Today in Madison there were 2 power substations that had fires, about 13,000 without power. It affected the down town area which caused State, City, County offices to close down. In my estimation (as a retired electrician) people said they heard explosions which I believe to be transformer failures. Since transformers of that size are oil cooled, they ruptured and the oil ignited. There was lots of black smoke as seen in the videos. Not much of any other explanations for the huge smokey fires.