Anestis G. Anastasiadis

Quantification of economic, environmental and operational benefits of Microgrids

Microgrids are Low Voltage distribution networks comprising various distributed generators (DG), storage devices and controllable loads that can operate either interconnected or isolated from the main distribution grid as one controlled entity. The effect of the use of a Microgrid Central Controller (MGCC) to achieve this co-ordinate operation with regards to the potential economic benefits and the power losses avoided in both the local network and the upstream network are presented. Finally, a methodology based on the marginal emissions curve of the upstream network is presented, taking also into account the calculated losses is used for the environmental assessment of the co-ordinate operation of Microgrids. All the above studies have been applied to a typical LV Microgrid interconnected to an actual MV network using actual market prices and DG bids reflecting realistic operational costs.

Operational and environmental benefits due to significant penetration of Microgrids and topology sensitivity

Distributed Generation (DG), has started becoming a reality in electricity networks. This analysis focuses more on a specific configuration of networks with DG, the Microgrid. Microgrids can operate in a coordinated way either interconnected to an upstream distribution network or autonomously in case of faults in the upstream medium voltage network, like the power systems of physical islands. Under this concept, the potential benefits for the upstream network can be significant in terms of both losses avoidance and emissions reduction. This analysis focuses on ways of evaluating these benefits on a group of typical microgrids. Especially for emissions impact assessment, the seasonal variation of the DG production is taken into account. This variation can also have significant impact on the losses reduction. Results from the application of the described approach to a typical LV Microgrid interconnected to an actual MV network using actual market prices and realistic operational costs of DG taking also into account different configuration of topology for one of the DG units

Carbon tax, system marginal price and environmental policies on Smart Microgrid operation

Purpose The purpose of this paper is to optimally operate a Smart Microgrid which is interconnected to the main grid so as to minimize expenditures associated with CO2 emissions. Microgrids could come into play to aid the network through CO2 emission reduction while increasing their efficiency through local generation. For this purpose, a Smart Microgrid incorporating Distributed Energy Resources (DER) especially Renewable Energy Sources (RES) is operated optimally while keeping the CO2 emissions in check in order to minimize the financial burden from emissions stemming from the carbon tax. Since the network is assumed to be interconnected with the main grid, there is a consideration of the expected emissions associated with the imported energy. Design/methodology/approach An economic/environmental dispatch problem is mathematically formulated using an objective function and the constraints that it is subject to. The methodology is applied on a typical 17-bus test distribution network, representing a Hell...

Application of voltage oriented control technique in a fully renewable, wind powered, autonomous system with storage capabilities

The main purpose of this paper is to examine the technological feasibility of a small autonomous network, with electricity storage capability, which is completely electrified by wind energy. The excess energy produced, with respect to the load requirements, is sent to the batteries for storage. When the energy produced by the wind generator is not sufficient, load’s energy requirement is covered by the battery system, ensuring, however, that voltage, frequency and other system characteristics are within the proper boundaries. For the purpose of this study, a Voltage Oriented Control system has been developed in order to monitor the autonomous operation and perform the energy management of the network. This system manages the power flows between the load and the storage system by properly controlling the Pulse Width Modulation pulses in the converter, thus ensuring power flows are adequate and frequency remains under control. The experimental results clearly indicate that a stand-alone wind energy system b...

Hydrothermal coordination in power systems with large-scale integration of renewable energy sources

Purpose – The purpose of this paper is to examine the feasibility of an ideal power network that combines many different renewable energy technologies such as wind power, concentrated solar power (CSP) and hydroelectric power. This paper emphasizes in finding the benefits arising from hydrothermal coordination compared to the non-regulated integration of the hydroelectric units, as well as the benefits from the integration of wind power and CSP. Design/methodology/approach – Artificial Neural Networks were used to estimate wind power output. As for the CSP system, a three-tier architecture which includes a solar field, a transmission-storage system and a production unit was used. Each one of those separate sections is analyzed and the process is modeled. As for the hydroelectric plant, the knowledge of the water’s flow rated has helped estimating the power output, taking into account the technical restrictions and losses during transmission. Also, the economic dispatch problem was solved by using artifici...