Name: balanced three-phase power calculation
Uploaded: 2024-07-08T13:19:58.000Z
Duration: 1 min 15 s
Channel: JoVE

여러 대의 중장비가 있는 제조 공장에는 균형 잡힌 3상 시스템으로 공급되는 상당한 전력이 필요합니다.
플랜트의 부하에 의해 흡수되는 순간 전력을 결정하기 위해 Y 연결 시간 영역 회로에서 분석이 수행됩니다.
위상 전압은 120도의 위상차를 가지며 2의 제곱근은 정확한 전력 분석을 위해 피크 전압을 RMS 값으로 변환하는 데 사용됩니다.
기계가 작동할 때 전원 공급 장치에서 전류를 끌어와 위상 전류와 해당 위상 전압 사이에 위상 지연이 발생합니다.
기계의 부하에 의해 끌어온 총 순간 전력은 세 단계 각각에서 순간 전력을 합산하여 계산됩니다.
얻어진 총 순간 전력은 거의 일정하게 유지되며 시간에 따라 변하지 않습니다. 이를 통해 위상당 유효, 무효 및 피상 전력을 계산할 수 있습니다.
총 유효 전력은 세 단계의 유효 전력의 합입니다. 마찬가지로, 총 무효 전력과 피상 전력이 계산됩니다.
이러한 결과는 Y 연결 부하와 델타 연결 부하 모두에 적용됩니다.

3상 회로의 전력

3상 시스템에는 와이와 델타의 두 가지 구성이 있습니다. 스타 구성은 3개 또는 4개의 와이어로 구성될 수 있습니다. 델타 구성에서는 구성 요소가 폐쇄 루프로 연결됩니다. 순시전력이란 정확한 순간의 전력값을 말하며 평형삼상계통에서는 일정하다. 이는 대칭성과 위상 관계로 인해 개별적인 변동에도 불구하고 3상의 순시 전력의 합이 시간이 지나도 일정하게 유지되기 때문입니다. 균형 잡힌 3상 시스템의 총 순시 전력은 일정하며 시간이 지나도 변동하지 않습니다.
유효, 무효 및 복합 전력:
위상당 평균 전력은 균형 잡힌 3상 시스템의 전체 평균 전력의 1/3입니다. 마찬가지로, 위상당 무효 전력은 시스템의 전체 무효 전력의 1/3입니다. 각 상별로 유효전력과 무효전력을 합친 복합전력도 전체 복합전력의 1/3을 차지합니다.
전력 계산의 동등성:
Delta 및 Wye 구성에는 모든 위상과 라인에 전압과 전류가 있습니다. 이러한 구성에서는 부하가 부하 끝의 각 위상에 연결됩니다. 부하에 의해 소비되는 전력과 와이 구성과 델타 구성 간의 등가성은 전력 계산까지 확장됩니다. Y형 연결 시스템이든 델타 연결 시스템이든 총 전력은 3상 각각의 전력의 합입니다. 이는 라인 및 위상 전압과 전류 간의 관계를 사용하여 계산할 수 있습니다. Y형 연결 시스템과 델타 연결 시스템의 경우:
<img alt="Equation 1" src="/files/ftp_upload/15133/15133_Equation_1.svg" style="height: 16px;">

여러 대의 중장비가 있는 제조 공장에는 균형 잡힌 3상 시스템으로 공급되는 상당한 전력이 필요합니다.
순간을 결정하기 위해 ...

Education

교육

JoVE Core

Electrical Engineering

전기공학

Unit 1

제1단원

Three-Phase Circuits

3상 회로

KEY TERMS AND CONCEPTS

주요 용어 및 개념

Power in a Three-Phase Circuit

balanced three-phase power calculation

Balanced three-phase power calculation depends on the wye and delta connections used in the circuit. A wye, or star, configuration can use three wires or four wires. A delta configuration connects the components in a closed loop. These connection types change how voltages and currents are arranged, but both are used in three-phase systems.

In a balanced three-phase system, instantaneous power is the power at one exact moment. Even though the power in each phase changes over time, the total instantaneous power stays constant. The three phase powers add together in a steady way because the system is symmetric and the phases are shifted from one another.

