Power Transmission

System Control Centre (SCC)

The Hydro-Québec system is one of the most automated power grids in the world
  • 160 remote measuring and signaling stations
  • 200 servers and workstations
  • 22,500 data acquisition points
  • 5,500 data elements updated every 3 seconds

Remote automatic systems perform most of the tasks needed to ensure the flow of energy from the power station to the home. These advanced supervisory control systems could be called the grid's "reflexes."

However, human intervention is constantly required to make important decisions related to system control and security, based on the most recent and relevant data available. These decisions are made at a centre that could be described as the “brain” of the power system. At Hydro-Québec, it’s called the System Control Centre, or SCC.

The strategic role of the SCC

The SCC operates round the clock and responds instantly to the power needs of Québec–its first priority–followed by those of its customers outside Québec. It regulates the generation and transmission of power, as well as energy interchanges with neighboring power systems through interconnections. There are 15 of these border-crossing facilities creating physical links with systems outside Québec.

To improve the decision-making process, the SCC centralizes all the information needed for system operation. Seven regional operating centres implement SCC decisions on power generation, transmission, and interchanges via interconnections. The SCC's multidisciplinary team includes about 150 experts, including planners, computer specialists, and technical maintenance and troubleshooting units.

A vast telecommunications network backing the power system

Hydro-Québec operates its very own telecom network. Its role is to transmit strategic data (e.g. for the supervisory control systems) and to enable verbal communications among utility personnel. Whether in urban centres or in remote areas, some 20,000 employees can talk to each other via this network. In fact, the telecommunications network covers over half of the province. Network signals are transmitted over more than 16,000 circuits using fibre-optic links, microwave and telephone cables. This network is like the “nervous system” of the company’s power transmission operations.

System operators in the driver's seat

With their "big picture" view and up-to-the-minute information, three system operators coordinate power grid operations. The generation system operator can request that a power station increase or decrease its output. The transmission system operator can call for the opening or shutting down of a power line. The interchange system operator oversees the delivery of electricity outside Québec as well as electricity imports from neighboring systems; when the demand for electricity is high in Québec, he has the authority to reduce or delay exports. System operators make real-time decisions; in other words, they have an immediate impact on power system performance and security.

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