A control system and method for a steam turbine steam valve

Abstract

The present invention provides a control system and method for a steam turbine steam valve, relating to the technical field of steam valve control, including a DEH control system, a valve control system, a signal transmission control system, and a system-specific regulation module. The DEH control system is used to receive the request of the overall system for the total steam flow rate entering the steam turbine and generate an opening command for the regulating valve. The valve control system is used to convert the opening command into an opening signal for each valve. The present invention uses a node timing module to time the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signals of each valve to each valve, and the start-up delay of the opening module. The delay statistical module calculates the average fluctuation N of the overall delay. The direct-through path module drives the opening module of the valve to pre-start N moments in advance when the DEH control system issues a signal, so as to reduce the delay of the valve opening.

Description

Technical Field

[0001] The present invention relates to the technical field of steam valve control, and particularly to a control system and method for a steam turbine steam valve. Background Art

[0002] A steam turbine, also known as a steam turbine engine, is a rotary steam power device. High-temperature and high-pressure steam passes through a fixed nozzle to become an accelerated air flow and then jets onto the blades, causing the rotor equipped with the blade row to rotate and perform work externally. A steam turbine is the main equipment of a modern thermal power plant and is also used in the metallurgical industry, chemical industry, and ship power plants.

[0003] In the prior art, as disclosed in Publication No. CN110173310A, "A Nuclear Power Plant Steam Turbine Steam Valve Regulation System and Its Safety Control Method" is specifically disclosed: The steam turbine steam valve regulation system includes an oil circuit unit, a GSE unit, a GRE unit, and a controller. The safety control method includes responding to an open valve command of the controller to control the open valve operation of the GSE unit and the GRE unit, or responding to a close valve command of the controller to control the close valve operation of the GSE unit and the GRE unit. The safety control method adopts the operation sequence of separate oil inlet or oil loss of the GSE unit and the GRE unit during both the open valve operation and the close valve operation to avoid the system oil pressure disturbance caused by excessive instantaneous oil consumption. However, in the above technology, there is a delay in the process of signal transmission response, which easily causes the opening degree of the valve to be difficult to quickly respond to the request of the overall system for the total steam flow entering the steam turbine, resulting in a certain instability in the system operation. Therefore, the present invention proposes a control system and method for a steam turbine steam valve to solve the problems existing in the prior art. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a control system and method for a steam turbine steam valve, which reduces the delay of the valve opening degree and improves the system stability.

[0005] To achieve the object of the present invention, the present invention is realized through the following technical solutions: A control system for a steam turbine steam valve includes a DEH control system, a valve control system, a signal transmission control system, and a system special supply adjustment module. The DEH control system is used to receive the request of the overall system for the total steam flow entering the steam turbine and generate an opening degree command for adjusting the valve. The valve control system is used to convert the opening degree command into an opening degree signal for each valve to control the operation of each valve opening degree module, so that the valve reaches the required opening degree.

[0006] The signal transmission control system includes a node timing module, a delay statistics module, and a direct connection path module. The node timing module measures the delays of the DEH control system transmitting the opening command to the valve control system, the valve control system transmitting the opening signals of each valve to each valve, and the start-up delay of the opening module. The delay statistics module is used to calculate the average fluctuation N of the overall delay. The direct connection path module is used to directly connect the DEH control system and each valve, and drive the opening module of the valve to pre-start N moments in advance when the DEH control system issues a signal.

[0007] A further improvement is that: in the DEH system, there are a receiving module, a speed control loop, and a load control loop. The receiving module is used to receive the request of the overall system for the total steam flow rate entering the steam turbine. The flow rate setpoint signals generated by the speed control loop and the load control loop are transmitted to the valve control system.

[0008] A further improvement is that: the valve control system includes a conversion module and an output module. The conversion module is used to convert the flow rate setpoint signal into an opening command signal for each valve. The output module is used to output the opening command signal for each valve to the opening module.

[0009] A further improvement is that: the opening module includes a valve control card and a servo amplifier. A valve position sensor is provided on each valve. The opening command signal of each valve is output to the valve control card and subtracted from the actual valve position signal of the valve position sensor, and then amplified by the servo amplifier to control the valve to reach the required opening.

