The purpose of the paper is to analyze the
transient stability of an industrial cogeneration system in Hsin-Chu Science-Based Industrial Park using ETAP software. The cogeneration system is installed two 161kV/161kV high-impendence transformers with tap-changer to connect with TPC for decreasing the short-circuit fault current and increasing the fault critical clearing time. The transient stability of three types of operation modes in cogeneration units, 3G1S, 2G1S, and 1G1S, is analyzed. Under the 3G1S operation mode, the system frequency immediately restores to 60Hz after tie line tripping with the TPC. Under the 1G1S and
2G1S operation modes, the system frequency will continuously decrease after tie line tripping with the TPC. The system frequency must perform the load shedding to put back to 60Hz.
