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

The importance of installing suitable and efficient protective apparatus on rural networks, at all stages of their development is emphasized. A typical protective scheme for an 11-kV and 33-kV rural distribution system which has been put into operation in a particular area of supply is described, and the reasons leading to its adoption are given. The practical difficulties met with in securing efficient operation and of carrying out proper maintenance are discussed. Some statistical records of fault interruptions are presented. These indicate the number and type of faults causing total or partial failures of supply and show the conditions under which the protective gear is called upon to function. The nature of the faults which occur on rural networks is analysed and a suggested standard form of keeping fault statistics is put forward for general adoption by undertakings distributing in rural areas.