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The hybrid microgrid (HMG) is an arrangement for empowering the society by using the renewable energy sources (RESs) connected with common DC bus terminal. The effective operation of the HMG relies on the transient response of the DC bus as well as the stability of the system state that may change due to the stochastic behavior of RESs and industrial loads. This work is motivated to develop a two‐level decentralized control strategy consisting of a non‐linear and linear control scheme to augment the transient stability and tracking performance of an HMG. Firstly, a non‐linear partial feedback linearization control framework combined with a PI regulator (PFLC‐PI) is designed for the transient stability enhancement of the common bus. Secondly, a linear unified controller (UC) is developed to guarantee the constant load voltages over the industrial loads through the control of the load‐side inverter. The UC effectiveness is measured by varying the load parameters associated with single‐ and three‐phase load networks. The obtained results are then compared with the existing controllers to guarantee the augmented performance of proposed two‐level controller. Additionally, an external parametric uncertainty is intentionally added to the single‐phase load network dynamics and studied to ensure the robustness of the controller. [ABSTRACT FROM AUTHOR]

Partial discharge is one of the main reasons for insulation degradation in high‐voltage apparatuses. Partial discharge is an ineluctable phenomenon that happens when a high electrical field is adjacent to an insulator. High‐frequency current transformers are widely used for detecting partial discharge current in high‐voltage equipment. Determination of the apparent charge in pico coulombs is essential for having a common understanding of results and verifying that the measuring system can obtain specified partial discharge magnitude correctly. To this end, a high‐frequency current transformer sensor and a partial discharge calibrator have been prepared to measure the current of the partial discharge (PD) pulses inside mineral oil. The constructed PD calibrator has been evaluated. The high‐frequency current transformer (HFCT) sensor has been simulated using a mathematical model‐based AC analysis and has been characterized and then calibrated using a calibration technique to measure the apparent charge of the PD pulses. Experimental results show the effectiveness of the HFCT sensor and the proposed calibration method. [ABSTRACT FROM AUTHOR]

Performance of the UAVs for a particular application can be enhanced by hybrid design, where take‐off, hover, and landing happen like rotary‐wing UAVs, and flies like fixed‐wing UAVs. A backstepping controller and an adaptive backstepping controller are designed for trajectory tracking and payload delivery in a medical emergency or medical substance delivery like vaccine delivery in the presence of wind gust. Simulation results show that the backstepping controller effectively tracks the trajectory during the entire flight envelope, including take‐off, hovering, the transition phase, level flight mode, and landing. A comparison between Backstepping, Integral Terminal Sliding Mode (ITSMC) and Adaptive Backstepping controllers for payload delivery show that the adaptive backstepping controller effectively tracks the altitude and attitude. ITSMC is capable of tracking the desired trajectory for a change in the mass but has sluggish response. The backstepping controller generates a steady‐state error in altitude during the mass change in biplane quadrotor. [ABSTRACT FROM AUTHOR]

Open circuit faults of island distribution lines account for more than 70% of the total number of faults in the distribution network. Failure assessment of lines plays a crucial role in the operational safety of the island distribution network. Aiming at the problems of multiple operational failure factors and difficulty in failure assessment, a failure assessment method of island distribution lines based on model‐data hybrid drive is proposed in this paper. Specifically, in order to accurately describe the actual operating status and failure mechanism of distribution lines in the typical island environment, model‐driven method is used to formulate a comprehensive operational failure index of distribution lines, which combines with the impact of strong wind and corrosion operation scenarios and the operating characteristics of lines. On this basis, to improve the accuracy of failure assessment under the influence of multiple factors in the island environment, an improved light gradient boosting machine model is constructed in a data‐driven manner. Finally, based on actual data from distribution network in Zhoushan, China, the case study reveals that the proposed method could effectively assess the operational failure of island distribution lines. [ABSTRACT FROM AUTHOR]

