OptiQU

Smart voltage control for increasing grid capacity

Coordinated voltage and reactive power control makes it possible to use the existing grid infrastructure more efficiently and avoid voltage-related bottlenecks. This is an innovative approach in which controllable local distribution transformers, decentralised generation and consumption facilities are intelligently networked and coordinated. This represents a fundamental shift in the operation of distribution grids and enables the integration of further renewable energy sources and new consumers such as heat pumps and electric vehicles.

Background and current challenges

The rapid expansion of photovoltaic systems, heat pumps and charging infrastructure for electric vehicles presents distribution system operators with major challenges. Combined with high levels of simultaneous demand, this is increasingly leading to voltage-related bottlenecks, particularly in the low-voltage sector, even before thermal limits are reached. Existing solutions such as controllable local distribution transformers (rONT) or Q(U) control operate exclusively at a local level – there is no coordination across grid levels. This results in sub-optimal utilisation of existing flexibility potential.

Project OptiQU: Coordinated voltage control in medium- and low-voltage grids

The OptiQU project aims to develop an intelligent, coordinated voltage and reactive power control system for medium- and low-voltage grid. It combines centralised and decentralised control approaches to achieve both optimal utilisation of flexibility and maximum robustness. The aim is to prevent voltage violations through the coordinated use of decentralised generation, controllable loads and local distribution substations, to increase the grid’s absorption capacity and, at the same time, to ensure system stability and the provision of reactive power for higher voltage levels.

Practical implementation and innovative concepts

The OptiQU project utilises modern communication technologies to link measurement data from local distribution substation and smart metering systems. Particular focus is placed on developing a decentralised logic as a fallback in the event of communication failures. The algorithms developed are being tested both in the laboratory and in field trials with grid operators.

Field testing and transferability

The solutions developed within the project will be validated through field testing carried out by the consortium partners Mitteldeutsche Netzgesellschaft Strom and Thüga Energienetze during the project’s duration. The results will be compiled into a guide for grid operators. OptiQU thus actively contributes to addressing the voltage band issue – particularly in rural areas – and accelerates the integration of renewable energies.