A checking device for a digital electro-hydraulic control system of a steam turbine

Abstract

A verification device for a digital electro-hydraulic control system (DEH) of a steam turbine is disclosed to address the problem of inconsistent processing cycles between the existing DEH system controller and the DEH upper-level control and monitoring system, resulting in inaccurate control of the turbine control valve by DEH control parameters. This invention includes a main control loop and a verification loop. The main control loop comprises an upper-level computer, a DEH controller, a servo card, a servo valve, and a turbine control valve connected in sequence. To address the feedback lag problem in the turbine control valve of the DEH system, by comparing control commands and feedback, the device guides technicians to adjust control parameters, optimize DEH control effects, and improve the control performance of the DEH system. This ensures the unit operates under optimal conditions, reduces heat consumption, improves energy conversion efficiency, and rapidly responds to changes in grid load demand, reducing energy waste caused by adjustment lag.

Description

Technical Field

[0001] This utility model belongs to the field of steam turbine testing technology, and relates to a calibration device for a digital electro-hydraulic control system of a steam turbine. Background Technology

[0002] The Digital Electro-Hydraulic Control System (DEH) for steam turbines represents a significant advancement in core control technology for large-scale generator sets. Its development is closely linked to the power industry's increasing demands for improved unit operating efficiency, safety, and flexibility. Traditional mechanical-hydraulic control systems, limited by large mechanical inertia, slow response, and low control precision, struggle to meet the demands of modern power grids for rapid frequency regulation, deep peak shaving, and coordinated control. In the 1980s, breakthroughs in microelectronics, hydraulic servo technology, and automatic control theory led to the gradual replacement of analog electro-hydraulic control systems (AEH), making DEH the standard configuration for supercritical, ultra-supercritical, and nuclear power turbines.

[0003] The direct control object of the DEH system is the turbine control valve. The control effect of the turbine control valve directly affects the safety of the generator set and the stability of the power grid system. The main problem faced by the existing DEH control system is the inconsistency of the system processing cycle: the processing cycle of the mainstream DEH system controller is 40ms, while the processing cycle of the DEH upper-level control and monitoring system is 1000ms. The lag of the DEH control and monitoring system cannot provide technicians with real-time and effective data, resulting in the DEH control parameters being unable to accurately control the turbine control valve action. Utility Model Content

[0004] The technical solution of this utility model is used to solve the problem that the processing cycles of the existing DEH system controller and the DEH upper-level control and monitoring system are inconsistent, and the DEH control parameters cannot accurately control the turbine control valve action.

[0005] This utility model solves the above-mentioned technical problems through the following technical solution:

[0006] A verification device for a digital electro-hydraulic control system for a steam turbine includes a main control circuit and a verification circuit; the main control circuit includes a host computer, a DEH controller, a servo card, a servo valve, and a steam turbine regulating valve connected in sequence.

[0007] The first output terminal of the host computer is connected to the first input terminal of the DEH controller, the first output terminal of the DEH controller is connected to the first input terminal of the servo card, the first output terminal of the servo card is connected to the input terminal of the servo valve, and the output terminal of the servo valve is connected to the input terminal of the turbine regulating valve.

[0008] The first output terminal of the turbine control valve is connected to the second input terminal of the servo card, the second output terminal of the servo card is connected to the second input terminal of the DEH controller, and the second output terminal of the DEH controller is connected to the input terminal of the host computer.

[0009] Furthermore, the verification circuit includes a signal generator, a data acquisition unit, a first signal amplifier, and a second signal amplifier; the second output terminal of the host computer is connected to the first input terminal of the data acquisition unit, the signal generator is connected to the input terminal of the first signal amplifier, the output terminal of the first signal amplifier is connected to the second input terminal of the data acquisition unit, the second output terminal of the servo card is connected to the input terminal of the second signal amplifier, the output terminal of the second signal amplifier is connected to the third output terminal of the data acquisition unit, the fourth input terminal of the data acquisition unit is connected to the first output terminal of the servo card, and the second output terminal of the turbine regulating valve is connected to the fifth input terminal of the data acquisition unit.

