CTT 12, CTT 25, CTB 25 — busbar and bushing-type MV current transformers up to 5000 A
CTT 12 and CTT 25 are busbar current transformers with cast epoxy insulation for indoor MV switchgear, CTT 12 is rated for primary current up to 5000 A and voltage 17.5 kV. The bushing-type CTB 25 for 24 kV combines the functions of a bushing insulator and a current transformer. The units are used for measurement and protection on feeders with high operating currents.
- CTT 12
- single-turn busbar type, 17.5 kV, 1000–5000 A, up to 3 cores, classes 0.2–3 / 5P, 10P (PX, TPX, TPY on request)
- CTT 25
- 24 kV, 100–2500 A, 5–60 VA
- CTB 25
- bushing type, 24 kV, 5–1250 A, 5–60 VA
- Secondary current
- 5 A or 1 A
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
CTT 12 is built as a single-turn bushing-type transformer, the primary winding is a copper bar busbar. The number and position of the busbars depend on the rated current. Up to 4000 A the busbars are arranged horizontally, above 4000 A vertically. Primary current according to the manufacturer is 1000–5000 A, highest operating voltage 17.5 kV.
Secondary current is 5 A or 1 A with a possible combination. Measuring circuits have accuracy classes 0.2, 0.2S, 0.5S, 0.5, 1 and 3, protection circuits 5P and 10P. By agreement with the manufacturer, special classes PX, TPX and TPY are developed for CTT 12. The stated class is kept within 25–100 % of the rated burden, and at a burden below 10 VA within 0–100 %. Continuous operating current is 120 % In, other values, for example 200 % In, can be ordered by agreement.
Secondary windings are wound on cores of grain-oriented alloys, up to 3 cores. All active parts are cast in epoxy compound, and this mass works at the same time as electrical insulation and as the mechanical base. The mounting position is arbitrary, the transformer is fixed with four screws on the base.
CTT 25 is intended for indoor switchgear with highest voltage 24 kV, primary current 100–2500 A and burden 5–60 VA. It is a bushing-type unit, but with an accessory set (primary conductor and locking inserts) it is also supplied in a sleeve version. The cores are made of grain-oriented steel or with permalloy, and the primary current ranges are switched on the secondary side. Dynamic current is up to 200 kA, operating temperature from −45 to +55 °C. The transformers are transported fixed on pallets and stored at temperatures from −50 to +60 °C.
CTB 25 is rated for 24 kV, primary current 5–1250 A and burden 5–60 VA. One unit combines a bushing insulator and a current transformer. Transformers of this group are installed in incomer and bus-section cells of 6–20 kV switchgear, on generator feeders, transformer busbar bridges and industrial substations with high operating currents.
Technical specifications
| CTT 12 | single-turn busbar type, 17.5 kV, 1000–5000 A, up to 3 cores, classes 0.2–3 / 5P, 10P (PX, TPX, TPY on request) |
|---|---|
| CTT 25 | 24 kV, 100–2500 A, 5–60 VA |
| CTB 25 | bushing type, 24 kV, 5–1250 A, 5–60 VA |
| Secondary current | 5 A or 1 A |
| Continuous current | 120 % In (up to 200 % by agreement) |
| Insulation | cast epoxy |
Replacement for
ТШЛ-10, ТЛШ-10, ТПШЛ-10, ТШЛ-20 (шинні до 5000–8000 А)
selected by purpose and main parameters, please confirm with our manager
Request a price and lead time
CTT 12, CTT 25, CTB 25 — busbar and bushing-type MV current transformers up to 5000 A. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8504 31 29 00 |
|---|---|
| HS, 6 digits | 8504 31 |
| CN (EU) | 8504 31 29 |
| HTSUS (USA) | 8504 31 40 35 |
| China customs tariff | 8504 31 10 00 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
What is the highest primary current of CTT 12?
Up to 5000 A at a highest operating voltage of 17.5 kV. Up to 4000 A the primary busbars are arranged horizontally, above 4000 A vertically.
How does CTB 25 differ from CTT 25?
CTB 25 is a bushing-type transformer for 5–1250 A that combines the functions of a bushing insulator and a CT. CTT 25 is a busbar type for 100–2500 A, both are rated for 24 kV.
Are the transient classes TPX and TPY available?
For CTT 12 the classes PX, TPX and TPY are developed by agreement with the manufacturer. The standard protection classes are 5P and 10P.
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