Voltage regulation in medium voltage (MV) distribution systems is still widely performed with the aid of substation on-load tap changer (OLTC). An OLTC can be operated with or without enacting the line drop compensation (LDC) module embedded in the OLTC control. However, in case of distribution systems with higher penetration of renewable and distributed generation (DG), it is well known that the DG reverse power flow can increase the number of OLTC tap operations under certain system conditions. On the other hand, voltage correction by DG is one of the promising concepts highly regarded by the researchers and engineers. In this paper, a methodology is proposed for Volt/VAr support by means of DG and dynamic adjustment of OLTC parameters. As an assessment tool, first order sensitivity of the regulating point voltage, estimated by LDC scheme, to change in reactive power support provided by voltage support DG is derived. The simulation studies are carried out on a test system using MATLAB software, and results have demonstrated the accuracy of proposed sensitivity and its application for dynamically updating the OLTC parameters for ensuring effective voltage control with the aid of synchronous machine based voltage support DG.