The Research About The Microprocessor Protection Device Base CAN Bus To The 35kV Power Line

With the developing of the computer network and the chip technology, the performance of controlling chips has been advanced greatly, the cost of them is reducing and the network almost go deep into the each corner of our life. The control network of field-bus control also plays an important role in the industry and other control system. Sine nineties of the twentieth century, the automatic control system has being transferred from DCS (Distributed Control System) to FCS (Field-bus Control System). In the 21 century the FCS will be the mainstream in the control field.Aimed at the defects of the product in existence, our line protection relay for 35kV no person switching station takes CAN bus as the system communication bus, which keeps ahead in the industry control. In the designing for hardware and software, the advanced idea and technique project are used.This paper describes the features and structure of CAN bus and based on it's principle, gives the connection of each protection unit with the system computer .The protection unit is based on the MCU of PHILIP's P8Xc591, which performs A/D conversion, protection and communication.Adopts the software architecture of real-time operation system, analyzes the characteristic of electric failure signal, discusses the differential filter, sine-cosine orthogonal filter that can pick-up the valid fundamental wave and harmonic and discusses the complex digital signal composed by them.Finally, explains that this scheme is viable according to the practical operation of this device.