22.5MW Battery Energy Storage System

Location: DeKalb, IL

About the Project

To accommodate a new 22.5 MW Battery Energy Storage System at a large wind energy center, an additional 34.5kV position was added to an existing 34.5/138 kV collector substation. The added position was made via a 1200A, 34.5kV breaker with metering class CTs and corresponding bus and line switches, and the BESS banks were connected with medium voltage underground cable.

No updates were required to the existing electrical equipment enclosure control battery bank; it was utilized and had space to accommodate the additions associated with this project.

Once the controls were updated to integrate the new position into the existing protection scheme, an ION meter was included for frequency monitoring. 

The battery manufacturer was responsible for the design associated with the step-down transformers, inverters, battery systems and corresponding HVAC requirements. Ulteig’s design demarcation was the connection to the 34.5kV/480V step-down transformers.

This battery energy storage system, which helps balance the power grid frequency, went into commercial service in November of 2014.

Project Photos