Abstract—This paper proposes a method to determine the Line Drop Compensator (LDC)-control parameters of an On-Load Tap Changer (OLTC) and Step Voltage Regulator (SVR) using a database with measured data from offline IT-switches. In a conventional determination method, the parameters are calculated based on the relationship between the sending voltage and the absolute value of current at the secondary side of the OLTC/SVR with a fixed power factor. However, the power factor changes with the interconnection of the Photovoltaic (PV) system. Hence, in the proposed method, LDC-control parameters are determined by the relationship between active current, reactive current, and sending voltage. In other words, the parameters are determined from the plane by taking these values as axes. The plane is determined by four measured data extracted from the database which have large voltage fluctuations in response to severe power flow. The effectiveness of the proposed method is verified by numerical simulations using a distribution system model with PV systems. Our results show that the proposed method can improve the amount of voltage violation by 35% compared to a conventional method.