Voltage Changes in a Medium-Voltage Distribution Network Caused by the Connection of a Wind Farm

This study aimed to analyse how wind-farm location and line-loading characteristics affect voltage variations in medium-voltage distribution networks. Simulations were performed in DIgSILENT PowerFactory using three 20 km radial MV lines with different conductor cross-sections. The wind farm was connected successively at selected line nodes, and its power was adjusted in each case to produce a 3% voltage rise at the point of connection. Three operating scenarios were considered: an unloaded line, a line with a resistive-inductive load and a line with a resistive-capacitive load. For the unloaded line, the voltage rise downstream of the wind farm remained constant at 3%, whereas the source’s effect on nodes closer to the HV/MV substation diminished rapidly, with values ranging from 0.021% to 0.097%. Under load, the voltage-change profiles became non-linear, and the maximum deviations exceeded those observed for the unloaded line. For a resistive-inductive load, the voltage change reached approximately 3.1–3.3%, and the largest deviations occurred not at the point of connection but farther downstream. These findings demonstrate that wind-farm hosting capacity cannot be assessed solely from the voltage at the point of connection. In many cases, the 3% criterion is satisfied at the point of connection while the same threshold is exceeded elsewhere in the network. The full line voltage profile and load characteristics should therefore be considered when planning the integration of renewable energy sources into MV networks.