QI. The figure below shows a one line diagram of a three-phase power network in which a load of 1.5 MV at a lagging power factor of 0.9 is supplied from a 33 kV/11 kV substation via a three-phase overhead line circuit. The impedance of the transmission circuit (0.2+j1.2)Q per phase, as shown. The voltage at the 33kV bus in the substation is maintained at 33.6 kV. Calculate (1) the voltage at the 11 kV load bus, (i) the current in the 11 kV transmission line, and (iii) the power and reactive power flows at the substation 33 kV bus.

QI. The figure below shows a one line diagram of a three-phase power network in which a load of 1.5 MV at a lagging power factor of 0.9 is supplied from a 33 kV/11 kV substation via a three-phase overhead line circuit. The impedance of the transmission circuit (0.2+j1.2)Q per phase, as shown. The voltage at the 33kV bus in the substation is maintained at 33.6 kV. Calculate (1) the voltage at the 11 kV load bus, (i) the current in the 11 kV transmission line, and (iii) the power and reactive power flows at the substation 33 kV bus.

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 3.23P: Figure 3.32 shows the oneline diagram of a three-phase power system. By selecting a common base of...

See similar textbooks

Similar questions

A three-phase line, which has an impedance of (2+j4) per phase, feeds two balanced three-phase loads that are connected in parallel. One of the loads is Y-connected with an impedance of (30+j40) per phase, and the other is -connected with an impedance of (60j45) per phase. The line is energized at the sending end from a 60-Hz, three-phase, balanced voltage source of 1203V (rms. line-to-line). Determine (a) the current, real power. and reactive power delivered by the sending-end source: (b) the line-to-line voltage at the load: (C) the current per phase in each load: and (d) the total three-phase real and reactive powers absorbed by each load and by the line. Check that the total three- phase complex power delivered by the source equals the total three-phase power absorbed by the line and loads.
A balanced three-phase load is connected to a 4.16-kV, three-phase, fourwire, grounded-wye dedicated distribution feeder. The load can be mode led by an impedance of ZL=(4.7+j9)/phase, wye-connected. The impedance of the phase conductors is (0.3+j1). Determine the following by using the phase A to neutral voltage as a reference and assume positive phase sequence: (a) Line currents for phases A, B, and C. (b) Line-to-neutral voltages for all three phases at the load. (c) Apparent. active, and reactive power dissipated per phase, and for all three phases in the load. (d) Active power losses per phase and for all three phases in the phase conductors.
A Y-connected load bank with a three-phase rating of 500 kVA and 2300 V consists of three identical resistors of 10.58. The load bank has the following applied voltages: Vab=184082.8,Vbc=276041.4, and Vca=2300180V. Determine the symmetrical components of (a) the line-to-line voltages Vab0,Vab1, and Vab2, (b) the line-to-neutral voltages and Van0,Van1, and Van2, (c) and the line currents Ia0,Ia1, and Ia2. (Note that the absence of a neutral connection means that zero-sequence currents are not present.)
A 40-km, 220-kV, 60-Hz, three-phase overhead transmission line has a per-phase resistance of 0.15/km, a per-phase inductance of 1.3263 mH/km, and negligible shunt capacitance. Using the short line model, find the sending-end voltage, voltage regulation, sending-end power, and transmission line efficiency when the line is supplying a three-phase load of (a) 381 MVA at 0.8 power factor lagging and at 220 kV and (b) 381 MVA at 0.8 power factor leading and at 220 kV.
PowerWorid Simulator case Problem 3_60 duplicates Example 3.13 except that a resistance term of 0.06 per unit has been added to the transformer and 0.05 per unit to the transmission line. Since the system is no longer lossless, a field showing the real power losses has also been added to the oneline. With the LTC tap fixed at 1.05, plot the real power losses as the phase shift angle is varied from 10 to +10 degrees. What value of phase shift minimizes the system losses?
Figure 3.32 shows the oneline diagram of a three-phase power system. By selecting a common base of 100 MVA and 22 kV on the generator side, draw an impedance diagram showing all impedances including the load impedance in per-unit. The data are given a follows: G:90MVA22kVx=0.18perunitT1:50MVA22/220kVx=0.10perunitT2:40MVA220/11kVx=0.06perunitT3:40MVA22/110kVx=0.064perunitT4:40MVA110/11kVx=0.08perunitM:66.5MVA10.45kVx=0.185perunit Lines I and 2 have series reactances of 48.4 and 65.43, respectively. At bus 4, the three-phase load absorbs 57 MVA at 10.45 kV and 0.6 power factor lagging.
Determine the bus admittance matrix (Ybus) for the three-phase power system shown in Figure 6.23 with input data given in Table 6.11 and partial results in Table 6.12. Assume a three-phase 100 MVA per unit base. TABLE 6.11 Bus input data for Problem 6.20 TABLE 6.12 Partially Completed Bus Admittance Matrix (Ybus) for Problem 6.30
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
With generator conyention, where the current leaves the positive terminal of the circuit element, if P is positive then positive real power is delivered. (a) False (b) True
In the above figure, a single line model of a three-phase power system is given. Base power 50MVA, base voltage 13.8kV according to its value, a) Per-unit values of power system circuit elements according to the given base power and base voltage values. calculate. b) The perunit you calculate by drawing the equivalent impedance circuit for one phase of the power system given in the figure. show on the values.
Assuming the voltage at the utility bus is 13.5 kV and the PV plant supplies 4.8 MW of power at 0.95 power factor lagging. Draw the diagram of the system and determine i) the per-phase voltage and current at the POI at the PV plant ii) the reactive power delivered and that which is lost in the line. Assume the line is modelled as a short line.
Question-2) The parameters of a three-phase transmission line are given as Z = (12.84 + j72, 76)Ω and y = j5, 83x10^-4 mho. At the end of the line, a power of 55 MVA with a power factor of 0.8 is drawn under 132 kV voltage. Accordingly, calculate the line head voltage, active and reactive power values per line, and voltage regulation of the line using the nominal π circuit.7-) Since 55 MVA power is drawn from the end of the line under the conditions mentioned above, calculate the line head voltage (phase-phase voltage) and enter it in the box below. (The value will be entered in kiloVolts. Only the amplitude value of the voltage will be entered. The phase value will NOT be entered!!! Two digits after the comma will be sufficient. )8-) Since 55 MVA power is drawn from the end of the line under the conditions mentioned above, calculate the active power value per line and enter it in the box below. (The value will be entered in MegaWatt. It will be sufficient to take two digits after…