Power utilities are facing major challenges as the demand of power system is growing exponentially. Therefore, the main attention is focused on Distributed Generation (DG) as they are providing many opportunities for the existing distribution system and becoming one of the key drivers of dealing with its issues. Voltage profile improvement, system loss reduction, reliability enhancement and electricity providing during peak load are the main challenges facing distribution systems. Thereby, the integration of renewable DGs such as Photovoltaic panels can be a good alternative to deal with these challenges. However, DGs integration benefits depend greatly on their placement and control strategy in the network. This work aims at selecting the most sensitive buses of the distribution network for DG units' allocation by means of three different sensitivity methods based on system losses reduction, voltage stability and voltage profile improvement. Advantages of integrating distributed generation are examined using voltage collapse index (L-index), loss sensitivity factor (LSF) and voltage performance index (VPI). These methods were executed on a typical IEEE-39 bus test distribution system using MATLAB tool box PSAT and the results were comparatively analyzed and discussed.