The 4×6 network: distribution system applications

The authors previously described the 4×6 network switching scheme for power delivery systems with emphasis on substations. It was shown that the 4×6 scheme requires up to 40% fewer breakers than traditional switching schemes and is inherently more reliable. The emphasis in this study is on distribution system applications. It is shown that transformer nameplate capacity can be reduced up to 33% using the 4×6 switching scheme, with equal or greater reliability. Through judicious use of open circuit breakers or other methods inherent to the 4×6 concept, short-circuit levels and ampacity requirements are reduced for further economy. Also, 4×6 facilitates modular construction for distribution substations, permitting use of standardized factory assembled packages of transformers and switchgear for maximum economy