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