[0010] A further improvement is that: the node timing module includes T1 node, T2 node, T3 node, and T4 node. The T1 node, T2 node, and T3 node are respectively built into the DEH control system, the valve control system, the opening module, and the valve. The delays of the DEH control system transmitting the opening command to the valve control system, the valve control system transmitting the opening signals of each valve to each valve, and the start-up delay of the opening module are calculated through the responses of the T1 node, T2 node, T3 node, and T4 node. And the node timing module has a built-in storage library, taking the timings of the three processes as a set, and marking a timestamp according to the set time.

[0011] A further improvement is that: the delay statistics module includes a calculation module and a value assignment module. The calculation module is used to calculate the average value N of the overall delay in each set. The value assignment module regularly assigns the average value N to the direct connection path module according to the timestamp of each set.

[0012] The further improvement lies in that: the direct-through path module includes a timer and a dual-channel transmission path. The timer times the DEH control system, and according to the current time, selects the delay average value N of the corresponding timestamp set. When the DEH control system processes the request for the total steam flow entering the steam turbine from the overall system, it judges the signal sending time point according to the constant processing duration, and sends a pre-start signal N time in advance.

[0013] The further improvement lies in that: the dual-channel transmission path adopts a redundant transmission mechanism. Channels A and B are copied simultaneously, and the two channels send the same time-triggered flow data information. Dual-network realizes dual-redundancy backup. Channels A and B perform decentralized transmission for scheduling, and send the pre-start signal to the opening module for pre-start.

[0014] The further improvement lies in that: the system special supply adjustment module includes a power supply module, an accompanying battery pack, an emergency control module and a switching module. The power supply module provides power for the DEH control system, the valve control system and the opening module. The accompanying battery pack is connected to the power supply module for charging. The power supply module and the accompanying battery pack are connected to the DEH control system, the valve control system and the opening module through the switching module. The emergency control module has the switching logic between the power supply module and the accompanying battery pack built in. In case of accidental power failure, the switching module controls the power supply module and the accompanying battery pack to perform zero-time switching. When there is an accidental power failure, the emergency control module controls the valve switch state to remain unchanged.

[0015] A control method for a steam valve of a steam turbine includes the following steps:

[0016] Step 1: The DEH control system receives the request for the total steam flow entering the steam turbine from the overall system, generates an opening command for the regulating valve, transmits it to the valve control system, and converts the opening command into an opening signal for each valve;

[0017] Step 2: The opening signals of each valve are output to the valve control card and subtracted from the actual valve position signals of the valve position sensors, and after being amplified by the servo amplifier, they control the servo valve to reach the required opening;

[0018] Step 3: During this process, the delays of the DEH control system transmitting the opening command to the valve control system, the valve control system transmitting the opening signals of each valve to each valve, and the start-up delay time of the opening module are counted through the responses of nodes T1, T2, T3 and T4;

[0019] Step 4: Take the statistical timing of the three processes as a set, mark a timestamp according to the set time, calculate the average value N of the overall delay in each set, and regularly assign the average value N to the direct-through path module according to the timestamp of each set;

[0020] Step 5: The direct-through path module selects the average delay N of the corresponding timestamp set according to the current time. When the DEH control system processes the total steam flow request, it determines the signal sending time point according to the processing duration, and dispersedly transmits through channels A and B N time in advance, and sends a pre-start signal to the opening module for pre-start.

[0021] Step 6: In case of accidental power-off, control the power supply module and the accompanying battery pack to perform zero-time switching, maintain the system power supply, and control the valve switch state to remain unchanged.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The present invention measures the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signals of each valve to each valve, and the start-up delay of the opening module through the node timing module, statistically calculates the average fluctuation N of the overall delay through the delay statistics module, and drives the opening module of the valve to perform pre-start N moments in advance when the DEH control system issues a signal through the direct-through path module, so as to reduce the delay of the valve opening and improve the system stability.

[0024] 2. The present invention measures the delay time by the responses of four nodes, takes the timings of three processes as a set, stamps time stamps, and calculates the average value N of the overall delay in each set, making the data more representative. The direct-through path module selects the average delay N of the corresponding timestamp set according to the current time and performs early signal transmission, which is beneficial to making the early time adapt to different time periods and solving the delay deviation caused by different loads in different time periods.

