Impacts of power quality events on supplying loads in an experimental open structure DC nanogrid under different operating conditions

• Low Voltage Open Structure Direct Current Nanogrid (LVOSDCN) composed of Off-The-Shelf equipment. • Power quality steady-state and transient events evaluated in a passively regulated DC nanogrid. • Increased voltage ripple and circulation of non-active power in a DC nanogrid, with the insertion of an inverter supplying AC loads. • Overvoltage occurrences in the LVOSDCN has a direct relationship with the irradiance value , state of charge of the battery energy storage systems and load demand. This paper presents an experimental study on Power Quality (PQ) using indicators to assess the impact on loads supplied by a Low Voltage Open Structure Direct Current Nanogrid (LVOSDCN) utilizing off-the-shelf equipment and passively regulated in 24 V, implemented in real scale in the Amazon Region. Four tests were performed to evaluate the regular occurrence of PQ events with different irradiance profiles and commercial loads. The characteristics of the distribution grid, measurement instruments, and load groups are presented. As a result, variations in RMS voltage under the influence of the irradiance profile reach values above 1.1 PU with a duration of over 1 min, causing failures in some loads. Oscillatory transient events, resulting from the activation of DC-DC converters with time below a few milliseconds, without causing impacts. Finally, the evaluation of voltage ripple using the RMS ripple factor showed maximum values ​​close to 5 %, with different magnitudes over time and at different points of the distribution grid, also having an increase in circulating non-active power. These results are important because the operation of the real scale nanogrid and experimental setup show the magnitudes at which these events can cause failures or damage to the loads supplied by this system.