Siemens has built power transformers for ultra-high-voltage grids that can be installed within one week. Until now, this process has taken several weeks. In the event of an outage, the new transformers can restore power in a period of time that in the past would have seemed impossible. Power transformers ensure the transmission of hundreds of kilovolts (kV) of electricity over long distances all the way to the end customer. If such a transformer fails in a large city, thousands of people can be affected. Ordering and delivering a new transformer has usually taken more than six months.