Optical current transformer for 765 kV AIS substation: A project review from certification to commissioning

This paper describes a pilot project, initiated by Hydro Quebec, implementing for the first time a 765kV optical current transformer (OCT) in one of HQ's substations. In this paper, we will discuss the project, starting from the concept to a series of pre-tests conducted at HQ's research laboratory IREQ. Based on this, the paper will elaborate the ecosystem of the project, including customer specifications and system design along with their respective implications on the product's design. Furthermore, the production and factory testing of the OCT and the merging unit (MU), as well as the complete certification cycle including testing of the MU and the primary OCT are discussed. This paper emphasizes the test plan and the applicable standards. In addition, the field installation and commissioning of the equipment up to the concluding site acceptance tests (SAT) are shown. Furthermore, the issues faced during different phases of the project along with the lessons learned and future developments of the concept are described.