Enhancing Defence Plans to match Future Power System Security Needs

The European policy goals on sustainability, security of supply and improved competiveness resulted in an increased share of renewables in generation, which in turn led to a higher loading of the transmission and distribution grids. The transition to a liberalized European market even further increased the loading of the power system. As a consequence the grid is being operated closer to its limits. These limits are determined by the different security criteria. Existing and new criteria will be considered. During high impact low probability events the system can violate this security limit and as a consequence enter the alert or emergency state or even evolve towards a black-out of the complete system. Therefore an analysis of the system needs to be made such that this evolution towards an instability can be detected.

The number of power flow controllable devices (PFC), such as phase shifting transformers and HVDC, in the power system has been steadily increasing and will even further increase in the upcoming years. The coordinated use of these power flow controllable devices in the first phase of the defense plans will be investigated. These devices offer an additional means of fast control to the operators or can be used in automatic system protection schemes to bring the system back to a normal situation.