[0010] Furthermore, the host computer sends a valve opening command signal to the DEH controller, and the valve opening command signal is a digital signal with a valve opening range of 0 to 100%.

[0011] Furthermore, the DEH controller receives the valve opening command signal, converts it into a control signal with a range of 4 to 20 mA, and sends it to the servo card.

[0012] Furthermore, the servo card converts the control signal into a DC voltage signal with a range of 0 to 10V.

[0013] Furthermore, the specific model of the data acquisition instrument is HBM GEN3i, which is used to acquire the first to fifth signals.

[0014] Furthermore, the first signal is a valve opening command signal issued by the host computer that has not been processed by the DEH controller;

[0015] The second signal is a control signal with a range of 4 to 20 mA issued by the DEH controller and signal generator. The second signal is converted into a valve command waveform of 0 to 100% by the first signal amplifier.

[0016] The third signal is a 4-20mA valve LVDT opening feedback signal converted by the servo card. The third signal is converted into a 0-100% valve feedback waveform by the second signal amplifier.

[0017] The fourth signal is a DC voltage signal with a range of 0 to 10V emitted by the servo card;

[0018] The fifth signal is the LVDT voltage feedback signal from the turbine control valve.

[0019] Furthermore, the processing cycle of the data acquisition instrument is set to 10ms.

[0020] The advantages of this utility model are:

[0021] This invention addresses the feedback lag problem in turbine control valves within a DEH system by designing a DEH control system and a process signal monitoring device. By comparing control commands with feedback, it guides technicians to adjust control parameters, optimize DEH control performance, and improve the control performance of the DEH system. This ensures the unit operates under optimal conditions, reduces heat consumption rate, improves energy conversion efficiency, and rapidly responds to changes in grid load demand, reducing energy waste caused by adjustment lag.

[0022] This invention utilizes a high-precision data acquisition instrument in the verification loop to simultaneously acquire command signals from the DEH controller and feedback signals from the servo valve. By analyzing the waveforms of the real-time command and feedback signals, technicians can be guided to obtain the correct adjustment parameters. The verification loop can also enable real-time monitoring of the signal processing systems at each stage of the DEH control loop, providing significant guidance for diagnosing control system faults. Attached Figure Description

[0023] Figure 1 This is a structural diagram of a verification device for a digital electro-hydraulic control system of a steam turbine according to Embodiment 1 of this utility model;

[0024] Figure descriptions: 10. Host computer; 11. DEH controller; 12. Servo card; 13. Servo valve; 14. Steam turbine regulating valve;

[0025] 20. First signal amplifier; 21. Second signal amplifier; 22. Signal generator; 23. Data acquisition instrument. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0027] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments:

[0028] Example 1

[0029] like Figure 1As shown, specifically, a verification device for a digital electro-hydraulic control system of a steam turbine is disclosed, including a main control circuit and a verification circuit; the main control circuit includes a host computer 10, a DEH controller 11, a servo card 12, a servo valve 13 and a steam turbine regulating valve 14 connected in sequence.

[0030] Furthermore, the first output terminal of the host computer 10 is connected to the first input terminal of the DEH controller 11, the first output terminal of the DEH controller 11 is connected to the first input terminal of the servo card 12, the first output terminal of the servo card 12 is connected to the input terminal of the servo valve 13, and the output terminal of the servo valve 13 is connected to the input terminal of the turbine regulating valve 14.

[0031] In this embodiment, the host computer 10 sends a valve opening command signal to the DEH controller 11, which is a digital signal representing the valve opening range of 0 to 100%. The DEH controller 11 receives the valve opening command signal and converts it into a control signal with a range of 4 to 20 mA and sends it to the servo card 12. The servo card 12 converts the control signal into a DC voltage signal with a range of 0 to 10 V, which is used to control the opening of the servo valve 13. The servo valve 13 is affected by voltage changes, and the opening of the turbine regulating valve 14 can be controlled by changing the opening size of the servo valve 13.

