8.10
라인 손실
소스-부하 연결의 다양한 구성에는 Wye(스타) 연결과 델타 연결이 포함됩니다. 선상 및 상 전압과 전류 간의 관계는 구성에 따라 다릅니다. 소스에서 전력을 공급하면 전선을 통해 부하로 전달되며, 이 전송 중에 일부 전력이 전선에 흡수되어 선로 손실이 발생합니다.
라인…
시간 영역에 표시되는 평형 3선 Y-Y 회로를 생각해 보십시오.이 회로는 위상별 등가 회로로 변환될 수 있습니다.
먼저 라인 전류가 결정된 다음 부하의 위상 전압이 결정됩니다.
그런 다음, 소스에 의해 전달되는 전력은 정현파 위상 전압 및 라인 전류의 유효 값을 사용하여 결정됩니다.
다음으로, 부하에 전달되는 전력은 라인 전류와 부하 저항을 사용하여 계산됩니다.
라인에서 손실된 전력은 라인 전류와 라인 저항을 사용하여 얻습니다.
그런 다음 3상 소스가 전달하는 총 전력, 3상 부하에 의해 수신된 총 전력 및 라인에서 손실된 총 전력이 결정됩니다.
라인에서 높은 비율의 전력이 손실되며, 이는 라인 전류를 최소화하여 줄일 수 있습니다.
그러나 이렇게 하면 부하 전류가 감소하여 부하에 전달되는 전력이 감소합니다.
부하 전류에 영향을 주지 않고 라인 전류를 줄이는 한 가지 방법은 3상 회로에 변압기를 도입하는 것입니다.
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Q1: How is line loss calculated in a balanced three-phase circuit?
Line loss for each wire is calculated by squaring the line current and multiplying it by the line's resistance. For balanced three-phase systems, this calculation is multiplied by three to account for all three phases. The total line loss represents power absorbed by the transmission wires during power distribution in three phase and single phase circuits.
Q2: What factors affect the amount of power lost in transmission lines?
Line loss is directly proportional to conductor length and inversely proportional to the conductor's cross-sectional area. Line resistance depends on material resistivity, conductor length, and cross-sectional area. Increasing the conductor's cross-sectional area or reducing line length minimizes power loss during transmission.
Q3: Why does reducing line current help minimize power loss without affecting load power?
Line loss depends on the square of line current, so even small reductions significantly decrease power loss. Transformers can reduce line current while maintaining the same load current and power delivered to the load. This allows power companies to transmit energy efficiently over long distances without compromising load power delivery.
Q4: How does voltage transmission strategy reduce line losses?
Power companies transmit power at higher voltages to reduce line losses. Since power equals voltage multiplied by current, increasing voltage allows current to decrease for the same power level. Lower current dramatically reduces line losses because loss is proportional to the square of current.
Q5: What is the relationship between line current and power loss in three-phase systems?
Power loss in transmission lines is proportional to the square of the line current multiplied by line resistance. A high percentage of power can be lost in lines when current is large. Minimizing line current is the most effective strategy for reducing power loss in three-phase transmission systems.
Q6: How does a per-phase equivalent circuit help analyze line loss?
The per-phase equivalent circuit simplifies analysis of balanced three-phase systems by allowing engineers to examine just one phase. This symmetry-based approach enables straightforward calculation of line current, phase voltage, and power loss. Results from one phase are then multiplied by three to determine total system performance.
Q7: What is the trade-off between reducing line current and maintaining load power?
Directly reducing line current decreases load current, which reduces power delivered to the load. Transformers solve this problem by reducing line current while preserving load current and power. This allows power companies to minimize transmission losses without sacrificing the power available to consumers.