Passive nuclear power plant alternating current valve electric device and control method thereof

Abstract

The invention provides a passive nuclear power plant alternating-current valve electric device and a control method thereof, and belongs to the technical field of valve devices. The passive nuclear power plant alternating-current valve electric device comprises a speed reduction transmission mechanism, an alternating-current motor and a stroke controller; the speed reduction transmission mechanism comprises a first-stage turbine worm speed reduction device and a first-stage bevel gear speed reduction device which are connected in sequence. The travel controller comprises a plurality of layers of travel switches, and a rotating shaft of the travel switch is linked with the speed reduction transmission mechanism; wherein at least two layers of travel switches used for outputting key control signals are specific travel switches, and the width of a metal contact piece on a rotating shaft of each specific travel switch is larger than that of a metal contact piece of each travel switch on the other layer, so that the travel switches are firstly switched on when the valve is opened or closed in place. Through accurate valve opening and closing state feedback of the valve electric device, it is ensured that a motor protection module in the alternating current power supply cabinet effectively controls operation of the valve.

Description

Technical Field

[0001] This invention belongs to the field of valve device technology, and particularly relates to an AC valve electric actuator for passive nuclear power plants and its control method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In the operating system of passive nuclear power plants, the valve opening and closing status feedback of AC valve electric actuators and the motor protection module in the AC power cabinet are key components to ensure the normal operation of valves.

[0004] However, existing technologies have significant drawbacks. Due to mechanical errors and other reasons, the feedback information on the open and closed valve status is ambiguous, making it impossible to distinguish the sequence of status indications and limit switches. This results in the motor protection module being unable to accurately obtain the actual operating status of the valve and perform effective control and protection. For example, when the valve is close to its limit open position, the sequence of the valve opening status and the valve opening limit signal cannot be effectively distinguished. If the valve opening limit precedes the valve opening status by more than 10ms, the motor protection will issue a fault alarm, incorrectly judging that the valve actuator is stalled. This requires the motor protection to be reset locally. During the period without resetting, the valve cannot be remotely controlled, affecting system safety, and the local reset work increases the workload of operators. On the other hand, when the valve is close to its limit closed position, the sequence of the valve closing status and the valve closing limit signal cannot be effectively distinguished. The motor protection may prematurely cut off the power, resulting in incomplete valve closure, which could lead to serious safety accidents and threaten the stable operation of the nuclear power plant. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention proposes an AC valve electric actuator for passive nuclear power plants and its control method, which improves the precise sequence of stroke control switches and the working accuracy of the valve electric actuator, strengthens the cooperation with the motor protection module, and achieves accurate status feedback and reliable control.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: In a first aspect, the present invention discloses an AC valve electric actuator for a passive nuclear power plant, comprising a reduction transmission mechanism, an AC motor, and a stroke controller; The speed reduction transmission mechanism includes a first-stage worm gear reducer and a first-stage bevel gear reducer connected in sequence; The stroke controller includes multiple stroke switches, whose shafts are linked to the reduction transmission mechanism; wherein, at least two stroke switches used to output key status signals are specific stroke switches, and the metal contact on the shaft of the specific stroke switch is wider than the metal contact of the other stroke switches, so as to be connected first when the valve is opened or closed. The AC motor is connected to the reduction gear transmission mechanism. According to the control command, the motor protection device adjusts the phase sequence on the power supply side through the contactor, thereby adjusting the forward and reverse rotation of the AC motor. Finally, the operation control of the valve is realized by controlling the reduction gear rotation mechanism.

[0007] In a further technical solution, the key status signals include a valve opening status signal and a valve opening limit signal; the specific limit switch is used to output the valve opening status signal, and the metal contact of the specific limit switch connects the valve opening status signal before the valve opening limit signal during the valve opening process.

[0008] In a further technical solution, the key status signals include a valve-closing status signal and a valve-closing limit signal; the specific limit switch is used to output the valve-closing status signal, and the metal contact of the specific limit switch connects the valve-closing status signal before the valve-closing limit signal during the valve-closing process.

[0009] A further technical solution also includes a handwheel, which is connected to the bevel gear reduction device through a manual / automatic switching mechanism to enable switching between manual and electric operation.

[0010] In a further technical solution, the transmission components of the device are made of alloy steel, the sealing components are made of fluororubber, the non-metallic parts are made of polyetherimide, and the device does not contain aluminum.

[0011] In a further technical solution, all the wires inside the device are irradiated and certified.

[0012] In a further technical solution, the wiring specifications of the wires are selected with a current margin of more than 50%.