[0032] Furthermore, the first output terminal of the turbine regulating valve 14 is connected to the second input terminal of the servo card 12, the second output terminal of the servo card 12 is connected to the second input terminal of the DEH controller 11, and the second output terminal of the DEH controller 11 is connected to the input terminal of the host computer 10.

[0033] In this embodiment, the turbine control valve 14 feeds back the opening signal to the servo card 12. The servo card 12 receives the opening signal and converts it into a feedback current signal with a range of 4 to 20 mA, which is then sent to the DEH controller 11. The DEH controller 11 then converts the feedback current signal into a feedback opening signal with a range of 0 to 100%. The host computer 10 collects the digital signal input to the DEH controller 11 and the feedback opening signal output. By comparing the waveforms of the input control command and the output feedback signal, technicians adjust the control parameters of the DEH, thereby adjusting the valve control accuracy.

[0034] The verification circuit includes a signal generator 22, a data acquisition unit 23, a first signal amplifier 20, and a second signal amplifier 21. The second output terminal of the host computer 10 is connected to the first input terminal of the data acquisition unit 23, the signal generator 22 is connected to the input terminal of the first signal amplifier 20, the output terminal of the first signal amplifier 20 is connected to the second input terminal of the data acquisition unit 23, the second output terminal of the servo card 12 is connected to the input terminal of the second signal amplifier 21, the output terminal of the second signal amplifier 21 is connected to the third output terminal of the data acquisition unit 23, the fourth input terminal of the data acquisition unit 23 is connected to the first output terminal of the servo card 12, and the second output terminal of the turbine regulating valve 14 is connected to the fifth input terminal of the data acquisition unit 23.

[0035] In this embodiment, the signal generator 22 is used to provide a signal source for system verification, simulate and send control signals to control the valve opening, and the data acquisition instrument 23 collects five sets of signals, namely the first to the fifth signals:

[0036] The first signal is a valve opening command signal sent by the host computer 10 that has not been processed by the DEH controller 11;

[0037] The second signal includes a control signal with a range of 4 to 20 mA issued by the DEH controller or signal generator. The second signal is converted into a valve command waveform of 0 to 100% by the first signal amplifier. When the unit is running normally, the control signal is issued by the DEH controller. When the unit is shut down, the control signal for calibration and testing is issued by the signal generator as a signal source.

[0038] The third signal is a 4-20mA valve LVDT opening feedback signal converted by servo card 12. The third signal is converted into a 0-100% valve feedback waveform by the second signal amplifier 21.

[0039] The fourth signal is a DC voltage signal with a range of 0 to 10V emitted by the servo card 12;

[0040] The fifth signal is the LVDT voltage feedback signal from the turbine control valve 14.

[0041] In this embodiment, the processing cycle of the data acquisition instrument 23 is set to 10ms. It is used to acquire the second signal of DEH control and the third signal converted by the servo card. Since the processing cycle of the data acquisition instrument (10ms) is much smaller than that of the host computer (1s) and the DEH controller (40ms), the data acquisition instrument is frequently acquired and updated by the host computer and the DEH controller in the form of an external device. The data acquisition instrument caches the data internally after each acquisition. By accumulating these high-frequency data, the data acquisition instrument can provide the latest and continuous data every time the host computer requests data. It can also ensure that the data acquisition instrument can provide the latest control data in each DEH controller cycle, assisting technicians in adjusting valve control parameters. It ensures that the high-frequency data acquisition (10ms) is synchronized with the DEH controller cycle (40ms), avoiding frame loss and failure to acquire in real time when the host computer acquires DEH control or feedback signals. This reduces data loss due to transmission delay or cycle mismatch and solves the problem of mismatch between the processing cycle of the host computer monitoring system and the DEH controller.

[0042] Based on the valve command waveform converted by the first signal amplifier and the valve feedback waveform converted by the second signal amplifier, the speed of the valve action response and the magnitude of the action can be determined. This allows for adjustment of the proportional and integral parameters of the servo card, guiding technicians to adjust valve control parameters according to the waveform, thereby changing the valve's action response rate and amplitude for rapid response to changes. In this embodiment, the data acquisition instrument 23 can be an HBM GEN3i from Germany.

