Openness local control unit of hydropower plant based on Ethernet

An openness local control unit(LCU) based on Ethernet is designed for medium and small hydropower plant.Its hardware and software are introduced.The structure that programmable logic controller(PLC) plus communication manager is presented,PLC and protection devices are connected directly with Ethernet,intelligent equipments with serial communication interface are indirectly connected with Ethernet by the communication manager.IEC 60870-5-104 protocol is adopted in communication between communication manager and master computer,Modbus protocol is used in communication between communication manager and PLC,OPC specification is taken in communication between PLC and mater computer.The LCU runs reliability with better universality,openness and lower cost.