Enhancing DER hosting capacity of unbalanced low-voltage distribution networks with network exchangers: An Australian case study

The rapid growth and subsequent utilization of distributed energy resources (DERs), particularly in low-voltage networks, is pushing distribution networks to the brink of their hosting capacity. Distribution network operators, especially in DER-rich countries such as Australia, are exploring novel technologies and effective strategies to enhance DER integration while maintaining network integrity, as an alternative to costly network upgrades. One such technology developed and introduced is the network exchanger (NEx), which aims to enhance hosting capacity by regulating voltage, mitigating current imbalance, and power factor correction at the distribution transformer. This paper presents a comprehensive evaluation of NEx, compared with on-load tap changers and distribution static synchronous compensators, through an extensive simulation study that models projected growth in photovoltaic and electric vehicle penetration as per the Integrated System Plan released by the Australian Energy Market Operator, using a large-scale, real-world distribution network comprising over 8000 buses, and located in Queensland, Australia. Simulation results indicate breaches in network integrity under business-as-usual conditions in both step-change and progressive-change scenarios. The performance of each technology is benchmarked across six low-voltage networks that exhibit higher levels of network violations and photovoltaic curtailment, with NEx resolving all voltage breaches and reducing transformer loading and photovoltaic curtailment by noticeable amounts, which can aid in delaying costly network augmentation.