[0013] In a further technical solution, the device is electrically connected to an external motor protection device; the stroke controller transmits the key control signal to the motor protection device, so that the motor protection device controls and protects the valve operation based on the precise sequence of the signals.

[0014] In a further technical solution, the primary bevel gear reducer is connected to an electric actuator and a valve.

[0015] Secondly, this invention discloses a control method for an AC valve electric actuator in a passive nuclear power plant, comprising: When the motor protection device receives a remote or local valve opening command, it outputs to the valve opening contactor coil circuit to activate the valve opening contactor contacts, which close the contactor contacts and energize the AC motor of the electric actuator. The valve then opens and begins to move. When the valve opens to near its limit position, the valve opening status indication is fed back to the motor protection device, followed by the valve opening limit indication. If the two indication signals are in the correct sequence, the motor protection device outputs to the valve opening contactor coil circuit to deactivate the circuit, the AC motor of the electric actuator is de-energized, and the valve opening action ends. When the motor protection device receives a remote or local valve closing command, it outputs a circuit to the valve closing contactor coil, causing the valve closing contactor contacts to close. This energizes the AC motor of the electric actuator, and the valve begins to close. When the valve closes to its near limit position, the valve closing status indication is fed back to the motor protection device. Subsequently, the valve closing limit indication is also fed back to the motor protection device. If the two indication signals are in the correct sequence, the circuit to the valve closing contactor coil is disconnected, the AC motor of the electric actuator is de-energized, and the valve closing action ends.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The AC valve electric actuator of the present invention can accurately distinguish the opening and closing valve status indication and the opening and closing valve limit switch sequence, meet the collaborative control requirements of the motor protection module in the AC power switch cabinet, and provide accurate and real-time valve stroke status information for the motor protection device by optimizing the different layer stroke control switch structure and the precision transmission structure. This ensures that the motor protection module can control the valve operation in a timely and effective manner based on accurate information, avoid valve operation failures caused by information deviation or control lag, and comprehensively improve the safety and reliability of the process system where the valves of the passive nuclear power plant are located.

[0017] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a front view of the passive nuclear power plant AC valve electric actuator described in Embodiment 1 of the present invention; Figure 2 This is a top view of the passive nuclear power plant AC valve electric actuator described in Embodiment 1 of the present invention; Figure 3 This is a structural diagram of the limit switch of the limit controller described in Embodiment 1 of the present invention; Figure 4This is a contact diagram (including each layer) of the limit switch described in Embodiment 1 of the present invention. Figure 5 This is the power supply control topology diagram described in Embodiment 1 of the present invention; In the diagram, 1-1 is a bevel gear reducer; 1-2 is an AC motor; 1-3 is an output shaft; 1-4 is a handwheel; 1-5 is a travel controller; 2-1 is a worm gear; 2-2 is a switching handle; 2-3 is a torque controller; 2-4 is a worm gear; 2-5 is a junction box; 3-1 is a metal contact piece; 3-2 is a contact rivet; 3-3 is a housing; 3-4 is a travel switch rotating shaft; and 3-5 is a connecting piece. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0022] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0023] Example 1 In one or more embodiments, an AC valve electric actuator for a passive nuclear power plant is disclosed, comprising a bevel gear reducer 1-1; an AC motor 1-2; an output shaft 1-3; a handwheel 1-4; a stroke controller 1-5; a turbine 2-1; a switching handle 2-2; a torque controller 2-3; a worm gear 2-4; and a junction box 2-5.

[0024] The reduction gear transmission mechanism includes a single-stage worm gear reducer and a single-stage bevel gear reducer connected in sequence; wherein, for example... Figure 2 As shown, the first-stage worm gear reducer is a built-in structure of the electric actuator, such as... Figure 1 As shown, an additional single-stage bevel gear reducer is provided to connect the electric actuator and the valve respectively, ensuring smooth power transmission and a high degree of consistency between the valve body state and the feedback state of the valve electric actuator. It can be matched with the motor protection module in the AC power cabinet to achieve precise position control, and effectively solves the problem of high loss of existing electric actuators, achieving precise position control and reducing device losses.

