The document discusses numerical distance relays and their advantages over old distance protection. It explains that numerical distance relays divide voltage by measured current to determine impedance and detect faults between the relay and reach point if impedance is lower than the reach point impedance. It also notes that numerical distance relays provide reliability, selectivity, suitability, sensitivity, speed and compatibility with IEC61850 standards. The document recommends retrofitting old distance protection with numerical distance relays.