Design of 154 kV class 100 MVA 3 phase HTS transformer on a common magnetic core

Abstract

We have proposed a high temperature superconducting (HTS) transformer which can substitute for a conventional oil transformer for power distribution in Korea. The conventional transformer is composed of three identical single phase transformers because of the limitations on volume and weight. Now the Korean power company has started to consider the possibility of a transformer on a common magnetic core because it can be a solution for the increment of capacity without new construction of substations. In this paper, we proposed an HTS transformer on a common core. Its capacity is the same as the previous HTS transformer, which was 100MVA, 154kV/22.9kV. The former is smaller and lighter than the latter. We assumed a transformer tank which covers the common core and windings. The tank also acts as a vacuum seal for a cooling system and so the cryostats for the windings do not need to have vacuum layers. The design parameters are compared with those of both a conventional one and an HTS transformer with separate cores.