Fault Detection of Grid-connected Looped Microgrid Based on Differential Energy Estimation in Time Domain

The proliferation of distributed generation (DG) in the emerging microgrid system is undermined due to substantial challenges associated with the protection. Due to the penetration of DGs, fault level in the microgrid changes significantly. To address this, a simple and fast protection algorithm, based on Teager-Kaiser Energy Operator (TKEO), is proposed in this paper for the protection of grid-connected 14 BUS looped microgrid. This scheme requires the current to be measured from both ends of the line for extracting the energy of the current signal. Further to detect and classify the fault and faulted line, the energy difference of the current signal is used. To verify the effectiveness of this proposed scheme, high impedance fault cases are also studied. This technique is principally relying on the energy difference of currents, not on current magnitude directly; therefore, it can subdue the difficulties that are associated with the dynamic current behaviour of a microgrid. Moreover, it does not suffer from the computational complexity; and thus, inherently fastening the detection process.