Yoshihiro Kitauchi

Experimental verification of fuzzy excitation control system for multi-machine power system

A fuzzy excitation control system (FECS), based on the fuzzy theorem and having the function of both AVR and PSS, was established to improve power system stability. This paper includes the results of experiments of the FECS on the AC/DC power system simulator of the CRIEPI. The FECS is compared with the conventional quick-response excitation system with optimized PSSs on a 4-machine long distance fish-bone type power system and various system configurations. The results show that the FECS increases the power transfer limit more than 20 (%) without any parameter tuning.

Influence of voltage sags on the power system with high penetration of photovoltaic power generation

The influence of voltage sags on systems with high penetration of photovoltaic power generation (PV) should be clarified not only for low-voltage networks but also for medium-and high-voltage networks. Because the Fault Ride Through (FRT) requirement is a promising solution for mitigating such influence, its improvement effect on voltage response was examined using a realistic model of the system in Japan including medium- and high-voltage networks. It was revealed that the slow voltage recovery phenomenon will occur following voltage sags due to the dynamic behavior of the PVs regardless of the FRT requirement. The results showed that the FRT requirement significantly improved the dynamic voltage response following voltage sags in case of no self-disconnection of loads. However, with self-disconnection of loads, the requirement could cause high post-disturbance steady-state voltages, leading to rejection of the PVs due to overvoltage relay operation.