3. Adaptive Numerical Distance Relaying Scheme

Impedance reach of numerical distance relay is severely affected by fault resistance (RF), fault inception angle (FIA), fault type (FT), fault location (FL), power flow angle (PFA), series compensation in transmission and load encroachment. This chapter presents a novel standalone adaptive distance protection algorithm for detection, classification, and location of faults in the presence of variable fault resistance under the influence of outlined parameters. It is based on adaptive slope tracking method to detect and classify the fault in conjunction with modified Fourier transform algorithm for estimation of fault location. Due to the adaptive setting of quadrilateral characteristics in accordance with variation in fault impedance, the proposed technique is highly accurate for detection and classification of faults with error in fault location estimation to be within 1%. Moreover, the proposed technique provides a significant improvement in operating time and estimation of fault location as compared to existing distance relaying algorithms which are the key attributes of multi-functional numerical relay for real-time implementations.