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The classical droop method is widely used in AC microgrid (MG) for sharing load among distributed generations. Apart from interlinking the DC sources, the voltage source inverters control the power flow from renewable energy sources. Thus, they contribute toward the demand side management (DSM) by employing the voltage reduction method (VRM). The VRM is widely utilized in the distribution system of the grid network, its concern is to reduce the voltage in a suitable manner so as to maintain the voltage within the acceptable limits, leading to power savings. However, the application of VRM in the stand-alone MG is very scarce. Thus, this paper attempts to apply VRM so as to achieve not only the benefits pertaining to voltage control but also power savings from DSM. The voltage–current (V–I) droop characteristics are of paramount importance for DSM using VRM to increase the number of consumers during high demand of electrical energy. One of the important contributions is modification of the P–f droop control to maintain the frequency of the MG within the permissible limit while applying VRM. In addition, the behavior of three-phase to ground fault is being investigated and competency of the control algorithm is validated through implementation on 5 bus stand-alone microgrid system and further, it is tested on IEEE 14 bus test system. The efficacy of the proposed approach is established through the comparison of the results with those for classical voltage and frequency-based droop schemes bereft of communication ability. The control mechanism has also been validated in real-time using schematic editor of Typhoon virtual HIL 402. [ABSTRACT FROM AUTHOR]

This paper presents a multifunctional scheme to reinforce the protection of Extra High Voltage (EHV)/Ultra High Voltage (UHV) transmission lines. The proposed scheme employs d–q transformed traveling waves and the time of incidence of first traveling waves at both ends of the line for fault detection and location respectively. Furthermore, the faults are classified using energy values of approximation coefficients and the phasors are estimated from the approximation coefficients. The traveling waves are nothing but detail coefficients. The detail and approximation coefficients are obtained using discrete wavelet transform multi-resolution analysis (DWT-MRA) of the 3-ɸ current signals. The proposed algorithm detects and locates a fault within a quarter cycle. The proposed scheme has been implemented on a two-bus and the WSCC-9 bus systems in EMTDC/PSCAD software to verify the efficacy and reliability. Also, it has been realized on a laboratory model of an EHV transmission line of length 200 km using NI cDAQ-9178 chassis, NI-9227 current sensor card, and LabVIEW software. The simulation and hardware results evince the protection reinforcing property of the proposed multifunctional scheme. [ABSTRACT FROM AUTHOR]