In this article, a community integrated energy system (CIES) coupled with electricity, gas and heat is investigated, which integrates with renewable energies such as photovoltaic and wind turbine. The main goal is to seek an optimal scheduling scheme, including reducing the operating costs and fully exploiting the demand response potential. Firstly, given the structure of CIES, the system equipment and loads are modeled and analyzed. Moreover, considering the user controllable degree, a comprehensive user satisfaction method is established based on the combination of subjective weight and objective weight method. This paper concerns the user controllable degree in the process of flexible load optimization so that some amounts of loads are transferred from peak periods to off‐peak periods to flatten the load curve. Three cases studies in the article show the influence of user controllable degree and satisfaction on CIES. Finally, the system model is solved using CPLEX solver in MATLAB optimization software. The results show that the operating costs and environmental costs are reduced by 9.31% and 3.24% due to the presence of user controllable degree and satisfaction. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Cloud energy storage system (CESS) technology is a novel idea to eliminate the distributed energy storage systems from the consumers into a cloud service centre, where CESS acts as a virtual energy storage capacity instead of the actual devices. This combination forms a grid-forming battery-supercapacitor cloud hybrid energy storage system (CHESS) which is responsible for maintaining the voltage stability and power balance at the common DC bus of the multiple NG system. By establishing such an access to CESS, the proposed model allocates optimal shares of charge/discharge capacities for home owners, minimizes the daily operation cost of each home and grants an optimal operation of household appliances. [Extracted from the article]

With the rapid increase of renewable energy generation worldwide, real‐time information has become essential to manage such assets, especially for systems installed offshore and in remote areas. To date, there is no cost‐effective condition monitoring technique that can assess the state of renewable energy sources in real‐time and provide suitable asset management decisions to optimize the utilization of such valuable assets and avoid any full or partial blackout due to unexpected faults. Based on the Internet of Things scheme, this paper represents a new application for the Supervisory Control and Data Acquisition (SCADA) system to monitor a hybrid system comprising photovoltaic, wind, and battery energy storage systems. Electrical parameters such as voltage, current, and power are monitored in real‐time via the ThingSpeak website. Network operators can control components of the hybrid power system remotely by the proposed SCADA system. The SCADA system is interfaced with the Matlab/Simulink software tool through KEPServerEX client. For cost‐effective design, low‐cost electronic components and Arduino Integrated Development Environment ATMega2560 remote terminal unit are employed to develop a hardware prototype for experimental analysis. Simulation and experimental results attest to the feasibility of the proposed system. Compared with other existing techniques, the developed system features advantages in terms of reliability and cost‐effectiveness. [ABSTRACT FROM AUTHOR]

Summary: In this paper, an innovative switching scheme named simultaneous space vector modulation (SSVM) is proposed for integrating various AC sources in the energy industry using a unified multiport converter. The proposed SSVM technique is applied to the multileg topology of a multiport converter, which is an encouraging option for the grid integration of renewable energy sources and multimachine drives. Considering the shared leg in the multileg converter, the proposed SSVM can utilize the utmost simultaneous switching states between different ports, resulting in lower switching loss and better DC‐link voltage utilization compared with the conventional sequential space vector modulation approach. A novel decision matrix concept is introduced to identify the simultaneous switching states. For this aim, according to the number of ports of the multileg converter, decision matrices containing valid simultaneous switching states are first calculated. Then, they are defined as look‐up tables in the proposed SSVM to be retrieved and exploited in every sampling period. The effectiveness of the proposed SSVM for a seven‐leg version of the multileg converter is assessed using the simulation analysis and real‐time validation. The capability of the proposed SSVM‐based multiport converter in grid integration of AC renewable energy sources is also verified considering two permanent magnet synchronous generator (PMSG)‐based wind turbines with real wind speed patterns. The simulation results confirm that the proposed SSVM is properly able to manage the power flow between different ports and improve the DC voltage utilization and switching loss compared with the sequential SVM. [ABSTRACT FROM AUTHOR]

This paper determines the optimal capacity of solar photovoltaic (PV) and battery energy storage (BES) with novel rule-based energy management systems (EMSs) under flat and time-of-use (ToU) tariffs. Four schemes are investigated based on the combinations of flat and ToU tariffs for buying and selling the electricity: (1) Flat-Flat, (2) ToU-Flat, (3) Flat-ToU, and (4) ToU-ToU. For each scheme, two configurations are evaluated: (i) PV only, and (ii) PV-BES. The optimization of the grid-connected household is evaluated based on one-year realistic data. An uncertainty analysis is presented based on the variations of insolation, temperature, and load. Sensitivity analyses are implemented based on the average daily load, the grid constraint, and the costs of PV and BES. The operational analyses for 48 h in summer and winter are carried out to evaluate the dynamic performance of the systems for high and low solar insolation. The effectiveness of the proposed model is verified by comparing the results with that of common EMS based on the net metering scheme. It is found that the COE of the proposed EMS for a PV-BES house with ToU-Flat scheme (as the best option) is 2 ¢/kWh lower than that of the net metering scheme. [ABSTRACT FROM AUTHOR]

