Abstract
This paper presents and tests three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types when the MG transferred to the islanding mode. The main contribution of this work is including the models of all micro sources which interfaced to the MG by power electronic inverters. Inverters in turns are provided with current limiters and this also included with the inverter models to exactly simulate the real situation in the MG during fault times. Results proved that the most suitable earthing system for MG protection during the islanding mode is the TN earthing system. That system leads to a suitable amount of fault current sufficient to activate over current pro-tection relays. With using TN earthing system, touch voltages at the faulted bus and all other consumer’s buses are less than the safety limited values during islanding mode. For the two others earthing systems (TT and IT), fault currents are small and nearly equal to the over load currents which make over current protection relay can not differentiate between fault currents and overload currents. All models of micro sources, earthing systems, inverters and control schemes are built using Matlab?/Simulink? environment.
Highlights
The earthing of an electricity supply network requires its network plant and customer electrical equipment to be connected to the earth in order to promote safety and reduce the possibilities of damage to equipment
This paper presents and tests three earthing systems (TT, TN and IT) for Micro-Grid (MG) protection against various fault types when the MG transferred to the islanding mode
It is observed from the results that the most suitable system is the TN earthing system
Summary
The earthing of an electricity supply network requires its network plant and customer electrical equipment to be connected to the earth in order to promote safety and reduce the possibilities of damage to equipment. A MG consists of a cluster of micro sources, energy storage systems (e.g. flywheel, battery, ultra capacitor, ...) and loads, operating as a single controllable system. The micro sources and flywheel are not suitable for supplying energy to the grid directly [11]. They have to be interfaced with the grid through an inverter stage. That unique nature of the MG requires a fresh look into the design and operation of the protection. This is the task of this manuscript. MG network included all micro sources, inverters and earthing system is presented in Sction 4.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
