The differences between conventional and smart grid distribution system are shown in Table I. TABLE I DIFFERENCES BETWEEN CONVENTIONAL AND SMART GRID DISTRIBUTION SYSTEM

This paper describes the concept and characteristics of smart grid distribution systems, basic difference between conventional and smart grid distribution systems, functional management and reliability evaluation of smart grid distribution systems. In smart grid distribution system, remotely controlled high rated power electronic switches are used in the place of normal disconnecting switches on feeder. In normal operation of distribution system, these act as normally closed switches. Whereas, in faulted conditions, the computer system at the control center will sense the fault location through the sensors, digital controls, G.I.S and will turn off the power electronic switches to isolate the fault section and as well as operate other protective devices to restore the loads under the un-faulted in less than one cycle period to maintain high reliability of the distribution systems. In this paper, the reliability indices of a radial distribution system for (i) conventional (non-automated), (ii) automated and (iii) smart grid configurations are calculated and the results are compared.