Adaptive Protection Methodology for Modern Electric Power Distribution Systems

Electric power distribution systems have been submitted to major changes related to the integration of communication infrastructure and new technologies such as distributed generators, electric vehicles, energy storage systems, smart meters with two-way communication, and digital protection equipment. However, in most cases, the functionalities available in the digital equipment are not fully exploited and the same protection rules applied to electromechanical relays are practiced. In this context, this work proposes a new adaptive protection methodology using the functionalities present or potentially present in modern protection equipment. A mixed integer linear programming model for the calculation of phase protection settings and a multi-objective mixed integer linear programming model for the calculation of neutral protection settings. Additionally, the use of operating zones, based on the Thevenin equivalent impedance, is proposed to trigger the automatic adaptation of the overcurrent protection equipment adjustments. Tests employing the proposed methodology in a real distribution system show that coordination and selectivity are guaranteed in the minimal operation time for different operation conditions. The results attest to the usefulness and efficiency of the proposed methodology in automating and guaranteeing the correct performance of the protection system. (AU)