Danny Morton

The concept of smart grids has been widely introduced to cope with energy transition towards sustainable energy system, which results in decentralization of the energy supply system. Among various solutions to accomplish the smart grids, clustering power systems approach (CPSA) has been proposed. Based on this approach, active interconnected cluster areas, operating similar to interconnected grids in transmission systems, are created in bottom-up direction from distribution level upwards to the upstream systems. In order to manage emerging cluster areas and concurrently facilitate their cooperation, this paper proposes hybrid framework of management systems. That is, both centralized and decentralized management systems are employed for operations under the CPSA. Besides, to add a level of cyber security, this paper also presents the integration of the adapted access control mechanism based on XACML data-flow model to the management systems. Lastly, the applications of the proposed hybrid framework are illustrated and discussed in use cases.

Decentralized, renewable energy sources has grown fast as a sustainable and clean alternative energy to overcome the carbon emissions caused by conventional power plants. However, this change leads to several challenges related to grid control, resulting in a need of new smart grid concepts. Therefore, Clustering Power System Approach (CPSA) has been introduced as a suitable smart grid concept. Meanwhile, the impact of small prosumers in power supply operation increases continuously and they will emerge from being passive to become active participants in smart grid and smart market operation. In a previous paper genetic algorithms (GA) has been introduced as an adequate optimization technique tackling the issue of economic optimization of smart prosumers in a case study. In this paper a case study for a whole cluster network with smart prosumers/households operating under individual requirements is carried out. Additionally, a market model containing auction based local energy markets (LEM) suitable to be implemented in the CPSA is introduced. This is the next step to achieve the goal of smart grid and smart market under the foundation of the CPSA. The results show that the GA based optimization in combination with the involvement of LEM provides economic benefits for smart prosumers.

The increase of electricity demand has raised requirements of more reliable and efficient grid operations as well as higher security of supply. Meanwhile, the transition towards clean and sustainable energy supply systems in the present power systems is under the spotlight [1]–[3]. High penetration of renewable energy sources (RESs), which are usually in the form of distributed generation (DG), can be expected. The RESs-based DG units can reside in distribution level, whose original purpose is to distribute power from electricity utilities to end users. Presently, to cope with the power penetration in distribution level, conventional power grids are being evolved into the smarter ones, known as smart grids. A smart grid is proposed to overcome the arising environmental and technical challenges [4], [5]. To smarten the grid, information and communication technologies are incorporated into the conventional power grids. They allow the cooperation of heterogeneous grid components, e.g. control centers and DG units, or users, e.g. operators and customers. Decentralization of grid control architecture is possible [6], and many actors can actively participate in the operation of the grid.

As the amount of decentralized generation is continuously increasing the control and maintaining of the grid stability becomes more complex. This is caused by the change of production capacities from the high voltage area into the distribution network. In order to ensure the stability of future smart grids a new 4-leg 4-wire inverter as a part of a power electronic regulator is introduced. The features of the 4-leg 4-wire topology in comparison to the 3-leg 4-wire topology and advantages of a multilevel inverter for harmonic compensation are shown. In combination with a powerful FPGA based controller complex algorithms for Space Vector Modulation and for control can be implemented. Finally the actual status of the hardware development including the technical data of the inverter is shown.

The increase of the share of distributed generations (DGs) based on renewable energy sources, which mostly reside in distribution networks, in current power systems can cause stability problems because traditionally the power is fed by bulk power plants through transmission systems. Accordingly, clustering power system approach (CPSA) has been devised to facilitate the integration of DGs to the power systems. Its key concept is to expand the mature control scheme and action of the transmission systems down to the distribution networks. Furthermore, the CPSA is aimed to be a solution for achieving future smart grids. In this paper, the principle of the CPSA and a strategy for CPSA-based power system operation for smart grids automation are delineated first. Then, a load flow calculation application is introduced for the demonstration of the CPSA-based power system operation. In the demonstration, online load flow calculation is performed under an exemplified interconnected clusters structure.

Renewable energy resources have become important because of the increasing costs of fossil fuels.
Up to now there has been little deregulation of the fossil fuel market and, therefore, the customer is not in the same position as with the electricity market where there is competition and an incentive to shop around for the best supplier. A good strategy for the customer is therefore to become less dependent on fossil fuels by installing renewable energy systems such as solar-assisted heat pumps. Significant research has been carried out in the field of solar-assisted heat pump system since the 70s but most of the technologies developed have stayed at the research level due to two primary reasons, namely poor control strategies and the inability to keep operating temperatures high enough to realize high coefficients of performance over the full year. Within the frame of the EC funded Endohousing project these issues are being investigated. The research focuses on the development of a system comprising a new unglazed solar roof collector and hi-tech control strategies to manage the effective movement of thermal energy in different sections of the system. The project has set up three houses using the endothermic technology. This paper is concerned with the initial set up, commissioning and run in of the systems. An evaluation of the first results of the technology is presented so that overall system optimisation can follow.

The application of renewable energy in power generation is steadily increasing. This rapid growth is supported by the recognition of these systems as an effective generation source with positive environmental and economical effects. A key element at the grid side of an isolated system is the inverter. This paper is concerned with the control strategies for three-phase voltage source inverters in PV/Hybrid power systems. The paper will first introduce the power system architecture of the system under study together with the different feeding modes. Further, the three-phase inverter topologies will be shortly discussed. Next, the paper attends to illustrate the control possibilities. The development of a four-leg inverter topology with a new advanced control approach based on symmetrical components is described briefly. Using this power electronics topology in combination with the developed control algorithms, the inverter performance can be improved. Simulation results obtained with the proposed control schemes are also presented.