VFT maintenance and operating performance

A Variable Frequency Transformer (VFT) has been in full commercial operation on the Hydro-Quebec TransEnergie system since December of 2004. The VFT is an interconnection device that is based on widely established technology. However, because the application of some equipment is unique, the maintenance requirements associated with VFT operation and ownership have become an item of interest. This paper provides information on the maintenance program that is being utilized at the Hydro-Quebec Langlois VFT installation. This represents the expected maintenance requirements for a typical VFT installation and is meant to provide a guideline for comparison of maintenance requirements for other interconnection technologies. This paper also discusses the availability performance of the first VFT installation and how it has been calculated for the Hydro-Quebec TransEnergie installation. The information presented in this paper reveals that the VFT is a simple and reliable interconnection device and does not require an extensive maintenance program. The availability performance of the VFT has been very good. The VFT should be considered a viable option for an interconnection device from a maintenance or reliability standpoint.