This paper solves a novel multi-objective optimal power flow (MO-OPF) problem for a hybrid power system consisting the thermal generators, wind energy generators (WEGs) and solar photovoltaic (PV) units with battery energy storage (BES) system. In this paper, three objective functions, i.e., total generation cost, transmission losses and voltage stability enhancement index are considered to be optimized simultaneously. The total generation cost minimization objective include the cost of conventional thermal generators, wind and solar power purchasing from the private owners and to reduce the risk due to the wind and solar power uncertainties. Here, the power output from the wind and solar power outputs are determined based on the Weibull probability distribution function. This paper utilizes a particle swarm optimization (PSO) based fuzzy satisfaction maximization technique to solve the proposed MO-OPF problem of a hybrid power system. Here, a modified IEEE 30 bus system is used to demonstrate the effectiveness of the proposed approach. The proposed technique is robust and faster which modifies the control variables effectively. The proposed approach can be useful to the system operator as the decision supportive tool to handle the hybrid power systems.

Keywords: Optimal power flow,Wind energy generators (WEGs), Solar PV power, Battery energy storage, Evolutionary algorithms, Uncertainty.

In the recent time, Permanent-Magnet Synchronous-Generator (PMSG) based variable-speedWind-Energy Conversion-Systems (WECS) has become very attractive to many researchers. The research aim is to analyse different synchronous machine and compare them based on their maximum power generation. This paper reviews various aspects of PMSG such as topologies with controlled and uncontrolled rectifier, grid-connected and standalone mode of operation with various control methods of PMSG based WECS and recent optimization approaches. The performance analysis of PMSG can be enhanced by adopting a number of control mechanisms with the benefit of advanced optimization techniques.Acomparative analysis is carried out based on the techniques used and their corresponding advantages and drawbacks are discussed.

Keywords: PMSG, WECSs, power generation, synchronous generator, gridconnected PMSG, standalone mode of PMSC, grid side converter (GSC), machine side converter (MSC).

Power consumption of cellular communication is growing at a very high rate due to the mass deployment of Base Stations (BSs). When traffic increases, the power consumption also increases, however this scenario differs in micro and macro BSs. Therefore intelligent energy management system as per traffic generated is very essential. The available models have not considered the impact of traffic load on energy consumption. These variations are analysed through regression models among power consumption and traffic load. Linear models have been proposed based on the measurements performed for ten consecutive days on three micro and three macro BSs. The results revealed that the proposed linear models fit better for macro BS than for micro BS. Energy consumption is observed to change along with the traffic load during high traffic, but during low traffic, energy consumption does not change. A macro BS is found to be more energy efficient than a micro BS due to its higher coverage range. On the contrary, a macro BS consumes about double power than that of a micro BS. Hence, micro BSs are suitable for areas with higher concentration of users where high data rates are required, whereas macro BSs are suitable to provide coverage only.

Keywords: Energy efficiency, power consumption, modelling, base station, coverage, cellular communication.

This paper proposes a three phase five-level inverter which uses a single DC (PV) source, unlike a conventional cascaded H-bridge (CHB) which requires multiple DC (PV) sources, and also a novel Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) for reduced voltage Total Harmonic Distortion (THD) compared to a conventional SHE-PWM. The proposed inverter uses reduced number of switches when compared to conventional inverter. The proposed three phase inverter is simulated inMATLAB with both conventional and new SHE-PWM techniques. The simulated waveforms of the line, phase voltages and load current are studied in detail. A comparison of THD values is for both conventional and proposed SHE-PWM is presented. This is followed by the hardware implementation of the proposed inverter with the new SHE-PWM, and the results for line, phase voltages and the load currents are again reviewed. The hardware results are found to match the simulation results. The results confirm that the proposed SHE-PWM has the ability to deliver a reduced THD when compared to a conventional SHE-PWM.

Keywords: Five-level inverter, Single DC source, Conventional Selective Harmonic Elimination, New Selective Harmonic Elimination,Total Harmonic Distortion, Photo-Voltaic (PV).