TABLE OF CONTENTS To assist in the understanding of the solutions, the original diagrams included in the Exercises have been redrawn, and where necessary, additional diagrams are included to illustrate the calculations.
| 1. | For the power system arrangement shown in Figure 1.6, complete Table 1.2, taking into account the operation of the circuit breakers as shown for each fault case. Please note that, as in Example 1.1, some of the circuit breakers that operated may have done so unnecessarily.
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Answers
| 1. | Fault F 1 was correctly cleared by the tripping of breakers 2 and 5; therefore breakers 3 and 4 operated incorrectly and should be entered in column 3. For fault F 2, breakers 25 and 26 should have opened to clear the fault. These are not shown in column 2; therefore they should be inserted in column 3 as having mal-operated. Breakers 21 and 22 should have been tripped by back-up protection and shown in column 5. Breakers 23 and 24 should not have tripped as the flow of fault current was against their directional settings and these two breakers should be placed in column 3 as having mal-operated. With the failure of breaker 25 to... |
