Harmonics content based protection scheme for Micro-grids dominated by solid state converters

Protecting Micro-grids containing micro-sources equipped with power electronics interfaces is a major challenge for engineers developing techniques to exploit renewable energy sources for electricity generation. Conventional techniques based on overcurrent protection have major limitations and new techniques have to be explored. The method described in this paper provides reliable and fast detection for different types of faults within the micro-grid. This proposed protection scheme consists of two main stages. The first stage is mainly used to identify the type of the fault and the second stage which utilise the THD to discriminate between the faulted zones and as a result the relay will trip and isolate the faulted section leaving the rest of the network un-affected. Analysis and simulation results are presented for different types of faults within the micro-grid.