S4: When the signal circuit is disconnected, KA5 disconnects the turning operation signal; The DCS host computer does not receive the cranking operation signal within 2 seconds, and issues an emergency stop command to stop the operation of the cranking drive device.

[0015] Further, in step S5: When the signal circuit is closed normally, the KA5 intermediate relay keeps the cranking operation signal feedback; The DCS host computer regularly collects feedback signals from the turning control cabinet and checks the signal delay and signal strength; The turning gear control cabinet is provided with a fault indicator light inside, which provides an alarm prompt when the signal is abnormal.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The present invention forms a signal loop by connecting 2JK in series with the inverter operation signal. When both signals meet the predetermined logical conditions, the intermediate relay KA5 is driven, and the cranking operation signal is fed back to the DCS host computer. When the signal loop does not meet the conditions, the DCS host computer can automatically issue a shutdown command, thereby stopping the operation of the cranking drive device in time. This control scheme effectively solves the shutdown delay problem caused by the complicated monitoring operation interface or the operator's failure to find the signal abnormality in time in the prior art, and avoids equipment damage and safety accidents caused by improper operation.

[0017] 2. The present invention optimizes the control logic of the signal loop and feedback mechanism to enhance the reliability and stability of the system. Compared with the prior art, the system has the advantages of simple structure, low failure rate, and fast response, which can improve the operational stability of the equipment and effectively overcome the signal independence and operational error risks existing in the traditional control method, ensuring the safety and stability of the equipment during downtime. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of the overall process of a small steam turbine turning gear and control method thereof to prevent reverse rotation of the present invention; Figure 2 It is a schematic diagram of the overall structure of a small steam turbine turning gear for preventing reverse rotation according to the present invention; Figure 3 It is a side view of the structure of a small steam turbine turning gear driving device for preventing reverse rotation according to the present invention; Figure 4This is an enlarged detail view of part A of a small steam turbine turning gear for preventing reverse rotation according to the present invention; Figure 5 The present invention discloses an electrical control circuit diagram of a small steam turbine turning gear to prevent reverse rotation and a control method thereof.

[0019] In the figure: 1. Steam turbine; 2. Conveying mechanism; 3. Feed pipe; 4. Turning gear connection device; 5. Turning gear drive device; 51. Reducer; 52. Drive shaft; 53. Ball screw; 54. Rotor; 6. Turning gear control cabinet; 7. Motor junction box; 8. Connecting wires. DETAILED DESCRIPTION

[0020] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and is not a limitation of the scope of protection, applicability or examples set forth in the claims. The functions and arrangements of the elements discussed can be changed without departing from the scope of protection of the contents of this specification. Various examples can omit, replace or add various processes or components as needed. For example, the described method can be performed in an order different from the described order, and various steps can be added, omitted or combined. In addition, the features described relative to some examples can also be combined in other examples.

[0021] As used herein, the term includes and variations thereof represent open terms, meaning including but not limited to. The term based on means based at least in part on. The terms one embodiment and an embodiment represent at least one embodiment. The term another embodiment represents at least one other embodiment. The terms first, second, etc. may refer to different or the same objects. Other definitions may be included below, whether explicit or implicit. Unless the context clearly indicates otherwise, the definition of a term is consistent throughout the specification.

[0022] Example See also Figure 1-5 , an embodiment provided by the present invention: a small steam turbine turning gear for preventing reverse rotation.

[0023] A conveying mechanism 2 is provided above the steam turbine 1, a feed pipe 3 is provided on one side of the conveying mechanism 2, a turning gear connecting device 4 is provided on one side of the steam turbine 1, a turning gear driving device 5 is provided on one side of the turning gear connecting device 4, the turning gear driving device 5 is electrically connected to a turning gear control cabinet 6, a connecting wire 8 is provided at one end of the turning gear control cabinet 6, and one end of the connecting wire 8 is connected to a motor terminal box 7; A reducer 51 is disposed below the turning gear driving device 5 , a driving shaft 52 is disposed on the top of the reducer 51 , a ball screw 53 is disposed at one end of the driving shaft 52 , and one end of the ball screw 53 is connected to a rotor 54 .

