Summary
The complexity of power system operation has increased over the last few years due to the increasing impact of renewable energy sources and uncertainty in global energy markets. The energy transition is shifting load and generation away from well-known patterns established over several decades. Systems designed to distribute energy from the transmission grid to the consumers are now seeing power flows that change direction depending on the time of the day and the weather, sometimes injecting power generated at the lowest voltage network up into the transmission grid. More remedial actions must be taken to ensure network stability, and increasingly these measures must be coordinated with distribution system operators (DSOs).
Read more Read lessWhile the task of finding the actions that resolve congestion and voltage problems is being increasingly supported by optimization tools, the coordination is still a time-consuming nonautomated task. In Switzerland the distribution grid is operated by over 600 different DSOs, each working with its own tools and data, hence a robust, decentralized and scalable solution is required. OPTESO (OPTimality with limited data Exchange between System Operators) has been conceived to address this task and has been tested with real-world data. OPTESO has been developed by Swissgrid together with two Swiss DSOs which operate high voltage distribution grids connected to the transmission grid and are often involved in coordinated remedial actions with Swissgrid.
OPTESO is a mechanism to coordinate Power Flow calculations between distinct but interconnected systems, and it is based on the Adaptive Direction Method of Multipliers
(ADMM). Applied to remedial action optimization, it ensures that the measures proposed by decision support tools are coordinated with the connected distribution system operators, via their own decision support tools. A consistent solution for the whole system is found with limited data exchange between system operators. Only data related to the common system boundaries need to be exchanged. This allows each system operator to use its own support tools and network models with only an additional interface to exchange minimal data. There is no need to merge network models, nor to centralize computation. Several Swiss DSOs welcomed positively the approach, as it does not require sharing the internal parts of their models.
OPTESO has been tested with static data from Swissgrid and two Swiss DSOs. The two DSOs are among the largest high voltage grids in the country and, combined, they account for about 8% of the total peak load of Switzerland. In addition, the validity of the approach has been proven by surveys with representatives of Swiss DSOs operating high voltage grids. The representatives confirmed the importance of the challenge and stated their interest for decentralized coordinated remedial actions optimization. A loop based on ADMM could significantly simplify the coordination of remedial actions among system operators. Swissgrid is improving its forecasting and decision support tools and will be ready for a pilot in the next years. After a pilot phase with a limited number of participants, all DSOs in Switzerland could progressively join OPTESO.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | C2_12310_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Switzerland |
| Study committees | |
| File size | 1 MB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
TOLETTI Ambra - Swissgrid Switzerland; WU Raphael - Swissgrid Switzerland; BUCHER Matthias - Swissgrid Switzerland; O' MALLEY Conor - Swissgrid Switzerland; STOECKLI Marcel - ELECTROSUISSE / CIGRE Switzerland NC Secretary
Keywords
decentralized optimization, network security analysis, remedial action optimization, TSO-DSO coordination
