Transformator de curent sumator

Transformator de curent sumator
Summation C.T. s are designed to summarize several synchronous A.C. currents of equal phase relation with any angle of phase diffe- rence, i.e. summarize the secondary currents of a number of main C.T.’s. The secondary circuits of the main C.T.’s are to be connected to the corresponding marked primary terminals of the summation C.T., i.e. each main C.T. feeds with its secondary current a specific portion of the primary winding of the summation C.T. The number of turns of the parti-cular sections of the primary winding must fit in with ratios of the main C.T’s. If all main C.T.’s have identical ratios, it is irrelevant for their secondary circuits to which section of the primary winding of the sum-mation C.T. they are connected.
producator: Lumel

Transformator de curent sumator



Main Transformer ratio:

                           500/ 5A

                           400/ 5A

                           300/ 5A

Total current = 1200/ 5A


Burden - 1 Ammeter

Required Active performance of the Current Transformer:

       Ammeter                                          1.5 VA

       Measurement Conductor Loss      1.5 VA

      Consumption in Summation CT     4.0 VA

      Total  VA                                            7.0 VA

The individual main transformer must provide it’s VA share from this 7.0 VA.

1. Main transformer 500/ 5A (500/ 1200) x 7 = 2.92 VA + additional lesses ≈ 3.75 VA*

2. Main transformer 400/ 5A (400/ 1200) x 7 = 2.33 VA + additional lesses ≈ 2.5 VA*

3. Main transformer 300/ 5A (300/ 1200) x 7 = 1.75 VA + additional lesses ≈ 2.5 VA*

* The VA valuesof the main transformer are to be rounded up to the corresponding values in our chart.


SUMMATION CURRENT TRANSFORMER are designed to summarize several synchronous alternating

currents of equal phase relation with any angle of phase di! erence. They are used to add secondary currents of

several main c.t.’s in order to measure with the CT only.



Applicable standard: IEC 61869-1/2

Case: self-extinguishing plastic

Connection: Two connection on each side. M4 screws with self lifting clamp strap.

Insulation class: E (max 120°C)

Maximum system voltage: 0.72 kV

Operating frequency: 50/60 Hz

Test voltage: 3 kV, 50 Hz, 1 min

Rated primary rating: (2...8) x 5A

Rated secondary output: 5A

Rated burden: 5; 10; 15; 20; 25 VA

Accuracy class: 0.5; 1

Ambient temperature: -25°C …+40°C

Storage temperature: -50°C…+80°C

Thermal short circuit current (Ith): 60 x In

Dynamic short circuit current (Idyn): 2,5xIth

Instrument security factor (FS): 5,10