This paper presents an analysis to show the impact of wind generation with different penetration levels and dispersion on the system voltage profile and the system reactive power requirement. Several scenarios with penetration levels from 5% to 35% and dispersion of wind generation have been investigated on a modified IEEE30bus network. The effects of the variation of reactive power requirement ranging from lower penetration levels (i.e., 5% to 15%), to higher penetration levels (i.e., 20% to 35%) is studied in details with a test system. The results obtained from different scenarios show that wind generation does not necessary contribute towards improving the transmission system voltage profile. Different wind penetration levels and location indeed changes the system operation. It also gives a signal to the utility on what penetration level and location is optimal with respect to reactive power losses and voltage profile, when confronted with sites having similar wind regimes.