With its 30,000 workers and an availabie power supply of 30,000 MW, Ontario Hydro is Canada's largest producer of electricity. Ontario Hydro obtains a good quarter of the energy from water-power.

For the cuerent to travel safely over 130,000 km of cables to the 3.5 million customers, 140 data stations collect information about the voltage level, current flow and faults. The system control center, which collects and analyzes all important data, is located in Clarkson near Toronto. Among the multitude of PHOENIX CONTACT INTERFACE components used here, there are two that are especially worthy of mention: the pluggable opto-coupler signal interfaces POSI, which provide secure isolation, are polarized and have integrated surge voltage protection, and the MCR current transducers, which convert currents up to 75 A into a 0 to 20 mA standard signal with high precision.