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.4 1.6
10 10
12 13.6 times higher than those set for terrestrial MVDC
applications IEC 62271-5.5 1.2
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.65
3 3.5 1. 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. Similarly, for rated
lightning impulse withstand voltage, the marine
.
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
7.01
proposal
[24], [72]
IEC TS
63471 [73]
(pole to
earth)
CIGRE
TB931
[74]
CIGRE
WG A3.
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
C37.40
proposal
(nominal)
1.3
6 6
