Name: delta-wye source and load connections
Uploaded: 2024-07-08T13:19:57.000Z
Duration: 1 min 16 s
Channel: JoVE

Un système équilibré delta-à-Y comprend une source équilibrée connectée en delta alimentant une charge équilibrée connectée en Y.
Dans ce circuit delta-Y, on suppose qu’une séquence abc positive exprime les tensions de phase, qui servent également de tensions de ligne de la source connectée en triangle.
La loi de tension de Kirchhoff peut être appliquée à une boucle dans le circuit pour dériver une relation entre deux des courants de ligne.
Comme on suppose une séquence positive, ces courants de ligne ont une différence de phase de 120 degrés, qui est utilisée pour déterminer l’un d’entre eux.
Les deux autres courants de ligne sont obtenus en utilisant la séquence de phase positive.
Les courants de phase du circuit delta-Y sont approximativement égaux aux courants de ligne.
Alternativement, la source connectée en triangle peut être remplacée par sa source équivalente connectée en Y.
Le circuit Y-Y obtenu est analysé en considérant un circuit monophasé équivalent et en déterminant les courants à trois lignes.
Ce circuit peut également être transformé en système delta-delta à des fins d’analyse, car la charge connectée en delta est souvent préférée en raison de la facilité de modification des charges individuelles.

le circuit delta-vers-y

Dans le circuit triangle-étoile, la source est connectée en triangle, tandis que la charge est dans une configuration en étoile. Cela signifie que la tension de phase de la source connectée en triangle est égale à la tension de ligne de la charge connectée en étoile. La connexion entre les courants à deux lignes provient de la source connectée en triangle. La différence de phase dans le système équilibré permet de calculer un courant de ligne en fonction de l'autre, en utilisant la séquence positive des phases. Dans le système triangle-étoile, les courants de phase dans la charge connectée en étoile sont directement égaux aux courants de ligne provenant de la source triangle, en raison de la configuration en étoile de la charge simplifiant le flux depuis la source triangle. La relation entre les courants de ligne et de phase dans une configuration en étoile montre que le courant de phase dans la charge connectée en étoile est égal au courant de ligne de la source connectée en triangle.
Une autre façon d'obtenir les courants de ligne consiste à remplacer la source connectée en triangle par sa source équivalente connectée en étoile. Les tensions ligne à ligne d'une source connectée en étoile sont en avance de 30 degrés sur leurs tensions de phase correspondantes. Cela signifie que chaque tension de phase de la source équivalente connectée en étoile est obtenue en divisant la tension de ligne correspondante de la source connectée en triangle par la racine carrée de trois et en décalant sa phase de -30 degrés. En conséquence, la source équivalente connectée en étoile a des tensions de phase décalées de 120 degrés en conséquence.
En convertissant une configuration triangle en configuration étoile, le système peut obtenir une meilleure régulation de tension et permettre l'utilisation d'un fil neutre. Ce fil neutre permet la mise à la terre du système, améliorant ainsi la sécurité et la stabilité.
La configuration équilibrée delta à triangle est utilisée pour transmettre de l'électricité sur de longues distances, où les niveaux de haute tension doivent être réduits à des niveaux utilisables pour un usage industriel, commercial et résidentiel.

le circuit Delta-vers-Y

Un système équilibré delta-à-Y comprend une source équilibrée connectée en delta alimentant une charge équilibrée connectée en Y.
Dans ce circuit delta-Y, un abc positif ...

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The Delta-to-Y Circuit

delta-wye source and load connections

A balanced delta-wye circuit connects a delta-connected source to a wye-connected load. In this setup, the phase voltage of the delta source equals the line voltage of the wye load. The source also sets the line currents that flow into the load.

For a balanced system, the phase difference between currents makes it possible to find one line current from the other by using the positive sequence of phases. In the wye-connected load, each phase current equals the line current from the delta source. That relationship makes current analysis simpler in the load section.

The line currents can also be found by replacing the delta source with an equivalent wye source. In that conversion, each phase voltage is the matching line voltage divided by the square root of three and shifted by -30 degrees. The line-to-line voltages of a wye source lead the phase voltages by 30 degrees, so the equivalent wye source keeps the phases spaced 120 degrees apart.

Changing a delta connection to a star, or wye, connection can improve voltage regulation. It also allows the use of a neutral wire. That neutral wire supports grounding, which improves safety and stability. Balanced delta systems are also used for long-distance power transmission, where high voltage must later be stepped down for industrial, commercial, and residential use.

Delta-Wye Source and Load Connections

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Wye Source and Delta Load Currents

A balanced wye source and delta load form a common three-phase circuit with no neutral line connection. The source is Y-connected, and the load is delta-connected. To analyze the circuit, the first step is to assume a positive phase sequence. These phase voltages are then used to find the line voltages that appear across the delta load impedances. In the wye source, the phase voltages are V an, V bn, and V cn. In the delta load, the line voltages are V ab, V bc, and V ca. These line voltages...

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the delta-to-y circuit

A balanced delta-wye circuit connects a delta-connected source to a wye-connected load. In this setup, the phase voltage of the delta source equals the line voltage of the wye load. The source also sets the line currents that flow into the load. For a balanced system, the phase difference between currents makes it possible to find one line current from the other by using the positive sequence of phases. In the wye-connected load, each phase current equals the line current from the delta source.

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key terms and concepts

Learn how a balanced delta source powers a wye load, how line and phase currents relate, and how a delta source can be converted to an equivalent wye source.

Delta-Wye Source and Load Connections | JoVE K12

JoVE Core Electrical Engineering offers easy-to-understand animated videos that cover fundamental concepts of electric circuits along with circuit analysis techniques. It incorporates first-order and second-order circuits using operational amplifiers and circuit transformation concepts. The inclusion of practical design examples and real-world applications through scientist-in-action videos adds significant educational value, making complex concepts accessible.

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Delta-Wye Source and Load Connections

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