Development of a real time power system dynamic performance monitoring system

Power systems have grown in both size and complexity, and the dynamic characteristics of the system vary as well. Though the installation of a power system stabilizer (PSS) may improve the dynamic stability problems of the system, it requires accurate system information in the design stage and on-site field tuning after installation. Several examples have shown that the PSS did not reach its expected performance due to inaccurate system characteristics that were used to determine the parameters of PSS. Therefore, more system operation information is needed to design and/or justify the installation of a PSS. An instance of poorly damped oscillations was observed in computer simulation between the tie-line of an industrial co-generation power system and the utility grid. In order to collect more operating information without affecting the system security, a programmable logic controller (PLC) based dynamic performance monitoring system (DPMS) which can detect and record both large and small scale oscillations on the tie-line was designed and installed at the substation. The recorded information will be valuable for system analysis and/or PSS design. A detailed description on DPMS and its laboratory testing results are discussed in the paper