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252kV Current Transformer (oil-immersed)CT Inverted Type

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252kV Current Transformer (oil-immersed)CT Inverted Type Product Details:

252kV Current Transformer (oil-immersed)CT Inverted Type

Current transformer (CT) is used for measurement of electric currents. When current in a circuit is too high to directly apply to measuring instruments, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and recording instruments. Current transformer also isolates the measuring instruments from what may be very high voltage in the monitored circuit. It commonly used in metering and protective relays in the electrical power industry.


According to the insulation medium, the current transformer can be divided in to SF6 CT and Oil immersed CT.

The SF6 current transformer is inverted type and is composed by the shell, main body, insulation bushing and foundation, which is insulated by SF6 gas.


The oil immersed current transformer mainly consists of primary body, expander, conservator, primary conducting rod, porcelain shell and mounting barrel and tank.  The oil current transformer can be divided into vertical and inverted type according to their structures.



IEC-60044 Instrument transformers

GB1208-2006 Current Transformer


Product structure

The overall structure of oil immersed inverted full enclosed structure, and main insulation adopts oil paper compound insulation.

They are made up of primary winding, body, expander, conservator, insulator, pedestal and secondary terminal box.  

The primary and secondary windings are equipped inside of conservator. Outgoing lines of secondary windings are led to terminal box on upper of pedestal through lead line.



Ø   Primary windings pass through geometric centre of the body with high dynamic stability capability and thermal stability of current can reach 50~63KA/3s.

Ø   Bushing of equipments adopts multi-terminal screen and multi main screen, and field intensity distribution on creepage of bushing is better distributed by optimization design.  Reliable main insulation and seldom be aging

Ø   Measurement and protective secondary windings are installed in shield cover to prevent invade and attach to secondary instrument and controlling system from high voltage when high energy discharge occurs.

Ø   The dielectric loss of the equipment is less than 0.3% which is ensured by the vacuum dry treatment with increasing pressure control.

Ø   All the accessories have passed the leakage tests.

Ø   Reliable stability of short-circuits (stable dynamic thermal)

Ø   Convenient operation and easy maintenance


Application: the current transformer is for the use of current measurement, electrical metering and relay protection in power system.


Typical specification:

Ø   Type: Oil-immersed Inverted Current Transformer

Ø   Highest system voltage: 252kV

Ø   Rated frequency: 50Hz

Ø   Rated power frequency withstand voltage (r.m.s):395/460kV

Ø   Rated lighting impulse withstand voltage (peak): 950/1050kV

Ø   Rated primary current:100~4000A

Ø   Rated secondary current:5 or 1A

Ø   Accuracy classes: 0.1;0.2; 0.2S;0.5;0.5S;5P;10P;

Ø   Rated output:10~50VA

Ø   Instrument security factor(FS):5;10

Ø   Accuracy limit factor(ALF): 10;15;20;25;30;40

Ø   Short time thermal current: 50~63/3 KA/s

Ø   Rated dynamic stable current:125~160KA

Ø   Outer dimension: 930*930*3750mm

Ø   Oil weight: 150KG

Ø   Product weight: 730KG

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