Recently, with the advent of power electronics, the use of DC technology might be an attractive option to be considered for energy transmission and distribution in power systems. DC technology offers advantages such as lower losses and higher controllability when compared to conventional AC transmission systems. Moreover, the use of voltage source converters (VSCs) offers the possibility to control active and reactive power independently in the AC grid, giving additional degrees of freedom to the system. In order to verify the operation of the power system power flow calculations are required. Conventional power flow methodologies do not consider DC grids and the controllability offered by them. In this sense, in this paper two novel integrated AC/DC power flow calculation methodologies (unified and sequential) are analyzed and then tested. Results show performance of both methodologies.

At present, European countries are seeking ways to reduce carbon emissions. To achieve this, they have set ambitious emissions reduction goals. Thus, in this paper, a novel strategic planning methodology is used in order to determine the most appropriate power system for Europe by the year 2050. The planning methodology jointly optimizes generation and transmission expansion alternatives considering renewable energy, energy storage and demand-side management, in order to minimize total costs. Technical and environmental aspects are considered by optimization model constraints. In this work, demand-side management is seen as an option to test the power system design under the assumption that a certain percentage of the load can be shifted. Moreover, sensitivity analyses are performed in order to evaluate the impact of different investment costs of storage technologies. Results show how different flexible demand levels, as well as different investment costs of storage technologies, technically and economically affects the future European power system.

Driven by decreasing prices for photovoltaic (PV) systems and incentive programs of different governments, almost 100 GW of PV and over 100 GW of wind turbines (WT) have been integrated in the European power system by 2014. In some areas, the electricity generation already exceeds the demand, curtailing generation or pushing the existing power transmission infrastructure to its limits in certain hours. In order to reach the European Commission's targets for 2050, the integration of renewable energies will require flexibility sources, independent of conventional generation, in order to provide standard security of supply. Together different flexibility sources will ensure the match between demand and supply at any given time. Energy storage systems can provide this flexibility by shifting the load temporally while transmission grids provide the shift of load spatially. Up to a certain extent, transmission capacity and storage capacity can replace each other, i.e. storage can reduce the load on transmission infrastructure by mitigating local peaks in load and/or generation. For the transition to a fully renewable energy system by 2050, major changes have to be achieved in the structure of the power system. The planning tool GENESYS is a holistic approach that optimises the allocation and size of different generation technologies, storage systems and transnational transmission corridors of a European power system. The source code for the mentioned tool is available free of charge under LGPL license. It can be freely parameterized by the user which allows the study of different power systems under individual assumptions with regard to load, generation potential and cost of the different system components. This publication will give an introduction to the planning methodology, the system model and the optimisation approach. Optimisation results obtained with GENESYS for a fully renewable electricity system for Europe and a cost structure expected for 2050 will be presented together with sensitivity analyses investigating main assumptions. Outcomes show the optimal allocation of PV and WT in a European power system, the resulting demand for storage capacities of different technologies and the capacity of the overlay grid. (C) 2016 Elsevier Ltd. All rights reserved.

In October 2014 the Research Campus Future Electrical Networks, funded by the Federal Ministry of Research and Education with around 10 million EUR over the next 5 years, was started at RWTH Aachen University. Focus of research is the utilization of dc-technology for electrical (distribution) grids. The publicly funded Research Campus consists of four different projects, which are closely cross-linked. Within one of these projects a research demonstration medium-voltage dc-grid is to be built by connecting several test benches in the megawatt range, other projects focus on control and automation as well as devices and grid technologies. This paper will present the project "Modelling, Planning, Design and Evaluation of dc-Distribution grids" which focuses on the development of network planning tools for dc and hybrid distribution grids as well as related interdisciplinary topics such as acceptance, electromagnetic compliance landscape and urban planning. Due to the interdisciplinary approach the project consortium consists not only of institutes from the Faculty of Electrical Engineering, but also of institutes focusing on political science, landscape architecture, urban planning, medicine, ergonomics, and technical communication. Under the project lead of the Institute of Power Systems and Power Economics (IAEW) at RWTH Aachen University they work closely interconnected in order to facilitate an interdisciplinary exchange and interaction. This paper will give a detailed overview on the different work packages of the project as well as on the project targets and the chosen methodologies.

Nowadays, power system strategic planning plays a significant role due to long-term ambitious goals imposed by many countries and regions. These objectives involve, amongst others, the inclusion of renewable energies in the electrical power system. Furthermore, spatial clustering methods are widely used in geography-related analyses to identify relevant areas for business decision making, especially in advanced analyses based on Geographic Information Systems (GIS). In this regard, these tools are today widely used to estimate potentials of renewable energy sources by using georeferenced information, such as solar radiation or wind speed. However, current planners consider political or electrical boundaries to perform the planning of the power system. In most cases this view seems inadequate due to the disregard and loss of geo-spatial information. This encourages the application of GIS tools to perform a regional analysis within the planning of the power system. In this paper, a new spatial distance measure is proposed to work with common spatial clustering algorithms to solve the geo-spatial clustering problem with non-spatial attributes and geographic non-overlapping constraints. The clustering is used to achieve the optimal regional division of the power system in terms of renewable energy sources considering GIS. On this basis, the European power system is chosen to evaluate the performance of the developed tool. Results are compared with existing manually selected regions used by other strategic planning methodologies in Europe and the functional benefit is pointed out.

Nowadays, Argentina is experiencing an energy crisis mainly due to an inadequate planning. On the other hand, several countries are beginning to consider social aspects in planning, such as the use of nuclear energy, which has sparked considerable controversy in recent years. Thus, in this paper a novel strategic planning methodology is used in order to determine the most appropriate power system for Argentina by the year 2050. The planning methodology jointly optimizes generation and transmission expansion alternatives considering renewable energy and energy storage, in order to minimize total costs. Technical and environmental aspects are considered by optimization model constraints. Results show how nuclear energy rejection technically and economically affects the Argentinean power system.