A Practical Methodology for Short-Circuit Current Determination in Power Converter-Dominated DC Microgrids

Abstract:
As the energy landscape evolves, Direct Current (DC) has become a key enabler for integrating renewable energy sources and supplying native DC loads. DC microgrids are expected to play a vital role in emerging systems, including industrial applications, by optimising energy exchanges among sources, loads, and machines. Despite this, understanding short-circuit currents presents significant technical challenges, complicating the selection and design of reliable protection schemes. This difficulty arises from the lack of comprehensive calculation standards and analytical methods for DC microgrids, and the highly diverse, topology-dependent behaviour of power converters. To address this gap, this paper proposes a practical methodology to determine short-circuit currents in DC microgrids with sufficient accuracy. The influence of sources and power converters is analysed, the general approach and conditions to consider are outlined, and relevant outputs are proposed in the context of emerging technologies.