The recent prolonged power outage at Japan Garden City in the capital was caused by technical faults in the housing complex’s own 33/11kV substation, not in the distribution network of the Dhaka Power Distribution Company (DPDC), according to the state-run utility company.
In a statement issued on Saturday, DPDC said electricity supply to the residential complex was fully restored at 8:02pm on July 10 after technical problems in the customer’s internal power distribution system were resolved.
Japan Garden City, a 33kV high-voltage consumer with an approved load of 9,400kW, comprises 26 residential towers and the Tokyo Square shopping mall. Electricity is supplied through the housing project’s own 33/11kV substation, while DPDC’s responsibility extends only up to the incoming 33kV supply point.
The utility said operation and maintenance of the internal power transformer, 11kV busbar, circuit breakers, switchgear and distribution network are the responsibility of the Japan Garden City authorities.
According to DPDC, the disruption began at 3:31am on July 7 when the 11kV incoming breaker inside the customer’s substation flashed over, causing the feeder to trip.
Although DPDC carried out an emergency shutdown and attempted to restore supply through an alternative source, the line could not be energised because of faults within the customer’s electrical system, it said.
A joint inspection later found heavy carbon deposits and moisture on the 11kV busbar, along with faults in one of the substation’s power transformers.
DPDC said the main cause of the outage was the failure of the customer’s 10/14MVA transformer and defects in the 11kV busbar and associated equipment.
The company also said restoration work was delayed because the housing authority did not initially appoint a qualified technical team or engineering firm to repair the damaged equipment.
To expedite the restoration, DPDC held an emergency meeting and, following instructions from State Minister and Dhaka-13 lawmaker Bobby Hajjaj, a reputed engineering firm was engaged to inspect the substation.
DPDC said its own engineers completed the necessary technical work inside the substation, while the firm appointed by the customer carried out testing and inspection.
Following the submission of a satisfactory test report and a formal request from the customer, the 33/11kV transformer was successfully re-energised at 11:00pm on July 9, it added.
The utility said electricity supply resumed to most buildings immediately after the transformer was restored. However, power to several buildings remained disrupted because of a separate fault in one of Japan Garden City’s own 11kV feeders.
That problem was eventually resolved, allowing full restoration of electricity across the complex at 8:02pm on July 10, according to the statement.
DPDC also expressed concern that the customer’s substation lacks a 33kV protection system, warning that any major fault could pose risks to the wider distribution network.
The utility advised the housing authority to carry out regular maintenance of its substation and associated equipment to prevent similar incidents in future.
DPDC thanked residents for their patience during the outage and said it would continue providing technical assistance and advice to ensure safe and reliable electricity supply