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Abstract: This paper introduces a new turbine governor, that is, the digital valve PCC programmable intelligent speed governor, which is undertaken by Tianjin KeYin Automatic Control Equipment Co., Ltd. Electrical part of the PCC (programmable computer controller) as the control center; electro-hydraulic conversion components using electromagnetic ball valve, mechanical amplification components using two-way cartridge valve, the use of non-lever, ignoring pipeline structure. The application results of power station show that the digital valve PCC programmable intelligent governor all performance indicators are better than the national standard, commissioning simple, easy maintenance, with high reliability. Keywords: Intelligent Governor PCC digital valve cartridge valve Preface At present, widely used turbine governor, mostly to PLC as the core. Developed by Tianjin KeYin Automatic Control Equipment Co., Ltd. digital valve PCC programmable intelligent governor with a new control concept to PCC as the control center, for the entire process of automation and control, the successful configuration by the solenoid valve and cartridge valve form a digital valve replacement The traditional electro-hydraulic converter and the main pressure valve. The controller is the core part of the governor. The controller completes the signal acquisition of the governor, the data calculation, the realization of the control law, the switching of the operating status, the output of the control value and other additional functions. Therefore, the choice of controller is crucial to the development of a new governor. At present, there are many controllers on the market, such as single-chip microcomputer, PLC, PCC, etc. However, since the speed governor is an industrial field device, the reliability is very high. The important principle of selecting a controller is to choose a controller which is suitable for industrial field and has strong anti-interference ability, high reliability, large choice and convenient operation and maintenance. After thorough research, analysis and comparison of various controllers, we found that the PCC of B & R in Austria is the most suitable controller to meet the above principles. Therefore, PCC is chosen as the Digital valve PCC intelligent governor control core. PCC stands for a completely new concept of control that combines the standard control functions of a programmable logic controller (PLC) with high reliability and scalability, as well as the industrial functions of an industrial computer (IPC) (computing power, timeliness Good, easy programming, etc.). It can easily handle the switch, analog, loop adjustment. And can use high-level language programming, with the mainframe analysis and computing capabilities. Its hardware has a unique new plug-in modular structure, allowing the system to be flexible and diverse expansion and combination. Software also has a modular structure, the system expansion only need to superimpose on the basis of the original use of software modules. PCC CPU is 32-bit, high efficiency, high-speed intelligent processor TPU, TPU function allows the system to achieve microsecond response time, and the CPU does not need to make any load. User memory capacity. Has a good electromagnetic compatibility and fieldbus full support for technology, reflects the direction of industrial development. Digital Valve PCC Intelligent Governor includes monotonic and dual adjustment models. This document describes the main features, functions, and make up of dual adjustment governors. 2. Digital valve PCC intelligent governor of the main features (1) a new control concept. Using a new generation of programmable computer controller different from conventional PLC --PCC, oriented control process, using high-level language, analysis and calculation ability, in the same CPU can run different programs. When the program is running only part of the program scan, high efficiency. (2) All PCC, with high reliability. From input to output, from the frequency measurement to the control pulse and other areas have achieved PCC. PCC MTBF MTBF up to 500,000 hours, or 57 years. (3) The advantages of multi-tasking. In traditional PLC, parallel processing is done by program scan. But in fact multitasking is the logic of parallel processing, the simpler and more direct method is to use multitasking technology. PCC just to meet this demand, when a task is waiting, the other tasks can continue to perform. The PCC divides the entire regulation control into several Task Classes with different priorities. The higher priority task level, the shorter the scan period, the lower the priority, the longer the scan period. The time-demanding procedures on the high-speed task-oriented, the general logic of the decision-making process on the ordinary task level, so that you can improve the performance of regulatory systems. (4) intelligent governor. Using adaptive variable structure, variable parameter parallel PID regulation, the use of conventional PID regulator improved algorithm [2]. Automatically identify the nature of the grid and automatically adapt to the special operation of the power plant, such as isolated network operation, or by the large grid solution to the small grid operation of the sudden load and other special circumstances, can ensure the stable operation of the unit. User-friendly design, with strong self-diagnosis, error-proofing, error correction and fault tolerance. When a fault occurs, the fault diagnosis screen pops up automatically and automatically displays the cause of the fault and the remedy. (5) using PCC high-speed counting module (HSC) frequency measurement. PCC up to 6.3MHz count frequency, with high frequency accuracy and reliability, so that the governor of the input channel - the reliability of the frequency measurement has been a fundamental guarantee. (6) The digital association method is adopted, and the modified curve can be modified in the field and the modified data can be memorized so that the optimum curve can be operated according to the actual conditions of the power station. The accuracy of the blade servo system is high. (7) The large memory of the PCC provides a resource guarantee for the intelligent governor. User Memory: 1.5 MB FLASH PROM. (8) The solenoid valve to do digital valve as electro-hydraulic conversion components. Completely solve the conventional governor electro-hydraulic conversion components