Abstract: The digital valve PCC programmable intelligent governor is a project funded by the Ministry of Science and Technology Innovation Fund. The electrical part is based on the PCC programmable computer controller. The software adopts high-level language. The electro-hydraulic conversion part adopts electromagnetic ball valve. The mechanical amplification component adopts two Through the cartridge valve, using no lever, ignoring pipeline structure. The practical application shows that the governor is easy to debug, easy to maintain and has advanced technical performance and high reliability. Keywords: intelligent governor PCC digital valve electromagnetic ball valve cartridge valve Yangtou station is located in Tongren City, Guizhou Province near the installation capacity of 2 X 8000KW, the turbine turbocharger shaft, head design for the 18 M. The original governor for a factory production of analog electro-hydraulic governor, mechanical control part of the use of electro-hydraulic converter, two amplification part of the main pressure valve, relay and main pressure valve open-loop no feedback; electrically Using analog electronic regulator, anti-jamming performance is poor; automatic operation, often malfunction. Since put into operation, with the long run, mechanical wear and tear, the aging of discrete electrical components seriously affect the safe operation of the unit. The main problems existing in the original governor are: 1) poor anti-jamming effect. Governor of the higher oil quality, often stuck, can not guarantee long-term automatic operation. 2) operation is not convenient. Due to mechanical wear and tear of the main pressure valve leakage caused by the relay drifting, and no feedback during manual operation, the operating staff must always continue to adjust, labor-intensive. 3) poor anti-interference ability. Any electromagnetic interference may cause the governor to malfunction. 4) Maintenance inconvenient maintenance. Too many adjustment steps, after each repair, only need to adjust the various throttle on the number of days. 2. Reconstruction program For the specific conditions of Yangtou hydropower station, draw up the following reconstruction plan: Plan one. Use ZFST-100 digital valve PCC programmable intelligent governor to replace the original governor. The use of mechanical and electrical cabinet form. Option 2. Retain the original governor main pressure valve, remove the original governor in addition to the main pressure control valve other than the use of stepper motor instead of electro-hydraulic converter, the use of PCC programmable intelligent regulator to replace the original analog electronics Regulator. The use of mechanical and electrical cabinet form. As the main pressure valve structure for the spool valve, the main pressure valve piston and bushing caused by the gap between the inevitable leakage, in order to reduce the main pressure valve piston and bushing leakage between the To the main pressure valve piston disc and bushing and the window to increase the lap between the volume, and the amount of overlap to increase the governor mechanical dead zone. Due to the inevitable leakage caused by the gap between the main pressure control valve piston and the bushing, mechanical feedback is required to compensate for manual operation, otherwise the relay will drift. As Yangtou hydropower station speed control system did not use mechanical feedback. Therefore, in the transformation of equipment, we must use no wire rope feedback (or lever feedback) structure, only the use of electrical feedback. Such as the use of the second program that is to retain the original governor main pressure valve, manual run-time load. Due to the load, increase the labor intensity of the operator. The solution using a digital valve governor can solve this problem. In summary, the use of a program is the best. In order to meet the requirements of safe and stable operation of the generating units and to realize "unattended" (less-manned) hydropower stations, Yangtou Hydropower Station of Tongren Local Power Company has been investigated and selected as a next-generation governor developed by Tianjin KeYin Automatic Control Equipment Co., Ltd.: ZFST-100 digital valve PCC programmable intelligent governor, the original governor has been the transformation of the whole transformation, the first to achieve the axial turbine blade set on the application of digital valve + programmable computer controller Intelligent governor. 3. Digital valve PCC programmable intelligent governor combined with the particularity of turbine governor, ZFST-100 digital valve PCC programmable intelligent governor, the choice of a new generation of programmable logic products other than conventional PLC-PCC, from the shellfish B & R2003, a programmable computer controller imported by B & R. It is for the automation process, rather than for the relay logic simulation, which is the B & R2003 concept. PCC represents a completely new concept of control that integrates the standard control functions of programmable logic controllers (PLCs) and the time-sharing multitasking operating system functions of industrial computers. 