Faulty voltage transformer fire likely caused Singapore substation power outage

What happened

A voltage transformer at a substation in Bright Hill, Singapore, is the likely cause of a power outage on 26 January 2019 that lasted about 1.5 hours and affected around 27,000 residents. According to preliminary investigations by the Energy Market Authority, the transformer started a fire in the substation. Protective devices detected the fire and activated automatically to isolate the fault, which cut supply to consumers in Ang Mo Kio, Bishan, Sin Ming, Toa Payoh and Thomson.

Lifts stopped and traffic lights went dark. SP PowerGrid restored supply to 80 per cent of affected consumers within 30 minutes and to the remaining consumers within 90 minutes. The outage came months after a larger disruption in September 2018 that affected more than 146,000 residents.

Contributing factors

A faulty voltage transformer at the substation is the likely cause, based on preliminary findings. SP PowerGrid engaged the original equipment manufacturer's experts to establish whether the failure resulted from design, manufacturing or material defects. An independent expert was asked to review the manufacturer's findings and recommendations.

Lessons learned

1. Protective devices that isolate a fault quickly help limit the area affected, but operators should check that settings and fault isolation are tuned to contain a substation fire.
2. After a component fails, operators should consider raising monitoring frequency on the same equipment and prioritising its replacement in maintenance rounds.
3. An independent review of the manufacturer's root cause findings helps establish whether a failure stems from design, manufacturing or material defects.

More lessons on electrical protection and isolation, detection and monitoring, design, standards and commissioning, from every incident on the register.

Source

The Straits Times (straitstimes.com)