Network fault resistance

The importance of the systematic determination of the network fault-resistance of a distribution system is referred to, particularly as regards systems employing cables insulated with vulcanized bitumen, or laid solid in bitumen. Supply requirements necessitate such measurement being made without isolating the mains. For direct-current distribution systems several well-known tests are available: the paper mentions modifications of one method which were successively devised to overcome deficiencies in the original test and to gain more accurate results. With alternating-current distribution, additional complications arise. A simple method has been developed to enable the fault resistance of a polyphase distribution network to be determined with reasonable accuracy and with a minimum of calucualtion. A portable testing equipment for this purpose is described.