ABB Medium Voltage MV Indoor Current Transformers CT's, 3.3kV up to 40.5kV - ABB TPU

ABB Power ProductsABB MV Indoor / Outdoor Current Transformers

ABB TPU Medium Voltage MV Current Transformers CT's

3.6kV 6.6kV 7.2kV 11kV 12kV 17.5kV 25kV 33kV 36kV 40.5kV 


ABB MV indoor current transformers support (post) type TPU are cast in epoxy resin and are designed for insulation voltages up to 36 kV (40.5 kV).

The ABB TPU indoor dry type transformers are arranged to act as a support for the conductor in the primary circuit. The TPU transformers are designed and can be manufactured in conformity with the following standards and recommendations: IEC, VDE, ANSI, BS, GOST and CSN, others on request.ABB TPU Medium Voltage Current Transformers

ABB TPU Medium Voltage Current Transformers (CT's) Characteristics

  • Supporting type
  • For measuring an protection with up to 6 secondary windings (12 clamps)
  • Secondary or primary reconnectable
  • Capacitive voltage divider in current transformer (CT) body for voltage indication available
  • Most electrical standards available
  • DIN dimensions according to 42600 part 8
  • Transparent secondary terminal cover as an option
  • Suitable for tariff metering
  • Sealable secondary terminal 

Medium voltage (MV) panels may require extra long creepage distance on the MV transformers - ABB current transformers can be customised with "ribs on the top” for this medium voltage application.

ABB TPU Medium Voltage Current Transformers (CT's) Ratings
Highest Voltage For Equipment 3.6kV - 40.5kV
Primary Current 10A - 3200A
Rated Short - Time Thermal Current Up to 100 kA /1 s
Secondary Current 1A or 5 A
Frequency 50Hz or 60 Hz 


ABB TPU indoor current transformers (CT's) can be provided with a medium voltage indication system.

The secondary windings on ABB TPU MV current transformers are used for measurement or protection purposes or for testing transformer winding. One terminal of each secondary winding used and one terminal of short-circuited and not used winding have to be earthed during the medium voltage transformer operation. The secondary transformer windings are lead out into a cast-type secondary terminal box with plastic cover. The terminal cover is sealable - terminals are provided with M5 screws for the termination and with entry holes for direct earthing (secondary terminal first row).

MV Medium Voltage Indoor Transformers - ABB indoor transformers should be mounted in dry indoor conditions where the ambient air is not significantly polluted by dust, smoke, corrosive gases, vapours or salt. ABB indoor transformers are designed for standard ambient indoor temperatures between -5 degrees Celsius to +40 degrees Celsius. ABB indoor transformers may be used in higher or lower temperatures. 


ABB TPU MV Indoor Supporting Current Transformers (CT's) Range:

ABB TPU 4x.xx Medium Voltage Current Transformers (CT's) - for insulation voltages from 3.6kV to 12kV

ABB TPU 5x.xx Medium Voltage Current Transformers (CT's) - for insulation voltages from 13.8kV to 17.5kV

ABB TPU 6x.xx Medium Voltage Current Transformers (CT's) - for insulation voltages from 24kV to 25kV

ABB TPU7x.xx Medium Voltage Current Transformers (CT's) - for insulation voltages from 36 kV to 40.5 kV.

ABB MV medium voltage current transformers are designed as single-or-multiple turn transformers, with one transformer ratio, or with the possibility to be switched over on the secondary or primary side.


Installation Advice for ABB Transformers - CT Type, MV Medium Voltage

Pre Installation CT Transformer Checks : i) visual inspection ii) electric withstand of insulation under the test voltage iii) electric withstand test of insulation of secondary transformer winding of the transformer under the test voltage 50 HZ Up = 2kV during 1 minute iv) measurement of insulation resistance of secondary transformer winding (towards the ground) using a varindor ohmmeter of the voltage 1000V.

Post Installation, Pre-Operation CT Transformer Checks : i) visual inspection ii) checking of proper installing (use of all holes for fixing, proper holding down of fixing bolts) iii) checking of distance between primary terminals of current transformers and the closest brackets of connecting bars iv) checking of proper grounding of terminals v) check legalisation leaden seal.

Operational CT Transformer Checks : i) live MV transformer visual inspections ii) inspections in no voltage state.

Live CT Transformer Checks Monthly  : i) condition of main insulation of the transformer ii) condition of the primary terminals iii) condition of supporting structures.

No Voltage CT Transformer Checks Periodically : i) measurement of the resistance of the MV transformer winding insulation or transformer secondary windings together with secondary circuits, which value can not be less than 10 megaohms ii) cleaning of the external surfaces of the indoor current transformer iii) complement of the coat iv) checking of holding-down of the fixing, terminal and grounding bolts. Refer to ABB Transformer O&M Instruction download for further information.

Mounting Indoor Current Transformers (CT) - the mounting position of ABB indoor transformers can be freely chosen, the medium voltage MV transformer is fixed using the mounting base with four M10 screws and washers - fastening must be done on a smooth surface. There is a M8 screw for earthing the MV transformer on the base plate.

ABB current transformers (CT's) for medium voltage electrical applications : i) CT transformers convert large currents in the primary circuit to an appropriate level for secondary circuit equipment (medium voltage relays and meters), ii) CT transformers insulate primary and secondary circuit from each other to protect the secondary equipment from the effects of large current appearing during the medium voltage MV operation (short circuits).




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