STKB / STKBz — prefabricated 24/0.4 kV transformer substations in a concrete enclosure up to 1,250 kVA
STKB and STKBz are prefabricated 24/0.4 kV transformer substations in a precast reinforced concrete enclosure, with a transformer up to 1,250 kVA. They supply residential districts in cities and suburbs, villages, parks and recreation areas, construction sites, industrial plants and workshops. The substations arrive on site fully assembled at the factory, which shortens the project schedule.
- MV switchgear
- 24 kV, 630 A, 16 kA 1 s, 40 kA peak
- LV switchgear
- 400 V; 2,000 A (STKB) / 1,250 A (STKBz); 16 kA, 32 kA peak
- Transformer rating
- STKB — up to 1,250 kVA; STKBz — up to 630 kVA
- Service access
- STKB — internal (corridor); STKBz — external
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The STKB is designed for internal service access. Its volume is divided into a transformer compartment, an MV switchgear compartment and an LV switchgear compartment, linked by an internal corridor, so operating and service work is done under a roof regardless of the weather. The B30 concrete enclosure is durable, the colour and finish are chosen to suit the surroundings, and the station can be placed right next to existing buildings. Ventilation is natural, a built-in oil containment pit protects the ground from contamination, and cable ducts in the foundation simplify connection. Cables are laid along orderly routes in line with distribution system operator standards. The versions include two-transformer designs and designs with a dedicated service corridor.
The STKBz is installed as a free-standing unit and serviced from outside. The enclosure consists of a reinforced concrete foundation with walls and a roof, and each compartment (transformer, MV switchgear, LV switchgear) has its own door made of aluminium profile, painted with primer enamel. Both substations work with MV cable networks in ring or radial configuration and with LV cable networks.
The MV switchgear is rated 24 kV and 630 A, with a short-time withstand current of 16 kA for 1 s and a peak current of 40 kA. The 400 V LV switchgear has 2,000 A in the STKB and 1,250 A in the STKBz, with 16 kA and 32 kA peak current. Frequency is 50 Hz, transformer rating is up to 1,250 kVA (STKB) or up to 630 kVA (STKBz), and the enclosure protection degree is IP43. The design ambient temperature ranges from −25 °C (lowest continuous) to +40 °C (short-term maximum), with a daily average of up to +35 °C.
The modular design allows the position of doors, ventilation, cable ducts and the dimensions to be changed to suit the project, and the transformer type and switchgear configuration are selected for the site. The MV compartment can house PEGASO air-insulated switchgear, RM-20 or RMt-20, gas-insulated or other switchgear by agreement with the manufacturer. The RM/RMt switchgear has been tested as part of the STKB 20/630 substation, and RT series switchgear is used on the LV side. The substations comply with PN-EN 62271-202, PN-EN 62271-200, PN-EN 62271-1, PN-EN 62271-201 and PN-EN 60529.
Technical specifications
| MV switchgear | 24 kV, 630 A, 16 kA 1 s, 40 kA peak |
|---|---|
| LV switchgear | 400 V; 2,000 A (STKB) / 1,250 A (STKBz); 16 kA, 32 kA peak |
| Transformer rating | STKB — up to 1,250 kVA; STKBz — up to 630 kVA |
| Service access | STKB — internal (corridor); STKBz — external |
| Enclosure | precast reinforced concrete, B30 concrete |
| Protection degree | IP43 |
| Frequency | 50 Hz |
| Features | oil containment pit, natural ventilation, cable ducts in the foundation |
Request a price and lead time
STKB / STKBz — prefabricated 24/0.4 kV transformer substations in a concrete enclosure up to 1,250 kVA. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What transformer rating can STKB and STKBz accommodate?
STKB up to 1,250 kVA, STKBz up to 630 kVA. The LV switchgear is rated 2,000 A and 1,250 A respectively.
What ratings is the MV switchgear of the substation designed for?
24 kV and 630 A, short-time withstand current 16 kA for 1 s, peak current 40 kA. Network frequency is 50 Hz.
How does STKB differ from STKBz?
STKB is serviced from inside, with an internal corridor linking the compartments. In STKBz each compartment has its own external aluminium profile door, and both substations have a protection degree of IP43.
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