PV Plant Black-Start Supported by Grid-Forming BESS: A Real EMT Study Based on OEM Models

Storage Systems (BESSs) are emerging as viable alternatives, particularly when operating under advanced Grid-Forming (GFM) control strategies.

This work assesses the plant-side black-start enabling stage of a utility-scale PV+BESS facility in Puerto Rico using high-fidelity electromagnetic transient (EMT) simulations and OEMprovided inverter control models. Among 48 BESS inverters, only four units operating in GridForming mode are used to stablish a local island and restore system voltage and frequency.

Later restoration stages, such as reconnection of the remaining 44 Grid-Following units and external grid synchronization are described but remain outside the simulation effort.

Simulation results confirm that the system maintained stable voltage and frequency throughout the energization process without triggering protection trips, even under low state-of-charge

(SOC) and varying ramp rates. Harmonic levels remained within limits (THDv < 3%,

THDi < 10%), and inrush-related transients did not cause significant distortion. The selected droop parameters enabled effective voltage–frequency regulation and coordinated energization.

These findings provide strong evidence that GFM BESS units can support reliable black-start services under realistic constraints, offering a replicable solution for modern grid restoration needs. Beyond its technical contribution, the study supports commercial validation efforts by replicating real-world operating conditions and control architectures.