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Benemérita Universidad Autónoma de Puebla Facultad de Ciencias de la Electrónica Licenciatura en Ingeniería Mecatrónica Tarea 5. Power Calculations in a Three-Phase System Materia: Sistemas Electrónicos de Potencia Docente: Gerardo Mino Aguilar NRC: 60122 Integrantes del equipo: Matrículas Alarcón Castillo Karen Araceli 202116808 Arrasquito Lima Francisco Andrés 202107394 Barragán Suárez Carlos 202107622 Bueno de la Rosa Carmen Guadalupe 202120529 Soriano Sánchez Diego Armando 202161538 Periodo: Primavera 2025 Índice 1. Active Power (P) 2 1.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Reactive Power (Q) 2 2.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Apparent Power (S) 3 3.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Instantaneous Power (p) 3 4.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5. Average Power 4 5.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6. RMS Power 5 6.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. Power Factor (PF) 5 7.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8. Total Harmonic Distortion (THDi and THDv) 6 8.1. Exercise: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1 1. Active Power (P) 1.1. Exercise: Calculate the active power for a three-phase system with line voltage VLL = 127V , line current IL = 10A, and a power factor cosϕ = 0,9. Solution P = V Icosϕ = (127V )(10A)(0,9) P = 1, 143W Answer: P=1,143W 2. Reactive Power (Q) 2.1. Exercise: Calculate the reactive power for the same system. Solution Using sin2ϕ+ cos2ϕ = 1 ⇒ sinϕ = √︁ 1− cos2ϕ = √︁ 0,19 Therefore sinϕ = ±0,436 Then Q = V Isinϕ Q = (127V )(10A)(±0,436) Q = ±553,72V AR Answer:Q = ±553,72VAR 2 3. Apparent Power (S) 3.1. Exercise: Calculate the apparent power. Solution S = V Icosϕ = (127V )(10A) S = 1270V A or S = √︁ P 2 +Q2 = √︁ 11432 + 553,722 S = 127,060V A ≈ 1270V A Answer: S = 1270VA 4. Instantaneous Power (p) 4.1. Exercise: For a single-phase system, the instantaneous voltage and current are given by v(t) = Vmsin(ωt) and i(t) = Imsin(ωt+ ϕ). Calculate the instantaneous power. Solution p(t) = v(t) · i(t) = Vmsin(ωt) · Imsin(ωt+ ϕ) Using the trigonometric identity sinA · sinB = 1 2 [cos(A−B)− cos(A+B)] Applying this p(t) = VmIm · 1 2 [cos(ωt− (ωt+ ϕ))− cos(ωt+ (ωt+ ϕ))] 3 Simplifying p(t) = VmIm 2 [cos(−ϕ)− cos(2ωt+ ϕ)] Since cos(−ϕ) = cos(ϕ) -para, the final expression is: p(t) = VmIm 2 [cos(ϕ)− cos(2ωt+ ϕ)] Answer: p(t) = VmIm 2 [cos(ϕ)− cos(2ωt+ ϕ)] 5. Average Power 5.1. Exercise: Calculate the average power for the above system. Solution The average (active) power in a single-phase system is calculated as: Pavg = VmIm 2 cos(ϕ) Since Vrms = Vm√ 2 and Irms = Im√ 2 , we can rewrite the formula as: Pavg = Vrms · Irms · cosϕ Answer: Pavg = Vrms · Irms · cosϕ 4 6. RMS Power 6.1. Exercise: Calculate the RMS value of the power. Solution Using the formula to approximate the power in RMS PRMS = VRMS · IRMS Since Vrms = Vm√ 2 and Irms = Im√ 2 , we can rewrite the formula as: PRMS = Vm√ 2 · Im√ 2 Answer: PRMS = Vm√ 2 · Im√ 2 7. Power Factor (PF) 7.1. Exercise: Calculate the power factor given the active and apparent powers. Solution Using the formula provided in class, the power factor is defined as: PF = P S Answer: PF = P S 5 8. Total Harmonic Distortion (THDi and THDv) 8.1. Exercise: Calculate the THDi and THDv if the fundamental current is I1 = 10A and the second harmonic is I2 = 1A, and the voltage distortion is similar. Solution The THD for the current (THDi) is calculated as: THDi = √︁∑︁∞ h=2I 2 h I1 Since only the second harmonic is considered (I2 = 1A): THDi = √︁ I22 I1 = 1 10 = 0,1 For THDv, if the distortion is similar, then: THDv = 0,1 Answer: THDi = 0,1 y THDv = 0,1 6 Highlight Active Power (P) Exercise: Reactive Power (Q) Exercise: Apparent Power (S) Exercise: Instantaneous Power (p) Exercise: Average Power Exercise: RMS Power Exercise: Power Factor (PF) Exercise: Total Harmonic Distortion (THDi and THDv) Exercise: