Distributed generators (DGs) would be installed in distribution systems. Penetration of DGs may bring some technical difficulties into distribution systems operation. To improve the acceptability for DGs dissolving technical issues, new scheme of system operation should be discussed. The authors have investigated active network reconfiguration in distribution systems utilizing IT switches. This paper presents two online network reconfiguration schemes under the normal operation; one is distribution loss minimization and another is preventive operation for contingency in distribution system. In order to realize the latter scheme, this paper develops a restoration process for the contingencies.