Advanced distance relay characteristics suitable for dynamic loading

Modern distance relays are designed with different characteristics in order to demonstrate that they can provide better protection and at the same time results in significant improvement of the performance of distance relays during wide area disturbances by preventing the operation of distance relays under dynamic load conditions. However, blocking the operation of the distance elements if a fault occurs at this time may result in a further degradation of the system conditions. The paper discusses in detail the effect of dynamic loading on different types of distance relays. Advanced microprocessor based relays offer a variety of different characteristics and functions that provide sufficient resistive reach to cover the expected range of fault arc resistances, while at the same time are not affected by encroachment of the load impedance in the distance characteristic.