The transmission system operates at 220kV, 110kV and 66kV, while distribution is mainly at 11kV and 400/230 volts. The supply is 50 hertz alternating current, at 230 volts single-phase or 400 volts three-phase.
CEM has now in operation twenty primary substations with a total installed capacity of 1,260 MVA in 220/110kV, 1,500 MVA in 110/66kV, and 1,752 MVA in 66/11kV, and also operates 1,245 customer substations (11/0.4kV).
|Canal dos Patos Substation||Lotus Substation|
Lines and Cables
Power network is made up of underground cables. The main high voltage network operates at 66kV, although some circuits operate at 110kV and 220kV. For distribution purpose, high voltage is initially converted to MV (11kV), and further reduced to 400/230 volts for customer use.
As of December 2012, CEM’s network comprises 281 km high voltage (220, 110 and 66kV), 617 km 11kV medium voltage and 780 km low voltage cables.
High voltage cable installation
Interconnections with Guangdong Province
The first 220kV interconnection with Guangdong Power Grid (GPG) has been commissioned since June 2008, consisting of 3 circuits connected at a 220/110kV substation “Canal dos Patos,” with importation capacity 1,050 MVA. With the second 220kV interconnection with GPG completed in Jun 2012, consisting of 2 circuits connected with another 220/110kV substation “Lotus,” the importation capacity has increased to 1,750 MVA.
Map of the Transmission and Interconnection Network