USING TACS FUNCTIONS WITHIN EMTP TO TEACH PROTECTIVE RELAYING FUNDAMENTALS

The purpose of this discussion is to provide an educational tool for i nvestigating relaying concepts by modeling digital relays using TACS f unctions within EMTP in a closed-loop manner. Various elements of digi tal protection systems are identified and organized to generate an sys tematic approach to modeling the actual hardware of relay systems. Dis cussion is limited to conventional relaying systems that monitor the v itality of the 60 Hz voltages and/or currents. TACS functions for tran sport delay and pulse generators are used to model dynamics associated with analog to digital conversion and sampling systems. DSP algorithm s convert a sequence of sampled data into a sequence of values for mag nitude and phase components. A simple example of a time overcurrent re lay is developed to demonstrate the techniques to implement relay cont rol in EMTP with TACS and illustrates the kinds of phenomena that can be studied using these techniques.