This paper presents an application of the probability-based analytical procedure in the framework of the adequacy assessment problem for bulk power systems. The proposed procedure includes two stages. At the first stage, generation capacity allocates between load buses in proportion with their power. Secondly, real power flows are distributed proportionally to the voltage angle difference, which helps to account for power losses in the power system adequacy indices assessment. The results show that power losses significantly affect the resultant adequacy indices of a bulk power system, therefore power losses analysis should be considered as an essential part of the adequacy assessment process. The proposed mathematical models and algorithms have been tested with a sample power system. For comparison purposes, the Monte Carlo simulation technique have been used as a benchmark. The comparison of the case study results has shown a high computational efficiency and an acceptable accuracy of the proposed probabilistic-analytical method (PAM).