Electrical Transformers and Transmission Lines

The voltage of electricity is stepped up in the generating substation for more efficient transmission and distribution with minimal loss and then stepped down at the receiving substation. The substation, as a component of the electrical power supply network is responsible for adjusting the amount of electricity to be transmitted at each site and for selecting the proper transmission system. (The plant which plays only the latter role, is called a switching station.) If the main substation handling voltages in excess of 170 kV is damaged as a result of earthquake, power transmission may stop although power generation may continue. On the other hand, transmission to consumer site will still be possible through the power supply network as long as the main substation is not damaged, assuming that all power-generating stations distributed countrywide will not halt at the same time due to the same earthquake.