Under a deregulated environment, wind power producers are subject to many regulation costs due to the intermittence of natural resources and the accuracy limits of existing prediction tools. This paper addresses the operation (charging/discharging) problem of battery energy storage installed in a wind generation system in order to improve the value of wind power in the real-time market. Depending on the prediction of market prices and the probabilistic information of wind generation, wind power producers can schedule the battery energy storage for the next day in order to maximize the profit. In addition, by taking into account the expenses of using batteries, the proposed charging/discharging scheme is able to avoid the detrimental operation of battery energy storage which can lead to a significant reduction of battery lifetime, i.e., uneconomical operation. The problem is formulated in a dynamic programming framework and solved by a dynamic programming backward algorithm. The proposed scheme is then applied to the study cases, and the results of simulation show its effectiveness.

This article investigates and compares various types of microgrids in the literature. The comparison is concerned with the economic operation of the micro-sources employed in different topologies and the reliability of the end-users. Also, the effect of each component on the performance of the overall microgrid is discussed in detail, e.g., the individual and centralized power converters, etc. The numerical simulation of a case study shows that the single AC and three wire network microgrid types are predominant over two others, namely single DC and hybrid AC-DC networks. The AC microgrid shows its benefits in market operations, while the three-wire network takes advantage of customizing loads as its reliability preferences. The DC microgrid is the worst case, suffering from high power losses and poor reliability.

This paper addresses unit commitment for micro-grid optimization including renewable sources, working under deregulated power market. As micro-grid supplies both of heat and electricity consumer, operational optimization must be done in coordination. So far in this paper, renewable energy sources are considered to be negative load, and batteries, as well, are used as the load flattened device to raise possibly operational function. In state of solution, dynamic programming method has been developed that solve out the maximum profit micro-grid that owner might achieve from energy trading in a day, either in isolated or connected mode.

This paper proposes a new approach to distribution system named Three-wire Network (3-NET). Considering the integration of different distributed generation (DG) technologies as well as the diversity of loads, the idea of 3-NET is splitting a single power network into three qualitatively different networks: (i) a high quality direct current (DC) network; (ii) a conventional alternating current (AC) network; and (iii) a low quality DC network. By this configuration, the multi-stage conversion of energy from DG sources can be reduced, whereas loads can be supplied with different power quality and reliability levels as desired. In order to evaluate the potential benefits of 3-NET, the operational strategy is formulated in a market model; the reliability performance is investigated using Monte Carlo simulation and quantified in terms of interruption costs. In the case study, the proposed 3-NET is considered for integrating a certain amount of DG into a specific distribution system and then compared with another system approach: hybrid AC–DC microgrid. The simulation shows that although the operation costs can be slightly higher, the 3-NET shows a great improvement in reliability performance in comparison with the hybrid microgrid. Copyright © 2013 John Wiley & Sons, Ltd.