As we know, three-phase meters with closed links between the current and voltage measuring circuits (C-P links) are produced and used with increasing frequency. If the meter under test do not allow for opening of the C-P links, then there is an unwanted connection between the voltage and current path at every meter position.

　　The required isolation therefore must be achieved by using transformer in the current circuits and in order to do this, MTE must be fitted with one current transformer for each test position. In this way, each meter under test is supplied with isolated currents via these current transformers, which normally have a current ratio of 1:1, and a phase error over required range small enough as not to introduce significant additional errors.

　　In April of 2004, SMS got the success of R&D and manufacture of this type meter testing equipment, which is the first success in China, Now it has a very good sell in home market.

　　In September of 2005, SMS take part in the tender for this type MTE held by NESA in Denmark, and SMS got the order