Patent ID: 7800355

Claim:
An apparatus for measuring electrical energy supplied to a rail traction unit by a high voltage line comprising: a first measurement device for measuring a current of the electrical energy drawn by the rail traction unit; a second measurement device for measuring a power supply voltage of the electrical energy supplied; a first electrical/optical converter converting electrical output signals from the first or second measurement device into light signals, the light signals conveyed by optical fibers to a first optical/electrical converter; and a low voltage power supply supplying low voltage power to the first and second measurement devices; the low voltage power supply including a second electrical/optical converter generating light which is conveyed by optical fibers to a second optical/electrical converter, wherein the first and second measurement devices, the first electrical/optical converter and the second optical/electrical converter are first components housed in a first space in an insulator of a high voltage line of the rail traction unit, and the first optical/electrical converter and the second electrical/optical converter are second components housed in a second space in the insulator, the first and second spaces being spaced apart, the optical fibers providing a link between the first components in the first space and the second components in the second space.