• Application in switch-disconnector/ fuse combination in
– Transformer feeders (T)
– Bus sectionalizer with switch-fuse combination (H)
• HV
HRC fuse-links according to DIN 43625 (main dimensions) with striker; “medium“ version according to IEC / EN 60282-1/ VDE 0670-4– As short-circuit protection for transformers– With selectivity – depending on correct selection – to upstream and downstream connected equipment– 1-pole insulated
• Requirements according to IEC/EN 62271-105/VDE 0671-105 fulfilled in high-voltage switch-fuse combinations
• Climate-independent and maintenance-free
•
8DJH-RRT Fuse assembly connected to the three-position switch-disconnector via welded-in bushings and connecting bars
• Arrangement of fuse assembly below the switchgear vessel
• Fuses can only be replaced if feeder is earthed
• Fuse slide for reference dimension 292 mm and 442 mm Option with three-position switch-disconnector
• Shunt release (f-release)
• “Tripped signal” of the transformer switch for remote electrical indication with 1 normally open contact.
Mode of operation In the event that an
8DJH-RRT HV HRC fuse-link has tripped, the switch-disconnector is tripped via an articulation which is integrated into the cover of the fuse box (see fi gure).In the event that the fuse tripping fails, e.g. if the fuse has been inserted incorrectly, the fuse box is protected by thermal protection. The overpressure generated by overheating trips the switch via the diaphragm in the cover of the fuse box and via an articulation. This prevents the fuse box from incurring irreparable damage.This thermal protection works independently of the type and design of the HV HRC fuse used. Like the fuse itself, it is maintenance-free and independent of any outside climatic effects.Furthermore, the HV HRC fuses (e.g. make SIBA) release the striker depending on the temperature and trip the switch-disconnector as early as in the fuse overload range.Impermissible heating of the fuse box can be avoided in this way.
Replacement of HV HRC fuse-links(without tools)
• Isolate and earth the transformer feeder
• Open the cover of the fuse access
• Replace the
8DJH-RRT HV HRC fuse-link.
Note to HV HRC fuse-links
According to IEC 60282-1 (2009) Clause 6.6, the breakingcapacity of HV HRC fuses is tested within the scope ofthe 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 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 confi guration of the switching devices and selection of the
8DJH-RRT HV HRC fuse 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, asuitable HV HRC fuse must be selected together with the fuse manufacturer.
