10.14 Selection Of Hv Hrc Fuse-Links - Siemens NXPLUS C Installation And Operating Instructions Manual

Electromagnetic
compatibility (EMC)
Protection against solid
foreign objects, electric
shock and water
Seismic withstand
capability (option)
Note to HV HRC fuse-links
806-9004.9 • INSTALLATION AND OPERATING INSTRUCTIONS • NXPLUS C • Revision 02
The a.m. standards as well as the "EMC Guide for Switchgear"* are applied during design,
manufacture and erection of the switchgear.
to be performed in accordance with the stipulations of the operating instructions. For
operation, the legal stipulations applicable at the place of installation have to be observed
additionally. In this way, the switchgear assemblies of this type series fulfil the basic
protection requirements of the EMC guide.
The NXPLUS C panels meet the following degrees of protection according to IEC 62271-200,
IEC 60529 and DIN VDE 0671-200:
• IP3XD standard for switchgear enclosure of operating front and side walls
• IP31D option for switchgear enclosure of operating front and side walls
• IP32D option for switchgear enclosure of operating front and side walls
• IP65 for parts under high voltage in panels without HV HRC fuses
NXPLUS C switchgear can be upgraded for regions at risk from earthquakes. For this upgrade,
earthquake qualification testing has been carried out in accordance with the following
standards:
• IEC 60068-3-3 "Guidance – Seismic test methods for equipment"
• IEC 60068-2-57 "Test Ff: Vibration – Time-history method"
• IEC 60068-2-59 "Test Fe: Vibration – Sine-beat method"
• IEEE 693-2005 "Recommended Practice for Seismic Design of Substations".
For installation on even and rigid concrete or steel structure (without considering building
influences), the tested ground accelerations meet the following requirements:
• Uniform Building Code 1997 (UBC) – Zone 4
• California Building Code 1998 (CBC) – Zone 4
• IEEE 693-2005 – High required response spectrum (Figure A.1).

10.14 Selection of 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.
To be observed during configuration of switching devices and selection of HV HRC fuse-links:
• Use only fuse-links satisfying the stated operating conditions.
• Use only fuse-links whose breaking capacity was tested at least with the maximum system
voltage.
In case of doubt, select a suitable HV HRC fuse-link together with the manufacturer.
The three-position switch-disconnector in the transformer feeder (transformer switch) was
combined with HV HRC fuse-links and tested in accordance with IEC 62271-105.
The following transformer protection table shows HV HRC fuse-links tested by Siemens for
protection of transformers, motors, and voltage transformers in the metering panel.
The fuse protection tables are valid for:
• Maximum ambient air temperature in the switchgear room of 40 °C according to
IEC 62271-1/VDE 0670-1000 considering the influence of the switchgear enclosure.
The 24-hour mean value is max. 35 °C (according to IEC 62271-1/VDE 0671-1)
• Requirements according to IEC 62271-105
• Protection of distribution transformers according to IEC 60787/VDE 0670-402
• Nominal power of transformer (no overload operation)
The specified HV HRC fuse-links make SIBA are type-tested back-up fuses according to
IEC 60282-1. The dimensions conform to DIN 43625.
1
Dr. Bernd Jäkel, Ansgar Müller, "Medium-Voltage Systems – EMC Guide for Switchgear",
Siemens AG 2012
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