Enhancing Grid Stability Through Reactive Power Support From Inverter-Based Resources (ibrs)

The increasing integration of renewable energy sources into the electrical grid presents challenges to voltage stability. While inverter-based resources (IBRs) lack significant inertia, and their limited fault current capabilities affect the maintenance of voltage stability, these devices can still play a crucial role in enhancing overall grid stability.

When utilized as reactive power support devices, IBRs function similarly to static synchronous compensators (STATCOMs). Recognizing the potential benefits of deploying small STATCOM-like devices throughout distribution circuits, Dominion Energy Virginia implemented a pilot project to examine the ability of a battery energy-storage system (BESS) to enhance system reliability and customer benefits.

Dominion Energy Virginia utilized a substation-based BESS to provide reactive power support. We determined that with the correct settings IBRs can quickly respond to changes in grid conditions by providing instantaneous voltage regulation. This reduces wear on the circulators, as the existing circuit regulator will only operate when the BESS is offline, or the state of charge is too low. The inverter’s reactive power support function was enabled, and the distribution transformer’s low-side voltage was observed to see if that function would stabilize the bus voltage. It has been observed that the voltage regulation has improved since the activation of the reactive power support function provided by the BESS inverter.

This paper will describe the effects of the BESS voltage regulation on the substation distribution voltage and the life extension of circuit regulators. It will also present simulation data illustrating the impact of the reactive power function before and after its activation. This feature of IBRs make them a valuable tool for regulators and grid operators, helping to ensure a stable and reliable power system.