Regarding the zero-sequence current protection on the low-voltage side of transformers
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Recently, I was working on a project where, for the grounding of the neutral wire on the low-voltage side of a transformer, it was required to use a zero-sequence current transformer for protection. I had no prior experience with this; so how is this implementation achieved? I don’t know how to choose the model or the transformation ratio; in addition, relay protection is also a concern. Where can I find information on this topic? It’s urgent
I remember that the TN-S system allows for the addition of a zero-sequence component. Regarding its specific applications and selection considerations: it is best to use this system when the three-phase load is relatively balanced. Equipment powered by 220V requires the use of an isolation transformer. In the few installations I’ve seen, the transformer current was roughly around 10% of the transformer’s rated current
I don’t think so. For the 500KVA transformer, the client suggested using a current transformer with a ratio of 800/5. I have no experience in designing such things. Additionally, the client also wants relay protection systems installed, and that falls outside the scope of our work as a design firm; therefore I’m not sure what to do