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. CPU operating efficiency, user memory capacity. These advantages provide a powerful resource guarantee for intelligent turbine governors. In the electrical machinery conversion, the use of electromagnetic valve instead of electro-hydraulic converter; In the amplification stage using two-way cartridge valve instead of the main valve. Governor generally reduces the oil quality requirements, fundamentally avoided the drawbacks of the electro-hydraulic converter card. As the digital valve technology is the use of high-speed solenoid valve as the pilot valve to two-way cartridge valve-based valve, and cartridge valve seal in the form of cone valve, the digital valve has a hydraulic lock function, effectively avoiding the relay Of the drift, so the main relay without mechanical feedback. So digital valve governor in Yangtou hydropower station applications, with the smallest changes to achieve the purpose of transformation of the machine. As the system of pilot solenoid valve with manual valve and accident valve function, reducing the internal structure of the governor, structurally reduced the entire governor system. Therefore, this type of governor to achieve a true sense of the non-lever, no pipeline; in the form of integrated block structure, simple and neat appearance, high reliability, excellent performance. Because no mechanical feedback, this type of governor in the layout of the unit without any restrictions, plant neat and beautiful. 3.1 The main features 1) The new control concept. Using a new generation of programmable computer controller different from the conventional PLC --PCC, oriented control process, can use high-level language, analysis and computing ability, in the same CPU can run different programs at the same time. 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. The average MTBF for conventional PLCs is 300,000 hours. 3) The advantages of multitasking. 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, non-other conventional PLC can be compared. 4) intelligent governor. Adopt adaptive variable structure, variable parameter parallel PID regulation. Automatic identification of the nature of the grid, and automatically adapt to the various special operation of the power plant, such as isolated network operation, and by the large grid solution to the small grid operation mutation 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. 5) 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 PCC signal synthesis and control pulse output. The electrical opening of the regulator (digital signal) and the actual displacement of the relay converted into a digital signal are compared internally by the PCC to output the control pulse signal. The amplified pilot signal directly drives the pilot solenoid valve. Give full play to the PCC multi-tasking capabilities. 7) Easy networking. With RS232 or RS485 communication interface, you can easily achieve man-machine dialogue, and communication with the host computer to improve the level of automation of power plants. 8) Flexible adjustment mode. Can achieve frequency adjustment, opening adjustment, power adjustment, and can be achieved between the adjustment mode without disturbance switch. 9) The large memory of the PCC provides a resource guarantee for the intelligent governor. User Memory: 1.5 MB FLASH PROM, much larger than the conventional 10KB memory. 10) Electromagnetic valve as the electro-hydraulic conversion element. Completely solve the conventional governor electro-hydraulic conversion components issue of oil issue, so that power plants can be completely reliable automatic operation. 11) Can adapt to various special operation modes of power station. Such as isolated network operation, and by the large grid solution for small grid operation mutation load and other special circumstances, can ensure the stable operation of the unit. 12) Function with fault lock ingot. Because the digital valve only on / off two states, and digital valve cone valve seal can be guaranteed without leakage at 31.5MPa, so the digital valve has a hydraulic lock function, so the series governor disappears in the frequency measurement signal and Power off, etc., with fault lock ingot function. 13) 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. 14) 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. 15) 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. 16) using digital association method. Paddle servo system with high accuracy. 17) zero disturbance hand / automatic switch. Due to automatic operation, the electromagnetic valve is in a loss of power after each action; and cut off the power that is manually operated. During manual operation, the electronic regulator tracks the actual opening of the relay. So digital valve governor to achieve zero-disturbance hand / automatic switch 3.2 The main function ZFST-100 digital valve PCC programmable intelligent governor with automatic, electric manual, manual three modes of operation, and can be unconditional bumpless switch . Has many functions, practicality is very intelligent, in addition to the conventional functions have the following main functions. 