[0025] 3. When the present invention encounters accidental power-off, it controls the power supply module and the accompanying battery pack to perform zero-time switching, maintains the system power supply, and controls the valve switch state to remain unchanged, effectively preventing disputes between the supply and demand sides caused by accidental valve closure. Description of the Drawings

[0026] Figure 1 is the system composition diagram of the present invention;

[0027] Figure 2 is the control schematic diagram of the present invention;

[0028] Figure 3 is the method flowchart of the present invention. Embodiment

[0029] To deepen the understanding of the present invention, the following will further elaborate on the present invention in combination with embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation to the protection scope of the present invention. Embodiment

[0030] According toFigure 1 , 2 As shown, this embodiment proposes a control system for a steam turbine steam valve, including a DEH control system, a valve control system, a signal transmission control system, and a system-specific regulation module. The DEH control system is used to receive the request of the overall system for the total steam flow rate entering the steam turbine and generate an opening command for the regulating valve. The valve control system is used to convert the opening command into an opening signal for each valve to control the operation of each valve opening module so that the valve reaches the required opening.

[0031] The signal transmission control system includes a node timing module, a delay statistics module, and a direct connection path module. The node timing module measures the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signal of each valve to each valve, and the start-up delay of the opening module. The delay statistics module is used to calculate the average fluctuation N of the overall delay. The direct connection path module is used to directly connect the DEH control system and each valve, and drive the opening module of the valve to pre-start N moments in advance when the DEH control system issues a signal. During use, the node timing module measures the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signal of each valve to each valve, and the start-up delay of the opening module. The delay statistics module calculates the average fluctuation N of the overall delay. The direct connection path module drives the opening module of the valve to pre-start N moments in advance when the DEH control system issues a signal to reduce the delay of the valve opening.

[0032] The DEH system includes a built-in receiving module, a speed control loop, and a load control loop. The receiving module is used to receive the request of the overall system for the total steam flow rate entering the steam turbine. The flow rate setpoint signals generated by the speed control loop and the load control loop are transmitted to the valve control system. The valve control system includes a conversion module and an output module. The conversion module is used to convert the flow rate setpoint signal into an opening command signal for each valve. The output module is used to output the opening command signal for each valve to the opening module. The opening module includes a valve control card and a servo amplifier. A valve position sensor is provided on each valve. The opening command signal of each valve is output to the valve control card and subtracted from the actual valve position signal of the valve position sensor, and then amplified by the servo amplifier to control the valve to reach the required opening. Specifically, the process of valve opening adjustment is as follows: The DEH control system receives the request of the overall system for the total steam flow rate entering the steam turbine and generates an opening command for the regulating valve, and transmits it to the valve control system, which converts the opening command into an opening signal for each valve; the opening signal of each valve is output to the valve control card and subtracted from the actual valve position signal of the valve position sensor, and then amplified by the servo amplifier to control the servo valve to reach the required opening.

[0033] The node timing module includes T1 node, T2 node, T3 node and T4 node, and the T1 node, T2 node and T3 node are respectively built in the DEH control system, valve control system, opening module and valve. The delays of the DEH control system transmitting the opening command to the valve control system, the valve control system transmitting the opening signals of each valve to each valve, and the start delay time of the opening module are counted through the responses of the T1 node, T2 node, T3 node and T4 node. And the node timing module has a built-in storage library, taking the timings of three processes as a set, and marking a timestamp according to the set time. The delay statistics module includes a calculation module and a value assignment module. The calculation module is used to calculate the average value N of the total delay in each set. The value assignment module regularly assigns the average value N to the direct-through path module according to the timestamp of each set. When in use, the delay time is counted through the responses of the four nodes, taking the timings of three processes as a set, marking a timestamp, and making the data more representative by calculating the average value N of the total delay in each set. Then the average value N is regularly assigned to the direct-through path module. The direct-through path module selects the average delay value N of the corresponding timestamp set according to the current time for early signal transmission, which is beneficial to making the advanced time adapt to different time periods and solving the delay deviation caused by different loads in different time periods.

[0034] The direct-through path module includes a timer and a dual-channel transmission path. The timer times the DEH control system, selects the average delay value N of the corresponding timestamp set according to the current time, and when the DEH control system processes the request for the total steam flow entering the steam turbine of the whole system, judges the signal sending time point according to the constant processing duration, and sends a pre-start signal N time in advance. The dual-channel transmission path adopts a redundant transmission mechanism, with channels A and B replicated simultaneously. The dual channels send the same time-triggered stream data information, and the dual networks achieve dual redundant backups. Channels A and B are dispersed for transmission scheduling, and the pre-start signal is sent to the opening module for pre-start. When in use, the direct-through path module selects the average delay value N of the corresponding timestamp set according to the current time for early signal transmission, making the advanced time adapt to different time periods and solving the delay deviation caused by different loads in different time periods. And it adopts a redundant transmission mechanism, using dual channels for signal transmission, which can effectively reduce the transmission delay and improve the data throughput.

