Incremental quantities based relays

In order to ensure reliability of power supply and stable operation of power system, faults should be identified quickly. For this, high speed directional elements have to be developed. It is known that while developing high speed protective elements, reliability is at risk as less data is used to take a decision. In this paper, review of a method for faulted phase detection using incremental voltages and currents is given. This method significantly improves the speed of directional element and this is can be operated in parallel with the conventional mho element to ensure reliability.