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Talbot Wind Farm Transmission Connection to Spence SubstationTransmission-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, and the IESO must conduct a System Impact Assessment. The same application form is used for both studies and is submitted to Hydro One and the IESO simultaneously.

Learn more about the IESO’s System Impact Assessment process.


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​   ​Technical Requirements 


Learn about each step in the connection process for large generators connecting to the transmission network


An opportunity for you to discuss your transmission generation project with Hydro One planning staff

   Learn about protection requirements needed to​ support generation connection applications 


Read about important connection requirements and considerations 
for transmission generation connections​

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