Turbine high and medium pressure control valve control device

Abstract

The utility model discloses a steam turbine high and medium pressure control valve control device which comprises an electrical direct current feeder cabinet, a power supply switching device, an AST1 electromagnetic valve group, an AST2 electromagnetic valve group, three independent rotating speed and protection modules and a DEH control system. By establishing a novel electrical valve control mode, the performance and the safety of a DEH system are greatly improved, the operation cycle of a controller can reach 40 ms and at least 20 ms, the control response requirements of primary frequency modulation and the like are better met, the heat dissipation performance of DEH hardware is good, heat dissipation of a fan is not needed, the service life can reach more than 10 years, and the service life of the DEH system is prolonged. Compared with an original DEH card with frequent failure rate, a terminal board and an aging shutdown controller, products with better performance and higher reliability are replaced, and the life cycle of the system is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine regulating valve control technology, and in particular to a steam turbine high and medium pressure regulating valve control device. Background Technology

[0002] The turbine control system DEH of a 300MW unit in a thermal power plant is the DEH-V type system from GE Xinhua, which was put into operation in 2007. Its functions include basic turbine control BTC and ATC, and it is equipped with 2 pairs of DPUs, 2 control cabinets, and 2 terminal cabinets. The SDP card is a dedicated DEH / MEH card that combines speed measurement and overspeed protection functions. In order to ensure redundancy design in the DEH system, 3 SDP cards are distributed in 3 different stations. The 3 SDP cards are used in conjunction with the SDP terminals to form a hardware 3-out-of-2 overspeed protection system.

[0003] The device has some shortcomings in its use. Specifically, the speed measurement of the DEH system of Unit #6 in this plant uses SDP cards, with three SDP cards corresponding to one terminal board. The three circuit breaker, three grid connection, and three speed signals are fed into the three SDP cards through one terminal board. This terminal board is powered by only one 24V power supply. If the power supply is lost or the electronic components age and cause a malfunction, the relays on the terminal board will not operate, all signals on the three SDP cards will be abnormal, the overspeed protection function of the DEH system will fail, which will cause unauthorized shutdowns or loss of normal protection for the unit, posing a great safety hazard. Utility Model Content

[0004] Therefore, in order to overcome the above-mentioned shortcomings, this utility model provides a steam turbine high and medium pressure regulating valve control device.

[0005] To achieve the above objectives, this utility model adopts the following technical solution: a steam turbine high- and medium-pressure regulating valve control device, including an electrical DC feeder cabinet, a power switching device, an AST solenoid valve group, three independent speed and protection modules, and a DEH control system. The DC feeder cabinet typically serves as a bus wiring device for high-voltage or low-voltage electricity, distributing power to various terminal devices. The electrical DC feeder cabinet is internally equipped with a power switching device, which is electrically connected to the AST solenoid valve group via control wires. The power switching device is often an actuator of a control system, capable of automatic switching between power sources to ensure continuous power supply to the circuit. This device typically consists of a main power supply, a backup power supply, a controller, and actuators. When the main power supply fails, it automatically switches to the backup power supply, thus ensuring continuous power supply to the circuit. The AST solenoid valve group is composed of a group of solenoid valves and an OPC solenoid valve. The DEH control system is integrated into the power switching device.

[0006] Preferably, the three independent speed and protection modules include three speed signals, a brake activation signal, a grid connection signal, and an output % overspeed signal. The control signals are all divided into three independent paths through the three speed and protection modules, and the internal three-out-of-two function of the speed and protection modules is canceled by a jumper. The three 103% overspeed protection signals are output to the OPC solenoid valve and each valve control card through a relay three-out-of-two terminal block.

[0007] In a further preferred embodiment, the DEH is a digital electro-hydraulic control system for steam turbines.

[0008] In a further preferred embodiment, the three independent speed and protection modules include three speed signals, a brake activation signal, a grid connection signal, and an output % overspeed signal. These are all divided into three independent paths through the three speed and protection modules. The internal three-out-of-two function of the speed and protection modules is canceled by a jumper. The three % overspeed protection signals are output to the OPC solenoid valve and each valve control card through a relay three-out-of-two terminal block.

[0009] In a further preferred embodiment, the speed signal is primarily used to monitor the turbine's rotational speed. It is acquired through a magnetoresistive or photoelectric speed sensor installed at the turbine shaft end. These sensors can accurately measure the turbine's revolutions per minute (RPM). In the DEH system, the speed signal is crucial. For example, during turbine startup, the DEH system uses the speed signal to control the opening of the steam valves, increasing the turbine speed according to a preset acceleration curve to ensure the turbine smoothly reaches its rated speed.

