Solar thermal plants are among the most promising technologies to replace fossil fuel standing applications. Among solar thermal technologies, parabolic troughs are considered as the most mature application in the market. The objective of this paper is to elaborate on comparison results of three different topologies of solar parabolic troughs field, in terms of performances and energy production. Thermolib software was used to perform the proposed power plants simulation with direct steam generation. Applying the proposed models. These models simulate the behaviour of both the solar field and the power block of a 1.2 kW solar thermal power plant. The results of this analysis demonstrating that the use of steam separator and superheater in a stand-alone solar power plant model is more advantageous in terms of steam temperature, steam quality and net electricity production in comparison to other models. The optimum topology showed that the maximum temperature of steam outlet reach 221°C, steam quality reach 1 and efficiency of power plant around 19.6 for model 3. © 2018 The Authors, published by EDP Sciences.