CTB size 2

Current transformer CTB size 2

CTB size 2

bushing current transformer, encapsulated in epoxy resin •  highest permissible system up to 36 kV  •  rated primary currents up to 4 kA  •  option: airtight bushing

Current transformers of CTB type are designed for indoor use at medium voltages. Epoxy resin casting (containing wounded cores inside) is the main electrical insulation. Excellent parameters of electrical insulation (including low level of partial discharges) are guaranteed.

The typical areas of application are switchgear cubicles and busducts of power generators. With regard to the possibility of sealing of the primary current conductor, CTB current transformers can be used as end‑bushings of the busducts with overpressure.

The epoxy resin castings are manufactured without primary current conductors. Inside diameter of the casting is 100 or 120 mm. If required, current transformer is equipped with primary current conductor manufactured according to Client’s requirements (length, size and type of terminals).

CTB current transformers have up to 4 cores for measuring and/or protection.

CTB current transformers can be mounted in any position.

Technical data:

highest permissible system voltage7.2/12/17.5/24/36 kV
power frequency withstand voltage, 1 min20/28/38/50/70 kV
impulse withstand voltage 1.2/50 µs60/75/95/125/170 kV
rated frequency50 or 60 Hz
rated primary current IPnup to 4 000 A
rated short–time thermal current Ith1s200 kA/1s (r.m.s. value)
rated dynamic current Idyn500 kA (peak value)
number of coresup to 5
rated secondary currents ISn1 A or 5 A or fractional
rated outputs Sn5 – 90 VA
accuracy classes0.2, 0.2S, 0.5, 0.5S, 5P, 10P, PX, PR
instrument security factor (FS)5, 10, 15
accuracy limit factor10, 20, 50
ambient temperature–25oC ÷ 80oC
weightca 30 – 100 kg
according to standardsPN-EN 61869-1:2009; PN-EN 61869-2:2012


CTB size 2
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CTB size 2
technical data
CTB size 2
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