Delivery of Primary Frequency Response over Weak Electrical Paths

Replacement of rotating machine generation sources with inverter based resources can change the trajectory of the primary frequency response. As generation sources interconnect to weak areas of the network and move farther away from loads, the time taken for a source to respond to a disturbance can get longer and the effective magnitude of the response that will be received may be smaller resulting in a frequency response that can have larger rates of change and lower nadirs/peaks. Thus, for future bulk power systems, it becomes imperative to consider the magnitude of frequency response as well as the time it would take for frequency response to actually provide the necessary beneficial impact. In addition, the locations across the system from where it would be most beneficial must be considered. Using two test networks, this critical aspect of frequency response along with possible solutions and mitigation schemes are illustrated in this paper.