School of Electrical Engineering, Vellore Institute of Technology, India
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A cluster of distributed generation (DG) is a Microgrid (MG) and load which acts as a heavy load or source in the context of actual grid. The sudden gust in the microgrid causes rise in fault current which surpasses the shortcircuit limit of network equipment by microgrid connection and also the increase in penetration of DG into the grid, the fault current level is also increased simultaneously. In order to overcome this problem, fault current limiter (FCL) could be arranged between the main network and microgrid. There are different types of FCLs, which have various designs and are made of various superconducting materials. Superconducting Fault Current Limiter (SFCL) is revolutionary protective device which has the ability to lower the fault current level within the fault current first cycle. The application of the SFCL would not only reduce the burden on network devices, but also offers connection for the betterment of the power system reliability. SFCL’s are broadly classified into three types: inductive, resistive and hybrid SFCL. In this paper, general characteristics of FCLs, the operating characteristics, current limiting capabilities ofSFCLare introduced into a simplified microgrid model system which is finally allowed that SFCL could reasonably bring about the function of microgrid stability improvement and fault current suppression.
Keywords: Distributed generation (DG), Microgrid (MG), Superconducting Fault Current Limiter (SFCL), fault current limiter (FCL), relays.
1PMO Specialist, KMD A/s Denmark
2Associate Professor, Department of Electrical Engineering, Veer Surendra Sai University of Technology, Burla, Odisha, India
3Assistant Professor, Department of Rail Road and Electrical Engineering, Woosong University, Daejeon, Republic of Korea
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To ensure the seamless working of the microgrid, another Smart Grid tool- the Fault current limiter (FCL) has been proposed to suppress the fault currents to the level such that the requisite protection coordination is possible. The FCL suppresses the fault currents from the utility grid and acts as a solution to the directional overcurrent relay coordination problem within the microgrid. The FCLs are unique in the way that they are ‘invisible’ during the normal unfaulted operation of the power system but come into picture at the time of fault. The contributing reactance from the FCL is instrumental in reducing the fault currents flowing inside the microgrid from the incoming transmission feeder during the time of fault. In this paper reactance FCLs are only being used for coordination of directional overcurrent relay (DOCR) settings. Symmetrical three phase faults are considered for relay coordination. The distributed generation (DG) considered here is the conventional synchronous generator directly connected to the medium voltage networks. The proposed solution is tested on a radial distribution system (the benchmark Canadian distribution system model) of 9 bus which is adequately connected to DGs within the microgrid. Further investigation of the proposed method has been carried out for three configurations i.e grid connected, islanded and dual. It is observed from the simulation results that the operating times of relays in the grid connected configuration are similar to the operating times of the relays in the islanded mode when the optimal settings are done for the dual configuration mode and the optimizer is unable to find out any setting for both configurations without the help of FCL in the incoming feeder within the given range of relay settings.
Keywords: Fault Current Limiter, Microgrid, Evolutionary Algorithm, Distributed Generation.
School of Electrical Engineering, Vellore Institute of Technology, Vellore-632014, India
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The renewable energy sources (RES) are stochastic in nature and requires an energy storage system to reduce power fluctuations. In this work, a three-phase grid connected hybrid renewable energy system (HRES) is designed with solar PVand fuel cell.Anew radial basis function network (RBFN) based maximum power point tracking (MPPT) controller strategy is designed for fuel cell and a fuzzy logic controller (FLC) is used for solarPVto extract the maximum power at different PEMFC temperatures and solar irradiation levels. In addition to this, a high step-up DC-DC boost converter (HSBC) is designed for fuel cell in order to provide high step-up voltage. The proposed hybrid energy system is designed by considering a 1.26kW proton exchange membrane fuel cell (PEMFC) with HSBC and a 950W solar PV system with conventional boost converter. The proposed system is simulated in MATLAB/Simulink platform to analyse the performance of the system.
Keywords: Hybrid renewable energy system, conventional boost converter, high step-up boost converter, MPPT, PV system, PEMFC.
1School of Electrical Engineering, VIT University, Vellore, India
2Dept. of EEE, Sri Krishna College of Technology, Coimbatore, India
3Dept. of ECE, Indian Institute of Information Technology, Design and Manufacturing, Kancheepuram, Chennai, India
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In this paper RBFN (radial basis function network) MPPT controller based 3-φ boost typeVienna Rectifier is designed for wind energy conversion system (WECS). The 3-φ boost type Vienna rectifier is accomplished to convert AC/DC conversion from the renewable energy systems of AC generating units and/or fromAC mains. This kind of rectifiers is very impressive where a unidirectional power flow is adequate in the network with high power density. The AC/DC rectifier provides a sinusoidal input current, improved power factor and low ripple at the input side. An RBFN controller based proposed system configuration is designed for 1kW wind energy conversion system in MATLAB/Simulink with a step up voltage of 230 V to 400 V at a turbine base speed of 12 m/s and the results are validated. The performance analysis of an RBFN controller based circuit topology is compared with the fuzzy logic-based SVPWM (space vector pulse width modulation) controller.
Keywords: Wind energy conversion system, PMSG (permanent magnet synchronous generator), MPPT (maximum power point tracking), Vienna Rectifier, RBFN, Fuzzy Logic Control based SVPWM.