G1 Bus 1 Bus 2 Line Bus 3 T2 Bus4 M1 j402 25 MVA Ye A 13.0 kV Xg1 =10% зо мVA 13.4/69 kV 20 MVA 66/13.2 kV 15 MVA 13.0 kV Xmi =15% 10% 10% e direct-axis subtransient reactances of the synchronous generator and otor are given above in the figure. The fault impedance (ZA) is 15.87 ohm ie generating is operating 25 MVA, 0.95 p.f. lagging, and at 10% above rate Itage when a three-phase fault occurs at bus 1. Determine each three-phase ult

G1 Bus 1 Bus 2 Line Bus 3 T2 Bus4 M1 j402 25 MVA Ye A 13.0 kV Xg1 =10% зо мVA 13.4/69 kV 20 MVA 66/13.2 kV 15 MVA 13.0 kV Xmi =15% 10% 10% e direct-axis subtransient reactances of the synchronous generator and otor are given above in the figure. The fault impedance (ZA) is 15.87 ohm ie generating is operating 25 MVA, 0.95 p.f. lagging, and at 10% above rate Itage when a three-phase fault occurs at bus 1. Determine each three-phase ult

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

Chapter9: Unsymmetrical Faults

Section: Chapter Questions

Problem 9.1P

See similar textbooks

Similar questions

Equipment ratings for the five-bus power system shown in Figure 7.15 are as follows: Generator G1:Â Â Â Â 50Â MVA,Â 12kV,Â X=0.2 per unit Generator G2: 100Â MVA, 15 kV, X=0.2 per unit Transformer T1: 50 MVA, 10 kV Y/138kVY,X=0.10 per unit Transformer T2: 100 MVA, 15 kV /138kVY,X=0.10 per unit Each 138-kV line: X1=40 A three-phase short circuit occurs at bus 5, where the prefault voltage is 15 kV. Prefault load current is neglected. (a) Draw the positive-sequence reactance diagram in unit on a 100-MVA, 15-kV base in the zone of generator G2. Determine (b) the ThĂ©venin equivalent at the fault, (c) the subtransient fault current in per unit and in kA rms, and (d) contributions to the fault from generator G2 and from transformer T2.
With the same transformer banks as in Problem 3.47, Figure 3.41 shows the oneline diagram of a generator, a step-up transformer bank, a transmission line, a stepown transformer bank, and an impedan load. The generator terminal voltage is 15 kV (line-to-line). (a) Draw the per-phase equivalent circuit, aounting for phase shifts for positive-sequence operation. (b) By choosing the line-to-neutral generator terminal voltage as the reference, determine the magnitudes of the generator current, transmiss ion-line current, load current, and line-to-line load voltage. Also, find the three-phase complex power delivered to the load.
What happens to a synchronous machine’s neutral impedance when it is converted to symmetrical components? a. It does not appear in symmetrical components. b. 3Zn is added to the zero-sequence circuit. c. Zn/3 is added to the zero-sequence circuit.
The one line diagram of a simple three bus power system is shown in figure Each generator is represented by an emf behind the subtraction 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. Athree phase fault occurs at bus 3 through a fault impedance of Zf=j0.19 per unit. a-using thevenin’s theorem obtain the impedance to the point of fault and the fault current in per unit. b-determine the bus voltage and line currents during fault
Problem 2 Two shunt generators A and B operate in parallel and their load characteristics maybe taken as straight lines. The voltage falls from 240V at no load to 200V at200A, while that of B falls from 245V at no load to 220V at 150A. Determine the bus bar voltage when supplying 66.9KW load. How is the load divided between two generators?
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.
A (500 MW) generator is delivering (180 MW) to infinite bus through the unit transformer and double transmission lines. The per-unit ractances for a given system are shown in figure below andall the reactances are based on (100 MW) base. The generator emf is ( 1.35p .u.). Determine whether the system remains stable after one circuit of the lines is switch off?
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.
Q1. The following figure shows the differential protection of power transformers with specifications of 20 MVA, 66/11 KV.Trans is No load.If a two-phase short circuit occurs between phases b and ¢ It is desirable to calculate the currents passing through the CTs and relays R, Y, B. If these relays are three overcurrent relays with inverse characteristics as T=0.63 / log (I / Iset) and Iset =0.5A.Will this work for short circuit relays? If yes, which relay works faster and at what time?
Consider a three-phase 13.8 kV, 25-MVA, Y-connected synchronous generator whose three-phase short-circuit losses are 52.8 kW at rated armature current. Calculate its armature resistance per phase. a-0.16 Ohm b-0.016 Ohm -1.016 Ohm: d- 603.2 A e-0.7 Ohm.
The one-line diagram of a simple power system is shown in Figure 9.20. Each generator is represented by an an emf behind the transient reactance. All impedances are expressed in per unit on a common MVA base. All resistance and shunt capacitances are neglected. The generation are operating on no load at their rated voltage with their emfs in phase. A three-phase fault occurs at bus 1 through a fault impedance of Z_f = j0.08 per unit. Using Thevenin's theorem obtain the impedance to the point of fault and the fault current in per unit. Determine the bus voltages and line currents during fault.
The symmetrical fault occurs in the terminals of the synchronous generator. Find the direct axis transient reactance of the synchronous generator under the transient period for the data given below, Leakage reactance(Xl)= 4.2 ohm, Armature reactance (Xad)= 8.8 ohm and field reactance (Xf)=2.6 ohm. a-8.60 b-5.50 c-6.21 d-2.01