Recently, photovoltaic generation (PV) has attracted a great attention as one of green power generations. Accordingly a large amount of PV systems will be installed in residential areas in the coming years. In such scenario, reverse power flow caused by PV in feeders may cause some problems such as voltage rise over upper limits in the distribution line, and the reverse power flow into the distribution substation. Battery energy storage system (BESS) is a promising option to solve the above both problems at the same time. However, the effect of BESS depends on location of BESS. Therefore, it is necessary to consider an appropriate location in the residential distribution system to install BESS to obtain an optimal effect. This paper investigates an optimal placement pattern of BESS in the residential distribution system with certain patterns of PV installation. It has been made clear that the obtained results can determine the best placement pattern of BESS with the minimum required BESS capacity and power loss.