Hv Hrc Fuse Assembly; Busbar System - Siemens NXPLUS C Installation And Operating Instructions Manual

Features
Mode of operation
Thermal protection
Basic scheme of fuse
tripping
806-9004.9 • INSTALLATION AND OPERATING INSTRUCTIONS • NXPLUS C • Revision 02
9.8

HV HRC fuse assembly

• With fuse slide for fuse replacement without tools
• HV HRC fuse-links according to DIN 43625 (main dimensions) with striker in "medium"
version according to IEC/EN 60282-1
- As short-circuit protection before transformers
- With selectivity to upstream and downstream connected equipment
- 1-pole insulated
• Reference dimension e of the fuse-links
- U = 12 kV: e = 292 mm (option: e = 442 mm)
r
- U = 24 kV: e = 442 mm
r
• Requirements according to IEC 62271-105 / VDE 0671-105 met for HV HRC fuse-links in
combination with the three-position switch-disconnector
• Thermal striker tripping when the corresponding HV HRC fuse-link is used
• Climate-independent and maintenance-free, with fuse boxes made of cast resin
• Arrangement of HV HRC fuse assembly below the switching-device vessel
• HV HRC fuse assembly connected to the three-position switch-disconnector via welded-in
bushings and connecting bars
• Fuse replacement is only possible when the feeder is earthed
• Option for HV HRC fuse-links: "Tripped" indication for remote electrical indication with a
NO contact
If a HV HRC fuse-link operates, the switch is tripped via an articulation which is integrated into
the cover of the fuse box.
If the fuse tripping fails, the sudden overpressure trips the switch via a diaphragm and the
articulation situated in the cover of the fuse box.
The thermal protection works independently of the type and design of the HV HRC fuse-link
used. The thermal protection is maintenance-free and independent of any outside climatic
effects.
The HV HRC fuse-links make SIBA (see page 47, "Selection of HV HRC fuse-links") release the
striker depending on the temperature and trip the switch-disconnector as early as in the
overload range of the fuses. Impermissible heating of the fuse box can be avoided in this way.
9.9

Busbar system

The busbar is single-pole insulated with silicone rubber. Each phase has a earthed layer on the
outside (screened busbar system). This design makes the busbar independent of climatic
effects.
As the busbar system is arranged outside the gas compartment, a panel extension,
replacement or doubling to increase current-carrying ability are possible within a very short
period of time without requiring any gas work.
Double-length busbars are available for bypassing a removed panel. Double-length busbars
make it possible to bypass a defective panel within a few hours, and switchgear operation can
continue. In order to keep the busbar stable, a busbar support must be installed starting from
a specific busbar length (see page 99, "Installing the busbar support").
HV HRC fuse-link in service condition
Fuse tripping through striker of HV HRC fuse-link
Fuse tripping due to sudden overpressure in the
fuse box
Description
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