Novel magnetic materials from VACUUMSCHMELZE GmbH & Co. KG, based in Germany, increase the performance of electronic watt-hour meters and current transformers. Current transformers feature almost constant, easily compensatable phase errors and small amplitude errors.

Due to a low temperature dependence of the magnetic properties, the temperature dependence of the transformer errors is basically determined by the linear temperature behaviour of the copper winding. The current transformers meet the requirements defined in the various technical standards for the device accuracy class.

In Europe these are usually IEC 62053-21-23 (formerly IEC 61036 and IEC 61268) for directly-connected meters, and IEC 62052-22 (formerly IEC 60687) for indirectly connected meters. In America ANSI standards C12.xx apply for both connection types. The new generation of current transformers is particularly appropriate, given the trend to move from electro-mechanical to electronic meters. They enable reliable, robust and accurate designs from highperformance industrial applications to cost-optimised residential solutions.

For more technical information, read the article entitled Novel magnetic materials increase performance of current transformers for electronic watt-hour meters, by Helmut Dönges, which can be found at www.smart-energy.com/vac/.