1.8 In the systems shown in Figure 1.21a and b, it is desired to achieve overlap between the zones of protection for the bus and the transmission line. Show how this may be achieved through the connection of CTs to the appropriate protection systems. Introduction to Protective Relaying 23

1.8 In the systems shown in Figure 1.21a and b, it is desired to achieve overlap between the zones of protection for the bus and the transmission line. Show how this may be achieved through the connection of CTs to the appropriate protection systems. Introduction to Protective Relaying 23

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 9.54P

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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.
Equipment ratings for the four-bus power system shown in Figure 7.14 are as follows: Generator G1: 500 MVA, 13.8 kV, X=0.20 per unit Generator G2: 750 MVA, 18 kV, X=0.18 per unit Generator G3: 1000 MVA, 20 kV, X=0.17 per unit Transformer T1: 500 MVA, 13.8/500YkV,X=0.12 per unit Transformer T2: 750 MVA, 18/500YkV,X=0.10 per unit Transformer T3: 1000Â MVA, 20/500YkV,X=0.10 per unit A three-phase short circuit occurs at bus 1, where the prefault voltage is 525 kV. Prefault load current is neglected. Draw the positive-sequence reactance diagram in per unit on a 1000-MVA, 20-kV base in the zone of generator G3. Determine (a) the ThĂ©venin reactance in per unit at the fault, (b) the subtransient fault current in per unit and in kA rms, and (c) contributions to the fault current from generator G1 and from line 1-2.
In a 7-bus system, the double line fault is occurred at bus -5. During fault the positive sequence potential difference between the bus-4 and bus-1is found to be 0.0175. what is the line impedance which is connected between bus-4 and bus-1 if the current flowing through transmission line is -j 0.148? Select one: O a. -jo.182 O b. +j0.1182 O c. -jo.1182 O d. +j0.182
Problem 5 Consider the system shown in the single-line diagram of Figure (3). All reactances are shown in per unit to the same base. Assume that the voltage at both sources is 1 p.u. a- Find the fault current due to a bolted- three-phase short circuit at bus 3. b- Find the fault current supplied by each generator and the voltage at each of the buses I and 2 under fault conditions. 0.04 p.u. 0.2 p.u. 0.06 p.u. 0.2 p.u. 0.25 p.u. G, 0.2 p.u. 0.2 p.u. 0.06 p.u. 0.06 р.и. 3 0.25 p.u. 0.25 p.u. G, Figure (3) Single-line diagram for Problem 5 ele
Consider the system shown in the single-line diagram of Figure (3). All reactances are shown in per unit to the same base. Assume that the voltage at both sources is 1 p.u. a Find the fault current due to a bolted- three-phase short circuit at bus 3 b- Find the fault current supplied by each generator and the voltage at each of the buses 1 and 2 under fault conditions 0.06 p.u. 0.2 p.u. 0.04 p.u. 0.25 p.u. 0.2 p.u. 0.2 p.. 0.2 p.u. 0.06 p.u. 0.25 p.u. Figure (3) Single-line diagram ele ver ele 888 ele 0.06 p.u. 0.25 p.u.
b) 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 LI. The total length 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 at the fault point F is measured to be 6.106 kA. G1 G1 G2 i) G2 T1 T2 T3 L1 11) 2 Rated voltage (kV) 20 20 20/33 20/33 33/11 11 T1 ΔΕ T2 T3 Figure Q2.1 Table Q2.1 Zero sequence reactance Xo (p.u.) 0.20 0.15 0.12 0.20 0.20 1.20 Positive sequence reactance X₁ (p.u.) 0.30 0.25 0.12 0.20 0.20 0.50 UNIVERSITY OF LIVERPOOL L1 (l-d) 5 Negative sequence reactance X₂ (p.u.) 0.35 0.30 0.12 0.20 0.20 0.50 Determine the zero, positive,…
A single-line diagram of a four-bus system is shown in fiugre. Equipment ratings and per-unit reactances are given as follows.Machines 1 and 2: 100 MVA 20 kV; X1= X2 = 0.2; X0= 0.04 Xn= 0.05 Transformers T1 and T2: 100 MVA 20Y/345Y kV; X1 = X2 = X0 = 0.08. On a base of 100 MVA and 345 kV in the zone of the transmission line, the series reactances of the transmission line are X1 = X2 = 0.15 and X0=0.5 per unit. (a) Determine the bus impedance matrix for each of the three sequence networks. (b) Assume the system to be operating at nominal system voltage without prefault currents when a bolted single-line-toground fault occurs on phase A at bus 3. Compute the fault current, the current out of phase C of machine 2 during the fault, and the line-toground voltages at the terminals of machine 2 during the fault. Total detailed answer is needed. The figure is attached.
The system values are given below. The bus 1 voltage after fault = 1.5 p.u The bus 2 voltage after fault = 1.2 p.u The line admittance between bus 1 and bus 2 (Y12 ) is = 0.8 p.u The post fault current current flow between bus 1 and 2 is ..............
b) A bolted line-to-line fault at bus 2. c) A bolted double line-to-ground fault at bus 2.
As shown in Figure 1, a synchronous generator and motor are rated 100 MVA, 13.8 kV.??"=0.2per unit, ??"=0.15per unit, and ??=0.305per unit. The synchronous generator is operating at 100 MVA, 0.95 p.f. lagging and at 1.05 per unit voltage when a three-phase short circuit occurs atbus 2. Please use the direct method to calculate the per-unit values of (a)subtransient generator current (??"); (b)subtransient motor current (??"); and (c)subtransient fault current (??). Please use the superposition method to calculate the per-unit values of (d)subtransient generator current (??"); (e)subtransient motor current (??"); and (f)subtransient fault current (??).
Figure below shows the single-line diagram of three-bus power system with generation at bus 1 and bus 3. The voltage at bus 1 is V₁ = 1.025/0° per unit. The voltage magnitude at bus 3 is fixed at 1.05 per unit with a real power generation of 250 MW. The scheduled load on bus 2 is marked on the diagram. Line impedances are marked in per unit on a 100 MVA base. Line resistances and line charging susceptances are neglected. By using Gauss-Seidel method and initial estimates of V₂(0) = 1.020° and V3(0) = 1.0520°, determine V₂ and V3. Perform calculation for one iteration. V₁ = 1.025/0° j0.1 Slack Bus j0.2 j0.4 j0.2 3 j0.1 250 MW 150 Mvar |V3|=1.05 P3 = 250 MW
QUESTION-1: In the radial network shown in the figure below, bus 1 voltage is 1.05 pu. Calculate: a) Current for a 3-phase to ground fault at bus 3. b) Current for a 3-phase to ground fault at bus 5. 1 2 3 4 5 6 j0.2 j1.0 j1.3I j1.7 1.0520 j0.6 j0.4