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This paper is aimed at making new proposals for developing future Electro-Magnetic Compatibility (EMC) standards tailored to DC microgrids in a frequency range between 9 and 500 kHz. In particular, new EMC proposals are made to reduce Electro-Magnetic Interference (EMI) with arc hazard detection and narrowband power line communication (PLC). To achieve this, first, arc detection requirements, PLC standards and existing EMC standards are reviewed. Next, new proposals are made to specify EMC requirements for equipment in DC microgrids in terms of conducted emission, immunity (9–500 kHz) and minimum impedance requirement (>40 kHz). The minimum impedance requirement is a new type of requirement and the relevant compliance testing method is developed. The new EMC proposals also distribute frequency bands to support arc detection and narrowband PLC. Then, to show the feasibility and advantage of proposed EMC codes, this paper develops a new arc detection method, which relies on only measuring the arc noise voltage (40–100 kHz) in a single point of the grid and does not need one or more current measurements. A total of three test cases are presented to show the feasibility of the arc detection method and the significance of having an EMC minimum impedance requirement. The executed tests for this paper also show that new EMC proposals are feasible and promising for DC microgrids. This concept and approach are the major novelties of this paper. The specific EMC threshold levels for conducted noise, immunity, and impedance within a frequency range between 9 and 500 kHz will need to be further fine-tuned based on the microgrid application parameters and further gathering of experimental data.

An increasing number of electrical loads and sources in the distribution grid require a conversion step from DC, or AC at variable frequency, to be connected to the traditional 50/60Hz AC grid. This sparks an increasing interest for Low Voltage DC microgrids as an alternative. LVDC grids enable a reduction of the losses and an increase of the transfer capacity compared to their AC equivalent. However, fast and selective fault protection still remains a major obstacle for the breakthrough of LVDC grids. The challenge is twofold: On the one hand, a protection strategy for fast fault identification is required, on the other hand there is a need for protection devices capable of fast fault clearance in an LVDC grid. This paper first gives an overview of the current state-of-the-art of fault indicators and methods for fault identification in DC grids, addressing the first part of the challenge. Subsequently, an overview is given of the interruption devices that are currently available for fault clearance in DC grids and their (dis)advantages, addressing the second challenge.

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