Authors: Reinhard BREHMER WIEN ENERGIE Stromnetz GmbH - Austria

1. A STRUCTURED APPROACH FOR SMART GRID IMPLEMENTATION • Authors: • Reinhard BREHMER WIEN ENERGIE Stromnetz GmbH - Austria • Thomas SCHUSTER WIEN ENERGIE Stromnetz GmbH – Austria • Theodor CONNOR Siemens AG - Germany • Christine SCHWAEGERL Siemens AG – Germany • Wolfram H. WELLSSOW Technical University Kaiserslautern - Germany Wellssow – DE – Session 5 – Paper ID 364

2. Challenges, Targets and Solution Development • Challenges • Meet environmental constraints • Increasing share of DG and new loads • Economical challenges; building new grids with regulated tariffs • Targets • Conversion • from top-down „blind“ distribution systems • to active, interactive, „intelligent“ and transparent MV/LV systems • Solution development • Start from objectives to be met rather than technologies • Identify technical feasibility • Analyse cost and benefit • Develop roadmap

3. Objectives of Distribution System Development

4. Storage Options for Active Power Balancing

5. Wien Energie Stromnetz GmbH (WES) • Biggest DSO in Austria • System characteristics • >11 TWh demand • 2,000 km2 supply area • 2 Million customers • 1,5 Million meters • 40 substations 380/110 kV to 20 or 10 kV • >10,000 MV/LV transformer stations • 22,000 km line length

6. WES Grid Concept as of today LV MV Ring feeder with open connections to other feeders Open meshed network with loop-through technique

7. The Way to a Future-Proof Distribution Grid • New Requirements at MV and LV levels • Securing power quality (e.g. voltage control) • Reduction of grid losses • Measures • Definition and implementation of new target structures for the MV- and LV-grid • Implementation of communication between all grid users to maintain high quality of supply

8. Technology Choice for the MV grid • Open-ring scheme will be kept • Elimination of abundant connections • New average number of transformer stations per line • 10 for the 10-kV-grid • Every 5th station with connection to another feeder • 20 for the 20-kV-grid • Every 10th station with connection to another feeder • Maximum line current 60 % of rated • Identification of important nodes • About 10 – 20 % of total • Adaptation for SCADA monitoring preferable via fiber optics

9. Technology Choice for the LV grid • Implementation of a LV control system • Each LV feeder measured at the transformer station • On-line power-flow calculation • 2 options for grid enhancement • Transformers with OLTC • High cost and difficult replacement • Additional switches placed in important nodes • Turns „open-meshed networks“ into „meshed networks“ • Comparably easy and stepwise implementation • Advantages of additional switches • Reduction of grid losses at LV level • Easier implementation • Knowledge of load-flow enables control of DG and EV charging

10. Roadmap • Stepwise transition from today to advanced smart • Will take minimum 20 years • Securing substantial investments for so many measures over such a long period(Regulation! New tariff-structure needed) • Optimization program started • Elimination of abundant lines • All new or refurbished transformer stations equipped with monitoring • Additional breakers and earth-fault indicators installed preferably in feeders with OHL

11. Contact Information • Email: wellssow@eit.uni-kl.deTel: +49 (0)631/205-2021 Fax: +49 (0)631/205-2168Secretary Mrs. Haessel +49 (0)631/205-2826www.eit.uni-kl.de/wcms/esem.html Univ.-Prof. Dr.-Ing. W.H. WellssowTechnical University KaiserslauternChair for Energy Systems and Energy ManagementErwin-Schrödinger-StrasseBuilding 11, Room 332D-67663 Kaiserslautern Germany