Abstract
Recently, numbers of distributed generators (DGs) connected to distribution systems have been increasing. The system operators should know how large capacity of DGs can be connected without problems to one feeder or one bank of the system to control the system appropriately. Conventionally, there are many studies on the protection for short circuit faults. However, there is few studies on the maximum capacity of DGs in the restriction condition of short circuit current (=12.5[kA], S.C.C).
The authors deal with sets of DGs that are dispersed on distribution lines widely and limited in the restriction condition of SCC. The maximum capacity of DGs is calculated by quantitative current analysis regarding several parameters such as line length, short circuit impedance of transmittion line and reactance of DGs, etc.
The following can be shown from the numerical calculation result.
The larger short circuit impedance of transmission system or the reactance of DGs becomes, the larger the maximum capacity of DGs becomes. The maximum capacity of DGs increases if the length of system is longer, or the distribution of DGs capacity is increasing linearly to the end of feeder. The maximum capacity of DGs increases if feeder number is more.