In this paper, a multi‐objective optimization technique is proposed for the planning of a networked microgrid based on peer‐to‐grid (P2G) and peer‐to‐peer (P2P) energy trading schemes. Two different criteria's including annual profit and energy index of reliability are taken into consideration to form a multi‐objective function. The networked microgrid consists of three individual microgrids containing their own combinations of generation resources, batteries and residential loads. All microgrids are connected together and also to the main grid to meet the energy exchange requirements of P2P energy trading. A cooperative game theory technique based on a particle swarm optimization algorithm is used to model the networked microgrid, and to find the suitable sizes of the players that simultaneously maximize the payoff values of both objective functions. Besides, a comparative analysis is carried out for both P2G and P2P energy trading schemes. The results show that the outcomes are maximum when both criteria are considered in the optimization and P2P energy trading is carried out. The sensitivity analysis is performed on the selected parameters and verified the right change 0.003% and 4.5% in discount rate and electricity prices, respectively. [ABSTRACT FROM AUTHOR]

The photovoltaic (PV) cells are highly sensitive to temperature variations. The linear variation of PV cells with operating temperature could lead to the loss of conversion efficiency and permanent damage of PV material. To address this critical issue, while improving the performance of solar photovoltaic system (SPVS) during the operating period, the deployment of a proper cooling system is a prime requisite in the design process. Considering this, two new and cost‐effective cooling techniques are proposed in this study, which can improve efficiency and increase the life of the PV panel. The first technique is the active cooling design with water. The proposed design enhances the access to PV cells to maximize cooling. The second one is an improved passive cooling technique that uses fins mounted on the backside of PV module. This further reduces the temperature by increasing the heat dissipation. Additionally, a third PV module without any cooling system is deployed as a reference margin. The techniques have been experimentally evaluated and a recommendation is made in order to reduce the temperature variation across the PV panel. [ABSTRACT FROM AUTHOR]

Due to the intermittent nature of the renewable energy systems (RESs), more specifically, solar panels and wind turbines, their sole use does not lead to a smooth and reliable power. To overcome this issue, the concurrent grid‐integration of RESs to form a microgrid is reported. In the DC‐bus microgrid, the produced power by RES is initially given to the shared DC‐bus through an individual source‐side converter and then transmitted to the utility via a common grid‐side converter. By increasing the number of RESs, the number of required power converters, and therefore, the investment cost also increase. Using the cost‐effective multi‐input low‐switch converters is a promising alternative to alleviate this significant need for individual converters. Recently, a nine‐switch‐based unified expandable power converter (UEPC) has been presented for concurrent integration of AC and DC sources with a tangible fewer switch count. This unified structure has been utilized in two configurations named AC‐AC‐AC and AC‐AC‐DC. In this paper, both configurations are evaluated and compared in terms of current stress and switching loss. Considering the current stress analysis, the best port for interfacing with the grid to lower the total current rating of power switching devices is also determined. The high‐performance capability of both configurations is finally verified using MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

Forced oscillation (FO) is a challenging problem as it could initiate power system instability due to resonance, especially when the frequency of FO and inherent electromechanical (EM) modes of power system coincide. Twin oscillation components (i.e. inter-area oscillation and FO in the range of 0.1-Hz to 0.8-Hz) are created due to uncertain and uncaptured oscillatory inputs in power systems. The FO may lead to power system instability even with very well-damped EM modes. Therefore, effective countermeasure, i.e., a FO damping method should be incorporated to suppress the FO. This paper presents the systematic design and development of a controller termed as a Force Oscillation Damping Controller (FODC) for damping FO considering uncertainties and disturbances. The FODC and conventional inter-area damping controller are activated at different stages to make sure both controllers operate effectively. An adaptive algorithm is applied to make sure that the FODC can keep the FO mode in stable region at all operating conditions. The FO detection using an event-triggered control is applied to start the operation of FODC during the forced disturbance. Study results in IEEE 14-machine South East Australian (SE-A) interconnected power system demonstrate the efficacy of the proposed FODC in damping major FOs. [ABSTRACT FROM AUTHOR]