issue of oil issue, so that power plants can be completely reliable automatic operation. (9) has the function of fault lock ingot. Because the digital valve only on / off two states, and digital valve cone valve seal can guarantee no leakage at 31.5MPa, so the digital valve has a hydraulic lock function, so when the frequency signal disappears and power off, etc. , With the function of fault lock ingot. (10) no lever structure. This series of governor uses digital valve hydraulic follow-up system, automatically when the electric feedback, manual without feedback, thus eliminating the lever, eliminating the dead zone caused by the lever to improve the accuracy of the speed control system, and no tube Road, the structure is simple, beautiful. (11) friendly man-machine interface. Using touch screen as a man-machine interface, vivid images, all Chinese display, easy to operate, you can display a lot of information at the same time. With screen saver to extend touch screen life. (12) easy to maintain easy debugging. Due to the high integration and high reliability of the PCC, there are not too many special requirements for operation and maintenance personnel. Debugging only needs to set adjustable figures such as figures and not too many potentiometers. 3. The main function of the digital valve PCC intelligent governor Digital valve PCC programmable intelligent governor with automatic, electric manual, manual three modes of operation, and can be unconditionally bumpless switch. Has many functions, practicality is very intelligent, in addition to the conventional functions have the following main functions. (1) No-load operation, can automatically track the system frequency, and fast grid. (2) With the frequency adjustment, opening adjustment, power adjustment of the three modes, and can be adjusted between the disturbance-free switch. Under the power regulation mode, it can accept the host computer control instruction to realize the power generation automatic control function (AGC). (3) Has a strong self-diagnosis, error-proofing, error correction and fault tolerance, and the fault information can be displayed on the screen, or send an alarm signal. Has the following online diagnostic and fault-tolerant features: Analog / digital converter and input channel fault; Feedback channel fault; Hydraulic control system fault; Program error and clock fault; Fault shutdown circuit; Operation error; Frequency loop fault; Other faults. (4) communication with the host computer functions, to accept the host computer control commands to the host computer to send the relevant information. (5) Open stop intelligent control. (6) auxiliary test function. Through the touch screen can be easily carried out static characteristics, no-load disturbance and no-load swing test. (7) with water level adjustment. (8) Wave control, in order to avoid load rejection when the upstream and downstream water level greater waves. (9) multi-level password protection. Holding the level of the password determines the size of the rights exercised on the system. The operator can only observe the routine display and carry out routine operations, maintenance personnel or managers can adjust parameters and other changes. (10) with polyline shut-off function, and by the standard cartridge valve to complete, simple structure, reliable action. 4. Digital valve PCC intelligent governor constitute Digital valve PCC intelligent governor block diagram shown in Figure 1. According to the requirements of users can use the mechanical and electrical cabinet type can also be used mechanical and electrical cabinet type. Structure layout is simple and reasonable, user-friendly design, easy maintenance, easy to operate. The governor on the touch screen, instruments, buttons, etc., installed in the corresponding cabinet dashboard, easy to observe and symmetrically arranged, all the instruments and control devices, the appearance of mutual coordination. 4.1 Regulator Structure The regulator is mainly composed of PCC CPU module, high-speed DI module, pulse output module, A / D conversion module, digital input / output modules, communication modules and racks. 4.1.1 Frequency Measurement Links The pros and cons of frequency measurement will directly affect the performance and reliability of the governor. This series of speed governor adopts the high speed digital input module DI135 frequency measurement with PCU TPU function, the frequency measurement process is simple, the frequency precision is high, the timeliness is strong and the reliability is high. Taking machine frequency measurement as an example, the frequency measurement procedure is as follows: Speed1 FUB LTXcpi8 (1) Fj = f / Speed1.DifCnt * Speed1.PCnt (2) Alias, FUB is an alias call command statement. In formula (2): Fj said unit frequency. f said PCC frequency measurement of the internal clock, up to 6.3MHz count frequency, with high accuracy and reliability of the frequency measurement, so that the governor input channel - a fundamental guarantee frequency measurement. Its frequency measurement accuracy is much higher than the conventional PLC frequency measurement accuracy. Speed1.DifCnt said the counter is added to the number of pulses. Speed1.PCnt said the number of cycles frequency measurement, measurement and then use multiple cycles to find the average, through the initialization process set Speed1.PCnt = 1, so you can ensure the timely measurement frequency. Traditional computer governor frequency measurement In order to avoid the sine wave positive and negative half-cycle asymmetry, need to be divided in order to ensure frequency accuracy. The frequency measurement in the PCC, TPU reads the count value between the rising edges of the two phases of the square wave signal without the need of frequency division, thus simplifying the circuit, improving the reliability of the frequency measurement, and the timeliness of the frequency measurement Doubled. 4.1.2 Digital Valve Control Digital valve control uses the high-speed digital output module DO135 with TPU function of PCC to output pulse-width modulation (PWM) signal according to the difference of electrical opening degree and actual opening degree. After power amplification, it drives Electromagnetic ball valve. Electromagnetic valve control process shown in Figure 2. Taking the control of the guide vane digital valve as an example, the program is as follows: DO4pwm FUB LTXdpwm4 (3) DO5pwm FUB LTXdpwm5 (4) Expressions (3) and (4) respectively call the pulse output function blocks LTXdpwm4 () and LTXdpwm5 (), DO4pwm and DO5pwm are aliases, and FUB alias calls the command statement. 