Calculating the Interconnection Limit from a Comprehensive Voltage Evaluation for Distribution Systems with Large Distributed Energy Resources

Japan is pursuing power source decarbonization and is thus reducing fuel‐based thermal power generation while promoting renewable energy resource use. Given the expected power fluctuations, this transition will require novel voltage management and control methods. This study investigates the current voltage management and control methods for distribution systems and the voltage control methods adopted by distributed energy resources (DERs). An equation is derived for accurately estimating the voltage under conditions in which the power flow is heavy and changes frequently. A method is proposed for calculating the hosting capacity (HC) using the derived equation and trial calculations are conducted on a standard distribution system model. The results indicate a lower HC than that of conventional operations. Finally, the study findings are summarized and a vision and recommendations for future research directions and challenges are provided, contributing to the national objective of achieving carbon neutrality by 2050. © 2026 The Author(s). IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.