Concept explainers
Let a series RLC network be connected to a source voltage V, drawing a current I.
(a) In terms of the load impedance
(b) Express
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Power System Analysis & Design
- a) You have been employed as an electrical engineer by a power transmission company to design a short transmission line to supply power to a light-industrial load consumer with power system specification as follows, a 3-ph, 60Hz overhead short transmission line with a line-to-line voltage of 23KV at the load end, line impedance of 2.48 ±j6.57Ω/phase, the industry has a cumulative consumption of 9MW with a power factor of 0.85 of lagging as a result of several induction motor on its production lines.As part of the regulations for connections to the grid, you are to provide justifications and values to the Energy Commission of Ghana.(i) What would be value of the voltage between the live conductor and the neutral, between live and live voltages at the industrial premises of the factory?(ii) What load angle would expect the factory to be operating at?arrow_forwardTopic: Maximum Power Transfer Theorem for an AC Circuit A. Calculate the value of the series impedance Zs B. Calculate the value of Cl such that the reactive component of ZL is equal to butopposite in polarity than the reactive component of ZS.arrow_forwardFind the characteristics of the load at the sending end and the efficiency of a three phase transmission line 160 km long delivering 15 MVA load at 110 kv, 50 Hz and 0.9 power factor (lagging) having inductance 1.356 mH/km per phase, capacitance 0.0085 uF/km per phase and resistance 40 ohms. Use nominal T-method Ans. Is = 70.3 20,8° Amp, Vsa.LD= 117.6 29.2 kV, power factor = 0.9898, n = 95.3%arrow_forward
- A HV transmission line having receiving end load is 300MVA, 50 Hz line from poin A to point B. Resistance 0.13 ohm/KM , for 160 KM Inductance XL= 0.4 ohm per kilometer Parallel admittance j318 × 10-6 Power Factor 0.8770, 0.8477 lagging, unity and 0.8770, 0.8477 leading Assume desired voltage at the receiving end of the transmission line is not less than 380kV., if the line is supplying rated voltage and apparent power at various power factors given Estimate : a. Sending end voltages b. Voltage regulation c. Efficiency of the transmission line d. Give a technical explanations on the results obtainedarrow_forwardA ower system is operating at 1000Mw, 132kV, 50Hz, with 0.8 p.f. laging in parallelwith another line at 750OMW, 132kV, 50Hz with 0.707 p.f. lagging. Both are interconnectedat the station and when the compensating device is on, the overall power factor isimproved to 0.9 lagging. Suggest suitable capacitors, shunt and series. Individual loadsand combined load are to improve power factor to 0.9 in all cases.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_forward
- A (medium) single phase transmission line 100 km long has the following constants : Resistance/km = 0·25 Ω ; Reactance/km = 0·8 Ω Susceptance/km = 14 × 10−6 siemens ; Receiving end line voltage = 66,000 V The line is delivering 15 000 kW at 0 8 power factor lagging. Assuming that the total capacitance of the line is localised at the receiving end alone, determine the sending end current Select one: a. 50 A b. 320 A c. 240 A d. None of The abovearrow_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_forwardThe time-domain expressions for three line-to-neutral voltages at the terminals of a Y-connected load are v AN = 169.71 cos (ωt+ 26 ∘ ) V, v BN = 169.71 cos (ωt− 94 ∘ ) V, v CN = 169.71 cos (ωt− 94 ∘ ) V, What are the time-domain expressions for the three line-to-line voltages vAB, vBC, and vCA?arrow_forward
- A transmission line has generalized circuit constants are A=0.93+j0.016,B=20+j140.The load at the receiving end is 60MVA, 50HZ, 0.8 power factor lagging. The voltage at the supply end is 132KV. Caluclate the load voltage and voltage regulation,Use nominal-π approximation.arrow_forwardA 3-phase, 50 Hz overhead transmission line, 100 km long, 110 kV between the lines at the receiving end has the following constants : Resistance per km per phase = 0·153 W Inductance per km per phase = 1·21 mH Capacitance per km per phase = 0·00958 µF The line supplies a load of 20,000 kW at 0·9 power factor lagging. Calculate using nominal p representation, the sending end voltage, current, power factor, regulation, and the efficiency of the line. Neglect leakage.arrow_forwardA 3-phase, 50 Hz overhead transmission line, 100 km long, 110 kV between the lines at the receiving end has the following constants : Resistance per km per phase = 0·153 Ω Inductance per km per phase = 1·21 mH Capacitance per km per phase = 0·00958 μF The line supplies a load of 20,000 kW at 0·9 power factor lagging. Calculate using nominal π representation, the sending end voltage, current, power factor, regulation and the efficiency of the linearrow_forward
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