Digital governor for hydraulic turbine
Forty in the electro-hydraulic converter developed by mechanical hydraulic turbine governor to electric hydraulic type, the turbine regulating performance is greatly improved and the function is expanded. However, the electro-hydraulic converter of oil cleanliness demanding, the user is difficult to achieve, often caused by electro-hydraulic converter blocking serious accidents caused by electric power production. Although the use of a variety of measures (such as the use of separate oil, improve oil cleanliness, the sliding sleeve rotates, to increase the sewage capacity etc.) accidents still occur. According to incomplete statistics, the fault of electric hydraulic converter rate for electro-hydraulic governor fault 40-60%, become the key to further improve the reliability of the governor.
Digital hydraulic cylinder simplifies system structure
The digital hydraulic cylinder has the function of the electro - hydraulic converter middle relay, feedback potentiometer and the comparison amplifying circuit. The manual operation can be realized by rotating the hand wheel, manual operation, manual operation and manual operation mechanism are not required, and the system is greatly simplified.
Digital hydraulic cylinder to improve the reliability of the system
Due to the reduction of the component, the failure rate is reduced, and the manual / automatic use of the same oil circuit, when the automatic control system failure, it will become a manual mode. When the fault is eliminated, the system will return to the automatic control mode. Because of the stepper motor in power still has considerable holding torque without mechanical locking and the corresponding control and operation circuit, you can also make the main servomotor to remain in a given position, never for various interference factors caused by relay crawl or unit slip load, coupled with high reliability digital hydraulic cylinder, it consists of system reliability greatly improved.
Digital hydraulic cylinder system can work under a wide range of hydraulic pressure
Because the gain of the digital hydraulic cylinder is much larger than the electro-hydraulic converter, combined with the use of mechanical feedback, so it and electro-hydraulic converter intermediate relay, a potentiometer system compared, oil pressure variation has little effect on, start the pump caused by relay position changes will be greatly diminished or even disappear.
Dynamic and static characteristics of digital hydraulic cylinder system
From the point of view of static characteristics and the position precision of digital hydraulic cylinder is easy to reach 0.1% or better, and intermediate servomotor position accuracy is affected by the potentiometer precision is 0.2% limit will not be higher than the the precision and linearity index, digital hydraulic cylinder can also achieve high performance.
From the point of view of dynamic characteristics, digital hydraulic cylinder can be in 1 second to go with a full stroke, is much higher than that of the control system requirements (2-8 seconds) and the transfer function strictly speaking is a second order process. However, the cut-off frequency of up to hundreds or even thousands of Hertz, much higher than the electro-hydraulic converter frequency level, in the speed control system can be as a proportion of the link. Digital hydraulic wake of cylinder is a hydraulic amplifier, the overall hydraulic system is a first-order process, the regulator loop stability problem does not exist.
Digital hydraulic turbine governor can achieve fast and precise regulation of the turbine, which makes the performance of the system in the grid connected and power transfer greatly improved. The governor in using digital hydraulic cylinder, greatly simplifies the structure, improves the anti-jamming and anti pollution capacity, improved the dynamic and static characteristics, and adapt to the trend of digital, a new technique is worthy to be popularized.