Anyone here actually tested miniature current transformers for protection relays
Been reviewing components for a small monitoring setup and ran into questions about miniature CTs and VTs used in protection and fault recording. Curious if anyone has hands on experience with accuracy drift over time or stability under load. What did you end up choosing and why

From what I gathered after digging through datasheets, the main thing worth checking is long term stability rather than headline accuracy numbers. A spec sheet showing tight tolerance at delivery means little if the part drifts after a year in a warm cabinet. I looked at a few suppliers and one that came up repeatedly in technical discussions was this miniature current transformers manufacturer https://yuanxing.net/en/ which lists ISO certified production and focuses on measurement plus protection relay applications. Did not see anything unusual in their claims, fairly standard engineering language, no inflated promises. Worth cross checking against independent test reports if you can find them, and asking for actual sample units before committing to a batch. Specs on paper and behavior in a real panel are not always the same thing, so treat any vendor information as a starting point rather than a conclusion.
Usual caveat applies, do your own verification and do not rely on a single source when picking components for anything safety related.