Development of high current draw lead transformer bushings designed in accordance with IEEE standards

Historically draw lead bushings, designed in accordance with IEEE Standards were limited in current carrying capacity to a maximum of 400 amperes through 69 kV and 800 amperes 115 kV and above. For most medium power transformers, the high voltage bushings were applied with draw lead conductors. However, the low voltage side of these transformers almost always required bottom-connected bushings. This meant that if these bushing ever had to be removed the transformer oil would be drained and people had to enter the transformer tank to disconnect and reconnect the bushing. This procedure was very costly and time consuming. To save these costs and provide a safer working environment, bushings with higher draw lead conductor capability were required.