Time-domain protection elements: Study and implementation

A new trend in the transmission line protection market is addressed in this paper: the time domain protection. The evaluated functions are embedded in an actual relay which integrates only time domain protection functions, based on the theory of traveling waves (TW) and incremental quantities (IQ) principle. Four protection elements are studied and implemented: two directional elements based on IQ and TW principles, called TD32 and TW32, respectively; an IQ-based distance element, called TD21; and a TW-based differential element, called TW87. To evaluate the performance of the studied time-domain protection elements, a wide variety of fault scenarios is simulated using the Alternative Transients Program (ATP). The obtained results show the modeled functions provide reliable and highspeed tripping, especially in severe fault cases.