Explosion at Biyagama station:

Islandwide power outage due to negligence - Technical report

by Rukshana Rizwie

The Ceylon Electricity Board (CEB) has received a damning technical report on the unusual explosion at the Biyagama sub station and the subsequent island-wide power outage attributing it to sheer negligence, lack of maintenance and inspection.

A detailed technical report to which the Sunday Observer had access found that the load tap changer of transformer No 2 exploded due to a fault in the diverter switch.

"Consequently, the lines connected to bus bar No.1 tripped off resulting in the failure of the total transmission system on March 13," the report said.

"It also revealed that the failure of the diverter switch was due to lack of inspection and maintenance of tap changing equipment."

The report recommends that inspections be carried out on all sister tap changing equipment at regular intervals as stated in the relevant operating instructions of the manufacturer.

The detailed technical report highlights glaring misses in routine maintenance work citing that 'this was an alarming situation and prompt action should have been taken to test the dielectric strength of all remaining sister tap changers of the BRS and Kotugoda grid substations.

However, the maintenance records of BRS do not show that such testing had been done.'

The report which recommends immediate action to prevent similar failures in the future said inspections should be carried out at regular intervals as stated in the manufacturer's operating instructions.

"Load Tap Changers (OLTC) are a complicated device and as such inspections should be carried out by highly trained personnel.