Line-interactive uninterruptible power supply (UPS) systems are good candidates for providing energy storage within a microgrid to help improve its reliability, economy, and efficiency. In grid-connected mode, can be imported from the grid by UPS charge battery. Power also exported when required, e.g., tariffs advantageous. stand-alone supplies local distributed loads in parallel with other sources. this paper, line-interactive control system presented discussed. flow is controlled using...

This paper is concerned with the design and control of a three-phase voltage source grid-connected interleaved inverter. topology enables use low-current devices capable switching at high frequency, which together ripple cancelation feature reduces size output filter inverter considerably compared to an equivalent classical two-level LCL using high-current lower frequency. Due its higher frequency low-filter component values, also has much bandwidth than inverter, improves grid harmonics...

In some situations, utilities may try to “save” the fuse of a circuit following temporary faults by de-energizing line with fast operation an upstream recloser before is damaged. This fuse-saving practice accomplished through proper time coordination between and fuse. However, installation distributed generation (DG) into distribution networks affect this due additional fault current contributions from resources. phenomenon recloser-fuse miscoordination investigated in paper help typical...

In inverter-based microgrids, the paralleled inverters need to work in grid-connected mode and stand-alone transfer seamlessly between two modes. mode, control amount of power injected into grid. however, island voltage while output is dictated by load. This can be achieved using droop control. Inverters have different set points during but they all their adjusted according ratings. However, sudden unintentional islanding (due loss mains), transient flow from with high low points, which...

This work presents the application of reinforcement learning for optimal resistive control a point absorber. The model-free Q-learning algorithm is selected in order to maximise energy absorption each sea state. Step changes are made controller damping, observing associated penalty, excessive motions, or reward, i.e. gain power. Due general periodicity gravity waves, absorbed power averaged over time horizon lasting several wave periods. performance assessed through numerical simulation...

In islanded ac microgrids consisting of renewable energy sources (RES), battery-based storage system (BESS), and loads, the BESS balances difference between RES power loads by delivering/absorbing that difference. However, state charge charging/discharging battery should be kept within their design limits regardless variations in load demand or intermittent RES. this paper, a supervisory controller-based on fuzzy logic is proposed to assure do not exceed maintaining stable flow. The...

A model-free algorithm is developed for the reactive control of a wave energy converter. Artificial neural networks are used to map significant height, period, and power take-off damping stiffness coefficients mean absorbed maximum displacement. These values computed during time horizon spanning multiple cycles, with data being collected throughout lifetime device so as train off-line every 20 horizons. Initially, random selected controller achieve sufficient exploration. Afterwards,...

The levellised cost of energy wave converters (WECs) is not competitive with fossil fuel-powered stations yet. To improve the feasibility energy, it necessary to develop effective control strategies that maximise absorption in mild sea states, whilst limiting motions high waves. Due their model-based nature, state-of-the-art schemes struggle deal model uncertainties, adapt changes system dynamics time, and provide real-time centralised for large arrays WECs. Here, an alternative solution...

This paper proposes an energy management system (EMS) for battery storage systems in grid-connected microgrids. The charging/discharging power is determined such that the overall consumption cost minimized, considering variation grid tariff, renewable generation and load demand. modeled as economic dispatch optimization problem over a 24 h horizon solved using mixed integer linear programming (MILP). formulation, therefore, requires knowledge of expected production demand next h. To achieve...

This paper presents a microgrid control strategy to unify the topology for energy storage systems and renewable sources inverters in an ac protect reliability from unintentional islanding instability using loops, which use thedc link voltage as feedback. bounds dc provides reliable operation microgrid. Simulation validates proposed strategy, experiment results extol concept.

In this article, reinforcement learning is used to obtain optimal reactive control of a two-body point absorber. particular, the Q-learning algorithm adopted for maximization energy extraction in each sea state. The controller damping and stiffness coefficients are varied steps, observing associated reward, which corresponds an increase absorbed power, or penalty, owing large displacements. generated power averaged over time horizon spanning several wave cycles due periodicity ocean waves,...

An effective introduction of distributed generation (DG) into existing distribution networks (DNs) calls for a review traditional power system protection concepts and strategies. New issues such as activeness DNs bidirectional flow require new solutions. This paper discusses challenges arising from the integration DG grid. It presents critically reviews state art Moreover, some alternate strategies are proposed their merits demerits discussed. (5 pages)

This study is concerned with control of grid connected inverters using odd-harmonic repetitive scheme. Owing to the inherent long convergence period control, a feedforward loop fundamental component voltage used make sure that inverter's output current bounded during period. The well-known deficiency in rejecting harmonics when varying frequency has been solved by an adaptive scheme which switching and sampling frequencies vary respect frequency. main qualities proposed controller are its...

Wave energy resources are intermittent and variable over both spatial temporal scales. This is of concern when considering the supply power to electricity grid. paper investigates whether deploying arrays devices across multiple spatially separated sites can reduce intermittency step changes in generated power, thereby smoothing contribution wave supply. The primary focus on southwest UK; SWAN model hindcast data analysed assess correlation resource variability levels with directionality....

An algorithm has been developed for the resistive control of a nonlinear model wave energy converter using least-squares policy iteration, which incorporates function approximation, with tabular and radial basis functions being used as features. With this method, controller learns optimal power take-off damping coefficient in each sea state maximization mean generated power. The performance is assessed against two online reinforcement learning schemes: Q-learning SARSA. In both regular...

Microgrids have limited renewable energy source (RES) capacity, which can only supply a amount of load. Multiple microgrids be interconnected to enhance power system availability, stability, reserve and control flexibility. This paper proposes novel structure scheme for interconnecting multiple standalone common alternating current (AC) bus using back-to-back converters. The presents high-level global droop controller that exchanges between microgrids. Each microgrid considered in this...

Reinforcement Learning (RL) provides a pathway for efficiently utilizing the battery storage in microgrid. However, traditional value-based RL algorithms used management focus on formulating policies based reward expectation rather than its probability distribution. Hence scheduling strategy is solely of rewards This paper focuses distribution which optimally reflects uncertainties incoming dataset. Furthermore, prioritized experience replay samples training are to enhance quality learning...

Abstract Grid-connected microgrids comprising renewable energy, energy storage systems and local load, play a vital role in decreasing the consumption of fossil diesel greenhouse gas emissions. A distribution power network connecting several can promote more potent reliable operations to enhance security privacy system. However, operation control for multi-microgrid system is big challenge. To design system, an intelligent multi-microgrids management method proposed based on preference-based...