Volume 22, Issue 5 - Special Issue Title: Emerging Sustainable Green Energy Technologies for Smart Grid; Guest Editors: Surender Reddy Salkuti, Papia Ray and Sandeep Vuddanti

Integration of distribution generation (DG) makes the growth of the microgrid protection scheme very challenging issues. Researchers from all over the world continuously are doing hard work for developing the microgrid protection schemes. A differential positive sequence power angle (DPSPA) based microgrid protection scheme is proposed in this paper using positive sequence (PS) components of voltages and currents. The DPSPA for the feeder is calculated considering both ends of voltage and current signal information, when it is more than threshold, internal fault is reported otherwise, it is an external fault. Taking into consideration the varying operational modes of the microgrid, variations in DG penetration, and variations in fault variables namely fault types, and fault locations, the proposed protection scheme is verified on a modified IEEE-13 bus feeder. Moreover, to test the robustness and efficacy of the suggested scheme, various non-faulty events including induction motor starting, non-linear loading, load switching, capacitor switching, and section cutoff have been conducted. The proposed scheme is also verified for external faults and it is found that it continues to be stable for the external faults. The findings exhibit this proposed scheme, which is based on DPSPA, can successfully protect the microgrid under changing operating conditions.

Renewable energy sources are becoming as one of the major generation strategies around the world. The wind energy systems have been technologically advanced and integrated to the power system in a rapid routine. This paper looks into the modelling as well as operational exploration of a three blade wind turbine connected to asynchronous generator. State-of-the-art wind turbine topologies and a comparative summary of real-time simulation technologies for electrical systems are described. A 2.4 MW wind turbine with three blades is modelled for the analysis of power characteristics. The shift from sub-synchronous to super-synchronous mode is analysed for type-A wind energy conversion system (WECS) with 2 MW asynchronous generator by using MATLAB/Simulink model. The step-by-step standard operating procedure for modelling and real-time simulation of 2 MW type-A WECS having asynchronous generator under hardware-in-the-loop platform is elucidated. The steady state and transient behaviours of the WECS are validated by the real-time emulation under a hardware-in-the-loop platform.

This article articulates the frequency control in an isolated microgrid (MG) under a centralized secondary controller. The penetration of distributed generators (DGs) which are weather dependant, and some of them are inertia less cause the instability in the MG. Besides this, unusual/abrupt load change, communication delay, and parameter change uncertainties make the MG more unstable. So, to restore the stability of the MG a sliding mode controller (SMC) is employed. The design of the SMC is carried by selfish herd optimization (SHO) algorithm. To validate the performance of SHO-SMC controller, it is compared with the results obtained by GOA-FOPID-(1+PI), SHO-PID, SHO- FOPID, and SHO-FOPID-(1+PI) controllers. Further, to establish an ameliorated dynamic response of the MG, SHO is modified by applying fuzzy logic named as fuzzy adaptive SHO (FA-SHO). In addition to this, in a two area MG, the potential of SHO/FA-SHO SMC controllers over SHO-SMC, and SHO/FA-SHO FOPID-(1+PI) controllers has been examined. Finally, with some crucial intermittent uncertainties like abrupt load change, time delay, and parameter variation, the robustness of the proposed controller is established.

This paper describes the normalized maximum correntropy criteria (NMCC) based seamless control of three-phase four-wire voltage source converter (VSC) for a grid-tied PV-Hybrid energy storage system (HESS). The micro-grid can operate in both islanded and grid-tied mode with seamless control. The seamless control facilitates the VSC control transition from grid current control (GCC) during grid-tied mode to voltage control during grid-isolated mode and back to GCC control with grid-resynchronized mode. The seamless control ensures the system stability and security of the personnel with reduces transients on the grid and load side of the system during the VSC control transition. The VSC is designed to fulfill the multi-objective including power quality enhancement, reactive power compensation, load balancing during unity power factor (UPF) operation. The VSC maintains the system stability during diverse dynamic conditions, inducing disturbances on grid side, load side and PV side of the system, i.e., Irradiation variation, unbalanced load, abnormal grid voltage, intentional islanding, specified power mode and grid-resynchronization. The hybrid energy storage system (HESS) consisting of lead-acid battery and ultra-capacitor (UC) further enhances the stability and disturbances handling capability of the grid-tied PV system. The functioning of the proposed system is found adequate as per IEEE 519 standards during steady and induced dynamic conditions.

