© by SEMIKRON / 2017-09-07 / Technical Explanation / SKiiP
4
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4.3 Isolation coordination
The isolation of the SKiiP
®
4 is designed according to EN50178 and EN61800-5-1. For working conditions
please refer to the datasheet SKiiP
®
4. 20601xxx and 20602xxx
Table 4—3: Isolation limits SKiiP
4
Isolation / Test level Min value
Creepage primary - secondary 14mm
Creepage secondary – heat sink potential 8mm
Clearance primary – secondary 14mm
Clearance secondary – heat sink potential 8mm
Partial discharge extinction voltage
(IEC60664-1) between primary and secondary
side of driver board
1900V rms; Q
PD
< 10pC
Rated surge withstand voltage (IEC60664-1)
primary to secondary
primary to heat sink
Part.Nr: 20601xxx
8kV
8kV
Part.Nr: 20602xxx
12kV
8kV
4.4 Installation altitude
Isolation coordination for SKiiP
®
4 is designed for overvoltage category III and for altitudes of up to 2000m.
The required clearance distances between mains-circuits and their environment for overvoltage category III
are listed in EN50178.
For an earthed-neutral system the rated isolation voltage is defined in chapter 5.2.16.1 of EN50178 as:
“…the peak value of the rated voltage between phase and earthed neutral point.”
Based on this standard sentence the rated isolation voltage in case of a grounded delta grid (Figure 4.1)
and a star grounded grid (Figure 4.2) can be derived as:
Rated isolation voltage in case of 690V grounded delta grid: 690V
Rated isolation voltage in case of 690V star grounded grid: 400V
Figure 4.1: Grounded delta grid Figure 4.2: Star grounded circuit network (690V-
TN-grid)
Based on the type of grid and the voltage level the required clearance distance for basic and reinforced
isolation can differ from the designed ones.
According to HD625 S1 and IEC60664-1 the maximum altitude can be calculated based on the factors
between required and designed clearance distances.
L
L
L
3
L23
1
3
U
L1
U
L2
L3
U
LL
LE
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