Minh Y Nguyen

Dynamic programming formulation of Micro-Grid operation with heat and electricity constraints

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.

A Comparison of Microgrid Topologies Considering Both Market Operations and Reliability

Abstract 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.

A New Framework of Demand Response for Household Customers Based on Advanced Metering Infrastructure Under Smart Grids

Abstract This article presents a new approach to the energy efficiency of households based on smart grid technologies applied to the existing power grid. The idea is to make the electrical appliances capable of actively responding to the condition of the upstream grid, e.g., the electricity price, which, under market environments, is passed to end-use customers through retailers or load aggregators. This both saves on the electricity bill for customers and improves the energy efficiency of the system as a whole. The key element is advanced metering infrastructure, which performs two main functions: (1) computing the so-called control policy for electrical appliances with anticipated data and (2) real-time control based on the above control policy and actual measurements. By stochastic optimization, the proposed scheme is capable of monitoring the uncertainty related to the electricity consumption in households, e.g., temperature and/or time and quantity demanded, etc. In addition, with the physical model taken into account, the problem can be applied to various appliances, including what were considered critical loads. The proposed scheme was tested in heat, ventilation, and air-conditioning systems; the simulation result showed the effectiveness in comparison with the traditional (on/off) scheme based on thermostats.

A New Approach for Corrective and Preventive Control to Unsolvable Case in Power Networks having DERs

Recently, Korean system operating conditions have gradually approached an upper limit. When a contingency occurs, the power system may have no solutions. Different from the cases of bad initial guesses or the solutions are too close to the solvability boundary in which numerical methods can be applied, for unsolvable cases, the only way to restore solvability would be structure modifications. In this paper, a new approach for corrective and preventive control to such cases is proposed in two steps: (i) finding any solution regardless its feasibility; (ii) for the infeasible solution, make it feasible with additional modifications at load buses having Distributed Energy Resources. The test case built based on the peak load profile of 2008 by KEPCO including 1336 buses is analyzed. Since reactive power compensation is optimized to restore solvability, all demands are met, therefore no blackouts happen. The proposed method was integrated in the LP program designed by power21 Corporation.

Novel Techniques for Real Time Computing Critical Clearing Time SIME-B and CCS-B

Realtimetransientstabilityassessmentmainlydependsonrealtimeprediction.� Unfortunately,�conventionaltechniquesbasedonofflineanalysisaretooslowandunreliablein� complexpowersystems.�Hence,�fastandreliablestabilitypredictionmethodsandsimplestability� criterionsmustbedevelopedforrealtimepurposes.�Inthispaper,�twonewmethodsforrealtime� determiningcriticalclearingtimebasedonclusteringidentificationareproposed.�Thisarticleis� coveringthreemainsections:�(i)�clusteringgeneratorsandrecognizingcriticalgroup;�(ii)�replacingthe� multimachinesystembyatwomachinedynamicequivalentandeventually,�toaonemachine� infinitebussystem;�(iii)�presentinganewmethodtopredictpostfaulttrajectoryandtwosimple� algorithmsforcalculatingcriticalclearingtime,�respectivelyestablishedupontwodifferenttransient� stabilitycriterions.�Theperformanceisexpectedtofigureoutcriticalclearingtimewithin�100ms� 150msandwithanacceptableaccuracy.� �

A New Battery Approach to Wind Generation System in Frequency Control Market

Wind power producers face many regulation costs in deregulated environment, which remarkably lowers the value of wind power in comparison with conventional sources. One of these costs is associated with the real-time variation of power output and being paid in frequency control market according to the variation band. This paper presents a new approach to coordination of battery energy storage in wind generation system for reducing the payment in frequency control market. The approach depends on the statistic data of wind generation and the prediction of frequency control market price to determine the optimal variation band which is then kept by the real-time charging and discharging of batteries, ultimately the minimum cost of frequency regulation can be obtained. The optimization problem is formulated as trade-off between the decrease in the regulation payment and the increase in the cost of using battery, and vice versus. The approach is applied to a study case and the results of simulation show its effectiveness.