FLOW-R – Flexible Local Grid Voltage and Active Power Controller

Success in the Field Test

The innovation project “Flexible Local Grid Voltage and Active Power Controller” (FLOW-R) was successfully completed in October 2017 after a three-year project period.

The research project was conducted as part of the “Sustainable Power Grids” funding initiative supported by the Federal Ministry for Economic Affairs, the Federal Ministry for the Environment, and the Federal Ministry of Research, and investigated how much renewable electricity could be integrated into the low-voltage grid without grid reinforcement using the FLOW controller designed in the project.

By 2050, 80 percent of Germany’s electricity supply is expected to come from renewable energy sources. However, because renewable power generators feed electricity into the grid based on availability, the flow of energy fluctuates greatly. In some cases, the amount of power being transmitted can even exceed demand. Especially in regions with many PV systems, the low-voltage grids—which account for about 65 percent of the German power grid—are reaching their thermal capacity limits.

Combined with the expected increase in electric cars in the near future, this could lead to grid overloads. If the load limit is exceeded, this can result in power outages and, in the worst case, cause fuses to blow.

The new FLOW controller was developed to ensure an optimal and stable supply in the future as well. The award-winning research project demonstrated that, with the help of information and communication technologies, the capacity of low-voltage distribution grids to accommodate increasing renewable energy generation can be increased and grid quality can be optimized.

Following extensive laboratory testing at the Technical University of Kaiserslautern, Pfalzwerke installed the FLOW controller in its grid in Heuchelheim-Klingen for a field test that lasted several months. The FLOW-R offers the advantage of being easy to install and not requiring costly upgrades to the distribution networks. The necessary communication technology was provided by PPC in the form of broadband power line (BPL) and further developed for the project.

Problem Statement

The “Flexible Local Network Voltage and Active Power Regulator” (FLOW-R) is a new piece of equipment that has been developed and tested to enable locally selective voltage regulation in a meshed low-voltage system. This system was designed to allow for the regulation of power distribution across the existing feeder circuits.

The controllers were strategically deployed within the smart grid and interconnected via networked control algorithms. To enable a cost-effective transition from the current grid to the target grid, the solution’s scalability and expandability were essential. The goal was for the FLOW-Rs to be able to relocate—thanks to their mobility and ease of reuse—in the event that the grid situation changes.

Procedure

The project included the scientific development of the new concept, the industrial implementation and testing of prototype FLOW-R units, and an operational and economic cost-benefit analysis. First, mathematical models were developed for various network topologies, and algorithms for network control were designed. In addition, a communication concept was developed to enable the FLOW-Rs to form a locally self-sufficient network. This required the design and implementation of a security architecture to protect against unauthorized access. After setting up the equipment and implementing the control algorithms, laboratory and field tests were conducted to verify the simulations and ensure proper functionality. PPC led the “Communication and Security Concept” work package. As part of this effort, the existing broadband powerline infrastructure was further developed for use in grid control based on the FLOW-R. The experience and concepts regarding security architecture developed during the project—which are designed to protect the control concept of local FLOW-Rs—are being used to further develop and safeguard other applications in future power grids.

Funded Collaborative Project

FLOW-R is funded as part of the 6th Energy Research Program of the Federal Ministry for Economic Affairs and Energy and the Federal Ministry of Education and Research. The project has been running from mid-2014 through mid-2017.