Adaptive real-time protection scheme for distribution networks with high penetration levels of renewable energy resources

Abstract

The increasing demands of electrical power have imposed a necessity to integrate renewable energy power sources (REPS) into electrical power networks. The presence of REPS within electrical distribution networks mandated an update in the settings of the overcurrent protection relays. In this paper, a real-time adaptive protection scheme is proposed to redefine the settings of the overcurrent protection relays by replacing the traditional time multiplier setting (TMS) with a newly proposed real-time adaptive time multiplier setting (ATMS). The proposed ATMS is formulated as the product of two factors namely; the acceleration factor (AF) and the tuning factor (TF). The AF is set as the ratio of the impedance seen by the relay during a fault to the pre-fault impedance. The TF is a multiplication constant that is determined offline prior to operation in order to optimize ATMS. The scheme was tested upon different radial and meshed bench-mark testing systems; the IEEE 34 system and the IEEE 30 bus system employing MATLAB software package. The proposed scheme proved its capability of optimizing the response of overcurrent relays and minimizing total operating time. In addition to its adaptability to different operational and loading conditions during the day.