Methods of Reducing short circuit current
Power Projects 
This blog describes the methods of limiting Short circuit current and how it impacts.
METHODS OF REDUCING SHORT CIRCUIT CURRENT
An electrical circuit in which a very low resistance path has been accidentally opened. When the resistance in a circuit decreases the current in the circuit increases drastically, which can damage the circuit and cause fires. As a result, we have used certain equipment and other concepts in order to reduce the short circuit current.
Increasing the cable length:
There are numerous approaches available to minimize the fault current in a low voltage system. Increasing the cable length is one technique.
The fault current in bus 03 is 24.997 kA, and the cable length is 30 meters. However, because the breaking current of a low voltage circuit breaker is 20 kA, increasing the cable length from 30 to 50 meters. reduces the fault current to within 20 kA. The fault current on bus 03 is now 19.024kA. The fault current will decrease when the cable length is increased. that is shown the Figure 1: ETAP simulation for different cable length
Lighting transformers:
A lighting transformer is nothing but a 1:1 transformer. The transformer turns ratio is the number of turns of the primary winding divided by the number of turns of the secondary coil
The fault current in bus 03 is 24.997 kA, and the cable length is 30 meters. However, because the breaking current of a low voltage circuit breaker is 20 kA, we have installed a lighting transformer between the cable and bus 03. The fault current is now within20 kA of the safe limit. The fault current on bus 03 is now 10.707 kA. The fault current will be reduced shown in figure 2.
Categories: : Short Circuit
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