Study On Local Control Unit Of Hydropower Station Based On PLC

Hydropower station's monitoring system is the foundation of hydropower station's integrated automation and it is the precondition to realize the unattended mode too.Along with the speed development of computer technology and electronic technology, the hydropower station's monitoring system with advanced techincal functions and the advantage of stable and reliable running is used widely.While Local Control Unit is the foundation and core of the computer monitoring system in hydropower station and the performance has direct influence on the working status of computer monitoring system.Take LianHua hydropower station as a research object, an introduction was made aiming at Local Control Unit in the hydropower station.The paper analyzed the development of automation technology in our country's hydropower station and described the overall design of the system. The temperature measurement unit, speed governing unit and communication unit in LCU were described in detail in the paper, the design of control programs were made too by using Unitypro programming software. Take Schneider Electric's PLC as a controller, which has had ripe use in hydropower station, temperature acquisition module of 8-channel was used in the system and the temperature data was sent to the generator set's PLC by remote communication. This method can complete the process of temperature data gathering within one second thus shortens the time of temperature gathering. Fast Ethernet of 100Mbps was adopted to communicate between generator sets and the upper machine . Generator sets connect with other local PLC through MB+ net, thus increases the transfer rate of the network.The system used touch screen as human-machine interface in LCU and configurations were made according to the system function,including the interface of generator sets'open and stop control,temperature monitoring interface and the alarm window interface. By now, the improved control system has been put into operation successfully and practice proved that this system could satisfy the request of spot's actual application and could achieve the expected goals, the system has superior performance and great benefits are brought to the hydropower station. All these really lay foudations for unattended mode in LianHua hydropower station.