A New Differential Protection Scheme for Busbar Considering CT Saturation Effect

The protection of busbar demands high integrity and high speed relaying scheme. This paper presents a new differential relaying scheme for the protection of busbar. The proposed scheme depends on the difference of the value of incoming and outgoing line currents of the respective phase at a particular bus. The proposed scheme has been tested extensively using the PSCAD/EMTDC software package with fault data generated, by modeling the existing 230 kV Indian power transmission systems. The proposed scheme provides stability against external faults, more sensitivity towards high resistance faults and better reliability in discriminating in-zone and out of zone faults. Moreover, the proposed scheme avoids the effect of early & severe CT saturation during heavy through faults.