[0025] Limit switches, such as Figure 3As shown, metal contact 3-1 is fixed on the rotating shaft 3-4 of the limit switch, and the metal contact 3-1 covering both sides of the rotating shaft 3-4 of the limit switch is electrically connected. When the rotating shaft 3-4 of the limit switch rotates to the horizontal direction, the contact rivets 3-2 on both sides are electrically connected, and finally the wiring terminals on the outside of the wiring piece 3-5 are electrically connected. The wiring piece 3-5 has a certain elasticity to ensure tight contact. The limit controller includes multiple layers of limit switches, whose rotating shafts are linked to the output shaft of the electric device body; among them, the two layers of limit switches used to output key control signals are specific limit switches. The metal contact 3-1 on the rotating shaft of the specific limit switch is wider than the metal contact of the other layers of limit switches. During synchronous rotation, the specific limit switch is the first to connect when the valve is opened or closed. The metal contact on the shaft of these two layers of limit switches is wider than the metal contact on the other layers of metal contacts. When the shafts of each layer of limit switches rotate synchronously, the specific limit switch contacts the contact on the wiring piece first, so the specific limit switch will connect at a certain angle earlier than other limit switches. When the valve is fully open or closed, a specific limit switch is activated before other limit switches, ensuring the sequential order of signals. Figure 4 As shown, specific limit switches are used for contacts 1, 2, 5, and 6 to ensure effective control of valve operation by the AC power supply side motor protection device.

[0026] like Figure 5 As shown, the development status limit signal and the valve closing status limit signal are sent to the motor protection device by the specific limit switch.

[0027] The motor protection device receives a remote or local valve opening command. The output of the motor protection device to the valve opening contactor coil circuit is activated, the valve opening contactor contacts close, the AC motor of the electric actuator is energized, and the valve opens. When the valve opens to near its limit position, the valve opening status indication is fed back to the motor protection device. Subsequently, the valve opening limit indication is fed back to the motor protection device. If the two indication signals are in the correct sequence, the output of the motor protection device to the valve opening contactor coil circuit is deactivated, the AC motor of the electric actuator is de-energized, and the valve opening action ends.

[0028] When the motor protection device receives a remote or local valve closing command, it outputs a circuit to the valve closing contactor coil, causing the valve closing contactor contacts to close. This energizes the AC motor of the electric actuator, and the valve begins to close. When the valve closes to its near limit position, the valve closing status indication is fed back to the motor protection device. Subsequently, the valve closing limit indication is also fed back to the motor protection device. If the two indication signals are in the correct sequence, the circuit to the valve closing contactor coil is disconnected, the AC motor of the electric actuator is de-energized, and the valve closing action ends.

[0029] The AC motor is connected to the reduction gear transmission mechanism. According to the control command, the motor protection device adjusts the phase sequence on the power supply side through the contactor, thereby adjusting the forward and reverse rotation of the AC motor. Finally, the operation control of the valve is realized by controlling the reduction gear rotation mechanism.

[0030] The handwheel is connected to the bevel gear reduction device via a manual / automatic switching mechanism to enable switching between manual and electric operation.

[0031] Furthermore, the key status signals include a valve opening status signal and a valve opening limit signal; the specific limit switch is used to output the valve opening status signal, and the metal contact of the specific limit switch connects the valve opening status signal before the valve opening limit signal during the valve opening process.

[0032] The key status signals also include a valve-closed status signal and a valve-closed limit signal; the specific limit switch is used to output the valve-closed status signal, and the metal contact of the specific limit switch connects the valve-closed status signal before the valve-closed limit signal during the valve-closing process.

[0033] Furthermore, the device's transmission components are made of alloy steel, the seals are made of fluororubber, and the non-metallic parts are made of polyetherimide. Both of these materials have good radiation resistance, and the entire device does not contain aluminum, which meets the requirements for use inside a containment facility.

[0034] Furthermore, all wiring inside the device is irradiated and certified.

[0035] Furthermore, the wiring specifications are designed with a current margin of over 50%, which can meet the needs of use in extreme environments and ensure good electrical performance over a 60-year lifespan.

[0036] Furthermore, the device is electrically connected to an external motor protection module; the stroke controller transmits the key control signals to the motor protection module, so that the motor protection module controls and protects the valve operation based on the sequence of signals.

[0037] Preferably, the entire electric device needs to pass product form qualification tests such as thermal aging, irradiation aging (excluding accident dose), vibration, and wear aging to ensure that the product can be used inside the containment and guarantee reliable operation.

[0038] Example 2 In one or more embodiments, a control method for an AC valve electric actuator in a passive nuclear power plant is disclosed, comprising: The motor protection device receives a remote or local valve opening command. The output of the motor protection device to the valve opening contactor coil circuit is activated, the valve opening contactor contacts close, the AC motor of the electric actuator is energized, and the valve opens. When the valve opens to near its limit position, the valve opening status indication is fed back to the motor protection device. Subsequently, the valve opening limit indication is fed back to the motor protection device. If the two indication signals are in the correct sequence, the output of the motor protection device to the valve opening contactor coil circuit is deactivated, the AC motor of the electric actuator is de-energized, and the valve opening action ends.

