Impact of 0.8 kV inverters on AC losses in a 2.2 MW PV plant

Abstract

The efficiency of photovoltaic (PV) power plants is critically influenced by power losses occurring during energy conversion and transmission, particularly within alternating current (AC) components. This study addresses the challenge of quantifying and minimizing these losses by focusing on PV system configurations that utilize inverters with an output voltage of 0.8 kV - a relatively high level for low-voltage applications. The primary objective is to analyze the distribution of active and reactive power losses across key AC elements, including low-voltage cables, medium-voltage cables, and transformers, and to evaluate the impact of inverter voltage on overall system performance. Through analytical modeling and simulation under varying operational scenarios, the research demonstrates that systems operating at 0.8 kV and unity power factor achieve the lowest total active power losses across internal AC components and grid connection lines. Although external line losses slightly increase due to higher grid injection levels, the total system losses are significantly lower than those observed in conventional 0.4 kV configurations - resulting in a reduction of 53.79 kW in active losses and approximately 13 kVAr in reactive losses at full capacity for a 2.2 MW installation. Structural analysis reveals that internal losses are predominantly concentrated in low-voltage cable lines 65-68%, followed by transformers (29-31%) and internal 10 kV cabling (3-4%).