A technical malfunction in a transformer triggered the March 11 national grid collapse that deprived parts of Dhaka of electricity supply for at least two hours.
The probe into the grid collapse, conducted by the Power Grid Company of Bangladesh, however, failed to determine the nature of the malfunction.
鈥楾he transformer is completely burnt. It burnt so bad that it is impossible to determine where the malfunction occurred,鈥� said BM Mizanul Hassan, chief engineer, PGCB.
Nine fire-fighting units battled the blaze for 12 hours at the Aminbazar power sub-station but failed to save the transformer with 325MVA capacity.
The simultaneous occurrence of the fire and the grid collapse is unusual and could be indicative of the grid not properly functioning.
鈥楿sually, fire does not follow tripping,鈥� said Mizan, who led the PGCB probe.
Tripping is a defense mechanism in the transmission system mainly to prevent overheating in equipment in an event of disruption or sudden fluctuation in power supply.
The PGCB probe, however, could not determine what was wrong with the grid to witness such an unusual occurrence.
The Aminbazar power sub-station is a critical point in the national grid, handling about 1,000MW with inputs from the Rapmal and Payra power plants.
The Aminbazar power sub-station is critical to sustain power supply in parts of Dhaka district and the capital.
Bought in 2019, the destroyed transformer was the best transformer at the Aminbazar sub-station. There was no replacement option at hand as such a transformer was not available at the moment, said PGCB officials.
The remaining transformers at the Aminbazar grid sub-station are running at their maximum capacities round the clock without a break.
鈥業t makes us a bit worried. Anything can happen any moment, particularly as power demand is increasing amid the heatwave,鈥� said Mizan.
Members of the PGCB probe body have a hypothesis about what caused the rather new transformer encounter such a serious malfunction.
The transformer might have been damaged while being transported to the Aminbazar sub-station about a year ago from the Gopalganj sub-station.
After it was bought, the transformer was initially installed at the Gopalganj sub-station.
Weaknesses at the Aminbazar sub-station could have serious consequences as its collapse could trigger a countrywide blackout, causing widespread damage in power plants depending on the sub-station for the evacuation of electricity.
The latest grid collapse, which occurred on a rather small scale, prompted authorities to reduce operations at the Rampal and Payra power plants and start electricity generation at peaking power plants to make up for a shortage of about 500MW.
Dhaka鈥檚 power distribution system is highly unreliable for it does not have enough sub-stations and the sub-stations it has are anything but well-equipped.
Power grid experts said that every power substation should have a standby transformer capable of meeting the substation鈥檚 power demand alone, a condition absent in Dhaka鈥檚 distribution network.聽聽聽
A power substation used in Dhaka usually comprises three transformers, explained engineers at Dhaka鈥檚 two distributors, Dhaka Electric Supply Company Limited and Dhaka Power Distribution Company Limited. All the transformers run at a time with no backup or standby support.
Dhaka鈥檚 power demand is about 3,500MW, which is about a fourth of the power consumed nationwide.
Home to about 20 million (two crore) people, Dhaka鈥檚 distributors operate in 500 square kilometer area, serving nearly three million (30 lakh) subscribers, including households and industries.
Installing an ideal distribution system is essential for Bangladesh to reduce its huge power overcapacity, according to sector experts.
Bangladesh鈥檚 current installed power generation capacity is over 27,566MW, about half of which remains idle mainly because of two reasons鈥攆uel crisis and poor power supply infrastructure.
Unreliable national grid has led to the building of an additional captive power generation capacity of 2,800MW operated by industries to meet own demand.
In another development on Monday, the supply of electricity from the Adani power plant in India plummeted in the morning hours to about 800MW from the usual level of 1,100MW due to the shutdown of a power line, according to the PGCB.
The Aminbazar sub-station saw one of its transformers explode in October 2023, leading to power outage in Dhaka due to the grid collapse.
Exactly a year ago in 2022, the national power grid collapsed, causing power outages in four divisions for up to 10 hours.
There were two other occasions of grid collapse after 2014. The causes of grid collapses were never known beyond doubt.