[0024] Furthermore, the turning gear connecting device 4 is connected to the turning gear driving device 5 via a flange, and the flange is provided with a plurality of evenly distributed bolt holes, and the diameter of the bolt holes is 12 mm.

[0025] Furthermore, a universal coupling is provided on the top of the reducer 51 of the turning gear driving device 5 , and the universal coupling is connected to the driving shaft 52 .

[0026] Furthermore, the motor of the turning gear driving device 5 is a three-phase asynchronous motor with a power of 75 kW and a voltage level of 380 V. The motor is coaxially connected to the reducer 51 through a mounting flange.

[0027] A small steam turbine turning gear to prevent reverse rotation and a control method thereof, the specific steps are as follows: Step S1: Collect 2JK and inverter operation signals, 2JK and the inverter operation signal are connected in series to form a signal loop, and drive the intermediate relay KA5; Step S2: The intermediate relay KA5 feeds back the cranking operation signal to the DCS host computer; Step S3: DCS determines the turning gear operation status according to the KA5 feedback signal; Step S4: When the signal loop is disconnected, KA5 disconnects the cranking operation signal, and the DCS host computer issues a stop command to stop the operation of the cranking drive device; Step S5: When the signal loop is closed normally, KA5 maintains continuous feedback of the cranking operation signal.

[0028] Furthermore, in step S1: The 2JK is collected by a limit switch installed on the turning gear connection device 4, and the limit switch is fixedly connected to the rotor 54 of the small steam turbine 1 through a flange; The cranking signal collected by 2JK is fed back to the cranking control cabinet and connected in series with the inverter operation signal to form a signal loop in the control cabinet to drive the intermediate relay KA5.

[0029] Furthermore, in step S2: The KA5 is used to feed back the cranking operation signal to the DCS host computer through the cranking control cabinet 6; The KA5 is connected to the signal processing module in the turning gear control cabinet 6 through electrical contacts, and the signal processing module has a redundant design; The turning gear control cabinet 6 is connected to the DCS host computer through a dedicated communication port.

[0030] Furthermore, in step S3: The DCS host computer determines the turning gear operation status according to the feedback signal from KA5; During the judgment process, the DCS host computer collects the current sensor data on the turning gear drive device 5 in real time to assist in judging that the turning gear drive device 5 is working normally.

[0031] Furthermore, in step S4: When the signal circuit is disconnected, KA5 disconnects the turning operation signal; The DCS host computer does not receive the cranking operation signal within 2 seconds, and issues an emergency stop command to stop the operation of the cranking drive device 5.

[0032] Further, in step S5: When the signal circuit is closed normally, the KA5 intermediate relay keeps the cranking operation signal feedback; The DCS host computer regularly collects the internal feedback signal of the turning control cabinet 6 and checks the signal delay and signal strength; The turning gear control cabinet 6 is provided with a fault indicator light inside, and provides an alarm prompt when the signal is abnormal. The small steam turbine is responsible for generating power by driving the generator through steam.

[0033] The operation of the steam turbine requires the turning operation to be performed when the equipment is shut down to ensure uniform cooling of the rotor and prevent thermal bending. The turning connection device is used to connect the small steam turbine to the turning drive device. During the shutdown process, the turning connection device is connected to the rotor through a series of mechanical structures to ensure the rotation of the rotor. The installation position of the turning connection device needs to ensure the accurate meshing position with the reducer. The turning drive device is used to provide power, drive the reducer to rotate through the motor, and then drive the rotor to rotate slowly. The motor of the turning drive device is a three-phase asynchronous motor with a power of 2.2kW and a voltage level of 380V, and is coaxially connected to the reducer through a mounting flange. The reducer is located below the turning drive device and is responsible for converting the high-speed rotation generated by the motor into a low-speed and high-torque output. The drive shaft is connected to the universal coupling of the reducer to transmit power to the ball screw, thereby driving the rotor to rotate. The ball screw transmits power through the drive shaft to drive the rotor to turn. The rotor is connected to the small steam turbine rotor through a mechanical connection during the turning process to keep the rotor rotating slowly and ensure its uniform cooling. The turning gear control cabinet is used to receive control signals and feed back turning gear operation signals to the DCS host computer through the intermediate relay KA5. The intermediate relay is connected to the signal processing module through electrical contacts, and the signal processing module is designed with a redundancy mechanism. The motor junction box is used to receive external power and is electrically connected to the turning gear control cabinet through connecting wires. The connecting wires are shielded copper wires to ensure signal stability and anti-interference capabilities.

