Protective systems. Part I: Protective systems for rural distribution up to 33 kV

General principles regarding protection are discussed, emphasis being laid on the importance of considering the prevention of faults as part of the problem equally with their isolation. From an analysis of the causes of interruptions, which show that a large number are only transient, and from the special conditions pertaining to a rural system, it is concluded that it is preferable to restrict the number of points at which automatic protection is provided, in order to facilitate the rapid resumption of supply. The methods of protection adopted in one large rural area are briefly described, together with a summary of the experience gained in operating several classes of equipment, including arc-suppression coils, automatic-reclosing switches and fuse gear.