4.2 Electro-hydraulic servo system composition Electro-hydraulic servo system is the executive body, it will directly affect the governor's performance and reliability. Digital valve governor to standard parts - solenoid valve as the pilot valve, instead of the traditional electro-hydraulic converter, proportional valve or stepper motor electro-hydraulic conversion components, with standard hydraulic components - two-way cartridge valve to enlarge the components instead of the traditional The main pressure valve ,. Its work is characterized by solenoid valve on and off control cartridge valve, cartridge valve on and off to control the relay. Electromagnetic valve working state only pass, off two states, which is equivalent to the digital circuit high, low two state (ie, 1, 0), it will be called the digital valve, the resulting tone The speed governor is called a digital valve governor. Using a quick-moving valve and trim valve in parallel hydraulic system. Because the speed valve and the trim valve can control the speed of the relay separately so that they are adjustable, therefore, the digital valve governor can well adapt to different capacity of the relay, to avoid the large unit relay capacity and governor Overshoot and undershoot caused by mismatch of main oil pipe diameter to achieve precise adjustment. Small fluctuations only fine-tune valve regulation, large fluctuations in speed while moving valve involved in regulation, greatly improving the dynamic performance. Cartridge valve seal in the form of cone valve, the cartridge valve has the function of hydraulic lock, cartridge valve zero leakage at 31.5MPa pressure. Relay zero drift after electromagnetic valve power failure, with the function of fault lock. So the series governor has good reason to remove the mechanical feedback. Because of the system's pilot solenoid valve has a manual valve and accident valve function, reducing the internal structure of the governor, so the governor to achieve a true sense of the non-lever, no pipeline; the mechanical part of the structure In the form of integrated block, it can be applied to high oil pressure system of 31.5MPa. Electromagnetic ball valve and cartridge valve have very low requirements on the cleanliness of hydraulic oil, strong resistance to jamming, good interchangeability of parts and components, , Without adjustment; the overall structure is simple, easy operation and maintenance, high reliability. 4.3 governor working process Governor automatic operation, received the boot order, in accordance with the pre-set boot rules boot. When the network frequency measurement is normal, the governor automatically selects the frequency adjustment mode, and the PCC performs PID operation according to the difference between the machine frequency and the network frequency, so as to be ready for fast network connection. When the network frequency measurement fails, the PCC automatically switches to ON Degree adjustment mode, PCC PID operation according to the difference between frequency and frequency given. The PCC outputs a pulse width modulation (PWM) signal according to the difference between the electrical opening and the actual opening, and drives the solenoid valve by power amplification to adjust the opening of the guide vanes to automatically run the unit in the no-load condition. After grid connection, such as for large grid operation, when the power measurement is normal, the power adjustment mode is automatically selected; when the power measurement fails, the mode is automatically switched to the opening adjustment. Such as isolated network operation, automatically select the frequency adjustment mode. Through the host computer or touch screen to change the power of a given value or opening of a given value, the regulator by the PI operation, to achieve load regulation. Upon receipt of the shutdown order, the governor automatically shut down the unit to complete the shutdown process. 5. Digital valve PCC intelligent governor applications At present, there are several digital valve PCC intelligent governor successfully put into operation in the hydropower station. Field test results show that the performance indicators are better than the national standard "turbine governor and hydraulic equipment technical conditions GB9652.1-1997." All commissioned governor did not appear any failure, the operation of the simple operation, maintenance workload is small. Taking the first governor of Yangtou hydropower station in Guizhou Province as an example, the installed capacity of the hydropower station is 2 X 8000KW, the turbine is an axial propeller and the designed head is 18M. Field test results are as follows: (1) speed dead zone: 0.015%. (2) Automatic no-load frequency swing value: ± 0.06%. PID tuning parameters for the no-load disturbance test run out of the preferred parameters, namely: bt = 45%, Td = 20s, Tn = 0.5s, (3) rejection 25% of the rated load, the relay immobility time is 0.18s. (4) rejection 100% of the rated load, the maximum speed up to 133.6% of the rated speed, more than 3% of the rated speed of the crest of a frequency from the first move to the opening of the relay to the unit speed swing value does not exceed ± 0.5% so far experienced the time of 27 S. 6. Conclusion The test results show that the digital valve PCC programmable intelligent governor of the various performance indicators are better than the national standard "turbine governor and hydraulic device technical conditions GB9652.1-1997." It not only solves the defects of the traditional governor, but also meets the requirements of the development of the modern turbine governor and lays the foundation for the unattended operation of the hydropower station. The project product has passed the "national small and medium-sized hydropower equipment testing center" technical testing. And successfully applied in a number of hydropower stations, users get the praise. W Ministry of Science and Technology in 2004 will be "digital valve PCC intelligent governor" identified as innovative fund support projects, Tianjin KeYin Automatic Control Equipment Co., Ltd. has been the Ministry of Science and Tianjin Science and Technology Commission for free funding for the technology Promotion as soon as possible to add momentum.
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