Electrical Safety for Battery Energy Storage Systems (BESS)

Choosing a Grounded or Ungrounded Ground-fault Solution for BESS

Battery Energy Storage Systems (BESS) are large-scale battery systems for storing electrical energy. BESS has become an increasingly important component to maintain stability in the electrical grid as more distributed energy resources (DER) are integrated.  Distributed energy resources often are sources of electrical energy such as photovoltaic systems or wind turbines which do not have steady and controllable energy production. A BESS allows energy from an intermittent energy source to be stored when production capability is high and demand is low and then later be used in times of high demand or as a backup for critical systems.

The benefits of utilizing battery-supported distributed energy resources include cost savings, clean energy, and reduced downtime. It is vital that the electrical integrity of the systems is properly monitored to maintain the benefits as there are some safety hazards associated with battery systems when not properly maintained and monitored. Li-Ion fire is one such hazard that can occur due to ground faults or poorly maintained battery management systems. Bender’s IMD EV technology and insulation monitoring devices provide early detection of insulation faults in battery energy storage systems, preventing potential hazards like Li-Ion fires.

Most BESS operate via an ungrounded system design, however, there are some grounded installations in use.  Grounded systems must also have proper ground fault protection to operate safely and minimize downtime. It is critical to monitor for ground faults at low leakage current levels to detect and clear issues before they trip a protection device (such as a breaker) and/or damage the batteries. Bender’s line isolation monitors, combined with regular LIM Testing, help maintain the electrical integrity of BESS systems by detecting faults before they lead to major issues. Our residual current monitors (RCM) are able to detect low-level AC and DC ground faults to indicate minor issues before they become major issues, such as equipment fires or system shutdowns. Regular LIM Testing, along with IMD EV technology, ensures that battery energy storage systems are operating safely, minimizing downtime and avoiding costly repairs.