Transmission-connected generators connect to Hydro One's high-voltage system at more than 50 kV (50,000 volts) and are registered with the Independent Electricity System Operator (IESO). Transmission lines, strung between metal towers or concrete poles, are not as plentiful as our distribution lines, which are most commonly strung between wooden poles.
For a transmission-connected facility, generators must have Hydro One conduct a Transmission Customer Impact Assessment, as well as a System Impact Assessment (same form as Customer Impact Assessment) conducted by the IESO.
Learn more about the IESO’s System Impact Assessment process.