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Ian_Brooks
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Not a homework question, Just trying to get more information about it. Its hard to find a textbook or a site that explains this well.
thanks
thanks
subtech said:It should be remembered that three phase fault current is limited only by the the reactance of the source and perhaps additionally the R and X of any conductors between the source and the fault point. The closer the fault to the source, the higher one should expect the fault current magnitudes to be.
If your interest in power system faults is strong, try searching for books by Paul M. Anderson, J. Lewis Blackburn, and Walt Elmore.
(there are others as well, these just came quickly to mind.)
Three phase balanced faults occur when there is a short circuit between all three phases of a three phase power system. This results in a direct path for current to flow, which leads to a high fault current. The high fault current is caused by the low impedance of the fault path, as the resistance is almost zero. Therefore, a large amount of current can flow through the fault, resulting in high fault currents.
Unlike single phase faults, which occur when there is a short circuit on only one phase of a three phase system, 3 phase balanced faults involve all three phases. This means that the fault path has a lower impedance, resulting in higher fault currents. 3 phase balanced faults also differ from unbalanced faults, which occur when the impedance of each phase is different, resulting in an uneven flow of current.
The high fault currents can cause damage to equipment and can also pose a safety hazard to individuals working on the power system. The sudden surge of current can also lead to power outages and disruptions in the flow of electricity. Additionally, high fault currents can cause problems with protective devices, such as circuit breakers, which may fail to operate correctly due to the large amount of current.
While it is not possible to completely prevent 3 phase balanced faults, measures can be taken to reduce the likelihood of them occurring. This includes proper maintenance and regular inspection of the power system, as well as using protective devices, such as fuses and circuit breakers, to quickly isolate and clear any faults that do occur.
Specialized equipment, such as fault detectors and power system analyzers, can be used to detect 3 phase balanced faults. Once a fault is detected, it can be resolved by quickly isolating the faulty section of the power system and restoring power to the unaffected areas. This can be done manually or automatically through the use of protective devices.