Proliferation of renewable energy sources (RESs) has increased the reliability and flexibility in the operation of the power networks. Nevertheless, different technologies of RESs with different sizes and grid-connection technologies may impose threats to the power grid's stability. This paper targets transient stability in distribution networks. More specifically, this paper investigates the allocation of different types of distributed generations (DGs) considering the maximization of transient stability margin. The latter maximization helps to minimize the deterioration of the inverter-based DGs. The transient stability based objective function (OF) basically relies on the critical and clearing angles. Besides transient stability, the improvement of voltage profile and minimization of power losses are taken into account. The proposed algorithm is implemented on the IEEE 33-bus test system and furthermore, several scenarios are conducted to ensure the effectiveness of the proposed algorithm under fault conditions.