[0039] When the motor protection device receives a remote or local valve closing command, it outputs a circuit to the valve closing contactor coil, causing the valve closing contactor contacts to close. This energizes the AC motor of the electric actuator, and the valve begins to close. When the valve closes to its near limit position, the valve closing status indication is fed back to the motor protection device. Subsequently, the valve closing limit indication is also fed back to the motor protection device. If the two indication signals are in the correct sequence, the circuit to the valve closing contactor coil is disconnected, the AC motor of the electric actuator is de-energized, and the valve closing action ends.

[0040] The descriptions of each embodiment in the above embodiments have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A passive nuclear power plant AC valve electric actuator, characterized in that, Includes a speed reduction transmission mechanism, an AC motor, and a stroke controller; The speed reduction transmission mechanism includes a first-stage worm gear reducer and a first-stage bevel gear reducer connected in sequence; The stroke controller includes multiple stroke switches, whose rotating shafts are linked to the reduction transmission mechanism; wherein, at least two stroke switches used to output key control signals are specific stroke switches, and the metal contact pieces on the rotating shafts of the specific stroke switches are wider than the metal contact pieces of the other stroke switches, so as to be connected first when the valve is opened or closed. The AC motor is connected to the reduction gear transmission mechanism. According to the control command, the motor protection device adjusts the phase sequence on the power supply side through the contactor, thereby adjusting the forward and reverse rotation of the AC motor. Finally, the operation control of the valve is realized by controlling the reduction gear rotation mechanism.

2. The passive nuclear power plant AC valve electric actuator as described in claim 1, characterized in that, The key control signals include a valve opening status signal and a valve opening limit signal; the specific limit switch is used to output the valve opening status signal, and the metal contact of the specific limit switch connects the valve opening status signal before the valve opening limit signal during the valve opening process.

3. The passive nuclear power plant AC valve electric actuator as described in claim 1, characterized in that, The key control signals include a valve-closing status signal and a valve-closing limit signal; the specific limit switch is used to output the valve-closing status signal, and the metal contact of the specific limit switch connects the valve-closing status signal before the valve-closing limit signal during the valve-closing process.

4. The passive nuclear power plant AC valve electric actuator as described in claim 1, characterized in that, It also includes a handwheel, which is connected to the bevel gear reduction device via a manual / automatic switching mechanism to enable switching between manual and electric operation.

5. The passive nuclear power plant AC valve electric actuator as described in claim 1, characterized in that, The device's transmission components are made of alloy steel, its seals are made of fluororubber, its non-metallic parts are made of polyetherimide, and the device does not contain aluminum.

6. The passive nuclear power plant AC valve electric actuator as described in claim 1, characterized in that, All wires inside the device are irradiated and certified.

7. The passive nuclear power plant AC valve electric actuator as described in claim 6, characterized in that, The wiring specifications of the wires are selected with a current margin of more than 50%.

8. The passive nuclear power plant AC valve electric actuator as described in claim 1, characterized in that, The device is electrically connected to an external motor protection module; the stroke controller transmits the key control signals to the motor protection module so that the motor protection module controls and protects the valve operation based on the sequence of signals.

9. The passive nuclear power plant AC valve electric actuator as described in claim 1, characterized in that, The first-stage bevel gear reducer is connected to the electric actuator and the valve.

10. A control method for an AC valve electric actuator in a passive nuclear power plant, characterized in that, include: When the motor protection device receives a remote or local valve opening command, it outputs to the valve opening contactor coil circuit to activate the valve opening contactor contacts, which close the contactor contacts and energize the AC motor of the electric actuator. The valve then opens and begins to move. When the valve opens to near its limit position, the valve opening status indication is fed back to the motor protection device, followed by the valve opening limit indication. If the two indication signals are in the correct sequence, the motor protection device outputs to the valve opening contactor coil circuit to deactivate the circuit, the AC motor of the electric actuator is de-energized, and the valve opening action ends. When the motor protection device receives a remote or local valve closing command, it outputs a circuit to the valve closing contactor coil, causing the valve closing contactor contacts to close. This energizes the AC motor of the electric actuator, and the valve begins to close. When the valve closes to its near limit position, the valve closing status indication is fed back to the motor protection device. Subsequently, the valve closing limit indication is also fed back to the motor protection device. If the two indication signals are in the correct sequence, the circuit to the valve closing contactor coil is disconnected, the AC motor of the electric actuator is de-energized, and the valve closing action ends.

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