Replacing Hv Hrc Fuse-Links - Siemens NXAIR Operating Instructions Manual

Operating the contactor panel with panel width 600 mm

14.19 Replacing HV HRC fuse-links

According to IEC 60282-1 (2009) Clause 6.6, the breaking capacity of HV HRC fuse-links is tested within the
scope of the type test at 87% of their rated voltage.
In three-phase systems with resonance-earthed or isolated neutral, under double earth fault and other
conditions, the full phase-to-phase voltage may be available at the HV HRC fuse-link during breaking.
Depending on the size of the operating voltage of such a system, this applied voltage may then exceed 87 %
of the rated voltage.
It must therefore already be ensured during configuration of the switching devices and selection of the
HV HRC fuse-link that only such fuse-links are used, which either satisfy the above operating conditions, or
whose breaking capacity was tested at least with the maximum system voltage.
In case of doubt, a suitable HV HRC fuse-link must be selected together with the fuse-link manufacturer.
Indicator for operating state of HV HRC fuse-links
On the front side of the contactor truck, there is an indicator for the two operating states of the HV HRC fuse-
links installed in the phases. The symbols indicate the following:
190
CAUTION
Burns
After tripping, the surfaces of HV HRC fuse-links are hot. Touching hot HV HRC
fuse-links may cause burns.
Put on personal protective equipment.
Let hot HV HRC fuse-links cool down before replacing.
NOTICE
Undetected damage
Even if the contactor truck shows no visible damages of a fault, the HV HRC fuse-
link may have tripped due to a fault.
Check the switching-device compartment for deformations when a fuse-
link has tripped.
Symbol Indication
Vertical bar position:
All HV HRC fuse-links are in service
Horizontal bar position:
At least one HV HRC fuse-link has tripped
NXAIR / ≤ 40 kA
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