That is the reason why the current emphasis in China is on the construction of 500kv extra-high-voltage lines and long-distance power transmission.

FORBES: Cracking China's Power Sector

At 400 kilovolts, a standard value for long-distance transmission, an alternating current 30 metres (100 feet) from the ground has a fortieth of the loss of a similar cable at ground level.

ECONOMIST: Power transmission