Wavelet operated single index based fault detection scheme for transmission line protection with swarm intelligent support

In this paper, an optimal wavelet operated single index-based relay is proposed for power transmission line protection. Apart from existing usage of wavelet transform in fault detection studies, swarm assistance is provided for optimal setting of threshold values for accomplishing fast and reliable detection of faults. For this threshold assistance, particle swarm optimization (PSO) is used. Here, three individual instantaneous current signals of three phases is processed through discrete wavelet transform and based on extraction of frequency coefficients, a unique fault detection index is designed. This way of threshold setting reduces excessive computational burden and produces 100% reliable results without violating accuracy during normal and extreme operating conditions of faults in a quick time. The performance of proposed method is evaluated by its own swarm intelligence in the process of optimal search of threshold by extensive case studies. This is not possible with manual checking of threshold by random case studies. All the results are carried out in MATLAB/SIMULINK environment.