To provide continuity of balancing demand and generation, renewable sources will be more active than today in near future due to the tendency of massive investment on renewable energy sources (RESs) by countries. However, due to the uncertain and intermittent nature of RESs, RESs would create problems on power system operations such as power quality, efficiency, stability and reliability. Owing to having problems with RESs integration, virtual power plant (VPP) has introduced to make this integration smooth without compromising the grid stability and reliability along with offering many other technoeconomic benefits. This study reviews structures, types, architecture and operations of VPP along with the status of present implementations worldwide. The types of VPP are introduced in details with the optimisation algorithm used with each type. In addition, VPP is linked with the most of the components in power systems such as distributed generation, active prosumers, transmission system operator and distribution system operator, grid services such as fault ride through, reactive power control as well as with the help of technology such as communications, control and optimisations. This study gives a comprehensive outline of transforming microgrid to VPP that is useful for researchers, consumers, prosumers and utility operators. [ABSTRACT FROM AUTHOR]

The design and the experimental validation of a continuous-time model predictive control (CTMPC) for a permanent magnet synchronous motor (PMSM) drive with disturbance decoupling is discussed. The CTMPC approach uses Taylor series expansion to derive a closed-form solution to the problem of model predictive control even though the system behaviour is described by a non-linear model. This type of controller requires an exact knowledge of the system model to guarantee an accurate prediction of the system behaviour, while the PMSM is usually subjected to model uncertainties and external disturbances such as the load torque. Moreover, in the proposed approach, the predicted speed tracking error is directly used to determine the required voltage command without the need for a cascaded control scheme. As a result, the load torque is seen as unmatched disturbance which makes exact disturbance decoupling more challenging. To overcome such a problem, a non-linear disturbance observer is designed and combined with the CTMPC method to enhance the prediction accuracy under parameter variation and unknown load torque. The feasibility of the proposed approach is experimentally investigated, and good transient and steadystate performances are obtained. [ABSTRACT FROM AUTHOR]

In this study, a state feedback control law is combined with a disturbance observer to enhance disturbance rejection capability of a grid-connected photovoltaic (PV) inverter. The control law is based on input-output feedback linearisation technique, while the existing disturbance observer is simplified and adopted for the system under investigation. The resulting control law has a proportional-integral (PI)/almost PI-derivative-like structure, which is convenient for real-time implementation. The objective of the proposed approach is to improve the DC-bus voltage regulation, while at the same time control the power exchange between the PV system and the grid. The stability of the closed-loop system under the composite controller is guaranteed by simple design parameters. Both simulation and experimental results show that the proposed method has significant abilities to initiate fast current control and accurate adjustment of the DC-bus voltage under model uncertainty and external disturbance. [ABSTRACT FROM AUTHOR]

This study presents a novel adaptive control scheme for variable-speed wind turbine (VSWT) driven permanent magnet synchronous generator (PMSG) to ensure its operation under different operating conditions. The adaptive control scheme is based on the affine projection algorithm (APA) which provides a faster convergence and less computational complexity than the least-mean-square algorithm. The proposed adaptive controller is used to control both the generator-side converter and the grid-side inverter without giving additional tuning efforts. Each vector control scheme for the converter/inverter has four APA-based adaptive proportional-integral (PI) controllers. Detailed modelling and the control strategies of the system under study are demonstrated. Real wind speed data extracted from Hokkaido island, Japan is used in this study. The dynamic characteristics of a grid-connected VSWT-PMSG are investigated in details to ensure the proposed controller operation under different operating conditions. The effectiveness of the proposed adaptive controller is compared with that obtained using optimised PI controllers by Taguchi method. The validity of the adaptive vector control scheme is verified by the simulation results which are performed using PSCAD/EMTDC environment. [ABSTRACT FROM AUTHOR]