In 2013 Transpower New Zealand Limited (TPNZ), a state-owned electric power transmission company in New Zealand, started a multi-year program to replace their inventory of aging oil-filled transformer bushings. Many of these bushings were showing deteriorating test results (power factor) and sealing systems. To date this program has identified 69 transformer banks (many of which are composed of single-phase units) that need their originally supplied bushings replaced; which equates to a requirement for approximately 500 bushings (including spares). Due to safety and environmental concerns TPNZ specified dry type bushings for the replacement program.
Because of the age of many of their transformers the biggest challenge for the program was to be able to get custom-engineered “like for like” replacement bushings. Because of the very simple manufacturing processes involved in the production of our RIF® bushings RHM International was able to offer TPNZ custom engineered designs for all their unique bushing requirements without affecting prices and lead times. TPNZ recognized the huge benefits this offered to both the program’s budget and schedule and made RHM International one of its program suppliers of dry type bushings.