This paper describes a simple determination method of the optimal operating threshold in step voltage regulators (SVRs) that allow us to avoid hunting operations even if multiple SVRs are installed in a distribution line, to which photovoltaic (PV) inverters are connected. The SVRs dealt with in this paper have either time integral action type or voltage integral action type. In the case of voltage integral action type, the response time varies according to the PV output fluctuation. In the proposed method, the average response time of voltage integral action type is first estimated with the facility information on the distribution line. Second, the operating threshold of multiple SVRs including voltage integral action type is decided based on the average response time of voltage integral action type. Simulation results showed the method can effectively reduce the number of hunting operations by 75% on average in an example distribution line with PVs.