generation or switching loads to adjacent substations, if available, to minimize outages of loads supplied from this type of facility. Cost of a single bus arrangement is relatively low, but also is the operational flexibility; for example, transfer of loads from one circuit to another would require additional switching devices outside the substation. Line connections to a single bus arrangement are normally straight forward, since all lines are
connected to the same main bus. Therefore, lines can be connected on the main bus in areas closest to the direction of the departing line, thus 111itigating lines crossing outside the substation. Due to the low reliability, significant efforts when performing maintenance, and low operational flexibility, application of the single bus configuration should be limited to facilities with low load levels and low availability requirements. Since single bus arrangement is normally just the initial stage of a substation development, when laying out the substation a designer should consider the ultimate configuration of the substation, such as where future supply lines, transformers, and bus sections will be added. As loads increase, substation reliability and operational abilities can be improved with step additions to the facility, for example, a bus tie breaker to minimize load dropped due to bus outages.