System Improvements Enhance the Reliability of the Power Plant Distributed Control System (DCS)

摘要

TAEAN TPP unit #1~#4 - bituminous coal firing plants, 500 MW/unit - suffered five times unit trip and twice sharp declines of power generating since 2001. The problems had happened frequently during operation, which were caused by the DCS communication error, faulty module and more seriously the communication error of DCS system redundancy for the plant operation safety insurance. We started the DCS system operation to have stable improvement from the basic. The improvement of DCS operation environment were followed by installation of the thermo-hygrostat to keep the air conditioned and by replacement of mat in front of electronic room to prevent dust from going into the room. In addition, we checked the grounding system on each DCS cubicles, upgraded the module EPROM, removed the remote bus (control network) communication noise and tuned frequent event telegram sources. And we finally analyzed the problem and found a solution to error messages in the CDS (Control Diagnostic System). We replaced modules that had possibilities of making fault. Moreover, we tested the redundant system with switching simulation while the plants were not in operation. After 3 years of effort and hard working of the engineers, the performance for the DCS operation environment and system checking had enhanced, also most of DCS operational problems are removed now. In conclusion, the plants have been working well without causing past DCS fault by communication error or module fault since Oct. 2005.