Dynamic investigation of congestion management methods for dynamic security assessment application

The large share of renewables in the generation mix and concomitant upgrading of the grid into a smart grid is making system operation more complex and highly dynamic. This necessitates swifter responsiveness to changes in system states in order to operate highly loaded grids in which dynamic security limits will likely become increasingly critical. Dynamic security assessment can be applied to detect potential hazards and to assist operators by recommending optimized countermeasures. This paper is focused on the identification of countermeasures against congestion, which can be employed in dynamic security assessments. These problems are generally counteracted by preventive redispatch using conventional power plants located far away. Managing the situation with technical efficiency requires factoring in distributed energy resources and loads. Based on a literature review, an extended Newton-Raphson algorithm has been chosen for this purpose. The algorithm has been modified to calculate optimal redispatch, factoring in loads, generators and slack generators. Optimal in this case denotes the most effective technical measures and solutions identified, which will return the system to its normal state with a minimum of adjustments. The suitability of the redispatch method is subsequently tested in a dynamic security assessment system. The results of the dynamic test reveal the utility of the proposed method. The redispatch amount can be reduced by factoring in generator performance after a fault.