The cause of Tuesday’s (18 September) blackout was due to tripping of two power generating units, according to Energy Market Authority’s (EMA) initial findings.
In a media release on Wednesday, EMA said that the electricity supply disruption happened from 1.18am to 1.56am, affecting about 146,500 customers.
The blackout affected residents living and working in the northern, western and eastern parts of Singapore such as Woodlands, Sembawang, Yishun, Jurong West, Marine Parade and Bedok.
A power generating unit at Sembcorp Cogen tripped, prompting other units in operation to automatically increase their supply automatically, EMA said. A separate power generating unit owned by Senoko Energy tripped while it was ramping up additional supply.
“The tripping of the two power generating units resulted in insufficient electricity supply to meet demand. In this case, the protection devices in the power system automatically disconnected electricity to about 146,500 consumers to rebalance the system,” EMA added.
To restore electricity supply, EMA instructed other standby power generating units, including unaffected units from Senoko and YTL PowerSeraya, to provide additional electricity supply.
Supply to consumers was progressively restored over 38 minutes, EMA said.
Investigations are ongoing and EMA is working with Sembcorp, Senoko and their equipment suppliers to find out the cause of the tripping and looking into additional measures to minimise the recurrence of such incidents.