As a countermeasure against the problem of frequency and dynamic stability caused by drops in a large capacity generator, a wide-area special protection system called the Block System Stabilizer (BSS) has been used for the last approx. 40 years by the Kansai Electric Power Company. The conventional BSS has been updated as the Bulk Power System Stabilizer. The new BSS has been developed based on the concept of improving fault detection functions, concomitant with changing the power system configuration from radial to loop, and thereby enhancing human operational functions.