Fuses
Power Fuse (Expulsion Type)
Features
◆ For protection of substation facility and extra-high voltage distribution line
◆ Suitable when COS and current limiting fuse is used/not used
◆ When station type power fuse is used, prevents accidents due to Arc/gas emission
This product is equipped with an excellent fuse unit in which the usable body is made up of nicke-chrome or silver wire. Therefore, its time-current characteristic is semi-permanently accurate, which makes it a reliable choice. It is also a perfect damage protection equipment that can interrupt fault current through its highly stable and sturdy fuse mounting.
- For protection of extra-high voltage distribution line and cable
- For protection of high-capacity transformer and MOF
- For protection of phase compensation condenser bank
- For use as backup fuse for cutout switch
- When surge current-susceptible current limiting fuse cannot be used
- When cooperative operation and protection with other over-current protective equipment is difficult.
- When use of current limiting fuse cannot be used due to the environment, difficulties in installation or handling.
Ratings
| Type | JFM-20(Indoor) | JFD-20(Outdoor) | SM-40(Indoor) | SMD-40(Outdoor) | ||||
|---|---|---|---|---|---|---|---|---|
| Opening style | Station | Drop-out | Station | |||||
| Fuse | JEU-20 1K~200K | SMU-40 *300E~400E | ||||||
| Ratings | kV | Nom. | 25.8 | 25 | ||||
| Max. Des. | 27 | 29 | ||||||
| BIL | 125 | 150 | ||||||
| Ampere (rms) | Max. | 200K | 400E | |||||
| Interrupting | Sym | 12,500 | 20,000 | |||||
| Asym | 20,000 | 32,000 | ||||||
* American S&c product
* The specification of this product may be altered without prior warning in order to improve its quality.
Reference data
Application Standard(Rated uninterrupted current and selection of current)
The following has to be considered when selecting a rated current for a current fuse.
- Should not operate in the estimated over-current(Fuse unit must fuse within 300s in 200~240% level of the rated current)
- Should not operate in transient surge current(Fuse unit must withstand 10 times the full-load current of a transformer for more than 0.1s)
- Cooperation with other protective equipmentWhen installing a current fuse indoors, it is advisable to use a model with a silencer.
Transformers protection fuse application guide
| Transformer rated capacity (kVA) | Transformer rated full-load current In[A] |
Transformer exiting/inrush current If=10ln |
Symmetrical fault current Virtual value Is=[A] 100ln/%Z | Range of fuse rated selection | ||
|---|---|---|---|---|---|---|
| 1Ø | 3Ø | Minimum | Maximum | |||
| – | 5 | 0.13 | 1.3 | 2.10 | 1K | 3K |
| – | 7.5 | 0.19 | 1.9 | 3.15 | 1K | 3K |
| – | 10 | 0.25 | 2.5 | 4.2 | 1K | 3K |
| 5 | 15 | 0.38 | 3.8 | 6.3 | 1K | 3K |
| 6.67 | 20 | 0.50 | 5.0 | 8.4 | 1K | 3K |
| 10 | 30 | 0.76 | 7.6 | 12.6 | 1K | 3K |
| 15 | 45 | 1.13 | 11.3 | 18.9 | 3K | 6K |
| 25 | 75 | 1.89 | 18.9 | 31.5 | 3K | 6K |
| 33 | 100 | 2.52 | 25.2 | 42.0 | 3K | 6K |
| 50 | 150 | 3.78 | 37.8 | 63.0 | 6K | 6K |
| 67 | 200 | 5.04 | 50.4 | 84.0 | 8K | 10K |
| 75 | 225 | 5.67 | 56.7 | 94.5 | 8K | 10K |
| 100 | 300 | 7.56 | 75.6 | 126.1 | 10K | 12K |
| 167 | 500 | 12.6 | 126 | 210.1 | 15K | 20K |
| 250 | 750 | 18.9 | 189 | 315.1 | 25K | 30K |
| 333 | 1,000 | 25.2 | 252 | 420.2 | 30K | 40K |
| 500 | 1,500 | 37.8 | 378 | 630.3 | 50K | 65K |
| 667 | 2,000 | 50.4 | 504 | 840.4 | 65K | 80K |
| 1,000 | 3,000 | 75.6 | 756 | 1,260.6 | 100K | 140K |
| 1,333 | 4,000 | 100.8 | 1,008 | 1,680.8 | 140K | 200K |
| 1,667 | 5,000 | 126.0 | 1,260 | 2,101.0 | 200K | 300E |
| 2,000 | 6,000 | 151.2 | 1,512 | 2,521.2 | 200K | 300E |
| 2,500 | 7,000 | 189.0 | 1,890 | 3,151.5 | 300E | 400E |
| 3,333 | 10,000 | 252.0 | 2,520 | 4,202.0 | 300E | 400E |
Considering the electric/mechanical characteristics of power fuse (current fuse), it is advised to use a fuse unit that is manufactured by the same company.