ARCING FAULT IN SUB-DISTRIBUTION BRANCH-CIRCUITS

It's well known the importance of short-circuit current evaluation for the design of any power system. Every system is subject to faults, mo reover short-circuits and ground faults can be expected in any point. Even if the maximum and minimum values are generally defined with refe rence at a bolted-fault, bolted short-circuits are rare and the fault usually involves arcing and burning; particularly the limit value of m inimum short-circuit depends really on arcing-fault. In earlier experi mental investigations into the functional simulation of insulation los s, in branch circuit conductors, the authors chosed to normalize the a rcing-fault simulation to be used in laboratory tests. This convention al simulation allows to characterize this intrinsically random phenome non by means of a probabilistic approach, in order to define in statis tical terms the expected short circuit value. The authors examine more closely the arcing-fault in the design of sub distribution branch-cir cuits as weak points of the installation. In fact, what they propose a re straightforward criteria, whether in the structure of the system or in the coordination of protection, which afford a more rational contr ol on arcing-fault.