Substations and transformer boxes eventually reduce the power to the 110 volts that toast your muffin in the morning, but the electrical noise on a high-voltage line can destroy data signals immediately.
To send power miles away without huge line losses demanded that electricity be stepped up to a high voltage, then stepped down again at the receiving end.
Local controllers (X-NET) gather this information and deliver to a web-controller via GPRS. The overhead sensors are line powered, and the X-NET Controller can be powered by a low voltage supply or a solar panel.