[0034] The 2JK signal is collected by the limit switch on the turning gear connection device, and the limit switch is fixedly connected to the rotor of the small steam turbine through a flange. When the rotor rotates to the predetermined position, the limit switch is triggered and a 2JK signal is generated, indicating that the turning gear has reached the specified position or state. In the control cabinet, the 2JK signal is logically connected in series with the inverter operation signal to form a complete signal loop. Specifically, the 2JK signal and the inverter operation signal are electrically connected in parallel or in series to ensure that the signal loop is closed only when both meet the predetermined logical conditions.

[0035] The signal circuit controls the cranking operation status through the intermediate relay KA5. When the 2JK signal and the inverter operation signal both meet the logical conditions, the signal circuit is closed, driving the KA5 relay on and off. The on-off state of the KA5 relay directly affects whether the cranking operation signal is fed back or not. When the 2JK signal and the inverter operation signal both meet the conditions, the signal circuit is closed, the KA5 relay is driven on and off, and the cranking operation signal is fed back to the DCS host computer. Signal circuit disconnection: If any signal does not meet the conditions, the signal circuit is disconnected, the KA5 relay is disconnected, and the cranking operation signal stops being fed back.

[0036] The KA5 relay feeds back the cranking operation signal to the DCS host computer through the cranking control cabinet. The cranking control cabinet is equipped with a signal processing module, which is connected to the KA5 relay through electrical contacts and adopts a redundant design to ensure reliable signal transmission. The cranking control cabinet is also connected to the DCS host computer through a dedicated communication port. When the DCS host computer receives the cranking operation signal fed back by KA5, it determines that the cranking drive device is operating normally. At this time, the DCS host computer will also collect the current sensor data on the cranking drive device in real time to further verify the normal working status of the cranking drive device. When the signal loop is disconnected, the KA5 relay disconnects the cranking operation signal. When the DCS host computer does not receive the cranking operation signal within 2 seconds, it immediately issues an emergency stop command to stop the operation of the cranking drive device. When the signal loop is closed normally, the DCS host computer regularly collects the feedback signal inside the cranking control cabinet, checks the signal delay and signal strength, and ensures the stability and reliability of the signal. There is also a fault indicator light inside the cranking control cabinet. When the signal is abnormal, an alarm prompt is provided to further improve the safety of the system.

[0037] Those skilled in the art should understand that the various embodiments disclosed above can be changed and modified in various ways without departing from the essence of the invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

[0038] It should be noted that not all steps and units in the above processes are necessary, and some steps or units can be ignored according to actual needs. The execution order of each step is not fixed and can be determined as needed. The device structure described in the above embodiments can be a physical structure or a logical structure, that is, some units may be implemented by the same physical entity, or some units may be implemented by multiple physical entities, or some components in multiple independent devices may be implemented together.

[0039] The specific embodiments set forth above describe exemplary embodiments, but do not represent all embodiments that can be implemented or fall within the scope of protection of the claims. The term exemplary used throughout this specification means to be used as an example, instance or illustration, and does not mean to be preferred or advantageous over other embodiments. For the purpose of providing an understanding of the described technology, the specific embodiments include specific details. However, these technologies can be implemented without these specific details. In some instances, in order to avoid making the concepts of the described embodiments difficult to understand, known structures and devices are shown in block diagram form.

[0040] The above description of the present disclosure is provided to enable any person of ordinary skill in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of protection of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is consistent with the widest range of principles and novel features disclosed herein.

