A radial feeder ABC is sectionlized into parts AB and BC. Part AB near the source, has a relay R1. and part BC at the far end has a relay R2. R1 is set on 125 % and R₂ is set on 150 % plug setting. CT ratio for both the relays is 500/1. For discrimination. a time grading margin of 0.5 sec is taken. Determine the time of operation of both the relays when a fault occurs at the end of the feeder section BC. The fault current is 5000 A. TMS of R1 is 0.2. Determine TMS of R2. Both the relays follow the characteristics given below.

A radial feeder ABC is sectionlized into parts AB and BC. Part AB near the source, has a relay R1. and part BC at the far end has a relay R2. R1 is set on 125 % and R₂ is set on 150 % plug setting. CT ratio for both the relays is 500/1. For discrimination. a time grading margin of 0.5 sec is taken. Determine the time of operation of both the relays when a fault occurs at the end of the feeder section BC. The fault current is 5000 A. TMS of R1 is 0.2. Determine TMS of R2. Both the relays follow the characteristics given below.

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

See similar textbooks

Similar questions

A) In the left figure, the transmission line is represented by inductance = 0.22/km, and the fault current IF = 2.82 < 45° kA, VA= 20 < 90° kV Then: 1) Find the value of RF 2) Determine the Z fault on the right figure. 3) Determine the fault distance from CT 4) What is the type of relay used in following diagram? 5) Check if this relay can detect this fault. 6) Suggest solution if this relay can't detect the fault. Loading Area 16 7 8 9 10 Zeaut B Fault Area F1 Re ZLond Relay
A transformer circuit breaker is equipped with 500/5 A C.T.s connected to a induction type over current relay. The relays have 125% plug setting and 0.4 time setting. If a 3- o fault current of 7500 A flows from C.T. and relays follow characterstics given by below table at (TMS = 1), then operating time of the relay will be PSM Operating time(sec.) 4 8 12 16 5 3 2.8 2.2
If an unsymmetrical fault occurs on phase C of a transmission line, what would make the fault symmetrical? A. if phase C of the transmission line opens B. If phases A and B become faulted C. If two different faults occur on phas a and b
Discuss the importance of relays in power system protection and fault detection.
Match the following. Fault clearing time Choose. Choose. Relay Sum of CB Opening time and arcing time High speed circuit breakers Tripping times between three and eight cycles Tripping times between three to eight minutes Monitoring device which gives instructions to Circuit breaker Making and breaking device tripping time between one second to eight second Sum of relay pickup time, CB Opening time and arcing time Sum of Relay pickup time and arcing time Circuit Breaker
A radial system shown in figure below is fed from a supply of 220 Volt. All impedance values are referred to 220V side (3 phase). When a three phase fault occurs at E, relay D will operate with 0.4 second longer than relay at E. Determine TSM (Time Setting Multiple) at A, B C and D by taking discrimination time (DT) equal to 0.4 second, and TSM at C is already set equal to 0.05. The protection data is as given in figure while IDMT relay characteristic is as in table.
Q2: A generator supplies motor through a star-delta transformer. The generator is connected to the star side of transformer. A fault occurs between the motor terminals and the transformer. The symmetrical components of the rubtransient current in motor and transformer toward the fault as table below laz(per unit) j2.0 lao(per unit) j3.0 las (per unit) Motof toward the fault Transformer toward the -0.8-j2.6 0.8-j0.4 j1.0 fault Assume X-X,- X2 for both the motor and gencrator. Describe the type of fault. Find (a) the prefault current, in line a, (b) the subtransient fault current in per unit and (c) the subtransient current in each phase of the gencrator in per unit. Gén. Motor
Discussion : 1- What are the advantages and disadvantages of this test ? 2- Why it's imporctical carry out actual load test on large rating transformers ? 3- What will be the current in the primary windings? i) When secondaries are not loaded ? ii) When secondaries are loaded ?
Explain the importance of fault analysis in power systems and the role of protective relays.
The current rating of an over current relay is 5 A. The relay has a plug setting of 150 % and time multiplier setting of 0.4. The CT ratio is 400/5. Determine the operating time of the relay for a fault current of 6000 A. At TMS = 1, operating time at various PSM are given in following table : PSM Operating time In seconds 2 4 10 5 5 8 10 20 4 3 2.8 2.4
Describe the principles of fault injection testing and its importance in evaluating system resilience under adverse conditions.
Below figure shows a single line diagram of a portion of a radial distribution system. The PS of Relay 3 (R3) is 75% of CT Secondary and time setting multiplier is given 0.1. The CT ratio is given with each relay and fault current of each in bus bar is given in figure. PS for R1 and R2 is set at 100%. Determine the operating time of each relay. Consider 0.25 sec for time coordination time interval. R30.297 R2 = .475 R1 = .654 A B C ID 1000/1 R₁ 10,000 A 800/1 800/1 M R₂ R₁ 8000 A 6000 A 5000 A