A metering CT becomes stable in real smart meter applications when it can maintain predictable ratio behavior, good linearity, proper burden compatibility, thermal consistency, and repeatable batch quality across practical operating conditions. Stability is not only about one good sample or one short test result. It is about whether the current transformer can continue supporting reliable measurement performance in real design, real production, and real field service. When these factors are evaluated together, project teams can choose CTs that bring stronger accuracy control and lower long-term risk.