fault detection in microgrids using positive, negative and zero sequences of voltage and current waveforms considering uncertainties of network topology

In this paper a new method for fault detection in microgrids is proposed considering uncertainties of their networks topologies. The new method is realized by wavelet and S transforms. The properties of three phase components and positive, negative and zero sequences of current and voltage waveforms which are used in fault detection, fault location and to determining the occurred fault type are mined by wavelet and S transforms. For this reason that the process of the fault detection in this method is independent from the network topology, so this method is capable to detect occurred faults in all dynamic states of the studied microgrid. To check the ability of the proposed method in fault detection, this method is implemented on a sample microgrid. The simulation results show that the proposed method is capable to distinguish between the occurred faults and the transient distortions in the network. Also the comparison of S transform and wavelet transform shows that although wavelet transform usage exceeds the speed of maintaining a decision, but the accuracy of S transform in differentiate between the occurred states in microgird is the premier property of this transform.