Q 3) The schematic diagram of a generator supplying two loads through a distribution system is shown below. Load A draws 8kW at a leading pf of 0.8, while load B draws 10kW at a 0.6 lagging pf. The terminal voltage at load B is 215 Vrms. Determine the voltage at the generator as well as the real power P, reactive power Q, and apparent power S, supplied by the generator. Assuming the terminal voltage at load B is the reference phasor and has the zero phase angle, i.e., the phasor of terminal voltage at load B is 21520° Vrms- 0.4 2 J0.8 N 0.40 J0.8 Q Load Load A B

Q 3) The schematic diagram of a generator supplying two loads through a distribution system is shown below. Load A draws 8kW at a leading pf of 0.8, while load B draws 10kW at a 0.6 lagging pf. The terminal voltage at load B is 215 Vrms. Determine the voltage at the generator as well as the real power P, reactive power Q, and apparent power S, supplied by the generator. Assuming the terminal voltage at load B is the reference phasor and has the zero phase angle, i.e., the phasor of terminal voltage at load B is 21520° Vrms- 0.4 2 J0.8 N 0.40 J0.8 Q Load Load A B

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter2: Fundamentals

Section: Chapter Questions

Problem 2.30MCQ: Under balanced operating conditions, consider the three-phase complex power delivered by the...

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Under balanced operating conditions, consider the three-phase complex power delivered by the three-phase source to the three-phase load. Match the following expressions, those on the left to those on the right. (i) Realpower, P3 (a) (3VLLIL)VA (ii) Reactive power, Q3 (b) (3VLLILsin)var (iii) Total apparent power, S3 (c) (3VLLILcos)W (iv) Complex power, S3 (d) P3+jQ3 Note that VLL is the rms line-to-line voltage, IL is the rms line current, and is the power-factor angle.
While the instantaneous electric power delivered by a single-phase generator under balanced steady-state conditions is a function of time havi ng two components of a constant and a double-frequency sinusoid, the total instantaneous electric power delivered by a three-phase generator under balanced steady-state conditions is a constant. (a) True (b) False
Is the power factor in Question 6 a leading or lagging power factor? Explain your answer.
Consider a 3-phase delta induction motor that is operating at 120 Hz. The motor (load) impedance, Z_Δ is given as (9+j12)Ω. The line-to-line voltage at the load is, ?_ab=416 ∠30ºVrms. Let the source be wye-connected, and line impedance be negligible. a) Draw the single-phase wye equivalent circuit and label all known parameters numericallyincluding load voltage. b)Determine the rms phase current phasors for each phase. c) Calculate the complex power consumed by the 3-phase load. d) Determine the capacitance value of each capacitor in a 3-phase delta capacitor bank needed to correct the load to a power-factor of 0.9, lagging.
Consider a 3-phase delta induction motor that is operating at 120 Hz. The motor (load) impedance, Z_Δ is given as (9+j12)Ω. The line-to-line voltage at the load is, ?_ab=416 ∠30ºVrms. Let the source be wye-connected, and line impedance be negligible. b)Determine the rms phase current phasors for each phase. c) Calculate the complex power consumed by the 3-phase load. d) Determine the capacitance value of each capacitor in a 3-phase delta capacitor bank needed to correct the load to a power-factor of 0.9, lagging.
In an energy transmission system with a power value of 100 MVA and a power coefficient of 0.8 reverse (inductive), the generator in a hydroelectric power plant was operated as an over-excited synchronous motor for grid power compensation and was connected to this system as a capacitive load of approximately 40 MVAR. Show the active, reactive and apparent powers on the phasor diagram (power triangle) and calculate the new power factor after the synchronous capacitor is connected.
A circuit is constructed with an AC generator, a resistor, capacitor and inductor as shown. The generator voltage varies in time as ε = Va - Vb = εmsinωt, where εm = 120 V and ω = 429 radians/second. The values for the remaining circuit components are: R = 61 Ω, C = 426 μF. The value for L is unkown. What is known is that the voltage across the generator leads the current in the circuit by φ = 48 degrees. 1) What is t1, the first time after t = 0 when the magnitude of the voltage across the inductor is maximum? 4) What is VL,max, the magnitude of the maximum voltage across the inductor? 5) What is VL = Vb - Vc, the voltage across the inductor, at time t = 0? Note that VL is a signed number.
Consider an ac network with an ideal transformer (with turns ratio of n:1) shown below where ZL=(1+j0) is the load impedance and Zs=(7−j24). Ideal transformer turns ratio n is chosen so that the average power delivered to the load is maximized. Under this scenario, the average power delivered to the load is given by
Suppose two generators supplying a load. Generator-1 has a no-load frequency of 61.5 Hz and a slopesp1 of 1 MW/Hz. Generator-2 has a no-load frequency of 62 Hz and a slope sp2 of 1MW/Hz. The twogenerators are supplying a real load totaling 2.5 MW at 0.8 PF lagging. Draw the resulting systempower-frequency or house-diagrams. Determine (a) at what frequency is the system operating, andhow much power is supplied by each of the generators? (b) if an additional 0.75-MW load wereattached to this power system. What would the new system frequency be, and how much powerwould the each generator supply now? (c) with the system in the configuration described in part (b),what will the system frequency and generators power be if the governor set points on generator-1 areincreased by 0.5 Hz?
S.2) The serial impedance of the 300 km power transmission line is 23 + j75 ohm / phase and the shunt acceptance is j500 microS / phase. A power of 50 MW with a power factor of 0.88 under 220 kV interphase voltage from the end of the power transmission line being shot. Using these data of the energy transmission line, a) Characteristic impedance of the energy transmission line, b) Natural apparent power of the energy transmission line according to the 220 kV interphase operating voltage, c) The values of the line parameters A, B, C and D of the transmission line using hyperbolic functions, d) Calculate the maximum power that the power transmission line can transmit.
Shown are two buses connected via a transmission line. Connected to Bus 1 is a generator(modelled as a voltage source V1), and to Bus 2 is a generator( with Voltage V2) and a load. The line impedance Z = R + jX is not known. Three-phase load is forecasted as 100MW + 60MVar. Generator at Bus 2 is scheduled to deliver 40MW and its excitation is adjusted for the machine to deliver 55 MVar. Voltage at Bus 1 is 241 KV angle 10 deg, while voltage at bus is 230 kV; use V2 as the reference for all angles. 1. What is the current (RMS) in amperes drawn by the load connected to Bus 2? 2. How much real power (in MW) is delivered by the generator connected to Bus 1? 3. What is the total real power loss along the line, in percent of the load? 4. What is the X/R Ratio of the line impedance?
A 13.8-kV, single-phase generator supplies power to a load through a step-up transformer, a transmisson line, and a step-down transformer as in the figure above. Assume the transformers are ideal. The load’s impedance is Zload = 200 L 36.870, and the transmission line’s impedance is Zline = 70 L 600 What are the transmision losses in Watts?