Helfried Brunner

DG DemoNet-Concept - A new Algorithm for active Distribution Grid Operation facilitating high DG penetration

While distributed generation (DG) from renewable energy resources is seen as key element of future energy supply, current electricity grids are not designed to integrate a steadily increasing share of distributed generators. The hierarchical network topology was designed for unidirectional power flows and passive operation. In order to avoid excessively expensive grid reinforcements, new solutions for active grid operation will be necessary. This paper introduces a set of innovative technical measures that allow a higher DG penetration within the grid. A new control algorithm for coordinated voltage control in an active distribution grid featuring these measures is proposed. Simulation results for an application of the algorithm in an actual Austrian distribution grid segment are presented.

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.

Improving power quality with coordinated voltage control in networks with dispersed generation

Rapidly increasing share of distributed generation (DG) in distribution networks introduced the need for active distribution network operation. As current distribution networks were not designed to integrate the power generation, the DG introduced many technical challenges in sense of power quality, network planning, protection schemes, voltage stability.... This paper presents the advantages of active approach in distribution network operation. The paper focuses on a voltage quality problem and introduces the coordinated voltage control technique to increase the share of DG in distribution networks and at the same time supply the customers with the required voltage quality.

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.

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.

How to Optimise the Over Production of PV Electricity into the Grid with the Implementation of ICT Devices - The OrPHEuS Project

The OrPHEuS project elaborates hybrid energy network control strategies for smart cities implementing novel cooperative approach for the optimal interactions between multiple energy grids. The OrPHEuS project aims at optimising the synergies between multiple energy grids by enabling simultaneous optimization for individual response requirements, energy efficiencies and energy savings as well as coupled operational, economic and social impacts. The project will investigate the implementation of the control strategies on specific use cases scenario in two demonstration sites located in the City of Skelleftea in Sweden and in the City of Ulm in Germany. The operational focus of the project is the cross-domain coupling of energy infrastructures in order to increase energy efficiency through energy transformation and grid coupling. In particular, the project researches scenarios for transition between energy resources and flexible infrastructures e.g. along Power-to-Heat processes. It investigates the balancing of fluctuating renewable energy generation against the flexibility in supply, demand and storage capacities within the power grid and via process coupling across energy networks. The project will look on technical as well as socio-economical aspects considered as multi-dimensional strategy framework. With respect to the hybrid energy characteristics, both demonstration sites are quite distinct. At the demonstration site in Sweden, the reduction of vertical production (driven unsustainable with fossil fuel) is in the centre of the targeted control strategies. Looking on the specifics of the Ulm testing site, the major issue is the balancing of the high penetration of solar generation under today’s operation with a pre-dominant operational challenge for PV control. The key focus is to define control strategies to increase the intake of the energy supply from PV on the roof generation into the grid while maximizing the benefits for the low voltage power grid. The 29th European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC) in Amsterdam represented a unique opportunity to present information on the methodology adopted by the OrPHEuS Consortium to optimise the synergies between multiple energy grids. On the occasion of the EU PVSEC the OrPHEuS Consortium focused the project presentation on how to optimise the PV electricity production with the implementation of Information and Communication (ICT) devices at the Ulm demonstration site, the Test area in Einsingen, which presents an over production of the PV electricity of 230 MWh annually. The average annual electrical consumption is around 1000 MWh.