The Application Study Of Local Control System In Hydropower Station Based On The GE90-30 PLC

In recent years, the automatic level of small hydropower stations improved increasingly with the technical reformed and necessary capacity enhanced. Most small hydropower stations combined the general control devices with computer monitored system to realize the automatic control. The control system of different hydropower stations has the distinct characteristics because of the various work conditions and operating requirements. The Tongbai power plant of Tiantai city was a undermined hydroelectric station which was constructed in 1970's. The Tongbai station needs more maintenance work and which security is worse at the same time by reason of the adoption of the routine equipments. This paper rebuilt the hydropower station based on the GE90-30 PLC control system and analyzed the local control unit part of the station.Firstly, the thesis summarized general situation of the hydropower station control system at home and abroad, and illuminated the general frame of control system and PLC's date acquisition, processing and configuration. Considered all kinds of PLC in small hydropower stations and the practical work condition of Tongbai station, the local control system was designed as a high-power programmable controller which comprised industry computers, GE90-30 PLC and electric energy AC sampling devices. According to the function analysis, the hardware part has the modular structure. The program was compiled with the flow manner and the flow pointer was imported to implement the sequence control. The relay interruption was used in every flow step simultaneously to achieve the requirements of hydropower station local control and the unattended operation mode. The trend of development of hydropower station automatic control system was prospected at last.