Name: balanced delta-delta power circuit
Uploaded: 2024-07-08T13:19:57.000Z
Duration: 1 min 17 s
Channel: JoVE

Un sistema bilanciato da delta a triangolo ha una sorgente e un carico collegati a delta.
Si presume che le sorgenti collegate a triangolo siano in sequenza positiva per esprimere le tensioni di fase, che sono identiche alle tensioni di linea.
Supponendo impedenze di linea pari a zero, le tensioni di fase corrispondono alla tensione attraverso le impedenze.
Le correnti di fase sono uguali al rapporto tra la tensione di fase e l'impedenza di carico per fase.
Le correnti di linea sono derivate dalle correnti di fase utilizzando la legge delle correnti di Kirchhoff ai nodi dei carichi collegati a delta.
Ogni corrente di linea è in ritardo di 30 gradi rispetto alla corrispondente corrente di fase, con la sua grandezza che è la radice quadrata di tre volte la corrente di fase.
In alternativa, il circuito da delta a delta può essere analizzato convertendo la sorgente e il carico nei loro equivalenti Y.
Per la sorgente collegata a Y, la tensione di fase corrispondente è uguale a ciascuna tensione di linea della sorgente collegata a triangolo divisa per una radice quadrata di tre e la sua fase è spostata di 30 gradi negativi.
L'impedenza di carico collegata a Y è uguale all'impedenza di carico collegata a triangolo divisa per tre.
Ora, il circuito monofase equivalente può essere utilizzato per determinare le tre correnti di linea.

il circuito triangolo-triangolo

In una configurazione triangolo-triangolo, la sorgente e il carico sono collegati a triangolo, formando un anello chiuso che divide la rete in tre fasi distinte. Questa configurazione rende le tensioni di fase identiche alle tensioni di linea. Supponendo che le sorgenti siano in sequenza positiva, le tensioni di fase possono essere espresse direttamente senza avere un filo neutro.


<img alt="Equation 1" src="/files/ftp_upload/15131/15131_Equation_1.svg" style="height: 13px;">

Le correnti di fase in un carico collegato a triangolo vengono calcolate dividendo la tensione di fase per l'impedenza di carico per fase:

<img alt="Equation 2" src="/files/ftp_upload/15131/15131_Equation_2.svg" style="height: 32px;">

In questa configurazione, la legge della corrente di Kirchhoff (KCL) fornisce la corrente di linea come somma vettoriale delle correnti delle restanti due fasi, portando al principio generale che ciascuna corrente di linea è la radice quadrata di tre volte l'entità della corrente di fase. In questo caso, la corrente di fase subisce un ritardo di 30 gradi a causa delle differenze di fase create dalla connessione a triangolo.

Le analisi di tali sistemi comportano la conversione della sorgente e del carico nei loro equivalenti stellari. Questa conversione semplifica il sistema trifase in un circuito equivalente monofase. La conversione prevede la regolazione sia dell'ampiezza che della fase delle tensioni di linea della sorgente collegata a triangolo:

<img alt="Equation 3" src="/files/ftp_upload/15131/15131_Equation_3.svg" style="height: 32px;">
<img alt="Equation 4" src="/files/ftp_upload/15131/15131_Equation_4.svg" style="height: 16px;">

Inoltre, l'impedenza di ciascun carico collegato a stella è un terzo dell'impedenza del carico collegato a triangolo.

Le configurazioni bilanciate triangolo-triangolo vengono utilizzate in applicazioni industriali per macchinari ad alta potenza, trasformatori e centri di controllo motori. Consentono un'efficiente trasmissione di potenza su lunghe distanze, riducono la distorsione armonica e facilitano il funzionamento regolare dei motori trifase mantenendo livelli di tensione costanti senza bisogno di una connessione neutra.

Il circuito Triangolo-Triangolo

Un sistema bilanciato da delta a triangolo ha una sorgente e un carico collegati a delta.
Si presume che le sorgenti collegate al delta siano in sequenza positiva per esprimere il ...

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The Delta-to-Delta Circuit

balanced delta-delta power circuit

A balanced delta-delta power circuit uses a delta-connected source and a delta-connected load. The two deltas form a closed loop that creates three separate phases. In this setup, the phase voltages are the same as the line voltages. If the source is in positive sequence, the phase voltages can be written directly, and no neutral wire is needed.

The delta-connected load current is found by dividing the phase voltage by the impedance of each phase. For line current, Kirchhoff’s Current Law (KCL) applies at each node. The line current is the vector sum of the currents from the other two phases. In a balanced delta connection, each line current has a magnitude of square root of three times the phase current. It also lags the phase current by 30 degrees because of the phase shift in the delta network.

To analyze the system more simply, the source and load can be changed into wye-equivalents. A wye connection is a star-shaped circuit that makes three-phase analysis easier. This conversion turns the three-phase network into a single-phase equivalent circuit. The delta-connected source voltages must be adjusted in both magnitude and phase during the conversion. The impedance of each wye-connected load is one-third of the delta-connected load impedance.

Balanced delta-delta systems are common in industrial settings. They are used for high-power machines, transformers, and motor control centers. They also support long-distance power transmission and can help reduce harmonic distortion. In three-phase motors, the steady voltage levels help smooth operation without the need for a neutral connection.

Balanced Delta-Delta Power Circuit

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the delta-to-delta circuit

A balanced delta-delta power circuit uses a delta-connected source and a delta-connected load. The two deltas form a closed loop that creates three separate phases. In this setup, the phase voltages are the same as the line voltages. If the source is in positive sequence, the phase voltages can be written directly, and no neutral wire is needed. The delta-connected load current is found by dividing the phase voltage by the impedance of each phase. For line current, Kirchhoff’s Current Law...

the delta-to-y circuit

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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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Explore how balanced delta-delta power circuits work, including line and phase voltages, line current, wye-equivalent conversion, and industrial uses.

Balanced Delta-Delta Power Circuit | 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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Balanced Delta-Delta Power Circuit

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