Implementation and Testing of a Hybrid Protection Scheme for Active Distribution Network

This paper describes implementation of a hybrid protection scheme consisting of both transient-based protection and conventional time over-current protection in a laboratory environment. Transient base protection scheme uses initial polarities of current transients to determine whether a fault is in the protected zone, while the conventional protection scheme confirms the existence of fault. The scope of testing is limited to testing the functionality and generic performance characteristics of hybrid protection scheme. The implementation consists of both hardware and software sections including power system modelling, sensor designing and programming of the conventional relay logic. The operation of the hybrid protection scheme is demonstrated using hardware-in-the-loop simulations.