Experimental Evaluation of DWT-Based Current Spike Comparator for Line Protection

The current spike comparator for line protection is based on the comparison of the sign of fault spikes extracted using discrete wavelet transform (DWT) at both line ends. In this paper, experimental investigation of the current spike comparator is presented. The scheme has been experimentally tested for various fault types covering wide range of fault location, fault resistance, fault inception angle, power swing and switching operations. A digital signal processing (DSP)-based setup is employed in the experimental phase of the study and results are compared with the simulation records. The results showed that, there is some constraints that affect the spike size especially in real-time such as inception angle, high impedance faults, mother wavelet, line model, and channel noise. This scheme is suitable for short transmission lines (R-L mutually coupled model). However, performance is further reduced for long transmission lines (distributed parameter model)