This paper investigates the impact of doubly fed induction generator (DFIG) based wind power generation on the long-Term voltage stability of a power system having dynamic loads such as induction motors. The investigation was carried out using a test system developed in DIgSILENT Power Factory. A detailed aggregated model of a DFIG wind farm is developed as the main source of wind generation. Three different dynamic load models have been used in the study and the results are presented as three different case studies. This research study has shown that the voltage stability is improved for a network comprised of induction motors, when the DFIG wind power generation is added to the system. However, this conclusion is not valid for all types of dynamic loads. Therefore, detailed studies have to be conducted using accurate aggregate dynamic load models to accurately characterise the voltage stability of a network.