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The proposal focuses on the role of data centres (DCs) and electric vehicle (EV) energy storage systems (ESSs) for frequency regulation and it provides a new opportunity for different resources to participate in the power sector. Frequency fluctuations are introduced with the emergence of inverter‐dominated renewable energy sources (RESs) as it does not provide rotational inertia to the grid, such as synchronous generators. In this study, the virtual synchronous generator (VSG) controlled inverter compensates for the lack of inertia. Particularly, this research work analyses the involvement of DC and EV batteries as ESSs in designing an integrated technical virtual power plant (VPP) to support frequency variations using the VSG concept. Microgrid (MG) simulations are performed in MATLAB/ Simulink platform. Case studies are carried out to validate the grid export and grid import performance of the model by using variations in the load and the solar irradiance of the MG. It is verified that bidirectional power flow takes place between the proposed VPP components and the grid that enables the grid with high penetration of RESs. The work provides a conceptual framework for future contributions towards the smarter usage of assets such as ESS and a greener future. [ABSTRACT FROM AUTHOR]

This study proposes a new modelling approach for studying low‐frequency oscillations (LFOs) in a droop controlled islanded microgrid. Due to the absence of inertia, these sources are more vulnerable to power and frequency oscillations. Their quick response can introduce faster electrical dynamics in the system which should be monitored from time to time. To ease the analysis process, this study proposes a simplified method for finding LFO in the microgrid. Inspired from the small‐signal automatic generation control model of the conventional grid, a transfer function based closed‐loop small‐signal model of inverter‐based islanded microgrid is presented in this study to study power‐sharing among the various inverters. The proposed model uses the concept of dynamic power flow through the network to find the power output of each source following load perturbations in a system. Time domain simulation results and eigenvalue analysis is provided to verify the effectiveness of the proposed small‐signal model. By comparing the results obtained with actual system simulation in MATLAB/Simulink, it is found that the proposed simplified model is able to predict the stability margin and the LFO of the system without using actual detailed state‐space modelling procedure. [ABSTRACT FROM AUTHOR]

For low‐voltage autonomous microgrids, the essential goal is maintaining stable voltage and frequency throughout its network for the smooth operation of distributed loads. The other goal is to maintain proportionate power‐sharing between multiple sources connected through voltage source converters (VSCs). For the particular case of a heavily loaded microgrid, any further increase in demand poses new problems. The VSCs proximate to the loads may overshoot beyond its maximum ratings. Owing to which the stability of the power supply, as well as the longevity of VSCs, may get compromised. Also, these sources provide power under varying composite loading conditions comprising both linear and non‐linear loads resulting in unbalancing in its network. To overcome these problems, a decentralised fast terminal sliding mode control strategy for active power‐sharing between parallel VSCs has been proposed. A detailed mathematical model based on Lyapunov's stability theory‐based study is designed to establish the operating stability of the proposed controller. To validate the proposed control strategy, MATLAB‐based simulation results are provided for possible loading scenarios. A comparative study for performance evaluation between the proposed controller and a conventional proportional ‐integral‐based controller is further carried out. Finally, the performance of the proposed controller is also validated in real‐time scenario. [ABSTRACT FROM AUTHOR]

This study proposes a modified decentralised droop controller for inverter‐based autonomous photovoltaics (PV) microgrids to address the problem of instability and slower power sharing between PV inverters. The proposed controller modifies the conventional droop mechanism in transient as well as in steady state by adding an auxiliary control signal in the power control loop of the inverters. The proposed approach offers three key benefits, i.e. improves active power sharing, enhances system stability and performs the secondary control action by nullifying the frequency deviation by using only one auxiliary signal in the control loop. The accuracy of the proposed modified droop controller is verified with the help of time‐domain simulations in MATLAB/SIMULINK. The results obtained show that the controller is able to improve the power sharing and stability of the microgrid as well as to restore frequency. The performance of the proposed control scheme is also validated by experimental results and small‐signal analysis. [ABSTRACT FROM AUTHOR]

This study presents the application of non‐linear disturbance observer (NDO) for automatic generation control of interconnected thermal area power systems considering generation rate constraints. In this work, any change in electrical power arising in the system due to either load change or change in power output of intermittent renewable energy sources is called a disturbance. This disturbance is estimated using an NDO and the same is rejected by giving an equivalent command to the governor of thermal power units to maintain a power balance in the system; thereby maintaining frequency and tie‐line power flows in each area of an interconnected power system. The analysis is presented on a two‐area power system and it is shown that the proposed control scheme effectively mitigates any active power imbalance in the system not only for normal operations but also when there is large communication delay in the system. The key advantages of the proposed scheme not only include faster frequency and tie‐line power control but also reduced control efforts as compared to other established control schemes. Furthermore, the proposed scheme requires the optimisation of only one control parameter in each area. Therefore, the scheme gives away the requirement of complex optimisation algorithms. [ABSTRACT FROM AUTHOR]

