Distributed generation: Exploitation of islanding operation advantages

The operation of distributed generation (DG) as an island still gives room for discussions between utilities and customers, both as owners of distributed generators. For the utility company, operation in an island of generators (islanding) whose control is in the consumerspsila hands, could cause a high risk of equipment failure and compromise personnel safety. Thus, utilities are normally opposed to islanding existence, demanding immediate disconnection in case of power supply shutdown. On the other hand, for customers who own DG, in auto-generation or cogeneration forms, islanding can represent the continuity of operation under conditions of reduced power, lower power quality, and limited production capability, with much smaller economic losses to those who would experience deep voltage sags or total blackout. A critical analysis of the situation is presented for the industrial customer, especially from the operation, protection and control point-of-view, in order to get maximum benefit of the islanding operation. The use of semi-rigid connection between the customer and utility is discussed. Steps and precautions for passing from and toward islanding are also analyzed.