Andreas Abart

DG DemoNet validation: Voltage control from simulation to field test

Refinements of the voltage control algorithm for the DG DemoNet concept have been developed extensively over the last years. Consequently the next step will be field tests prior to the deployment. This paper describes the (re-)design of the existing prototype algorithm, offline and online simulation environments and testing of the implementation to prepare the central voltage control unit for the field test. The communication links - PLC and radio link - and the MV grids - ‘Großes Walsertal’ and ‘Lungau’ - impose different challenges for the validation of the voltage controller. During the porting of the prototype to the production implementation, the algorithm has run through a major code revision and re-design, to ensure a more general and modular approach for the voltage control algorithm.

Analysis environment for low voltage networks

Making the best use of low voltage networks will play an important role the in future, because of the increase of photovoltaic and electric vehicles connected to the households. For better understanding and modeling of low voltage networks, the Power Snap Shot method has been developed. This work describes the principles of the information and communication system to automatically manage the measurement data and analyze the grid models by means of automated load flow simulation.

Optimisation of LV networks with high photovoltaic penetration — Balancing the grid with smart meters

This paper presents the latest results of several research activities in the field of low voltage network optimization in regard to unsymmetrical power infeed from distributed generators. A method for balancing networks with a high number of single-phase generators is proposed. By applying the method, the voltage unbalance can be reduced, the available voltage band can be better utilized and the hosting capacity for distributed energy resources extended.

The IGREENGrid Project: Increasing Hosting Capacity in Distribution Grids

Distributed Renewable Energy Sources (DRESs) are increasing rapidly in distribution grids, and their integration into the electricity system is one of the most relevant problems facing these networks. The objective of our project, IntegratinG Renewables in the EuropEaN electricity Grid (IGREENG rid), was to analyze and select the most promising research and development (R&D) solutions to this problem. For this purpose, four research institutions (Institute of Communications and Computer Systems of the National Technical University of Athens, Ricerca sul Sistema Energetico, Austrian Institute of Technology, and Tecnalia) and eight European utilities studied six large demonstration projects: Eberstalzell and Koestendorf (Energie AG Oberösterreich Netz and Saltzburg AG) in Austria; Proyecto de Redes Inteligentes del Corredor del HenarE in Spain, known as PEICE (Iberdrola Distribución Eléctrica and Gas Natural Fenosa); Sperchiada in Greece (Diacheiristis Ellinikou Diktyou Dianomis elektrikis Energeias); Isernia in Italy (e-distribuzione); Zukunftsnetze in Germany (Innogy SE); and Venteea in France (Enedis). IGREENG rid had a budget of €6.6 million, partially funded by the European Commission, and was in development for almost four years.

The Proof Is in the Putting: Large-Scale Demonstrations of Renewables Integration Showcase Real-World Solutions

The safe and reliable integration of the levels of renewable energy source (RES) penetration expected in the European Union (EU) by 2020 requires the implementation of new technologies to demonstrate the effectiveness of new practices for managing the system and the assessment of the economic impact and replicability potential of the proposed solutions.

DG-demonet smart LV grid - increasing hosting capacity of LV grids by extended planning and voltage control

This paper describes the impact of different voltage control strategies on low voltage grids with a high share of decentralized generation. These control strategies use the on-load-tap-change capability of new MV/LV-transformers as well as the capability of new PV inverters and other flexible devices to control active and reactive power. The control strategies were operated in field tests in three Austrian LV grids. The demonstrated impact of these control strategies on voltage band usage is faced with an extended planning approach that uses all available measurement data from the grid for a more accurate prediction and optimization of grid voltages.

Validation of aggregated harmonic current source models based on different customer type configurations

Harmonic voltages are important voltage quality parameters defined in EN 50160. For harmonic voltage studies in electricity networks, harmonic emission of loads is often modelled as harmonic current source. In this paper harmonic current sources were parameterised on the basis of measure-ments of total harmonic current emission of several different low voltage networks. Measurements from low voltage net-works with different typical customer configurations were used: residential, offices and PV. A real medium voltage electricity distribution network of an Austrian distribution system operator, with significant consumption of residential and office customers, was chosen for this analysis. In order to automate the harmonic load flow calculations in DIgSILENT PowerFactory for every 10-minute interval of one week, a script in DIgSILENT Programming Language - DPL was developed. Harmonic voltage results from the harmonic load flow simulation are compared with the results of harmonic voltage measurements from power quality monitoring system installed in this network. The goal of this paper is to assess the suitability of the approach, where only background harmonics and key harmonic current sources are modelled. Since the approach provided good results, it can be used in future work as a basis for optimising the number and locations of power quality monitors in electricity distribution networks.

Hosting capacity of LV networks with extended voltage band

This paper presents the results of investigations on the voltage band management in low voltage networks considering two promising network integration solutions to enhance the hosting capacity for e.g. high PV penetrations. The critical length defined as border between current and voltage constraints is calculated for typical overhead lines and cables. The extension of the available voltage band by the use of e.g. on load tap changers in secondary substations allows a substantial increase of the hosting capacity which can be further increased by the use of reactive power based voltage control. However, the actual benefits of a voltage band extension or voltage control measures can only be used for feeders exceeding the critical length. In this paper, the critical length for different types of feeders is calculated and the implications are discussed. In addition, the impact of an extension of the voltage band and of the use of network integration solutions on network losses is investigated.