[0043] Furthermore, by comparing the processing times of the five sets of signals acquired by the data acquisition instrument 23 in the test loop, the system fault point can be determined. For example, by comparing the first signal and the second signal, the processing time of the valve control system to the control valve command signal issued by the host computer 10 can be calculated; by comparing the second signal and the third signal, the processing time of the command issued by the servo card 12 to the DEH controller 11 can be calculated; and by comparing the third signal and the fifth signal, the delay time from the valve receiving the command from the servo card 12 to the valve action can be calculated. Based on the above calculation results, if the turbine control valve 14 is found to be poorly following the signal, the fault point can be quickly located using the data acquisition instrument 23, guiding technicians to handle the fault.

[0044] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A verification device for a digital electro-hydraulic control system of a steam turbine, characterized in that, It includes a main control circuit and a verification circuit; the main control circuit includes a host computer, a DEH controller, a servo card, a servo valve and a turbine control valve connected in sequence; The first output terminal of the host computer is connected to the first input terminal of the DEH controller, the first output terminal of the DEH controller is connected to the first input terminal of the servo card, the first output terminal of the servo card is connected to the input terminal of the servo valve, and the output terminal of the servo valve is connected to the input terminal of the turbine regulating valve. The first output terminal of the turbine control valve is connected to the second input terminal of the servo card, the second output terminal of the servo card is connected to the second input terminal of the DEH controller, and the second output terminal of the DEH controller is connected to the input terminal of the host computer. The verification circuit includes a signal generator, a data acquisition unit, a first signal amplifier, and a second signal amplifier. The second output terminal of the host computer is connected to the first input terminal of the data acquisition unit, the signal generator is connected to the input terminal of the first signal amplifier, the output terminal of the first signal amplifier is connected to the second input terminal of the data acquisition unit, the second output terminal of the servo card is connected to the input terminal of the second signal amplifier, the output terminal of the second signal amplifier is connected to the third output terminal of the data acquisition unit, the fourth input terminal of the data acquisition unit is connected to the first output terminal of the servo card, and the second output terminal of the turbine regulating valve is connected to the fifth input terminal of the data acquisition unit.

2. The verification device for a digital electro-hydraulic control system of a steam turbine according to claim 1, characterized in that, The host computer sends a valve opening command signal to the DEH controller. The valve opening command signal is a digital signal with a valve opening range of 0 to 100%.

3. The verification device for a digital electro-hydraulic control system of a steam turbine according to claim 2, characterized in that, The DEH controller receives the valve opening command signal, converts it into a control signal with a range of 4-20mA, and sends it to the servo card.

4. A verification device for a digital electro-hydraulic control system of a steam turbine according to claim 3, characterized in that, The servo card converts the control signal into a DC voltage signal with a range of 0 to 10V.

5. A calibration device for a digital electro-hydraulic control system of a steam turbine according to claim 1, characterized in that, The specific model of the data acquisition instrument is HBM GEN3i, which is used to acquire the first to fifth signals.

6. A calibration device for a digital electro-hydraulic control system of a steam turbine according to claim 5, characterized in that, The first signal is a valve opening command signal sent by the host computer that has not been processed by the DEH controller; The second signal is a control signal with a range of 4 to 20 mA issued by the DEH controller and signal generator. The second signal is converted into a valve command waveform of 0 to 100% by the first signal amplifier. The third signal is a 4-20mA valve LVDT opening feedback signal converted by the servo card. The third signal is converted into a 0-100% valve feedback waveform by the second signal amplifier. The fourth signal is a DC voltage signal with a range of 0 to 10V emitted by the servo card; The fifth signal is the LVDT voltage feedback signal from the turbine control valve.

7. A calibration device for a digital electro-hydraulic control system of a steam turbine according to claim 5, characterized in that, The processing cycle of the data acquisition instrument is set to 10ms.

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