| The pumped storage unit plays the special role in the power system, which runs in turbine-generator mode or pump-motor mode, with many operation cases and frequent transition between cases. The governor for pumped turbine is most important control device, which provides the plant's safety operation and enhances the power system's quality. This paper reviews the improvement of the governor and pumped storage technology, then propose and develop the PLC(Programmable Logic Controller) based double-regulating governor for pumped turbines and the control parameters optimization based on system identification . The proposed governor for pumped turbines is composed of PLC as the core, the stepped motor as the electro-hydraulic transforming part and fluid drive unit. The mixed programming not only makes the system software have good readability and clear logic, but also can use the complex and advanced control strategy. The governor features double regulation for the guide vane and the blade. The intelligent start-up is applied. Compared with the conventional two-segment start-up, the intelligent start-up can make the unit achieve quick start-up, without over speed, independent with the head. The governor regulates automatically the guide vane and the blade in pump operation, to provide the highest efficiency. The governor embedded a test subsystem and the function of failure detection and diagnose. These can be convenient with the operators know the state of the unit group and the governor, easily maintain the governing system. A new PID controller optimization design scheme based on system identification and reference model is proposed. The parameter model of the unit to be controlled is identified. Then, the parameters of the PID controller are optimized in constraint of a set of performance indices. The governor has finished the experimentation in the manufactory. The test results demonstrate: the function is content with the control requirement for all kinds of pumped turbines; it has high reliability; and the performance is better than that specified by China Standard GB/T 9652.2-1997. It will be put into operation in site soon. |
