SSK (BS) — high-voltage fuses for load-break switch–fuse combinations
SSK high-voltage fuses of class BS for load-break switch–fuse combinations at voltages 6/12, 10/24, 20/36 and 40.5 kV. They protect power transformers in medium voltage networks up to 3150 kVA. The dimensions are the same as for a standard HH fuse-link.
- Rated voltage
- 6/12; 10/24; 20/36; 40.5 kV
- Rated current (examples)
- 63–100 A (12 kV, e=292/442 mm); 63–112 A (24 kV); 50–71 A (36 kV, e=537 mm); 63–90 A (40.5 kV)
- Breaking capacity
- 63 kA (12/24 kV), 40 kA (36 kV), 25 kA (40.5 kV)
- Class
- BS, optimised Back-Up
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The SSK is a special version of DIN high-voltage fuses for load-break switch–fuse combinations that protect power transformers in medium voltage networks. By the manufacturer's classification it is class BS, an improved Back-Up, created to meet the requirements of IEC 62271-105. This extends the field of application of the combinations to transformers of higher power.
The design follows the standard HH fuse-link and consists of a robust ceramic insulating tube that withstands high temperatures and internal pressure, quartz sand for arc extinction, and a high-purity silver fuse element with calibrated constrictions. The fuse-link operates in a few milliseconds and reduces the arc energy to a minimum. The main component is a striker with a temperature limiter. It operates on overheating and causes all-pole tripping of the load-break switch, which matters in enclosed switchgear with limited heat dissipation.
Compared with a standard fuse-link of the same rating, the SSK has a faster time-current characteristic and in a number of cases lower power losses. The characteristics are coordinated with the short own break time of the switch and take the transformer magnetising inrush current into account. In the combination the SSK replaces more expensive circuit breakers for transformers up to 3150 kVA. On the LV side, in the scheme according to VDE 0670-402, NH fuse-links of class gTr are used.
Typical items of the range: 6/12 kV, 63–100 A, length e = 292 and 442 mm, 63 kA. For 10/24 kV these are 63–80 and 80–112 A, e = 442 mm, 63 kA. For 20/36 kV 50–71 A, e = 537 mm, 40 kA. For 40.5 kV 63–90 A, e = 537 mm, 25 kA.
They are used at transformer substations of distribution networks, industrial substations, wind power plants (the transformer of each turbine and the farm substation) and solar plants. The SSK complies with VDE 0670-402 (transformer protection) and VDE 0671-105 / IEC 62271-105 (coordination with the load-break switch), and provides selectivity with LV fuses even at high transformer short-circuit voltage. The dimensions are identical to standard HH fuse-links (DIN 43625), so they are easy to install during modernisation, and many switchgear manufacturers include the SSK in recommended lists. The fuse-links are fully recycled through the NH/HH-Recycling e.V. system.
Technical specifications
| Rated voltage | 6/12; 10/24; 20/36; 40.5 kV |
|---|---|
| Rated current (examples) | 63–100 A (12 kV, e=292/442 mm); 63–112 A (24 kV); 50–71 A (36 kV, e=537 mm); 63–90 A (40.5 kV) |
| Breaking capacity | 63 kA (12/24 kV), 40 kA (36 kV), 25 kA (40.5 kV) |
| Class | BS, optimised Back-Up |
| Transformer protection | up to 3150 kVA |
| Striker | with temperature limiter, all-pole tripping |
| Standards | IEC 62271-105 / VDE 0671-105, VDE 0670-402, DIN 43625 |
Request a price and lead time
SSK (BS) — high-voltage fuses for load-break switch–fuse combinations. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What transformer power does a combination with the SSK protect?
Up to 3150 kVA. In such a combination the SSK replaces more expensive circuit breakers.
What voltages and breaking capacity are SSK fuses produced for?
For 6/12, 10/24, 20/36 and 40.5 kV. The breaking capacity is 63 kA for 12 and 24 kV, 40 kA for 36 kV and 25 kA for 40.5 kV.
What standards do SSK fuse-links comply with?
VDE 0670-402 for transformer protection and VDE 0671-105 / IEC 62271-105 for coordination with the load-break switch.
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