Enabler of introducing distributed generators and its effect to power distribution systems

Many distributed generators (DGs) may be installed in power distribution system as the cost of DG decreases and as environmental issues are of more concern. In the power distribution system where a lot of DGs are connected, it is estimated that such problems may occur as voltage wave distortion (deterioration of power quality) and protection of distribution feeders although many favorable effects to the power system are also expected on the other hand. In this paper, the author discusses the effects of DGs in distribution system, and some numerically analytical examples are shown for the effect of DGs in power distribution system. Then, new concepts for the future distribution system are introduced, and how they can cope with the above situation is explained. Among them, FRIENDS (flexible, reliable and intelligent energy delivery system) is selected, and illustrated as an enabler of introducing DGs in distribution system.