Claims

1. A small steam turbine turning gear for preventing reverse rotation, comprising a steam turbine (1), a turning gear driving device (5), and a turning gear control cabinet (6), wherein: A conveying mechanism (2) is provided above the steam turbine (1), a feed pipe (3) is provided on one side of the conveying mechanism (2), a turning gear connecting device (4) is provided on one side of the steam turbine (1), a turning gear driving device (5) is provided on one side of the turning gear connecting device (4), the turning gear driving device (5) is electrically connected to a turning gear control cabinet (6), a connecting wire (8) is provided at one end of the turning gear control cabinet (6), and one end of the connecting wire (8) is connected to a motor terminal box (7); A reducer (51) is provided below the turning gear drive device (5), a drive shaft (52) is provided on the top of the reducer (51), a ball screw (53) is provided at one end of the drive shaft (52), and one end of the ball screw (53) is connected to a rotor (54).

2. A small steam turbine turning gear to prevent reverse rotation according to claim 1, characterized in that: The turning gear connecting device (4) and the turning gear driving device (5) are connected via a flange plate, and the flange plate is provided with a plurality of evenly distributed bolt holes, and the diameter of the bolt holes is 12 mm.

3. A small steam turbine turning gear to prevent reverse rotation according to claim 1, characterized in that: A universal coupling is provided on the top of the reducer (51) of the turning gear drive device (5), and the universal coupling is connected to the drive shaft (52).

4. A small steam turbine turning gear to prevent reverse rotation according to claim 1, characterized in that: The motor of the turning gear drive device (5) is a three-phase asynchronous motor with a power of 75 kW and a voltage level of 380 V. The motor is coaxially connected to the reducer (51) via a mounting flange.

5. A small steam turbine turning gear to prevent reverse rotation and a control method thereof, which is implemented based on a small steam turbine turning gear to prevent reverse rotation according to any one of claims 1 to 4, and is characterized in that: The following steps are involved: Step S1: Collect 2JK and inverter operation signals, 2JK and the inverter operation signal are connected in series to form a signal loop, and drive the intermediate relay KA5; Step S2: The intermediate relay KA5 feeds back the cranking operation signal to the DCS host computer; Step S3: DCS determines the turning gear operation status according to the KA5 feedback signal; Step S4: When the signal loop is disconnected, KA5 disconnects the cranking operation signal, and the DCS host computer issues a stop command to stop the operation of the cranking drive device; Step S5: When the signal loop is closed normally, KA5 maintains continuous feedback of the cranking operation signal.

6. A small steam turbine turning gear and control method for preventing reverse rotation according to claim 5, characterized in that: in step S1: The 2JK is collected by a limit switch installed on the turning gear connection device (4), and the limit switch is fixedly connected to the rotor (54) of the small steam turbine (1) via a flange; The cranking signal collected by 2JK is fed back to the cranking control cabinet and connected in series with the inverter operation signal to form a signal loop in the control cabinet to drive the intermediate relay KA5.

7. A small steam turbine turning gear and control method for preventing reverse rotation according to claim 5, characterized in that: in step S2: The KA5 is used to feed back the cranking operation signal to the DCS host computer through the cranking control cabinet (6); The KA5 is connected to a signal processing module in a turning gear control cabinet (6) via an electrical contact, and the signal processing module has a redundant design; The turning gear control cabinet (6) is connected to the DCS host computer via a dedicated communication port.

8. A small steam turbine turning gear and control method for preventing reverse rotation according to claim 5, characterized in that: in step S3: The DCS host computer determines the turning gear operation status according to the feedback signal from KA5; During the judgment process, the DCS host computer collects current sensor data on the turning gear drive device (5) in real time to assist in judging whether the turning gear drive device (5) is working normally.

9. A small steam turbine turning gear and control method for preventing reverse rotation according to claim 5, characterized in that: in step S4: When the signal circuit is disconnected, KA5 disconnects the turning operation signal; The DCS host computer does not receive a cranking operation signal within 2 seconds, and issues an emergency stop command to stop the operation of the cranking drive device (5).

10. A small steam turbine turning gear and control method for preventing reverse rotation according to claim 5, characterized in that: in step S5: When the signal circuit is closed normally, the KA5 intermediate relay keeps the cranking operation signal feedback; The DCS host computer regularly collects the internal feedback signal of the turning gear control cabinet (6) and checks the signal delay and signal strength; The turning gear control cabinet (6) is provided with a fault indicator light inside, which provides an alarm prompt when the signal is abnormal.

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