4.9 Given the system shown in Figure 4.24, calculate the currents in breakers 1, 3 and 5 for a fault at X for the following three conditions: (a) system normal (SIN); (b) line 1-2 open; (c) line 3-4 open. Select and set the appropriate relays from Appendix D for the relays at breakers 1, 3 and 5. Neglect load, and assume breaker 5 needs no coordination. 1 -j1.5- 2 70 v. 3 中 j0.5 5 4 中 j0.8 70 v. Figure 4.24 System diagram for problem 4.9 4.10 You are given that the system shown in Figure 4.25 has a 110/220 kV autotransformer. The positive, and zero-sequence impedances in ohms or percent are as shown in the figure the

4.9 Given the system shown in Figure 4.24, calculate the currents in breakers 1, 3 and 5 for a fault at X for the following three conditions: (a) system normal (SIN); (b) line 1-2 open; (c) line 3-4 open. Select and set the appropriate relays from Appendix D for the relays at breakers 1, 3 and 5. Neglect load, and assume breaker 5 needs no coordination. 1 -j1.5- 2 70 v. 3 中 j0.5 5 4 中 j0.8 70 v. Figure 4.24 System diagram for problem 4.9 4.10 You are given that the system shown in Figure 4.25 has a 110/220 kV autotransformer. The positive, and zero-sequence impedances in ohms or percent are as shown in the figure the

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 3.47P: Consider the oneline diagram shown in Figure 3.40. The three-phase transformer bank is made up of...

See similar textbooks

Similar questions

Consider the oneline diagram shown in Figure 3.40. The three-phase transformer bank is made up of three identical single-phase transformers, each specified by X1=0.24 (on the low-voltage side), negligible resistance and magnetizing current, and turns ratio =N2/N1=10. The transformer bank is delivering 100 MW at 0.8 p.f. lagging to a substation bus whose voltage is 230 kV. (a) Determine the primary current magnitude, primary voltage (line-to-line) magnitude, and the three-phase complex power supplied by the generator. Choose the line-to-neutral voltage at the bus, Va as the reference Account for the phase shift, and assume positive-sequence operation. (b) Find the phase shift between the primary and secondary voltages.
Show me how is solution will be if fualt happened before transformers or in one of generator
Does winding geometry in transformers (winding method) have an effect on zero sequence impedance values in transformers?
The one-line diagram of a simple power system is shown in Figure below. The neutral of each generator is grounded through a current-limiting reactor of 0.25/3 per unit on a 100-MVA base. The system data expressed in per unit on a common 100-MVA base is tabulated below. The generators are running on no-load at their rated voltage and rated frequency with their emfs in phase. G Stark Item Base MVA Voltage Rating X' x² 20 kV 20 kV 20/220 kV 20/220 kV 100 0.05 0.15 0.15 0.10 0.10 220 kV 0.125 0.125 0.30 0.15 0.25 025 0.7125 0.15 100 100 0.15 0.05 0.10 0.10 0.10 100 0.10 100 100 Lu La 220 kV 0.15 220 kV 0.35 100 A balanced three-phase fault at bus 3 through a fault impedance Zf= jo.I per unit. The magnitude of the fault current in amperes in phase b for this fault is: Select one: A. 345.3 B. 820.1 C. 312500 3888888 产产

A single line diagram of a power system is shown in Figure Q2.1. The neutrals for the generators and transformers are solidly grounded. The motor neutral is grounded through reactance ?? = 0.05 per unit on the motor base. i）Calculate the phase currents in kA following a three-phase fault at busbar 2. ii) Calculate the phase currents in kA when a phase-alpha-to-ground fault occurs at busbar 2.
Q2. The single-line diagram of a simple three-bus power system is shown in Figure-2. Each generator is represented by an emf behind the sub-transient reactance. All impedances are expressed in per unit on a common MVA base. All resistances and shunt capacitances are neglected. The generators are operating on no load at their rated voltage with their emfs in phase. A three-phase fault occurs at bus 3 through a fault impedance of Zf = j0.19 per unit. (i) Using Th'evenin's theorem, obtain the impedance to the point of fault and the fault current in (ii) Determine the bus voltages per unit. ) j0.05 j0.075 j0.75 2 j0.30 j0.45 Figure-2: Single line diagram of the power system network for Q2 3
The single line diagram of a power system is shown in Figure Q2.1 including generator and transformer winding connection and earthing details. The parameters for this system have been calculated on a common 100 MVA base and are given in Table Q2.1. All resistances and shunt susceptances are neglected. This system experiences a single line to ground fault at a point F on line L1. The point F is at a distance d from Bus 4 along the line L1. The total length ?? of the line L1 is 50 km. Note that the location of ?? is not drawn to scale in Figure Q2.1. The fault current at the fault point F is measured to be 6.106 kA. i) Determine the zero, positive, and negative sequence Thevenin equivalent impedances as seen at the fault point F. These should be evaluated in per unit and shown as a function of d.ii) Use the sequence impedances calculated in part (i) to determine the distance d of the fault (in km) from Bus 4.
1. FIGURE 52 shows the one-line diagram of a simple three-bus power system with generation at bus I. The voltage at bus l is V1 = 1.0L0° per unit. The scheduled loads on buses 2 and 3 are marked on the diagram. Line impedances are marked in per unit on a 100 MVA base. For the purpose of hand calculations, line resistances and line charging susceptances are neglected a) Using Gauss-Seidel method and initial estimates of Va 0)-1.0+)0 and V o)- ( 1.0 +j0, determine V2 and V3. Perform two iterations (b) If after several iterations the bus voltages converge to V20.90-j0.10 pu 0.95-70.05 pu determine the line flows and line losses and the slack bus real and reactive power. 2 400 MW 320 Mvar Slack 0.0125 0.05 300 MW 270 Mvar FIGURE 52
4. Why adopt open delta test instead of direct loading test to calculate the efficiency of large transformers?
What are FACTS (Flexible Alternating Current Transmission Systems) devices, and how do they enhance power system control?
1 Example-1: In a single-loop distribution system shown in the figure consider the generator to be of infinite short-circuitcapacity and with a voltage of 1.0 pu. Determine the fault currents flowing in circuit breakers B1, B2 and Bz for a Three phase to ground fault in the midde of line 4-5 when: a) Both transformers, T, and T2 are in service b) Only T1 is in service 1 T1 2 From То Impedance 0.0 + j0.01(T,) 0.0 + j0.01(T2) 0.0 + j0.08 0.02 + j0.05 0.01 + j0.03 0.0 + j0.06 0.01 + j0.09 0.01 + j0.09 1 B. B2 Вз -머 3 4 4 T2 7 6 5 6. 7 7
The single line diagram of a power system is shown in Figure Q2.1 includinggenerator and transformer winding connection and earthing details. The parametersfor this system have been calculated on a common 100 MVA base and are given inTable Q2.1. All resistances and shunt susceptances are neglected. This systemexperiences a single line to ground fault at a point F on line L1. The point F is at adistance d from Bus 4 along the line L1. The total length l of the line L1 is 50 km.Note that the location of d is not drawn to scale in Figure Q2.1. The fault current atthe fault point F is measured to be 6.106 kA. i) Determine the zero, positive, and negative sequence Thevenin equivalentimpedances as seen at the fault point F. These should be evaluated in per unitand shown as a function of d.ii) Use the sequence impedances calculated in part (i) to determine the distance dof the fault (in km) from Bus 4. It's different from the answer, please don't send it