The focus of this work is to analyse the performance of automatic generation control (AGC) of two area four units interconnected deregulated power system for implementing modified sine cosine algorithm (MSCA) to design the conventional PID and fuzzy‐PID (FPID) controllers. Each area consists of thermal generating unit with reheat turbine and a gas generating unit. Thermal generating units of both areas are employed with appropriate generation rate constraint. At first, sine cosine algorithm (SCA) is modified to implement MSCA technique and superiority of MSCA is proved over SCA using four benchmark functions. Then the work is extended to design the conventional PID and FPID controllers using both the algorithms. Three different situations of deregulated markets are considered. For the design of optimal controller gains integral time absolute error is taken as the objective function. To analyse the dynamic behaviour of the deregulated power system undershoot, overshoot and settling time are considered as transient parameters. After the analysis, it is found that MSCA‐based FPID controller exhibits a better transient response in terms of less undershoot, overshoot and settling time. Robustness analysis is performed by varying some of the important parameters of the power system to show the proposed FPID controller is less sensitive to parametric variations. [ABSTRACT FROM AUTHOR]

This work deals with an implementation of a unique control approach for the power quality enhancement in solar photovoltaic (PV) based grid interfaced system. In this work, a robust control technique with strong filtering capabilities is implemented. A single‐phase two‐stage grid interacted solar PV topology is considered with a second‐order sequence filter as a test system for the validation of the power quality enhancement features. The system constitutes a PV array, a boost converter, a DC link capacitance, a voltage source converter (VSC), an interfacing inductor and a ripple filter. A boost converter is used at a primary stage of proposed topology, which supports the extraction of maximum power from the solar PV array. In addition, the VSC feeds the solar PV power into the grid. It also provides harmonics elimination and power factor correction. A new maximum power point tracking technique avoiding a drift feature is adopted for the fast dynamic performance. The implementation of the solar PV system is performed and the harmonic profile of grid current is observed in compliance to the IEEE‐519 standard. [ABSTRACT FROM AUTHOR]

This study presents an optimal control operation of a photovoltaic‐battery based standalone microgrid, feeding non‐linear loads. To ensure continuous power supply to the critical loads during low insolation or low battery state of charge, a diesel generator (DG) is used as an auxiliary generator. This cost effective hybrid system with maximum utilisation of the renewable as well as fossil fuel based generators can be employed in hospitals, telecom stations in remote areas. In order to nullify the effect of non‐linear loads on the DG, modified enhanced phase‐locked loop (EPLL) based power quality conditioner is used. The characteristic equation of conventional EPLL is amplitude dependent, thus, the controller tuning parameters need to be modified if the input signal varies over a large range. The presented controller overcomes this problem making the system more robust in eliminating noise and harmonics and extracting fundamental component of a given signal. This component is drawn from the DG with the help of a voltage source converter, thus, making its current always distortion free. The proposed control scheme is simulated in MATLAB. Furthermore, experimental verification is done on a laboratory prototype of the same. The steady state and dynamic responses of the system validate its satisfactory performance. [ABSTRACT FROM AUTHOR]

Modern power system involves growing use of open channel communication in secondary frequency regulation which introduces time delay in the automatic generation control loop which may lead to system instability. This study proposes a novel power system frequency stabiliser (PSFS) which is a modified secondary controller in order to improve the system stability in the presence of large communication delays. An auxiliary signal is added to the secondary controller to provide additional damping. The gain of the controller is obtained by meta‐heuristic methods. The proposed controller is first developed on a single area hydropower system and the same is then applied on the Western System Coordinating Council 3‐machine, 9‐bus power system. Furthermore, to show the effectiveness of the proposed PSFS in a large practical multi‐area system; it is also applied to the IEEE 39‐bus system. Results show that the proposed controller significantly improves the stability of a power system operating with large communication delay which is first considered as constant and then the stability improvement with the proposed PSFS in the presence of random communication delays is also shown. The PSFS performance is tested by the results obtained with MATLAB/Simulink simulations and further verified on a real‐time simulator. [ABSTRACT FROM AUTHOR]

