Optimization of retrofit period for control system in thermal power plants

There are thermal power plants constructed in South Korea in 1990s. Usually it is estimated 25-30 years as economic life. On contrary, because the control systems for thermal power plants consist of high-technology electronic components, the economic life is estimated 10-30 years. The large variation is based on operation environment. According bath-tub curve, the faults increases during the beginning of operation after construction completion. and the end of system life. It is effective to retrofit existing system before increase of faults. By the way, it is effective to shorten the period of retrofit of existed system. But, the curtailment of the retrofit construction period causes unit trip. As for this point, it is necessary of optimization of construction period and procedures without unit trips or fault.