This morning at 10:07am, a flash fire broke out at the substation of the Singapore Power building on Somerset Road. This led to a blackout in the vicinity for some 20 minutes. During the same period, other areas experienced an over-voltage condition in the utility power supply. This was an extended period of elevated supply voltage, high enough to cause several problems at my workplace, causing disruptions to normal operations for many hours later even after the utility power was back to normal.
When the blackout occurred in parts of the power grid, the sudden loss of some load caused voltage in the grid to go up. I’m just making some guesses here. I suppose normally there are some means to regulate the grid’s voltage, and this might have been managed through a control centre at the Singapore Power building. Now, perhaps the blackout at the substation there knocked out the control centre, causing the voltage in the power grid to go bonkers. The official story is that the blackout started at 10:07am, and was restored at 10:25am. This is precisely the time logged by the monitoring systems of my UPSes. At 10:07am, there was a 2-second voltage dip, followed immediately by an over-voltage condition that lasted until 10:25am.
This is actually not the first time that a blackout somewhere in Singapore has led to significant over-voltage condition at my workplace. This time, however, the problem led to tripping of many aircon chiller plants, damage to building automation systems, damage to door access control systems, etc. Even the elevator in one of my building died, and the lift technician was seen on site for some hours.
I hope Singapore Power has a good explanation about what happened.