Debt-Corrected Voltage-Sensitivity Scheduling for Electric Vehicle Charging: The Trade-Off Between Energy Delivery and Location-Based Equity

Charging more vehicles without violating distribution-feeder limits is an important aim of coordinated electric vehicle (EV) charging. Yet a voltage-aware scheduler may favour customers connected to electrically stronger buses, leaving others with a smaller share of their requested energy. This paper examines that trade-off using debt-corrected sensitivity–urgency (DCSU) scheduling. The controller retains the voltage screening of a sensitivity-based online heuristic but raises the priority of vehicles at high-sensitivity buses when their group has received less charging service. Its correction uses only information available at the dispatch time. On a scaled IEEE 33-bus feeder with 40 synthetic test days and 260 charging requests per day, DCSU reduced the difference in energy-service fractions between low- and high-sensitivity groups from 11.89 to 6.44 percentage points. The improvement cost 1.07 percentage points of overall energy delivery: 91.45%, compared with 92.52% for the original scheduler. Neither controller crossed the modeled 0.950-p.u. voltage floor or the assumed 2.55-MW feeder limit in these tests. However, DCSU reduced the percentage of fully satisfied vehicles from 65.75% to 60.12%. The study therefore shows both the value and the cost of correcting a location-dependent bias in a simple online charging rule. All demand, arrival and photovoltaic profiles are synthetic; the findings should not be interpreted as field-validated operating performance.