Power System an integrated network that interconnects installations for generation, transmission and distribution of electricity. Bangladesh has two distinct geographical zones separated by the Padma-Jamuna river system. Major generation takes place in the east zone that has hydropower facilities and a good number of natural gas fields for providing fuel. The west zone has no such resources and produces power by using thermal fuel. The electricity is generated at 50 hertz and at a nominal voltage of 11 kilovolts (kV) or, in some cases, 15 kV, to be stepped up through transformers to 66 kV, 132 kV or 230 kV for feeding to the grid. The generation and transmission of power in Bangladesh historically remained a monopoly of the power development board (PDB). The PDB grid comprises seven 230 kV lines extending over 419 km, thirty-five 132 kV lines (2,469 km) and one 66 kV line (167 km). The lines are of either single or double circuits.

The longest line in the 230 kV category is the 179-km east-west interconnector linking Ghorasal in the east zone and Ishwardi in the west zone. It can transfer up to 450 MW power to the west. In 132 kV category, the longest line is 273 km between Kaptai and Shiddhirganj, both in the east zone. The maximum transmission capacity of this line is 240 MW. The 230 kV lines are connected with the 132 kV lines through 230/132 kV tie-bus transformers. Similarly, the 66 kV line is connected to the 132 kV line through a 132/66 kV transformer. The 132 kV lines are connected to the distribution network through 132/33 kV, and in some cases, 132/11 kV step-down transformers.

The total number of grid substations housing the 230/132 kV, 132/66, 33 or 11 kV and 66/33 or 11 kV transformers is 70. The distribution to individual consumers is done through a network of mainly 33/11 kV and 11/0.4 kV lines spread along tens of thousands of kilometres. The responsibility of power distribution is now shared by three public utilities - PDB itself, the Dhaka Electricity Supply Authority (desa) and the rural electrification board (REB). Their market share in the sale of electricity is 38%, 50% and 12%.

The generation of electricity in the country falls short of the demand that has been growing at the rate of approximately 10% per annum. At present, the total generation fluctuates between 1800 MW and 2100 MW against a peak demand of 2300 MW, although the installed production capacity is 3150 MW. The power generation is hampered by ageing, derating and forced outages of plants and inadequate fuel supply resulting in low per capita availability of power (95 kilowatt-hour), load shedding to the tune of about 500 MW in a summer day, persistent low voltage profile and frequent power failure in the grid or in a wide area. There is also an inherent nonuniformity in the location of the load centres and generating stations, which, in the event of a fault in a section, restricts the scope of splitting the grid into a number of islands that can run independently and match the load with generation and supply flows. Along with efforts in balancing, modernisation, rehabilitation and expansion, the government has undertaken programmes to encourage production and distribution of power at private sector initiatives and allow foreign private investment in the sector. [S Shahnawaz Ahmed]