Service Restoration in Distribution Systems with a Load Tap Changer

Distribution network restoration can be achieved by changing the operational state of sectionalized switches (SS) and tie switches (TS). Service restoration aims to optimize radial topology with minimum out-of-service loads plus the minimum number of switching operations to meet consumers' satisfaction. In this paper, the sequential opening branch (SOB) has been proposed with method theory of graph based on buses connectivity to check radial structure. To further improve voltage profile, power loss as well as out-of-service loads, Tap Changer has been proposed. The tap changer operates by altering the number of turns at the primary side transformer; therefore, linearly regulating the output voltage. Three case scenarios of the tap changer have been proposed, namely, on-load, off-load, and on-load with DGs. To verify the effectiveness of the method as well as tap changer in service restoration, the standard IEEE 33 buses and standard IEEE 69 buses have been tested with two different load levels.