[0010] In a further preferred embodiment, engaging the brake is an important step in starting the steam turbine. The brake engagement signal indicates that the steam turbine's safety system is ready. When the operator issues the brake engagement command, the system will reset the emergency trip device of the steam turbine. This process involves the linkage of multiple parts such as mechanical, hydraulic and electrical systems. For example, the brake engagement signal will reset the emergency trip throttle, allowing the safety oil and secondary oil to build up oil pressure, creating conditions for subsequent operations such as opening the main steam valve.

[0011] In a further preferred embodiment, the grid connection signal is used to indicate that the turbine has been successfully connected to the power grid. After the turbine speed reaches the rated speed and all parameters stabilize, and when the synchronization conditions such as voltage, frequency, and phase are consistent with the power grid, the grid connection operation will be performed. After the grid connection signal is issued, the turbine begins to bear the load of the power grid. For example, once the grid connection signal is received, the DEH system will switch the control mode from speed control to load control, and precisely control the power output of the turbine by adjusting the steam intake according to the power grid demand and dispatch instructions.

[0012] In a further preferred embodiment, in the context of turbine control in the DEH system digital electro-hydraulic regulation system and other related systems, the "two-out-of-three" approach typically refers to redundant selection logic for some key signals such as the aforementioned speed signal, brake signal, and grid connection signal. Specifically, when judging an important state or performing a critical operation, two signals that simultaneously meet the conditions are selected from these three signals as valid judgment criteria. For example, for the triggering of certain protection actions of the turbine or the judgment of the start-up conditions of important control links, when any two of the three signals simultaneously exhibit abnormal states, such as two signals showing abnormally high speeds or meeting specific requirements, such as two signals indicating successful grid connection, the system will execute the corresponding operation based on this "two-out-of-three" logic judgment, such as triggering protection shutdown or completing load adjustment control after grid connection. This design can improve the reliability of the system and avoid incorrect control decisions caused by malfunctions or failures of a single signal.

[0013] The beneficial effects of this utility model are:

[0014] This invention significantly improves the performance and safety of the DEH system by establishing a novel electric valve control method. It ensures that the controller's operating cycle can reach 40ms with a minimum of 20ms, better meeting the control response requirements of primary frequency regulation, etc. The DEH hardware has good heat dissipation, eliminating the need for fan cooling and extending its service life to over 10 years. Compared to the original DEH, which suffered from frequent failures in its cards, terminal boards, and aging, discontinued controllers, this invention replaces these components with superior performance and higher reliability, thus extending the system's lifespan. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the optimized power supply design scheme in this utility model;

[0016] Figure 2 This is a schematic diagram of the original power supply design of the DEH system in this utility model. Detailed Implementation

[0017] To further explain the technical solution of this utility model, a detailed description is provided below through specific embodiments.

[0018] Please see Figure 1 (Schematic diagram of the optimized power supply design) and Figure 2 (Schematic diagram of the original power supply design of the DEH system) This utility model provides a steam turbine high and medium pressure regulating valve control device, including an electrical DC feeder cabinet, a power switching device, an AST1 solenoid valve group, an AST2 solenoid valve group, three independent speed and protection modules, and a DEH control system. The DC feeder cabinet 1 is usually used as a bus wiring device for high-voltage or low-voltage electricity, and then distributes the power to each terminal device. The electrical DC feeder cabinet is equipped with a power switching device inside. The power switching device is electrically connected to the AST1 solenoid valve group through control wires, and the power switching device is electrically connected to the AST2 solenoid valve group through control wires.

[0019] Power switching devices are devices that can automatically switch between power sources to ensure continuous power supply to the circuit. These devices typically consist of a main power supply, a backup power supply, a controller, and actuators. When the main power supply fails, it will automatically switch to the backup power supply to ensure continuous power supply to the circuit. The AST1 solenoid valve group consists of 3 solenoid valves and OPC solenoid valves, while the AST2 solenoid valve group consists of 4 solenoid valves and OPC solenoid valves. The DEH control system is integrated into the power switching device.

[0020] The three independent speed and protection modules include three speed signals, a brake activation signal, a grid connection signal, and an output 103% overspeed signal. All of these are divided into three independent paths through the three speed and protection modules. The internal three-out-of-two function of the speed and protection modules is canceled by a jumper. The three 103% overspeed protection signals are output to the OPC solenoid valve and each valve control card through a relay three-out-of-two terminal block.

