Most market operators provide daily data on several market processes, including the results of all market transactions. The use of such data by electricity market simulators is essential for simulations quality, enabling the modelling of market behaviour in a much more realistic and efficient way. RealScen (Realistic Scenarios Generator) is a tool that creates realistic scenarios according to the purpose of the simulation: representing reality as it is, or on a smaller scale but still as representative as possible. This paper presents a novel methodology that enables RealScen to collect real electricity markets information and using it to represent market participants, as well as modelling their characteristics and behaviours. This is done using data analysis combined with artificial intelligence. This paper analyses the way players' characteristics are modelled, particularly in their representation in a smaller scale, simplifying the simulation while maintaining the quality of results. A study is also conducted, comparing real electricity market values with the market results achieved using the generated scenarios. The conducted study shows that the scenarios can fully represent the reality, or approximate it through a reduced number of representative software agents. As a result, the proposed methodology enables RealScen to represent markets behaviour, allowing the study and understanding of the interactions between market entities, and the study of new markets by assuring the realism of simulations.The restructuring of Electricity Markets (EM) has created a new design of the electricity sector, becoming a new global trend. The monopoly model gave way to a non-vertical structure that allows the development of a free competition market, as it allows the liberalization of potentially competitive segments, such as production, transportation and distribution [1]. These changes provide conditions for the establishment of a more competitive market but also more complex, where the laws of supply and demand stimulate the quality of service, reduce costs and increase efficiency. The growth of complexity creates new challenges, namely the difficulty in decision making due to markets unpredictability and the high number of associated variables [2].Simulation started to play a key role in supporting decision-making in the electricity sector. It allows studying and analysing the profiles and strategies of market participants and, thus, model market behaviour and forecast proposals [3]. Such characteristics enable the establishment of conditions conductive to decision making, turning the simulators into essential tools to support the necessary decisions on major investment environments.Simulation tools applied to EM are designed to help market entities to respond efficiently to market unpredictability. Each one of the surrounding entities may present different behaviours resulting from the context and its goals, having an immediate impact on the results obtained in the market [4]. Therefore, simulators allow to perform a stu...