Introducing A New Type of Protection Zone for the Smart Grid Incorporating Distributed Generation

One of the performance criteria of protection is selectivity which aims to minimise the area shut down following fault occurrence. Selectivity is facilitated by splitting the electrical power network into zones. Protection schemes are incorporated into each zone to provide primary protection and back-up protection for external faults. The integration of distributed generators is contributing to the transformation of the power grid to a distributed architecture that incorporates hybrid microgrids and energy storage systems. This transformation impacts the sensitivity, stability and speed of the existing protection schemes leading to possible loss of selectivity, especially at the distribution level. This paper proposes a new type of protection zone, the Busbar Area Protection (BAP) zone that extends to include a busbar and all feeders fed from that busbar. The BAP zone facilitates protection that is able to eliminate the impact of DG integration on selectivity, while significantly reducing the protection component count at a busbar to only one primary relay irrespective of the number of feeders terminating at that node, in contrast to most other protection relaying systems that require at least one relay dedicated to each feeder. The protection operates under smart grid environment with intelligent electronic devices (IEDs) exchanging voltage measurements using peer-to-peer communications.