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Harry Bloomfield[_3_]

submitted this idea :
A 400 kV National Grid circuit may carry 1 kA in each of its three phases,
thus transmitting a power of 700 MW.
A 132 kV distribution circuit may carry 300 A in each of its three phases,
thus transmitting a power of 70 MW.
An 11 kV distribution circuit may carry 150 A in each of its three phases,
thus transmitting a power of 3 MW.
A 400 V final distribution circuit may carry 200 A in each of its three
phases, thus transmitting a power of 150 kW.

(Remember, these voltages are phase-to-phase voltages, the phase-to-earth
voltages are 1.73 times lower. Thus (400 kV/1.73) x 1kA x 3 = 700 MW.)

Also remember it is a grid. Those are likely maximums and the actual
current flow can be in either direction, depending upon where there is
demand and what generating stations are online.