Abstract
In urban area, there are growing needs to ensure a bulk power distribution, a service reliability and an interconnection to dispersed-generators. It is effective to improve Network Distribution System for the above view. Regular Network Systems are often used for the area, but coordinations of the protection are complex as usual.
This report describes the protective coordinations of the regular network system that performs a bulk power distribution and includes dispersed-generators. The interconnections influence the coordination of substation protective relays and network protectors at the primary feeder fault. The increase of the network currents associated with the bulk network system makes the protection difficult at low-voltage grid cable fault.
