TEL TAVRIDA ELECTRIC VCB15 LD, User Manual

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Figure 48
Insulating clearance limitations of HD
ISM with low upper terminal
Figure 49
Insulating clearance limitations of HD
ISM with high upper terminal
Short circuit current Minimum clearance (a)
25 kA 150 mm
31.5 kA 190 mm
Table 5 - Minimum clearances due to electromagnetic influence
The recommended minimum open air clearances between phase to phase and phase to earth are stated in
Table 6. Shorter distances shall be verified by a voltage test.
Power frequency rated voltage Impulse test voltage (BIL) Minimum clearance (L2)
12 kV 75 kV 120 mm
17.5 kV 95 kV 140 mm
Table 6 - Minimum clearances due to rated insulation voltage
Minimum clearances due to rated insulation voltage
Figure 47
Electromagnetic clearances limitations
L2