Determinação das condições operacionais do sistema de refrigeração de geradores através da análise de parâmetros do modelo equivalente.

Abstract

In Brazil, due to the relevance of hydroelectric generation, regulatory agencies have created indicators to measure the generated energy quality, which, if not respected, the generating agents may be penalized. Therefore, the main types of maintenance must be addressed by the planning sector of the energy industry to seek for high level of availability of the generating units (GU). In general, a GU is composed of several subsystems, such as cooling system, injection and circulation and oil system, among others, which are responsible for maintaining the appropriate operational conditions for the main components. The number of unplanned interventions has increased due to the golden mussel which causes structural damage to hydroelectric generation equipment such as the generator's cooling system. This system captures the upstream water which is distributed to the radiators where the thermal exchange with the generator hot air is carried out. Through the sensors contained in this system, variables such as water flow and temperatures are acquired which allows modeling of an equivalent circuit model, which represents the generator's cooling system. The parameters behavior in this model were analyzed before and after three maintenances in the year of 2018. The methodology of similarity degree analysis creates a generator cooling system intervention need metric which after the maintenance as result has its value decreased from 80% to approximately 20%. The probabilistic methodology detailly evaluates the parameters of the equivalent model according to the classification region in which they are. After the interventions, as result the parameters tend to the same and better classification areas. In conclusion, both methodologies assess the momentary operational condition of the generator's cooling system and allow interventions to be programmed with the regulatory agencies and decreasing the number of urgent interventions.