The fundamental principle of operating electrical power grids is directly determined by the electromechanical behavior of synchronous generators. The grid frequency serves as a central control variable and is an indicator of the balance between active power generation and consumption. With the phasing out of nuclear and coal power plants and the increasing renewable-based electricity generation, a significant number of synchronous generators are also disappearing. This results in the necessity to adapt and further develop the interconnected grid operation to new conditions.

Synchronous generators establish grid-forming behavior by impressing a voltage. In the future, more power electronic converters will be implemented in the power grid through the connection of DC systems for offshore wind farms or HVDC links. Due to the lack of mass inertia, these converters exhibit much faster dynamic behavior and more diverse control possibilities than synchronous generators and fundamentally differ from them in their electrical behavior. The more diverse control possibilities of these converters can be advantageously utilized in the future to achieve grid-forming, i.e., voltage-impressing control behavior from the perspective of interconnected grid operation. This requires converters to set a voltage in terms of magnitude and phase (angle) at the grid connection point through suitable control algorithms.

One way to assign a working point to a voltage-impressing-controlled converter based on grid status through communication is angle-based interconnected grid operation, known as angle control. There have already been academic studies on this for a system with classical synchronous generators (Garner H. 1950).

In the DisrupSys project, against this background, the angle-based interconnected grid operation in converter-dominated energy supply systems will be researched and developed while maintaining the active and reactive power balance. The focus is on how the interconnected grid can be transformed in this respect.

Based on the planned grid expansion according to the Network Development Plan, this project touches all processes of interconnected grid operation. The mechanisms of grid operation common today are to be redefined or further developed in light of new equipment technologies.

Today, the grid-forming function is provided by all power plants equipped with synchronous generators. The balance of an energy imbalance in the electrical grid occurs initially instantaneously through the rotating masses of the generator-turbine sets and with a slight time delay through the various stages of power-frequency control. The provision of control power is no longer necessarily coupled to conventional power plants but can be provided by all equipment that fundamentally has the capability to regulate up or down in compliance with the control power provision requirements. Thus, facilities of all kinds connected with converters can also provide control power individually or pooled.