Methods of Limiting Short Circuit Current
If Single Line to Ground Fault to be limited inorder to prevent the core damage in rotating machines, then Neutral Grounding Resistor (NGR) or Neutral Grounding Transformer Resistor (NGTR) is the ideal choice. However it will not reduce the Phase fault currents.
Actual Short circuit current will increase due to addition of sources, adding parallel transmission lines / transformers etc. If the short circuit current exceeds the rating of the Switchgear / substation due to expansion, then there are two possible ways
1. Upgrade the system to higher Short Circuit Current (This results huge cost, Long Time and Large Interruption time)
2. Use Short circuit Limiting Techniques.
Different techniques are available to reduce the short circuit current at different Voltage. Depends on the system and needs better choice may be selected.
Watch the video in the below Link from 51:10 to get more idea.
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