[0035] The system special supply regulation module includes a power supply module, an accompanying battery pack, an emergency control module, and a switching module. The power supply module provides power for the DEH control system, the valve control system, and the opening module. The accompanying battery pack is connected to the power supply module for charging. The power supply module and the accompanying battery pack are connected to the DEH control system, the valve control system, and the opening module through the switching module. The emergency control module has the switching logic between the power supply module and the accompanying battery pack built in. In case of an unexpected power outage, the switching module controls the power supply module and the accompanying battery pack to perform a zero-time switch. When there is an unexpected power outage, the emergency control module controls the valve switch state to remain unchanged. During use, in case of an unexpected power outage, by controlling the zero-time switch of the power supply module and the accompanying battery pack, the system power supply is maintained, and the valve switch state is controlled to remain unchanged, effectively preventing disputes between the supply and demand sides caused by the accidental closing of the valve. Embodiment

[0036] According to Figure 1 、 2 As shown in Figure 3, this embodiment proposes a control method for a steam turbine steam valve, including the following steps:

[0037] Step 1: The DEH control system receives the request of the overall system for the total steam flow entering the steam turbine, generates an opening command for the regulating valve, transmits it to the valve control system, and converts the opening command into an opening signal for each valve.

[0038] Step 2: The opening signals of each valve are output to the valve control card and subtracted from the actual valve position signals of the valve position sensors. After being amplified by the servo amplifier, they control the servo valve to reach the required opening.

[0039] Step 3: During this process, the response of nodes T1, T2, T3, and T4 is used to count the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signals of each valve to each valve, and the start-up delay time of the opening module.

[0040] Step 4: The statistical timings of the three processes are taken as a set, and a timestamp is marked according to the set time. The average value N of the overall delay in each set is calculated. According to the timestamp of each set, the average value N is regularly assigned to the direct-through path module.

[0041] Step 5: The direct-through path module selects the average delay value N of the corresponding timestamp set according to the current time. When the DEH control system processes the total steam flow request, it judges the signal sending time point according to the processing duration, and dispersedly transmits through channels A and B N time in advance, and sends a pre-start signal to the opening module for pre-start; to reduce the delay of the valve opening, improve the system stability, and make the advanced time adapt to different time periods, solving the delay deviation caused by different loads in different time periods.

[0042] Step 6: In case of accidental power failure, control the power supply module and the accompanying battery pack to perform zero-time switching, maintain the system power supply, and control the valve switch state to remain unchanged. This effectively prevents disputes between the supply and demand sides caused by accidental valve closure.

[0043] The control system and method for the steam valve of a steam turbine time the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signals of each valve to each valve, and the start delay of the opening module through the node timing module. The overall delay fluctuation average N is statistically calculated by the delay statistics module. The direct-through path module drives the opening module of the valve to pre-start N moments in advance when the DEH control system issues a signal, so as to reduce the delay of the valve opening and improve the system stability. Moreover, the present invention counts the delay time through the responses of four nodes, takes the timing of three processes as a set, stamps a time stamp, and calculates the average N of the overall delay in each set, making the data more representative. The direct-through path module selects the average N of the delay of the corresponding time stamp set according to the current time for early signal transmission, which is conducive to making the early time adapt to different time periods and solving the delay deviation caused by different loads in different time periods. At the same time, in case of accidental power failure, the present invention controls the power supply module and the accompanying battery pack to perform zero-time switching, maintains the system power supply, and controls the valve switch state to remain unchanged, effectively preventing disputes between the supply and demand sides caused by accidental valve closure.

