Modelling and Optimisation of Design of Non-Conventional Instrument Transformers

In this paper, we have proposed, modelled and optimised several designs of non-conventional instrument transformer (NCIT) for high voltage overhead transmission lines (400kV). We have discussed several parameters and investigated how they influence the sensitivity of our NCIT, consisting of magnetic shape memory (MSM) element, magnetic circuit and an LVDT (linear variable differential transformer). One of the most used conductors in these lines, 528-Al1/69-ST1A ACSR conductor (old code MOOSE), was modelled together with the MSM element and the magnetic circuit in ANSYS APDL. Based on the obtained results we have given suggestions on how NCIT could be designed taking into account a choice of the most appropriate material for this application. The way how the model was developed was presented as well as calculations of errors in the model in ANSYS APDL for electromagnetic problems.