Name: balanced wye-to-wye neutral current
Uploaded: 2024-07-08T13:19:57.000Z
Duration: 1 min 19 s
Channel: JoVE

Los sistemas Y-a-Y balanceados de cuatro hilos constan de tres fuentes de voltaje sinusoidal y conectadas en Y balanceadas y cargas con el cable neutro conectando ambos nodos neutros de la fuente con la carga.
La impedancia de carga para cada fase es igual a la suma de las impedancias de fuente, línea y carga. Las impedancias de fuente y línea se descuidan para simplificar el sistema.
Teniendo en cuenta la secuencia de fase positiva, los voltajes de fase determinan los voltajes de tres líneas
La ley de voltaje de Kirchhoff se aplica a cada fase, y se determina que las corrientes de línea tienen magnitudes iguales y diferencias de fase de 120 grados.
Su suma es igual a cero, lo que implica corriente cero en el cable neutro.
En un sistema Y equilibrado, la potencia total entregada a la carga trifásica es tres veces la potencia entregada en cada fase.
Para un sistema Y-Y desequilibrado con una carga desequilibrada, las corrientes de línea están desequilibradas, lo que da como resultado una corriente neutra distinta de cero.
Otro método para analizar un sistema equilibrado de Y a Y es considerar una fase y analizar su circuito monofásico equivalente para determinar su corriente de línea. A continuación, la secuencia de fases produce las otras dos corrientes de línea.

el circuito y-a-y

The Y-to-Y Circuit

En un sistema equilibrado de cuatro cables estrella a estrella, la disposición involucra fuentes y cargas de voltaje sinusoidales conectadas en estrella, conectadas a través de un cable neutro que conecta los nodos neutros de la fuente y la carga. La impedancia de carga está conectada a través de cada fase de la carga. La fuente conectada en estrella se puede conectar a la carga conectada en estrella en disposiciones de cuatro y tres hilos. Un sistema trifásico se considera equilibrado cuando la carga en cada fase es igual, lo que genera un flujo de corriente y un ángulo de fase uniformes en todas las etapas. Por otro lado, en un sistema desequilibrado, las variaciones en la impedancia de carga o los voltajes de la fuente dan como resultado corrientes de línea desiguales.
El análisis de la configuración del circuito estrella-estrella de cuatro hilos es relativamente sencillo. En esta configuración, cada impedancia de la carga trifásica se conecta directamente a través de su voltaje de fase respectivo desde la fuente trifásica. Suponiendo una secuencia de fases positiva y condiciones equilibradas, los voltajes de fase son fundamentales para analizar el sistema. Estos voltajes de fase influyen directamente en los voltajes a través de cada impedancia de carga.
<img alt="Equation 1" src="/files/ftp_upload/15129/15129_Equation_1.svg" style="height: 32px;">
<img alt="Equation 2" src="/files/ftp_upload/15129/15129_Equation_2.svg" style="height: 32px;">
<img alt="Equation 3" src="/files/ftp_upload/15129/15129_Equation_3.svg" style="height: 32px;">
La corriente en el cable que conecta el nodo neutro de la fuente al nodo neutro de la carga es:
<img alt="Equation 4" src="/files/ftp_upload/15129/15129_Equation_4.svg" style="height: 16px;">
La ley de voltaje de Kirchhoff, cuando se aplica a cada fase de un circuito trifásico equilibrado, confirma que la suma de los voltajes alrededor de cualquier circuito cerrado es cero. Esto conduce a corrientes de línea de igual magnitud pero con cambios de fase de 120 grados entre ellas. Estas corrientes efectivamente suman cero en cualquier punto, lo que justifica por qué el cable neutro no transporta corriente en condiciones de equilibrio.
En un sistema estrella a estrella desequilibrado, las variaciones en la impedancia de carga o los voltajes de la fuente dan como resultado corrientes de línea desiguales. Cada fase del sistema se trata como un circuito monofásico para calcular su corriente de línea. Sin embargo, las corrientes para las fases restantes requieren un análisis individual en lugar de una deducción basada únicamente en la secuencia de fases, ya que cada fase puede verse influenciada de manera única por sus condiciones eléctricas específicas.

El circuito Y-a-Y

Los sistemas Y-a-Y balanceados de cuatro hilos constan de tres fuentes de voltaje sinusoidal y conectadas en Y balanceadas y cargas con el cable neutro conectando ambos ...

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balanced wye-to-wye neutral current

A balanced wye-to-wye circuit uses three wye-connected sinusoidal voltage sources and three wye-connected loads. A neutral wire links the neutral node of the source to the neutral node of the load. The load impedance is connected across each phase of the load.

The source and load can be connected in either a four-wire or a three-wire arrangement. A three-phase system is balanced when each phase has the same load. In that case, the current flow and phase angle are uniform across the system. If the load impedance or source voltages differ, the system becomes unbalanced and the line currents are no longer equal.

The four-wire wye-wye circuit is relatively easy to analyze. Each load impedance is connected directly across its own phase voltage from the three-phase source. With a positive phase sequence and balanced conditions, the phase voltages are the key to finding the voltages across each load impedance.

Kirchhoff's Voltage Law applies to each phase of a balanced three-phase circuit. The sum of the voltages around any closed loop is zero. This produces line currents with equal magnitude and 120-degree phase shifts. Their sum is zero at any point, so the neutral wire carries no current when the system is balanced.

An unbalanced wye-to-wye system must be treated differently. Changes in load impedance or source voltages create unequal line currents. Each phase is handled as a single-phase circuit to find its line current. The other phases must be analyzed on their own, since each one may be affected by its specific electrical conditions rather than by phase sequence alone.

Balanced Wye-to-Wye Neutral Current

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the y-to-y circuit

A balanced wye-to-wye circuit uses three wye-connected sinusoidal voltage sources and three wye-connected loads. A neutral wire links the neutral node of the source to the neutral node of the load. The load impedance is connected across each phase of the load. The source and load can be connected in either a four-wire or a three-wire arrangement. A three-phase system is balanced when each phase has the same load. In that case, the current flow and phase angle are uniform across the system. If...

the y-to-delta circuit

Wye Source and Delta Load Currents

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the delta-to-delta 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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key terms and concepts

Learn how balanced and unbalanced wye-to-wye circuits work, why the neutral wire carries no current in balanced conditions, and how line currents are analyzed.

Balanced Wye-to-Wye Neutral Current | 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 Wye-to-Wye Neutral Current

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