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A control system for a steam turbine steam valve, comprising a DEH control system, a valve control system, a signal transmission control system, and a system-specific regulation module, characterized in that: The DEH control system is used to receive the request of the overall system for the total steam flow entering the steam turbine and generate an opening command for the regulating valve. The valve control system is used to convert the opening command into an opening signal for each valve to control the operation of each valve opening module, so that the valve reaches the required opening; The signal transmission control system includes a node timing module, a delay statistics module, and a direct connection path module. The node timing module measures the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signal of each valve to each valve, and the start-up delay of the opening module. The delay statistics module is used to calculate the average fluctuation N of the overall delay. The direct connection path module is used to directly connect the DEH control system and each valve, and drive the opening module of the valve to pre-start N moments in advance when the DEH control system sends a signal; The node timing module includes T1 node, T2 node, T3 node and T4 node. The T1 node, T2 node and T3 node are respectively built into the DEH control system, the valve control system, the opening module and the valve. The response of the T1 node, T2 node, T3 node and T4 node is used to measure the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signal of each valve to each valve, and the start-up delay time of the opening module. The node timing module has a built-in storage library, taking the timing of the three processes as a set and marking a timestamp according to the set time; The direct connection path module includes a timer and a dual-channel transmission path. The timer measures the DEH control system and selects the average delay N of the corresponding timestamp set according to the current time. When the DEH control system processes and receives the request of the overall system for the total steam flow entering the steam turbine, it judges the signal sending time point according to the constant processing duration and sends a pre-start signal N time in advance.

2. The control system for a steam turbine steam valve according to claim 1, characterized in that: The DEH control system has a built-in receiving module, a speed control loop and a load control loop. The receiving module is used to receive the request of the overall system for the total steam flow entering the steam turbine. The flow setpoint signals generated by the speed control loop and the load control loop are transmitted to the valve control system.

3. The control system for a steam turbine steam valve according to claim 2, characterized in that: The valve control system includes a conversion module and an output module. The conversion module is used to convert the flow setpoint signal into an opening command signal for each valve. The output module is used to output the opening command signal of each valve to the opening module.

4. A control system for a steam valve of a steam turbine according to claim 3, characterized in that: The opening module includes a valve control card and a servo amplifier. A valve position sensor is provided on each valve. The opening command signal of each valve is output to the valve control card and subtracted from the actual valve position signal of the valve position sensor, and then amplified by the servo amplifier to control the valve to reach the required opening.

5. A control system for a steam valve of a steam turbine according to claim 1, characterized in that: The delay statistics module includes a calculation module and a value assignment module. The calculation module is used to calculate the average value N of the overall delay in each set. The value assignment module regularly assigns the average value N to the direct connection path module according to the timestamp of each set.

6. The control system for a steam turbine steam valve according to claim 1, wherein: The dual-channel transmission path adopts a redundant transmission mechanism. Channels A and B are replicated simultaneously, and the two channels send the same time-triggered stream data information. Dual-network realizes dual-redundancy backup. Channels A and B perform decentralized transmission for scheduling, and send a pre-start signal to the opening module for pre-starting.

7. A control system for a steam turbine steam valve according to claim 1, characterized in that: The system's special supply regulation module includes a power supply module, an accompanying battery pack, an emergency control module, and a switching module. The power supply module provides power for the DEH control system, the valve control system, and the opening module. The accompanying battery pack is connected to the power supply module for charging. The power supply module and the accompanying battery pack are connected to the DEH control system, the valve control system, and the opening module through the switching module. The emergency control module has the switching logic between the power supply module and the accompanying battery pack built in. In case of an accidental power outage, the switching module controls the power supply module and the accompanying battery pack to perform a zero-time switch. When there is an accidental power outage, the emergency control module controls the valve switch state to remain unchanged.

8. The control method of a control system for a steam turbine steam valve according to claim 1, characterized in that, It includes the following steps: Step 1: The DEH control system receives the request of the overall system for the total steam flow entering the steam turbine, generates an opening command for the regulating valve, transmits it to the valve control system, and converts the opening command into an opening signal for each valve. Step 2: The opening signals of each valve are output to the valve control card and subtracted from the actual valve position signal of the valve position sensor. After being amplified by the servo amplifier, it controls the servo valve to reach the required opening. Step 3: During this process, the response of nodes T1, T2, T3, and T4 is used to count the delay of the DEH control system transmitting the opening command to the valve control system, the delay of the valve control system transmitting the opening signals of each valve to each valve, and the start-up delay time of the opening module. Step 4: Take the statistical timing of the three processes as a set, mark a time stamp according to the set time, calculate the average value N of the overall delay in each set, and regularly assign the average value N to the direct-through path module according to the time stamp of each set. Step 5: The direct-through path module selects the average delay value N of the corresponding time stamp set according to the current time. When the DEH control system processes the total steam flow request, it judges the signal sending time point according to the processing duration, and dispersedly transmits through channels A and B N time in advance, and sends a pre-start signal to the opening module for pre-starting. Step 6: In case of an accidental power outage, control the power supply module and the accompanying battery pack to perform a zero-time switch, keep the system powered, and control the valve switch state to remain unchanged.

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