Design And Development Of DCS Isolation Device

Distributed Control System(DCS) requires communication with external system,which mainly consists of Supervisory Information System(SIS) and Management Information System(MIS). SIS and MIS are connected with DCS as well as the Internet,which causes the invasion of the viruses and malicious programs, finally resulting in the fault of units. Therefore, the isolation measures between DCS and SIS is very important.In recent years, the research of DCS isolation technology has made great progress, which guarantees the safe operation of generating units.In this paper, firstly the development of the DCS isolation technology in recent years is introduced. After analyzing the pros and cons of different DCS isolation measures such as bridge protocol, firewall technology and the one-way physical isolation device, the design requirement of DCS isolation device is concluded and an idea of communication isolation hardware based on FPGA is put forward. In the aspect of hardware design, UDP is selected as the internal Ethernet protocol, which implements in FPGA as four sub-modules, sending, receiving, buffer and check. While ensuring real-time and reliability of internal communication, the module of monitoring and replacement is added to ultimately achieve capabilities of unhindered pass-through in positive direction and data isolation in the reverse direction after massive simulation and debugging. In software design, application program of upper computer network monitor is capable of logical configuration after analyzing the data package through the isolation device. A network monitoring algorithm based on Mac address statistics is introduced,which predicts and detects the abnormal communication according to the usage frequency of individual Mac address and finally serves logical configuration with reliable reference, the threat level of corresponding addresses. After all, the developed DCS isolation device of FPGA with the upper monitor algorithm together guarantee the system transmitting data one way out of the system while providing a quantified monitoring safety standard, thus checking the data security of DCS.