Reactive power management

 

Reactive power management in the distribution grids

Both the increasing integration of renewable energies and new loads in distribution grids can lead to violations of the permissible voltage band, especially in girds with long lines or a high proportion of overhead lines. When selecting the possible solutions, in addition to the conventional grid expansion, the option of using reactive power management is also available to increase the integration potential. Complex calculations are necessary for the cost-optimal planning and evaluation of these controls.

Against this background, various optimization algorithms as well as decentralized control approaches for static voltage maintenance are developed at the IAEW and applied in various projects. Through integration into powerful simulation environments, individual calculations for gird operators can also be carried out and different options compared.

When integrating renewable generators into the distribution grid, problems with static voltage maintenance can occur which can be solved with decentralized reactive power supply. Distributed low-voltage feed-in is of particular importance in this context. The challenge is the optimal parameterization of decentralized methods for voltage maintenance, which is both effective and minimizes side effects such as increased grid load. To solve this challenge, the U-Control project has developed a procedure which allows optimum parameterisation of characteristic curves for each grid area. With this method, compliance with normative specifications can be achieved with minimum grid load due to unnecessary reactive power. The embedding in a complex simulation software allows the calculation of numerous scenarios.

Reactive power management in transmission grids

The reactive power budget of the transmission grid is being lastingly influenced by the restructuring of the electricity supply system in the context of the energy transition and is placing increasing demands on efficient reactive power management.

Due to the increasing generation from renewable energy sources with the elimination of conventional generation plants connected to the transmission grid, a significantly rising demand for reactive power sources in the transmission grid is becoming apparent. At the same time, the volatile character of feed-in from renewable energy sources requires increased flexibility in the provision of reactive power.

There is therefore a need for efficient control strategies for reactive power management that make optimum use of the reactive power sources and technologies available in the future to cover the reactive power demand. At the same time, it is necessary to identify the technologies and their locations that guarantee adequate supply of sufficient reactive power potential.