Use Case
Optimizing Voltage for Electric Vehicle (EV) Charging
Electric vehicle sales are booming in the U.S., with 2021 purchases nearly doubling 2020 levels. Can existing electric power system infrastructure handle the increased EV charging? Some distribution transformers have extra capacity to handle the additional load, but others will be strained. Adding dynamic VAR control at the distribution transformer is an effective way to improve grid edge voltage with EV charging.
Sentient Energy Grid Edge ControlTM
The Edge of Network Grid Optimization (ENGO-V10) device and Grid Edge Management System (GEMS) work together to create the Grid Edge Control solution. ENGO-V10 is a single-phase dynamic VAR controller (DVC) that autonomously injects up to 10 kVAR in 1 kVAR increments. GEMS software provides real-time visibility of edge voltages, aggregates data, and enables remote configuration of devices.

How It Works
ENGO-V10 can be installed with either a pole mount or padmount distribution transformer and GEMS is installed at the utility operations facility or can be hosted in the cloud. Here’s how the Grid Edge Control system works for EV charging:
- EV Causes Voltage to Sag – In the graphic above EV charging causes voltage to sag with minimum voltage dipping six volts from 114.5 V to 108.5 V. For lower rated transformers just a few EV chargers can overload the transformer.
- kVAR Injection – The ENGO-V10 dynamic VAR controllers sense the voltage sag and inject kVARs on a sub-cycle basis. This fixes low voltage outliers and compresses the voltage profile in the network.
- Voltage Profile Improved – ENGO addresses the voltage sag caused by EV charging and improves and maintains the voltage profile above the ANSI-A voltage limit (114V).
Results
Sentient Energy’s Grid Edge Control solution improves the voltage profile at distribution transformers serving EV charging. This improves power quality and reduces flicker during charging and reduces strain on transformers extending their useful lives. With Grid Edge Control utilities can effectively address increasing EV charging loads with existing distribution assets.