Swarm Intelligence-based Directional Relaying Approach for Power Network

In this article, swarm intelligence-based supportive threshold setting mechanism is introduced to enhance the directional relay performance during faults. For the estimation of fault direction, phase angle of positive sequence current (PPSC) is calculated using discrete Fourier transform. Instead of considering the immature decisions based on variation of PPSC directly, four swarm evaluated thresholds are extracted with particle swarm optimization algorithm (PSO) with an acceptable delay. Among four available thresholds, two thresholds are termed as main thresholds and other two are supportive thresholds. Together, three thresholds are involved in the process of detection and estimation of forward faults, and one threshold is used for reverse fault direction estimation. This combined threshold setting mechanism in directional relaying is a new attempt for its performance enhancement. The improvement of the proposed directional relay with supportive threshold setting mechanism is compared with the existing directional relay techniques and the simulation work is carried out in MATLAB-SIMULINK environment. The results carried out in this paper show the enhancement of the directional relay performance with additional intelligent thresholds which produce 100% accurate results against tested cases.