Practical Charts for Sizing Neutral Grounding Elements for Machine-Based Distributed Energy Source Step-Up Transformers

One of the challenges resulting from the adoption of machine-based distributed energy resources lies within the intersection of protection and performance grounding. These are strongly interrelated and conflicting subjects that dictate the occurrence of ground fault overvoltage and the effectiveness of ground overcurrent protection. Currently, there remains a gap in the distribution planning of most jurisdictions in formulating these aspects and adopting simple and practical measures to balance these subjects. This letter introduces a simulation-based method to develop a set of practical charts intended to be used as a sizing guideline for neutral grounding elements, which are to be employed in the associated step-up transformers. This solution became pivotal to the electrical utility conducting the research and has allowed planning engineers to simplify design and streamline cooperation between the utility and large-scale DER developers.