The same one-third relationship applies to average power, reactive power, and complex power. The average power in each phase is one-third of the total average power. The reactive power per phase is also one-third of the total reactive power. Complex power, which combines active and reactive power for each phase, is likewise one-third of the total complex power.

These power rules apply to both wye-connected and delta-connected loads. In both configurations, the load is connected to each phase at the load end. The total power is the sum of the power in the three phases. It can be found by using the known relationships between line voltage, phase voltage, line current, and phase current in either a wye or delta system.

Balanced Three-Phase Power Calculation

three-phase circuits

How Three-Phase Power Delivers Electricity

Three-phase power is a major part of AC power distribution, especially where steady and efficient electricity delivery is needed. AC systems are grouped into single-phase, two-phase, and three-phase systems. These categories help describe how power moves from the source to the load. Single-phase circuits are common in homes. They usually use a two-wire system that connects one AC source to loads. These circuits can supply everyday appliances such as lamps, televisions, and microwaves at 120 V...

generation of three-phase voltage

Three-Phase AC Generator Windings

A three-phase AC generator uses rotating magnet windings and a stationary stator to make three-phase voltage. The rotor carries a magnet that spins inside the stator. The stator holds the three-phase winding, and mutual induction creates the voltage. The stator windings are spread evenly around the inside of the stator. They are placed 120 electrical degrees apart. These windings consist of three separate coils, or groups of coils, called phases. The phases can be connected in a Y, or star,...

three-phase voltages

Three-Phase Power Connections

Three-phase power connections use balanced voltages that are equal in magnitude and separated by 120 degrees. A three-phase generator produces these voltages, and the balance helps reduce power loss while keeping energy delivery steady to connected loads. Three-phase sources can be arranged in either wye or delta form. The loads connected to the system can also use wye or delta. This flexibility gives control over how the system is designed and managed. In a wye connection, one end of each...

the y-to-y circuit

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 y-to-delta circuit

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...

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...

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.

power in a three-phase circuit

Balanced three-phase power calculation depends on the wye and delta connections used in the circuit. A wye, or star, configuration can use three wires or four wires. A delta configuration connects the components in a closed loop. These connection types change how voltages and currents are arranged, but both are used in three-phase systems. In a balanced three-phase system, instantaneous power is the power at one exact moment. Even though the power in each phase changes over time, the total...

power distribution in three-phase and single phase circuits

power-distribution-in-three-phase-and-single-phase-circuits

Single-Phase vs. Three-Phase Power Loss

Single-phase and three-phase circuits distribute electrical power in different ways. Single-phase power is common in homes, while balanced three-phase power is widely used in industrial settings with heavy machinery. Both systems deliver energy, but their current flow and wire needs are not the same. A single-phase circuit usually uses a two-wire system. The current depends on the power absorbed by the load and the line voltage. Because wire loss from resistance follows the square of the...

line loss

Reducing Power Loss in Three-Phase Lines

Three-phase power lines can lose energy as electricity travels from the source to the load. This line loss affects how efficiently power reaches the load. In balanced three-phase circuits, the symmetry makes the analysis easier because one phase can represent the whole system. The source-load connection can use wye, also called star, or delta configurations. These setups change the relationship between line voltage, phase voltage, line current, and phase current. A per-phase equivalent circuit...

reducing line loss

Cutting Heat Loss in Three-Phase Lines

Three-phase power systems can lose energy as heat in transmission lines because the wires have resistance. This line loss becomes important when electricity travels over a distance. A common solution is to use transformers to change the voltage and current in the system. The setup uses two three-phase transformers. A step-up transformer is placed at the source, and a step-down transformer is placed at the load. Raising the voltage at the source lowers the current in the transmission lines, and...

key terms and concepts

Learn how balanced three-phase systems handle instantaneous, active, reactive, and complex power in wye and delta connections for high school physics.

Balanced Three-Phase Power Calculation | 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.

electrical engineering

Balanced Three-Phase Power Calculation

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