ABSTRACT
Since the mid-1980s, a number of analog control circuits have been replaced by digital control circuits in power stations and substations in Japan. This is the case for any industrial product, such as automobiles and home appliances, due to the advancement of digital circuit technologies. However, electromagnetic compatibility (EMC) environments are becoming a signicant problem for digital circuits, which are sensitive to high-frequency electromagnetic waves such as switching surges (SS) and lightning surges (LS).
