Testing with new technologies: The KEMA Labs experience

The requirements for instrument transformers are international standardized. National regulators often set requirements regarding metrology. Optical instrument transformers also called Low Power Instrument Transformers (LPITs) transmits the measured currents and voltages in the form of sampled values by IEC 61850 protocol ​​to a fully digital energy meter .

Product standards are, therefore, being developed for these new components in the electricity grid within the international standardization organization IEC TC13, IEC TC38 and IEC TC57.  In this respect, the KEMA Labs experts actively participate within the international standardization organizations.

To test if the LPIT fulfill the requirements of the Dutch electricity metering code , KEMA Labs has been commissioned by the Dutch Transmission System Operator (TSO) in collaboration with the Dutch Metrology Institute (VSL) and several manufacturers. To research the interoperability and the system accuracy of an energy measurement system the setup contains a LPITwith IEC 61850-9-2 samples value output connected to an energy meter with digital input. These components communicate via a communication network equipped with an Ethernet Switch with added a time synchronization clock. This time synchronization is necessary to obtain the required accuracy of the measurement.

During the research, the following measurements were performed at KEMA Labs Arnhem (The Netherlands) , using traceable and calibrated measuring equipment:

1. Accuracy of the complete measuring device, i.e. from primary components to pulse LED on the front of the energy meter. The accuracies are determined for different currents, but also inductive as well as capacitive loads.
2. Ratio error as well as phase displacement of the current transformers at different loads.
3. Ratio error as well as phase displacement of the voltage measurement at different loads.

For challenging measurements and testing, please contact marketing@kema.com .