Scott-T Transformer Connection Shirye-shirye na Scott-T Transformer

Taifuka: Tushen Scott-T wata matsayin tattalin tushen maimaitoshen tushen bayan gida biyu don in iya kawo kananan 3-fase zuwa 2-fase da kuma kawo kananan 2-fase zuwa 3-fase. Maimaitoshen tushen bayan gida biyu suna cikin hanyar tushen amma sun yi aiki na tushen gida. Babu tushen an sanya shi ne main transformer, kuma babu tushen an sanya shi ne auxiliary ko teaser transformer.

Rabtaba tana bayyana tushen Scott-T:

• Main transformer yana da tappi a fili D kuma yana haɗa da layin B da C a faden 3-fase. Winding primary yake yana labari BC, kuma winding secondary yake yana labari a₁a₂.

• Teaser transformer yana haɗa da terminal A da tappi D. Winding primary yake yana labari AD, kuma winding secondary yake yana labari b₁b₂.

Don tushen Scott-T, ana amfani da maimaitoshen tushen guda-guda da za su iya taka da tushen primary da Tp turns kuma tare da tappi a 0.289Tp, 0.5Tp, da 0.866Tp.

Diagram Phasor na Tushen Scott Connection

Voltage line na 3-fase system mai karfi—VAB, VBC, da VCA—suna nufin a rubutun da ta nan, wanda aka nuna a hakan itace triangle mai karfi. Rubutu tana nuna winding primary na main transformer da teaser transformer.

Fili D yana ba winding primary BC na main transformer zuwa biyar. Saboda haka, number of turns a BD yana daga DC, both being Tp/2. Voltage VBD da VDC suna da muhimmanci da voltage VBC.

Voltage between A and D is

Teaser transformer yana da rating primary voltage na √3/2 (i.e., 0.866) times that of the main transformer. When the voltage VAD is applied to the teaser transformer's primary winding, its secondary voltage V2t leads the main transformer's secondary terminal voltage V2m by 90 degrees, as depicted in the figure below.

To maintain the same voltage per turn in the primary windings of both the main transformer and the teaser transformer, the number of turns in the teaser transformer's primary must be be √3/2 Tp.

Consequently, the secondaries of both transformers have identical voltage ratings. The secondary voltages V2t and V2m are equal in magnitude but separated by 90º in phase, thereby producing a balanced 2-phase system.

Position of Neutral Point N

The primary windings of the two transformers can form a four-wire connection to a 3-phase supply if a tap N is provided on the teaser transformer's primary such that:

• The voltage across AN, denoted as VAN), equals the phase voltage, i.e.,VAN= Vt/√3.

The same voltage turn in portion AN, ND and AD are shown by the equations,

The equation above indicates that the neutral point N divides the primary winding of the teaser transformer in the ratio:AN:ND = 2 : 1

Applications of Scott-T Connection

The Scott-T connection finds practical use in the following scenarios:

• Electric Furnace Installations: It enables the parallel operation of two single-phase furnaces while drawing a balanced load from a three-phase supply, ensuring efficient power distribution and system stability.

• Single-Phase Load Management: Commonly applied in electrified rail systems (e.g., electric trains), where single-phase loads are scheduled to maintain near-equal loading across all three phases of the supply, minimizing imbalance and optimizing grid performance.

• Phase Conversion Between Systems: Facilitates bidirectional power flow between three-phase and two-phase systems. While it can convert both ways, practical applications predominantly focus on three-phase to two-phase conversion, as two-phase generators are rarely used in modern power systems.