The kick-off meeting of WG CIGRE A3.50 ‘On-site calibration and verification of the accuracy of instrument transformers’ was held on April 5 at RSE headquarters in Milan.

Paolo Mazza, Head of the ‘Measurements and Diagnostics of T&D Components’ research group, Transmission and Distribution Technologies Department, convener of WG A3.50 and Italian member of Study Committee A3, participated in the session.

The activity of WG A3.50 includes the preparation of the Technical Brochure, aimed at defining the state of the art and current evolutions in the electrical system, as well as the preparation of tutorials and webinars that will be presented in future CIGRE Sessions, including all aspects related to calibration and field verification of the accuracy of measurement transformers, which are increasingly important both for traditional measurement and protection applications and for new requirements related to metering, power quality and phasor measurements.

The methodologies and equipment featuring in the brochure include LiOnHV, an emblematic System Research product designed and developed by RSE as part of a collaboration with INRiM, Terna and Italian and European companies such as REMAZEL and Schniewindt.

LiOnHV, an acronym for Live, On-Site verification of the accuracy of HV instrument transformers, consists of a methodology and equipment for field verification of the accuracy of voltmetric and amperometric transformers. The distinguishing feature of RSE’s equipment, in addition to the accuracy of the reference measurement systems used, is that it can be installed by means of live working methods, thus without impact on normal plant operation: the methodology proposed by RSE is one of two available internationally with such features.

There is considerable international attention on the subject at the moment. In early June, the kick-off meeting of the EU project ENSURE – Electric Energy and Supply Reliability will take place; its WP1 will focus on the field calibration of measurement transformers, with INRIM and RSE at the forefront among the partners.

RSE’s efforts to improve the accuracy of measurements of voltage, current and their derivatives continue with the development and testing of new methodologies and prototypes, in both System Research and Mission Innovation.

Reference is made to the following websites for further information:

• CIGRE
• CIGRE Italian national committee
• Study committee A3