A transformer, circuit breaker is equipped with 500/5 A CTS connected to a induction type over current relay. The relays have 125% Plug setting and 0.4 time multiplier setting. If A 30 fault current of 7500 A flow, from C T. and relays. Follow characteristics given by below. Table at (TMS = 1), then PSM Operating Time (sec) 4 8 12 16 5 3 2.8 2.2

A transformer, circuit breaker is equipped with 500/5 A CTS connected to a induction type over current relay. The relays have 125% Plug setting and 0.4 time multiplier setting. If A 30 fault current of 7500 A flow, from C T. and relays. Follow characteristics given by below. Table at (TMS = 1), then PSM Operating Time (sec) 4 8 12 16 5 3 2.8 2.2

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 7.1MCQ

See similar textbooks

Similar questions

complet The equivalent reactance of the double circuit line under post fault condition is................than fault condition.
What is the difference between OLTC and transformers
b) A fault occurs at bus 3 of the network shown in Figure Q4. Pre-fault nodal voltages throughout the network are of 1 p.u. and the impedance of the electric arc is neglected. Sequence impedance parameters of the generator, transmission lines, transformer and load are given in Figure Q4. V₁ = 120° p.u. V₂ = 120° p.u. V₂ = 1/0° p.u. V₂= 120° p.u. jXj0.1 p.u. JX2) 0.1 p.u. jX0j0.15 p.u. jXn-j0.2 p.u. 1 JX(2)-j0.2 p.u. 2 jX)=j0.25 p.u. JX20-10.15 p.u. jXa(z)-j0.2 p.u. 4 jX2(0)=j0.2 p.u. jXT(1) j0.1 p.u. jXT(2)=j0.15 p.u. jXT(0)=j0.1 p.u. Figure Q4. Circuit for problem 4b). = jXj0.1 p.u. j0.1 p.u. - JX(2) JXL(0) 10.1 p.u. = (i) Assuming a balanced excitation, draw the positive, negative and zero sequence Thévenin equivalent circuits as seen from bus 3. (ii) Determine the positive sequence fault current for the case when a three- phase-to-ground fault occurs at bus 3 of the network. (iii) Determine the short-circuit fault current for the case when a one-phase- to-ground fault occurs at bus…
What is the purpose of phase failure relays?
Describe the concept of fault analysis in power systems. What types of faults can occur, and how are they mitigated?
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
4. What do you mean by transformer connection Ydl and Dy11?
Problem #2: A transformer is fed from a 100 MVA, 18 kV generator via a 5-cycle breaker. Generator reactance are: X"F18%, X'=25%, Xe=120%. A three-phase fault occurs at the load side of the breaker when the transformer was unloaded. Find: A)The sustained short circuit current in the breaker. B) Initial symmetrical rms current in the breaker. C) Maximum de short circuit component in the breaker.
Explain the concept of fault analysis in power systems. What are the different types of faults, and how are they analyzed and mitigated?
Discuss the concept of fault analysis in power systems. What are the types of faults and their effects?
8. A three-phase 50 Hz, 200 MVA, 220/66 kV transformer has a clock number of Yd11. The transformer winding resistances are 2.0 N and 0.12 A, and the leakage reactances are 10 0 and 0.6 N for the high voltage side and low voltage side respectively. (a) Sketch the phase voltage phasor diagrams for the high-voltage side and low-voltage side of the transformer and from the phasor diagrams obtain its connection diagram. (b) Calculate the per-unit impedance of the transformer referred to the high-voltage side. (c) Calculate the full-load copper losses of this transformer. (d) Calculate the efficiency of the transformer when it supplies 90% of full-load at a power factor of 0.85 lagging, if the core losses are equal to 3 MW.
iv. The swing equation can be considered mathematically, as a equation due to the v. The main objects of fault analysis are term.