The 13.2 kV 50-Hz generator feeds a load over a line with (Zload) impedance Zline. Load is 80on + j500N and impedance of the line is 20 + j300 a) If the generator is directly connected to the load as given in (a), what will be the line losses? b) If the generator is connected to the load using step-up and step-down transformers as given in (b), what will be the line losses? c) How much is the increase in efficiency compared to (a) from (b)? Zline (a) 1:10 10:1 Zline Tr1 Tr2 (b) Zload Zload

The 13.2 kV 50-Hz generator feeds a load over a line with (Zload) impedance Zline. Load is 80on + j500N and impedance of the line is 20 + j300 a) If the generator is directly connected to the load as given in (a), what will be the line losses? b) If the generator is connected to the load using step-up and step-down transformers as given in (b), what will be the line losses? c) How much is the increase in efficiency compared to (a) from (b)? Zline (a) 1:10 10:1 Zline Tr1 Tr2 (b) Zload Zload

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

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.31P

See similar textbooks

Similar questions

in distribution transformers; What is 30 degrees phase shift in delta-star connection? What are the disadvantages? (can you explain with drawing?)
The reactance of a generator is given as 0.25 per-unit based on the generator’s of 18 kV, 500 MVA. Find its per-unit reactance on a base of 20 kV, 100 MVA. a. 0.0505 b. 0.0605 c. 0.0405 d. 0.0606
Two alternators rated 400 MW and 600 MW are operating in parallel. The droopcharacteristics of their governors are 3% and 4% respectively from no loadto full load. Assuming that the alternators are operating at 50 Hz at noload, how would a load of 1000 MW be shared between them? What will be thesystem frequency at this load?
Three zones of a single-phase circuit are identified in the figure with a generator voltage specification of 240 V. The zones are connected by the transformers T1 and T2, whose ratings are shown below.Using base values of 30 kVA and 240 volts in zone 1, draw the pu circuit and determine the pu impedance and pu source voltage. Then calculate the load current in pu and in amperes.*Round the final answer to four decimal places, polar form, and label it with the correct units.
Q2) A 13.2-kV single-phase generator supplies power to a load through a transmission line. The load's impedance is Ztoad 500 236.87° ohm , and the transmission line's impedance is Zine = 60 253.1° ohm. To reduce transmission line losses to 0.0103 of its losses without using the transformers design and use two transformers T1 between the generator and the transmission line and T2 between the transmission line and the load.
What is the main direct cause of reactive power in AC system?A. Resistance of transmission linesB. Inductance and capacitance in the loadsC. Ideal transformer connected in the systemD. Power produced by generator
Connect three single-phase transformers in Y-Y, with subtractive polarity, so that the line-to-line voltages on the primary are 30 degrees delayed to their respective line-to-line voltages on the secondary. It should show each step that is needed to make this connection (example: the phasor diagram) and should show the final connection of the three transformers including the polarity markings. Assume phase A on the primary is terminal "H1".
In the system shown in Figure 1, the transformers are connected star-star with both star points grounded and the generators are connected in star with thier star points grounded. The system base is 15 MVA. The transformers all have reactances of 0.04 p.u. on this 15 MVA base. The reactances of all other elements are given in Table 1 (in 2) and the voltage levels are given in Table 2. p.u. G1 p.u. T1 jö Per-Unit Convert all values to p.u. on a 15 MVA base. Xa= p.u. Xc₂= XL = V BABE G1 2 X 9 T3 Figure 1: A section of the distribution system T1 L Table 1: Sequence reactances (2) 3 G1 L G2 0.3 0.59 0.01 4 L 9/10 10 Fault Voltage What is the voltage at bus 3 (in Volts) after the fault has occurred? Vp= V T2 5 T2 34 10/4 Table 2: Voltage bases (kV) G2 4 T3 10/9 | G2 Fault Current A three-phase fault with a fault reactance of 0.01 p.u. occurs at bus 3. Calculate the fault current flowing at the fault point in KA. Ip=-j KA So
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?
2- Draw and explain the phasor diagram for two transformers in parallel.
Q2) A 13.2-kV single-phase generator supplies power to a load through a transmission line. The load's impedance is Zload = 500 236.87° ohm, and the transmission line's impedance is Zline = 60 253.1° ohm. To reduce transmission line losses to 0.0103 of its losses without using the transformers design and use two transformers T1 between the generator and the transmission line and T2 between the transmission line and the load.
Two 7970-V:230-V single-phase transformers with impedance with respect to their secondaries of 1.5 + j3 and 2 + j4.5 ohms are connected in parallel to a 7900-V source. Their secondaries are supplying a common load of 30 + j40 ohms. A. What is the magnitude of the voltage across the load in volts? (2 decimal places) B. What is the magnitude of the total current supplied by the 7900-V source in amperes? (3 decimal places) C. What is the efficiency of the parallel transformers combined in percent? ( 1 decimal place)