Draw the per-unit impedance diagram of the network shown in Fig. 1, calculated to a common base of 50 MVA. Determine: (i) (ii) The rms fault current (in kA) and the fault level (in MVA) for a three-phase symmetrical short- circuit fault at bus no. 4. The rms fault current (in kA) and the fault level (in MVA) for a three-phase symmetrical short- circuit fault at bus no. 5. T₁ 132kV/33kV 50 MVA X=0.15 pu bus 1 1600 MVA Fault Level bus 2 40 km OHL X=0.4 2/km T3 T₂ 132kV/33kV 50 MVA X=0.15 pu 30 km OHL X=0.42/km bus 3 Cable j2.20 bus 4 33kV/11KV 15 MVA X=0.1 pu bus 5 Cable j2.5 Ω Figure 1 T4 33kV/11KV 12 MVA X=0.12 pu bus 6

Draw the per-unit impedance diagram of the network shown in Fig. 1, calculated to a common base of 50 MVA. Determine: (i) (ii) The rms fault current (in kA) and the fault level (in MVA) for a three-phase symmetrical short- circuit fault at bus no. 4. The rms fault current (in kA) and the fault level (in MVA) for a three-phase symmetrical short- circuit fault at bus no. 5. T₁ 132kV/33kV 50 MVA X=0.15 pu bus 1 1600 MVA Fault Level bus 2 40 km OHL X=0.4 2/km T3 T₂ 132kV/33kV 50 MVA X=0.15 pu 30 km OHL X=0.42/km bus 3 Cable j2.20 bus 4 33kV/11KV 15 MVA X=0.1 pu bus 5 Cable j2.5 Ω Figure 1 T4 33kV/11KV 12 MVA X=0.12 pu bus 6

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

Chapter7: Symmetrical Faults

Section: Chapter Questions

Problem 7.31P: A three-phase circuit breaker has a 15.5-kV rated maximum voltage, 9.0-kA rated short-circuit...

See similar textbooks

Similar questions

Even though the fault current is not symmetrical and not strictly periodic, the rms asymmetrical fault current is computed as the rms ac fault current times an asymmetry factor, which is a function of _______.
A three-phase circuit breaker has a 15.5-kV rated maximum voltage, 9.0-kA rated short-circuit current, and a 2.50-rated voltage range factor. (a) Determine the symmetrical interrupting capability at 10-kV and 5-kV operating voltages. (b) Can this breaker be safely installed at a three-phase bus where the symmetrical fault current is 10 kA, the operating voltage is 13.8 k V, and the (X/R) ratio is 12?
Draw the per-unit impedance diagram of the network shown in Fig. 1, calculated to a common base of 100 MVA. Determine: (i) (ii) The rms fault current (in kA) and the fault level (in MVA) for a three-phase symmetrical short- circuit fault at bus no. 6. The rms fault current (in kA) and the fault level (in MVA) for a three-phase symmetrical short- circuit fault at bus no. 2. T₁ 132kV/33kV 80 MVA X-0.12 pu bus 2 Load 30 km X+0,4 82/km bus 4 T₁ 33kV/11kV 12 MVA X-0.08 pu bus 5 Load V bus 1 1800 MVA Fault Level T₂ 132kV/33kV 80 MVA X-0.12 pu Load Load 12 km X 0.24 52/km Figure 1 T₁ 132kV/11kV 60 MVA X-0.1 pu bus 3 20 km X-0.24 02/km Load bus 6
Q3: - A three-phase fault occurs at bus-1 of the network shown in figure below. The pre-fault voltage is 1.05 PU and the pre-fault load current is neglected. (45%) i) determine the bus impedance matrix. ii) calculate the sub-transient fault current and the contribution to the fault current from the transmission line. T1 T2 T.L j0.1 PU 10.1 PU j0.105 PU G jXdg j0.15 PU M jXdm $0.2 PU
i) An equation for the fault current when a single-line-to-ground fault occurs ii) derive an equation for voltage under a single-line-to- ground fault condition.
The system values are given below. The bus 1 voltage after fault =6.18 p.u. The bus 2 voltage after fault = 2.54 p.u. The line admittance between bus 1 and bus 2 (Y12 ) is =3.25 p.u Then the post fault current flows between bus 1 and 2 is Post fault current l is
Consider the single-line diagram of a power system shown below. The transient reactance of cach part of the system is as shown in table and expressed in p.u. on a common 100 MVA base. A three-phase fault with impedance of 0.16 p. occurs at bus (5). Determine short- circuit capacity (fault level) and short circuit current? Assume the fault voltage at bus (5) equal 112 KV
Q.3 When a line-to-ground fault occurs, the current in faulted phase 'a' is 100A. The zero-sequence current in phase 'c' is r
7.In a line-to-ground fault we can expect that A) There are no currents to ground. B) The voltages at the fault point with respect to ground are zero in all three phases. C) The current in the faulted phase flows to ground. D) There are short circuit currents in all three phases. E) N. A.
Q.3 When a line-to-ground fault occurs, the current in faulted phase 'a' is 100A. The zero-sequence current in phase 'c' is
1 Xine = j0.30 %3D G M X" = j0.15 X" = j0.20 Xiine = j0.30 Xiine = j0.30 %3D 1. Find the Thévenin equivalent looking into bus 3. 2. Calculate the subtransient fault current for a bolted three-phase fault at bus 3. Pre-fault voltage is VF 1Z°, and pre-fault current is neglected. 3. Distribute the fault current between the motor and generator.
Data obtained from a short circuit test on a 132 kV 3-phase circuit breaker with earthed neutral are as follows: -the power factor fault was 0.3. -the recovery voltage was 0.75 of the full line value. -the breaking current was symmetrical. -the restriking transient had a natural frequency of 1600 Hz. Estimate the rate rise of the recovery voltage. Assume that the fault is grounded.