On The Processing Of The Recorded Data For The SF6 Circuit Breakers From The Transformation Substation 110/20/6kV Craiova South

The assurance of the reliability for the transformation substations is one of primary goals of the manufacturers and distributors of electricity. Therefore, a proper monitoring and maintenance program is required. The circuit breaker is a complex device, subject to the thermal and mechanical stresses during the normal or fault currents switching. The substations are frequently equipped with SF6 circuit breaker. The circuit breaker components subjected to the thermal stresses are the main contacts which suffer electrical erosion and the nozzle which is subjected to the ablation process. The ablation process appears because of the energy radiation which is transferred from the electric arc. As a result of the ablation, the nozzle geometry, the gas pressure and the electric withstand are changed. Based on the recorded data from the transformation substation 110/20/6kV Craiova South, the mass loss from nozzle, the admissible number of disconnections and the throat nozzle diameter are computed. The graphical representations highlight the impact of the interrupted current, of the arcing time and of the integral I2t over the mentioned ones. Consequently, if the switching process and the time arc value are controlled, the thermal wear can be limited and the equipments users may provide a maintenance program with minimal costs and an increasing of the lifetime.