Comparison of high‐speed adaptive and nonadaptive backup overcurrent protection on fuse feeders with sensors

Abstract

Summary In traditional power distribution systems, feeder fuses are coordinated with a backup relay without using adaptive protection and sensors. The backup relay is set by selecting the maximum fuse ampere rating and using the relay's resident functions. Because of this, the backup relay is set at the same inverse time‐current curve for all fuses. In this study, to improve the speed and selectivity of the backup relay at busses with different fuse ampere ratings, the backup relay was set at different inverse time‐current curves depending on the maximum ampere rating of the fuses they are connected to. Tests for the adaptive backup overcurrent protection showed how the backup relay selected the settings based on the connected maximum ampere rating fuse, and the relay speed increased up to 32.86%. The backup relay adaptive protection improved the selectivity and speed for clearing the faults, respect to the nonadaptive protection.

Assessment of the Phase-to-Ground Fault Apparent Admittance Method with Phase/Ground Boundaries to Detect Types of Electrical Faults for Protective Relays Using Signature Library and Simulated Events

“…e protection algorithm for the PGFA admittance method with phase/ground boundaries was performed in a MATLAB/Simulink model, using simulations with a time step of 50 microseconds for the simulated grid events, at the 12.47 kV Riverside-EPB of Chattanooga utility grid. However, in the signature library events (SIGID-931, SIGID-932, SIGID-933, and SIGID-934) for the optical power line sensor deployed on the field at the 46 kV EPB of Chattanooga electrical substation, the sampling frequency of the events was 20,000 Hz that represents 333.33 samples per cycle, based on equation (23), and a time step of 50 microseconds, based on Equation (22). It shows the important role of the sampling frequency in the computational burden process for the PGFA admittance method with phase/ ground boundaries.…”

“…e PGFA admittance method with phase/ground boundaries was evaluated to detect the types of electrical faults by using the grid simulation and signature library event modes. e assessment of protective relay algorithms is usually performed with software simulations and models that represent the ideal current and voltage sensors with relays in the loop [23,24]. en, simulated electrical fault currents are not affected by the saturation of measurement transformers as they would be in a real scenario.…”