Medium voltage DC (MVDC) grids for an all-electric society

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For example, considering rated withstand voltage, the insulation levels specified for marine MVDC applications IEEE Standard 1709 [69] are on average for the same rated voltage approximately 1.5 Insulation levels As detailed throughout this paper, due the constant nature and issues such as corrosion risk, the insulation requirements for DC- based components are significantly different from their counterparts. Similarly, for rated lightning impulse withstand voltage, the marine .65 3 3.5 1.6 times higher than those set for terrestrial MVDC applications IEC 62271-5. There significant discrepancy the insulation levels currently specified for MVDC equipment.65 Standardization for MVDC grids Table 7-3 Overview proposals and existing standards defining voltage ranges Voltage (kV) Marine IEEE guideline 1709-2018 [69] Railway EN standard [70] GB (China) standard 35727- 2017 [71] CIGRE C6-TB793 proposal [13] IEEE C37.01 proposal [24], [72] IEC TS 63471 [73] (pole to earth) CIGRE TB931 [74] CIGRE WG A3.4 1. Considering just short circuit ratings, likely parameters could include: § Rated short time withstand current (Ik) § Rated peak withstand current (Ipd) § Rated time peak short-circuit current (tpd) § Rated duration short-circuit current (tkd) § Rated joule integral value (Ej) § The energy switching device can withstand in the closed position, with regard the short- circuit waveform 7.3 6 6.2 18 20 22 24 25 30 33 35 35 40 50 55 70 77 Ultimately, likely that equipment ratings for MVDC components will need cover many more characteristics than their counterparts.40 proposal (nominal) 1.5 1.6 10 10 12 13