1) No-load operation, the system can automatically track the frequency, fast and network. 2) With 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 issue a warning signal. 4) The communication with the host computer function, to accept the host computer control commands to the host computer to send the relevant information. 5) Open stop intelligent control. 6) with parameter memory function. When the power is lost, the PCC can save the contents of the data memory, so that operators can easily modify the parameters and be memorized. 7) With water level adjustment. 8) 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. 9) AC and DC dual power supply, when the AC power failure, the DC power automatically, DC power failure, keep the current opening unchanged. 10) No-load operation, when the machine frequency signal disappears, the opening will be kept below the no-load opening to prevent over-speed. When the machine frequency signal disappears, it will automatically switch to the network frequency measurement circuit, keep the normal power generation operation, and send out the machine frequency fault signal at the same time. 3.3 governor working process digital valve PCC intelligent governor block diagram shown in Figure 1. When the governor is running automatically, it will start up according to the preset power-on rules after receiving the power-on order. 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 being connected to the grid, if it is running for the large power grid, it will automatically switch to the opening adjustment mode. Such as isolated network operation, automatically select the frequency adjustment mode. Through the host computer or touch screen to change the power set point, 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. 4. The field test results were carried out on-site static and dynamic tests, the first governor field test results are as follows: 1) speed of the dead zone: 0.015% 2) no-load disturbance test governor automatic operation, select multiple PID tuning parameters, select Frequency swing value and overshoot smaller, stable fast, the regulation of a small number of adjustment parameters as a no-load operating parameters, namely: bt = 45, Td = 20, Tn = 0.5 on the disturbance: 48.00Hz to 52.00Hz, Under the interference: 52.00Hz to 48.00Hz PID adjustment parameters on the interference / under the disturbance of the highest (low) value (Hz) the number of adjustments (times) adjustment time (s) bt = 45 Td = 20 Tn = 47.46 1 7 3) The no-load frequency swing value will switch the governor to automatic position. The PID adjustment parameter is the no-load operation parameter optimized by the last step test. The unit will open to the rated speed. After the unit is stable, observe the unit frequency swing value, every three minutes, a total of three times, take the average swing value. Maximum value Minimum value Fj (Hz) 50.03 49.98 Fj (Hz) 50.02 49.96 Fj (Hz) 50.04 49.99 Automatic no-load frequency swing value: ± 0.06% 4) 25% of the rated load rejection, the relay immobility time of 0.18s. 5) 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) sudden load test sudden increase, sudden 25% of the rated load, very stable to a new condition, fully in line with the actual operation of the power plant. 5. Conclusion The test results show that all the performance indexes of ZFST-100 digital valve PCC programmable intelligent speed governor produced by Tianjin KeYin Automatic Control Equipment Co., Ltd. are better than the national standard "Turbine governor and hydraulic device technical conditions GB9652 .1-1997 ". The first one has been put into operation for two years and the second has been put into operation for one year. Practice shows that there is no fault on the governor, the operation personnel are easy to operate, the maintenance workload is very little, the labor intensity is greatly reduced, Operating personnel. The governor fully meet the power station "unmanned" (less watch) requirements. The successful transformation of the governor has brought considerable economic benefits to Yangtou hydropower station. References [1] Rice Jianguo. Improvement of conventional digital PID regulator algorithm. Large Motor Technology, 1998 (4) [2] Qi Rong. Principle and Application of Programmable Computer Controller. Xi'an: Northwestern Polytechnical University Press, 2002. Liu Zhongliang male, engineer of Tianjin KeYin Automatic Control Equipment Co., Ltd., engaged in research and development of turbine governor. Mi Jianguo male, master, Tianjin KeYin Automatic Control Equipment Co., Ltd., senior engineer, engaged in turbine governor research and development work. Wang Zhongjiang Male, Tongren City, Guizhou Province, local power company engineers, company management and power plant electrical design work.
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