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40.5kV Current Transformer (oil-immersed)CT

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40.5kV Current Transformer (oil-immersed)CT Product Details:

40.5kV Current Transformer (oil-immersed)CT

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:

This type current transformer is oil immersed enclosed, mainly made up of primary body, expander, conservator, primary conducting rod, porcelain shell, mounting  barrel and tank.

The body is made up of primary winding and secondary winding, the primary winding is U shape and primary conducting rod is semicircle aluminum pipe or paper rectangular copper wire.

Primary winding are divided into two parts and with totally 4 connectors leading out from conservator.

The current ratio will be varied through the connection type of consevator1s outer connecting piece change.

Secondary windings are fixed at the bottom of support, the connectors of secondary windings are lead out from secondary connection board of tank`s outlet box. Outer cables are connected inner box through outgoing hole at the bottom of outgoing box.



Ø   The moisture content of body is treated completely under 5Pa vacuum and medium doesn’t rise again.

Ø    Partial discharge is small and performance is reliable.

Ø   With high capability of short time withstand thermal current.

Ø   Secondary connection board is made of cast epoxide resin, so the air proof and damp proof feature is obvious.

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 Vertical Current Transformer

Ø   Highest system voltage: 40.5kV

Ø   Rated frequency: 50Hz

Ø   Rated power frequency withstand voltage (r.m.s):95kV

Ø   Rated lighting impulse withstand voltage (peak): 200kV

Ø   Rated primary current:5~2000A

Ø   Rated secondary current:5 or 1A

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

Ø   Rated output:20~50VA

Ø   Instrument security factor(FS):5;10

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

Ø   Short time thermal current: 5.3~50/3 KA/s

Ø   Rated dynamic stable current:13~125KA

Ø   Outer dimension: 300*300*1805mm

Ø   Oil weight: 40KG

Ø   Product weight: 160KG

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