Output Of Renewable Sources Research Articles

AC microgrid with battery energy storage management under grid connected and islanded modes of operation

The inevitability of energy storage has been placed on a fast track, ensued by the rapid increase in global energy demand and integration of renewable energy with the main grid. Undesirable fluctuations in the output of renewable sources is the main downside that call for manageable energy storage units. This study presents the viability of battery storage and management systems, of relevance to microgrids with renewable energy sources. In addition, this paper elucidates the development of a control algorithm for the management of battery power flow, for a microgrid connected to a mains electricity grid, is presented here. A shunt active filter algorithm for improving the power quality of grid is also implemented with power flow management controller. The overall management system is demonstrated for on grid and off grid modes of microgrid with varying system conditions. A laboratory scale grid–microgrid system is developed and the controllers are implemented.

Hybrid renewable energy resources incorporated optimal power flow using single phase multi-group teaching learning-based optimiser

The latest scenario of electrical system consists of conventional generating units along with the renewable energy resources. The proposed article recommends a method for the solution of optimal power flow, integrating with wind generating units, solar photovoltaic system and hybrid solar with small hydro power that is run-of-river with traditional coal-based generating stations. The irregularity of renewable source's output intensifies the complications of the optimal power flow issue. In the proposed work, lognormal, Weibull and Gumble probability density functions are also utilised for predicting power outputs of the renewables, respectively. The modified IEEE-30 bus test system is used to validate the results, which is incorporated with wind-solar-small hydro generating plants. The single phase multi-group teaching learning-based optimiser is used as the optimisation tool and the simulation results are compared with the newly developed algorithm.

Variance-Aware Optimal Power Flow: Addressing the Tradeoff Between Cost, Security, and Variability

Recent work has studied modifications to DC optimal power flow (DC-OPF) computations so as to better account for risk arising as a result of stochastic variation in the output of renewable sources. Typically such modifications rely on mathematical constructs, such as chance-constraints, that can still yield convex formulations. However, numerical simulations show that the computed policies can translate into power flow patterns with high variance. We introduce a number of convex variants of OPF that tradeoff variance and cost minimization, describe practical algorithms for the solution of such problems, and present numerical experiments.

Implementation of an electrolysis system with DC/DC synchronous buck converter

A synchronous buck DC–DC converter that can be used to produce hydrogen through electrolysis by using the energy generated from renewable energy sources has been designed and implemented. The reason for selecting this topology is that the voltage level at the output of renewable sources, such as solar cells and storage batteries, is about 12 V DC, and the voltage level required for electrolysis is about 2 V DC. Traditional buck converters have low efficiencies at low output voltages since the voltage drops on the components are comparable to the output voltage. The converter has been designed and tested at 25 A output current. Two different electrodes were used for electrolysis and the effect of electrode opening on the operation was observed. In addition, the stability analysis of non-linear electrolysis system load has been performed.

Co-Optimization of Output and Reserve with Significant Penetration of Renewables

Co-optimization of output and reserve is necessary in order to provide maximum benefit to both consumers and producers. Once renewable generation sources like wind or solar begin to make up a large proportion of the generation mix, this co-optimization becomes much more difficult since the output of renewable sources is not well-known in advance. In this paper, a uniform reliability level is used as a constraint in the process of output and reserve. The proposed model is tested on the modified 5-bus PJM system. The co-optimization is performed by sequential quadratic programming techniques. The results show that the co-optimization results are strongly related to the uncertainties of wind power, the reliability level of the system, and the reliability of generators when wind makes up a significant portion of the generation mix.