This study presents the fuzzy logic integrator gain‐tuned improved second‐order generalized integrator (GI) for a double‐stage grid‐interfaced photovoltaic (PV) system. The proposed system includes the functionalities of feeding active power to the grid, power factor correction, grid currents balancing and system isolation under grid side faults. Moreover, the smooth system operation is ensured under weak distribution grids where grid voltage is subject to huge diversions. Furthermore, automatic protection scheme for the system under grid‐side faults is also established with the proposed algorithm for increased reliability. The fuzzy‐tuned GI provides advantages of efficient and effective extraction of load current fundamental component under steady‐state and dynamic grid conditions. The non‐linear frequency error variation is compensated here using fuzzy logic‐based self‐tuning integrator gain of the controller. The controller is improved to mitigate the possible DC component in the load current. The neutral current in the loads is nullified by using a four wire system. The adaptive DC bus voltage helps to minimize the switching losses and prevents unexpected tripping of the PV inverter. The system is experimentally verified using a prototype built in the laboratory. [ABSTRACT FROM AUTHOR]

This study proposes a grid supportive control scheme for a single‐phase photo‐voltaic (PV)‐based inverter to mimic the behaviour of a synchronous generator during grid voltage/frequency variations. The converter embedded with the proposed controller, termed as a 'single‐phase synchronverter', transforms a large segment of rooftop PV, which is, in general, single phase, to an ancillary service provider in compliance with the grid code (i.e. if the grid code allows rooftop PV to provide inertial/primary frequency/voltage response). Owing to fluctuations in incident solar irradiation, a battery has been connected at the dc link to take care of the variability in PV output power. The challenges involved in extending the three‐phase synchronverter philosophy to a single‐phase converter have been discussed and the performance of the resultant single‐phase synchronverter to different values of virtual inertia and droop/regulation has been analysed. An experimental setup is developed and the system behaviour for different operating conditions has also been studied. [ABSTRACT FROM AUTHOR]

All the sources are required to supply the scheduled power to the system as directed by the system operator, within a time frame of operation. The fluctuating nature of wind makes supplying the scheduled power a challenging task. To address this, gas turbines are proposed to augment the wind generator to work as buffer owing to their high ramping capability. However, the cost of gas turbine increases with increased ramp rates, whereas, operating efficiency and the life time decreases. Hence, to relieve the buffering gas turbines from higher ramp rate requirements, emulation of inertia of the wind generator is proposed in this paper. The controller is designed to operate in inertia emulation mode whenever there is a retardation of rotor of the wind turbine and the proposed ramp controller will be in action only for first few seconds after the fall in wind speed. While emulating the inertia, the performance of the proposed control philosophy with different ramp rates is investigated in this paper. Guide lines for the selection of the ramp duration and ramp rate for seamless transition from inertia emulation mode to maximum power extraction mode are also suggested in this paper. [ABSTRACT FROM AUTHOR]

The diesel‐photovoltaic (PV) based hybrid AC microgrid systems with conventional control philosophies deliver very good performance in the grid connected mode. However, once the microgrid is isolated from the main grid the same philosophies which control the PV at its maximum power can make the microgrid unstable. In this connection, this study proposes a novel neuro‐fuzzy controller to ensure the smooth transition of microgrid from grid connected mode to isolated mode, to retain the system stability even in isolated mode and to deliver the superior performance in grid connected mode as well. The considered artificial neural networks is trained with PMPP–Temp against VMPP characteristic, first of its kind. The fuzzy part of the controller derives the reference voltages subjected to the limits provided by the ANN. This study describes how well the data analytics can be utilised to retain the power system stability in emergencies. The proposed controller has been evaluated under different operating conditions and is exhibiting superior performance in achieving the desired control objectives. Results from the numerical simulations are confirmed from the experiments in real‐time environment. [ABSTRACT FROM AUTHOR]

Sluggish tracking for change in solar irradiations is the main demerit of the perturb and observe (P&O) algorithm because of its fixed perturb. To overcome this, an adaptive tracking algorithm based on Takagi–Sugeno fuzzy implications is proposed in this study. Input to the fuzzy controller is the error between conductance and incremental conductance which is otherwise zero at the maximum power point. The P&O algorithm and the proposed algorithm along with the recently published adaptive incremental conductance algorithm are examined for their performance efficacy on a photovoltaic (PV) generating system with fabricated as well as real irradiation data. As a case study, all the considered algorithms are validated under partial shading conditions also. The effectiveness of the proposed algorithm is verified for the tracking of the maximum power point of a PV system in steady as well as changing irradiations and the conclusions are supported through some experimental validations. [ABSTRACT FROM AUTHOR]