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Chapter 2 Solutions
Power System Analysis and Design (MindTap Course List)
- A three-phase system includes a 346.4 V line-to-line supplying a three-phase motor rated 15KVA 0.8pf lag plus additional balanced constant impedance loads. The single-phase representation of the system is shown below. Assume that sources and loads are Y-connected. 1. What is the RMS value of the line current, I in A? 2. If this set of loads will be supplied through a service transformer. What should the minimum size of the transformer in kVA? 3. What should be the size of three-phase capacitor(that will be added to the load mix) to improve power factor to almost 0.95 lag?arrow_forwardA balanced Δ connected load with impedance 63 + j216 Ω/Ø 50∠0 ° Ω/Ø It is connected in parallel to a balanced Y-connected load with impedance. Parallel loads have an impedance of 1 + j3 Ω/Ø fed from one line. Y the magnitude of the connected load from line to neutral is 750 V a) Calculate the magnitude of the current in the line feeding the loads? b) Calculate the magnitude of the phase voltage at the sending end of the line? c) Find the total apparent, average and reactive powers provided by the sources?.arrow_forwardDesign a power factor correction circuit with the value of parallel capacitance needed tocorrect a load of 179 kVAR at 0.85 lagging pf to unity pf. Assume that the load issupplied by a 110-V (rms), 60-Hz line.arrow_forward
- Please answer help for "c" and "d". The total power delivered to a balanced three-phase load when operating at a line voltage of 2400√3V is 720 kW at a lagging power factor of 0.8. The impedance of the distribution line supplying the load is 0.8 + j6.4Ω/ϕ. Under these operating conditions, the drop in the magnitude of the line voltage between the sending end and the load end of the line is excessive. To compensate, a bank of Y-connected capacitors is placed in parallel with the load. The capacitor bank is designed to furnish 576 kVAR of magnetizing reactive power when operated at a line voltage of 2400√3V. a. What is the magnitude of the voltage at the sending end of the line when the load is operating at a linevoltage of 2400√3V and the capacitor bank is disconnected?b. Repeat (a) with the capacitor bank connected. c. What is the average power efficiency of the line in (a)?d. What is the average power efficiency in (b)?e. If the system is operating at a frequency of 60 Hz, what is the…arrow_forwardA 3-phase Y-connected load draws power from a 3-phase Y-connected source. The source voltage, ?=440∠0º?_rms and the load impedance, Z_y=(30+j15) Ω. The line impedance, Z_line= (1+j1)Ω and the system operates at 60 Hz. a) Draw the single-phase equivalent circuit and label all given quantities numerically. b) Calculatethe rms line (phase) current phasor in each phase. c) Calculate the total active or real power supplied by the source. d) Calculate the total active or real power consumed by the load. e) Calculate the total line loss i.e. the total activepower lost due to line. f) Determine the power efficiency of the system.arrow_forwardA three-phase, Y-connected synchronous generater supplies current of 10 A having phase angle of 20º lagging at 400 V. Find the load angle if Xs = 10 ohms per phase. Assume Rs to be negligible. Also, calculate the total generated real and reactive power.arrow_forward
- Fast Answer please A balanced ∆ connected load with impedance 63 + j216 Ω⁄∅ 50∠0° Ω⁄∅It is connected in parallel to a balanced Y-connected load with impedance. Parallel loads have an impedance of 1 + j3 Ω⁄∅fed from one line. Y the magnitude of the connected load from line to neutral is 750 V.a) Calculate the magnitude of the current in the line feeding the loads?b) Calculate the magnitude of the phase voltage at the sending end of the line?c) The total apparent, average and reactive powers provided by the sources areA balanced ∆ connected load with impedance 63 + ?216 Ω⁄∅ 50∠0° Ω⁄∅It is connected in parallel to a balanced ?-connected load with impedance. Parallel loads have an impedance of 1 + j3 Ω⁄∅fed from one line. Y the magnitude of the connected load from line to neutral is 750 V.a) Calculate the magnitude of the current in the line feeding the loads?b) Calculate the magnitude of the phase voltage at the sending end of the line?c) The total apparent, average and reactive powers…arrow_forwardS.4) the length of a three-phase power transmission line with a Nominal operating voltage of 69 kV is 16km. The impedance of the transmission line per unit length is 0.125 + j0.4375 ohm/km. From the end of the line, a 56 MW star connected load is fed with a power coefficient of 0.8 back under a 64 kV interphase voltage. If the line head voltage of the transmission line is 69 kV, calculate the capacity and power of the star-connected capacitor to be shunted into the load connected to the end of the line.arrow_forwardA 4200-V, three-phase transmission line has an impedance of 4+j ohms per phase. If it supplies a load of 1 MVA at 0.75 power factor, find: (a) the complex power (b) the power loss in the line (c) the voltage at the sending end. *Ans. S=0.75+j0.66 MVA, PL=25.14 kW and VS=4.492∠ − 1.912°kV Use four decimal places.arrow_forward
- Three triphasic loads associated in parallel are powered by a balanced triphasic source: LOAD 1: 250 kVA, Power Factor (PF) = 0,8 (delayed) LOAD 2: 300 kVA, PF = 0,95 (advanced) LOAD 3: 450 kVA, PF = 1 If the line voltage is 13,8 kV, calculate the line current (in ampère). Suppose the line impedance is zero.arrow_forwardWhen the three identical star-connected coils are supplied with 400 V, 50 Hz, 3-phase supply, the 1-phase wattmeter whose current coil is connected in line R and pressure coil across the phase Rand neutral reads 6 kW and the ammeter connected in R-phase reads 30 Amp. Assuming RYB phase sequence find: (i) the power factor, of the load, (ii) resistance and reactance of the coil (iii) reactive power of 3-phase load and (iv) Apparent Power Power Factor, of the Load Reactance Resistance Reactive Power Apparent Powerarrow_forwardA 530 kV, three phase transmission line with a 350 km length. The series impedance Z =(0.11+j0.72) Ω/ph/km and shunt admittance y = (j73 x e(-7)) S/ph/km. Evaluate the equivalent π-model and T-model parameters.arrow_forward
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