link: Back to Visit our installations

Image: Virtual Visit
  Geographic location
  The James Bay territory
  Access infrastructures
  The Robert-Bourassa hydroelectric development
  The dam
  The dikes
  The spillway
  The spillway deck
  The reservoir
  The intake and the headrace
  The underground facilities
  The machine hall
  The scrollcase
  The generating units
  The surge chamber
  The tailrace tunnels
  The control room
  Radisson village
  Radisson substation
  The James Bay transmission system


Image : Radisson Substation

Radisson substation is by far the largest substation on the Hydro-Québec grid. Its surface is large enough to accommodate 100 football fields, and it has a transfer capacity of 6,600 MW. Located 16 km from the Robert-Bourassa hydroelectric development, Radisson substation has three functions.

First of all, it serves as a switchyard, routing electricity to two of the six 735-kV lines in the James Bay transmission system.

It steps the voltage up from 315 kV to 735 kV so that the electricity generated by La Grande-2-A and La Grande-1 can be brought onto the grid. Conversely, it can step the voltage down for supply to the DC converters.

It converts 315-kV AC current to ±450-kV DC current and can send 2,200 MW south over the Radisson–Nicolet–Des–Cantons line (a multiterminal direct-current system).

Electricity is transmitted at extra high voltage (735 kV) mainly because this is the most cost-effective option. After all, it takes two to three 315-kV lines to do the work of a single 735-kV line. Besides, transmission losses are smaller with high-voltage lines. Between James Bay and Montréal (more than 1,000 km apart), transmission losses vary from 4.5% to 8%, depending on operating conditions and temperature.


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