[0021] In this embodiment, priority is given to the following: **Speed ​​Signal:** The speed signal is primarily used to monitor the turbine's rotational speed. It is acquired through a magnetoresistive or photoelectric speed sensor installed at the turbine shaft end. These sensors can accurately measure the turbine's revolutions per minute. The speed signal is crucial in the DEH system. For example, during turbine startup, the DEH system uses the speed signal to control the opening of the steam valves, increasing the turbine speed according to a preset acceleration curve to ensure the turbine smoothly reaches its rated speed. **Braking Signal:** Braking is an important step in turbine startup. The braking signal indicates that the turbine's safety system is ready. When the operator issues the braking command, the system resets the turbine's emergency tripping device. This process involves the linkage of multiple mechanical, hydraulic, and electrical components. For example, the braking signal resets the emergency tripping throttle, allowing safety oil and secondary oil to build up oil pressure, creating conditions for subsequent operations such as opening the main steam valve. **Grid Connection Signal:** The grid connection signal indicates that the turbine has successfully connected to the power grid. Once the turbine reaches its rated speed and all parameters stabilize, grid connection will be initiated when synchronization conditions are met (such as voltage, frequency, and phase parameters being consistent with the power grid). After the grid connection signal is issued, the turbine begins to bear the load of the power grid. For example, upon receiving the grid connection signal, the DEH system will switch the control mode from speed control to load control, precisely controlling the turbine's output power by adjusting the steam flow rate according to the power grid's demand and dispatch instructions.

[0022] In this embodiment, prioritizing the use of "two out of three" in turbine control scenarios such as DEH systems (Digital Electro-hydraulic Control Systems), "two out of three" typically refers to redundant selection logic for some critical signals (such as the aforementioned speed signal, brake activation signal, and grid connection signal). Specifically, when judging an important state or performing a critical operation, two signals that simultaneously meet certain conditions are selected as valid judgment criteria. For example, for the triggering of certain protection actions of the turbine or the judgment of the start-up conditions of important control links, when any two of the three signals simultaneously exhibit abnormal states (e.g., two signals indicating abnormally high speed) or meet specific requirements (e.g., two signals indicating successful grid connection), the system will execute the corresponding operation based on this "two out of three" logic, such as triggering protection shutdown or completing load adjustment control after grid connection. This design can improve the reliability of the system and avoid incorrect control decisions due to malfunctions or failures of a single signal.

[0023] See Figures 1-2 When in use, the device is installed on the outside of the steam turbine via the DC feeder cabinet 1. By activating the power switching device, the power switching device provides the electrical energy required by the equipment, ensuring that the DEH control system can operate normally.

[0024] The medium carbon steel DEH control system determines the triggering conditions for certain protective actions of the steam turbine or the start-up conditions of important control links. When any two of the three signals are in an abnormal state at the same time, such as two signals showing abnormally high speed or meeting specific requirements, such as two signals indicating successful grid connection, the system will control the corresponding execution operations of the AST1 solenoid valve group and the AST2 solenoid valve group according to this "two out of three" logic judgment. This includes triggering protective shutdown or completing load adjustment control after grid connection, thereby protecting the steam turbine.

[0025] Furthermore, by triggering the independent speed and protection module 5, multiple sets of signals, including speed signal, brake signal, grid connection signal, and output 103% overspeed signal, are simultaneously transmitted to the turbine's electrical control unit and execution unit. This ensures that the turbine can reach a stationary state in a short time. At the same time, the speed and protection module 5 is structurally capable of converting the signal data into three sets of data, ensuring that if one set of data fails, the other two sets of data can simultaneously stop the equipment operation.

[0026] The control method of this utility model is to control the device by manually starting and stopping the switch. The wiring diagram of the power element and the supply of power are common knowledge in the field. Since this utility model is mainly used to protect mechanical devices, the control method and wiring layout will not be explained in detail.

[0027] The control method of this utility model is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the field. Since this utility model is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail.

[0028] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A steam turbine intermediate and high pressure regulating valve control device, characterized in that: It includes an electrical DC feeder cabinet, a power switching device, an AST1 solenoid valve group, an AST2 solenoid valve group, three independent speed and protection modules, and a DEH control system. The electrical DC feeder cabinet is equipped with a power switching device inside. The power switching device is electrically connected to the AST1 solenoid valve group via a control wire, and the power switching device is electrically connected to the AST2 solenoid valve group via a control wire. The AST1 solenoid valve group consists of 3 sets of solenoid valves and OPC solenoid valves. The AST2 solenoid valve group consists of 4 sets of solenoid valves and OPC solenoid valves. The DEH control system is programmed into the power switching device.

2. The turbine intermediate and high pressure regulating valve control device according to claim 1, characterized in that: The three independent speed and protection modules include three speed signals, a brake activation signal, a grid connection signal, and an output 103% overspeed signal. The control signals are divided into three independent paths through the three speed and protection modules, and the internal three-out-of-two function of the speed and protection modules is canceled by a jumper. The three 103% overspeed protection signals are output to the OPC solenoid valve and each valve control card through a relay three-out-of-two terminal block.

3. The turbine intermediate and high pressure regulating valve control device according to claim 2, characterized in that: The three speed signals are mainly used to monitor the rotational speed of the steam turbine. They are obtained by a magnetoresistive or photoelectric speed sensor installed at the end of the steam turbine shaft.

4. The turbine intermediate and high pressure regulating valve control device according to claim 2, characterized in that: The grid connection signal: The grid connection signal is used to indicate that the steam turbine has been successfully connected to the power grid.

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