This paper proposes a hybrid learning algorithm based super twisting sliding mode control (STSMC) of a hybrid wind/photovoltaic (PV) power system for grid connected applications. The gating pulses of the voltage source converter (VSC) are generated by employing adaptive reweighted zero attracting least mean square (RZA-LMS) algorithm. The control law acquiring the super-twisting algorithm generates a continuous and saturated control signal to regulate a hybrid system influenced by disturbances. The proposed control injects sinusoidal currents into the grid with low total harmonic distortion (THD) which improves the steady state & dynamic performance of the system by mitigating power system problems like harmonic injections besides giving satisfactory results under dynamic loading, varying wind speeds and solar insolation. It is a chattering free control which enhances the quality of disturbance rejection and sensitivity to parameter variation. It also caters to abnormal conditions like voltage distortions, DC link variations and reduces the latter by a factor of 80 V besides reducing switch stress by a factor of 5 V. This control exhibits robustness against model uncertainties and external disturbances. Also, the loss component is reduced which decreases the unmodelled losses. It also ensures efficient power flow between the grid, hybrid source and the load. The efficacy of the system is verified in MATLAB/Simulink. Improvements are also observed during dynamic conditions in terms of reduced fluctuations, steady state error and peak overshoot.

In this paper optimal location and sizing of Non-dispatchable Distributed Generation (NDG) based distributed generation (DG) is investigated by considering uncertainty of NDG. In present study a solar photovoltaic (SPV) is considered as NDG because SPV based DG has uncertain nature of generated power because it is powered by solar irradiance which has uncertain characteristics. To investigate the uncertainty of intermittent nature of solar irradiance Beta Probability Density Function (BPDF) based PDF is considered for addressing the uncertainty of solar insolation. For determining the optimal size of DG unit an analytical based methodology is developed. In this study optimal capacity of NDG is estimated by deriving the expressions of DG unit at each bus. Further, a multi-objective index factor ( MIF ) is designed in order to find out the candidate bus for DG placement. The proposed technique is applied on IEEE 33-bus distribution network. The obtained results reveal that proposed technique provide almost similar result to that of other method which is available in literature.

In recent period, electricity need is increasing because of automatic control systems in developing modern societies. So it is necessary to estimate the consumption and needs of a particular sector to match the generation and demand for whole society. This task is performed by the modeling of electricity demand, in which many tools/plans and policies are involved. According to which, tariffs are made to benefit the society as well as energy suppliers. Electricity demand modeling is also needful when any of the generation plant is going to be installed, especially in the case of solar PV plant, in which number of panels, area, and balance of system completely depends upon the electricity demand. Hence in this work, modeling is proposed for electricity demand after analyzing various sectors. After the proper energy audit in initial stage, hybrid generation system (Thermal/Solar PV/DG/Batteries) will be modeled to match the demand in peak hours using metaheuristics optimization techniques. Low carbon emission and energy storage are the key features of power generation using solar PV system, which are very beneficial for any state of India.

A robust decentralized model predictive control (DMPC) design is proposed for frequency stability of hybrid renewable power systems considering high renewables energy penetration and nonlinearity effects. The Egyptian power system (EPS) considered as a test system comprises both traditional power stations (i.e., steam, gas, combined cycle, and hydraulic power plants) and renewable energy sources (RESs). Where the considered RESs contain both the wind power generated from Zafarana and Gabel El-Zeit wind farms and the solar power generated from Benban solar park, which is considered one of the world’s largest photovoltaic (PV) plants. To obtain an accurate insight into a real modern power system, this research takes into account the effects of the important nonlinearity such as generation rate constraints (GRCs), governor deadband (GDB), and communication time delay (CTD). The designed control is set based on the DMPC for each subsystem independently to ensure the frequency stability of the whole system as each subsystem has different characteristics and operating constraints than the others. Moreover, the decentralized control scheme has become imperative for large power systems due to the high cost of transmitting data over long distances and the probability of error occurrence with the centralized control scheme. To verify the effectiveness and robustness of the proposed DMPC for the EPS, it is compared with the centralized MPC (CMPC) scheme in different operating conditions. The simulation results, which are conducted using MATLAB/SIMULINK ® software, emphasized that the proposed DMPC scheme can effectively handle several load disturbances, high uncertainty in the system parameters, and random communication delays. Hence, it can regulate the grid frequency and ensure the robust performance of the studied renewable power system with high RESs penetration and maximum communication delays in the system.

As the exhaust rate of the conventional sources has geared up already, this is compelling the power industries to install the power plants based on the non-conventional sources so that future demand of the energy supply can be fulfilled. Among the various sources of renewable energy like wind, hydro, tidal etc., solar energy is the most easily accessible and available renewable energy source. Ensuring the feasibility of any energy source not only technical but also the economical perspective is the most important criteria. This paper has incorporated both the perspective and has done the techno-economic analysis to determine the optimum combination of the PV array size and battery size to minimize the overall electricity generation per unit. In this paper, a standalone solar PV system has been analyzed for the location of Jamshedpur, where an effort has been done to choose the optimum combination of the solar array and battery size within the desired range of LLP so that the electricity generation cost per unit can be minimized. The overall duration of the analysis has been done for a year and the outcome of the research has been verified with the help of MATLAB software.