National Grid, Malaysia (Malay: Grid Nasional) is the high-voltage electric power transmission network in Peninsular Malaysia. It is operated and owned by Tenaga Nasional Berhad (TNB) by its Transmission Division[1]. There are two other electrical grids in Sabah and Sarawak operated by Sabah Electricity Sdn Bhd and Sarawak Electricity Supply Corporation respectively.
The system spans the whole of Peninsular Malaysia, connecting electricity generation stations owned by TNB and Independent Power Producers (IPPs) to energy consumers. A small number of consumers, mainly steel mills and shopping malls also take power directly from the National Grid.
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The beginnings of the National Grid was slowly taking shape in 1964 when the Bangsar Power Station was connected to the Connaught Bridge Power Station, with the line subsequently extended to Malacca[2].
By 1965, a plan was set to connect the electricity generating plants that were spread out all over the country. Plants identified to be linked were located at Paka in Terengganu, Temengor, Kenering, Bersia and Batang Padang in Perak, Connaught Bridge, Kapar and Serdang in Selangor, Cameron Highlands in Pahang, Perai in Penang, Port Dickson in Negeri Sembilan, Pergau in Kelantan, Pasir Gudang in Johor and in Malacca.
The central area network with Connaught Bridge Power Station in Klang was the precursor of the energy grid; it also tapped into the Cameron Highlands Hydro scheme from the Sultan Yussuf Power Station, and was extended into a western network. Late in the 1980s, the loop was finally complete with the placement of Kota Bahru within the grid[3].
More than 420[4] transmission substations in the Peninsular are linked together by approximately 11,000 km[5] of transmission lines operating at 132, 275 and 500 kilovolts (kV). The 500 kV transmission system is the single largest transmission system to be ever developed in Malaysia. Begun in 1995, Phase 1 involved the design and construction of the 500kV overhead transmission lines from Gurun, Kedah in the North along the west coast to Kapar, in the central region and from Pasir Gudang to Yong Peng in the south of Peninsular Malaysia.
The total distance covered for the 500 kV transmission lines is 522 km and the 275 kV portion is 73 km. Of the lines constructed, only the Bukit Tarek to Kapar sections had been energized at 500 kV. The remaining lines are presently energized at 275 kV. Later, in order to cater for the additional power transmission requirements from the 2,100 megawatt (MW) Manjung Power Station, the 500 kV system was extended from Bukit Tarek to Air Tawar and from Air Tawar to Manjung Power Station. In 2006, the 500 kV lines between Bukit Batu and Tanjung Bin were commissioned to carry the power generated by the 2,100 MW Tanjung Bin Power Station.
A project involving laying a 730 km high-voltage direct current transmission line and a 670 km undersea cable for the 2,400-megawatt Bakun hydroelectric dam has been considered[6]. This may connect all three of Malaysia's electric utility companies with state grids: Tenaga Nasional Berhad (TNB), Sarawak Electricity Supply Corporation (SESCO) and Sabah Electricity Sdn Bhd (SESB). Many of Sabah and Sarawak's generation plants are still not interconnected to a grid.
The original 117 MVA, 132 kV Single Circuit Line HVAC interconnection of 80 MW with Electricity Generating Authority of Thailand (EGAT) was commissioned in 1981[7], linking Bukit Ketri in the state of Perlis with Sadao in Thailand. A second interconnection was made via the HVDC Thailand-Malaysia rated at 300 kV HVDC and 300 MW transmission capacity.
In the South of Malaysia, the National Grid is connected to the transmission system of Singapore Power Limited (SP) at Senoko via two 230 kV submarine cables with a transmission capacity of 200 MW.
Power generation capacity connected to the Malaysian National Grid is 19,023 megawatt, with a maximum demand of 13,340 megawatt as of July 2007 according to Suruhanjaya Tenaga[8]. The generation fuel mix is 62.6% gas, 20.9% coal, 9.5% hydro and 7% from other forms of fuel[9].
Distribution lines of 33 kV, 22 kV, 11 kV, 6.6 kV and 415/240 volt in the Malaysia distribution network connect to the National Grid via transmission substations where voltages are stepped down by transformers.