Dynamic Performance Evaluation of a Transportable Energy Storage System Supplying Off-Grid Loads
Abstract
This study analyzes the dynamic behavior of a power electronic converter, integrated into a Transportable Battery Energy Storage System (TBESS), operating in grid-forming mode to supply an isolated power system. Simulations were conducted using PSIM software. The evaluation focused on transient events, including grid energization, short-circuits, and sudden load changes. The converter demonstrated reliable and rapid control response: during startup, the 380 V/60 Hz grid connection was established, with voltage and current waveforms stabilizing in approximately 150 ms. The system exhibited adequate dynamic stability during disturbances, with stability often restored in approximately 100 ms. Specific findings include: Sudden resistive load connections caused RMS voltage to decrease by approximately 10%, but the controller restored the voltage to 95% of nominal in roughly 66 ms. When integrating Photovoltaic (PV) generation, load voltage rises of up to 11% above nominal were corrected within about 100 ms (with small phase unbalance fully corrected in 200 ms). The system maintains high power quality, achieving a Total Harmonic Distortion (THD) of 2%, which is well below the maximum limits established by PRODIST (10% for voltages up to 2.3 kV and 8% for 2.3 kV to 69 kV). These results confirm the TBESS's suitability for off-grid operation and its capability to effectively coordinate active and reactive power, highlighting its potential to support power outages and enhance supply continuity for critical loads in a distribution network.
Keywords
TBESS, Distribution Network, Off-Grid, Transient events