Improved relay coordination and relay response time by integrating the relay functions

This paper describes a practical method for improving relay coordination for high current faults by reducing the relay operating times by integrating the relay functions. This results in reduced fault duration at high currents, which minimizes equipment damage. Two examples of relay coordination for a typical distribution system using traditional relays, reclosers and new universal relays are presented. A protection scheme with integrated relay functions has been implemented in a new universal protective relay, which includes modular hardware and software components that can be combined into numerous configurations. It integrates protection, metering, control, communication and programmable logic control (PLC) into a single device. The hardware platform makes it possible to manipulate input voltage and current samples through different algorithms to obtain quantities such as phasors, symmetrical components and frequency. When the quantities are combined, the relay makes faster and more accurate decisions about faults in the system.