Preventive Actions Following Power Failure of 26 January 2019

13 Mr Leon Perera asked the Minister for Trade and Industry (a) what is the extent of the power failure on the afternoon of 26 January 2019; (b) what are the reasons for the failure; (c) what has been the trend in occurrences of such power failures in the past five years; and (d) what steps are being taken to minimise such failures going forward.

The Senior Minister of State for Trade and Industry (Dr Koh Poh Koon) (for the Minister for Trade and Industry): Mr Speaker, the power failure that occurred on 26 January at 1.30 pm affected about 27,000 consumers in Ang Mo Kio, Bishan, Sin Ming, Toa Payoh and Thomson.

Based on EMA's preliminary investigations, the disruption was likely due to an equipment fault at a substation at Bright Hill. The suspected cause is a faulty voltage transformer which started a fire in the substation. Immediately after the fire was detected, electrical protective devices were automatically activated to isolate the fault so that the downstream equipment would not be damaged. This resulted in the cut in power to the affected consumers. SP Power Grid (SPPG), the national grid operator was able to restore supply to 80% of consumers within 30 minutes and fully restored power supply to the remaining 20% of consumers within 90 minutes.

This is the first power failure incident involving a faulty voltage transformer in the past five years. Our power system remains one of the most reliable in the world. Over the past six years, Singapore's average annual disruption per consumer ranged from 12 seconds to 4.2 minutes, which includes the most recent incident. In comparison, major cities such as Osaka, New York, Hong Kong and London experienced an average disruption per consumer of between five minutes and 21 minutes in FY17.

EMA will thoroughly investigate each incident and take appropriate regulatory action if necessary. SPPG has since adopted higher frequency of condition monitoring for the specific equipment that had failed, and will prioritise the replacement of that particular component in future rounds of substation maintenance. SPPG has also set up an internal investigation committee to investigate this incident. In addition, SPPG has engaged the Original Equipment Manufacturer's experts to review and advise if the failure was due to design, manufacturing or material defects. SPPG has also engaged an independent expert, CHUBU Electric from Japan, to review the findings and recommendations of the equipment manufacturer. EMA will continue to work closely with SPPG to ensure high standards of reliability for our power system.

Mr Leon Perera (Non-Constituency Member): I thank the Senior Minister of State for his detailed reply. Just a few supplementary questions. Firstly, could the Senior Minister of State share if the trend of such major blackouts have been on the increase or decrease over the last five years or so. That is the first question.

Secondly, based on analysis of the recent incidents, does the Government believe that there are any systemic issues that need to be addressed, whether it is in terms of equipment maintenance or training of staff or any other issues. This is, of course, bearing in mind that, according to media reports, there was another major outage affecting some regions of Singapore in September last year, and I believe about 150,000 consumers were affected by that.

Thirdly and lastly, is there a protocol that is agreed with the power suppliers for when these kinds of disruptions happen, automatically or otherwise, there is a certain time period within which the power supply must be resumed and is that something that is tested from time to time?

Dr Koh Poh Koon: Mr Speaker, as I said earlier in my reply, this is the very first incident in which a voltage transformer has failed in the past five years, so there is no trend relating to this particular component. Other incidents may have happened in the recent past but this does not necessary indicate as a systemic issue because they pertain to either different parts of the system or actually could have been just due to human error.

On the previous incident, I have actually shared the findings in the earlier PQ reply so I will not repeat it here.

As far as protocol to ensure that our system is robust and resilient, let me just share that SPPG's distribution control and customer service monitors and controls the distribution network around the clock to ensure that electrical supply can be restored quickly in the event of power supply disruption to our consumers. And supply could general be restored typically within three hours by switching to an alternate feed or deployment of mobile generators. This is for the distribution network resilience. On preventive maintenance, SPPA practises the combination of both time based and condition based maintenance regimes. So, that is the kind of SOP or protocol as the Member had asked. And they carry out maintenance in accordance with the Original Equipment Manufacturer's recommendation to ensure reliable operation of equipment. In addition to periodic maintenance, SPPA adopts a condition monitoring regime in sensing and tracking the health of the assets which includes technologies to detect insulation deterioration, abnormal oil contents in our electric city cables and equipment, amongst others.

This ensures that impending failures are properly mitigated before it actually happens. But of course, as equipment gets replaced overtime, new models come on, they could well be unknown unknowns of how whether the design itself, the material itself could lead to future fault. This is where we work closely with equipment manufacturers to see if the design or the material that they use for the manufacturing could have been a cause of it. And some of these investigations will require us working very closely with the stakeholders and may take some time before we detect them.

Mr Leon Perera: I thank the Senior Minister of State for his reply. Just one last supplementary question, which is on the trend in such incidents of major blackouts. Has that been an increasing trend or decreasing trend or more or less stable in the last five years?

Dr Koh Poh Koon: Mr Speaker, as I said before, we would be worried about a trend if the same component or the same system within the electrical grid across different sub-stations fail repeatedly. But while they may be several incidents that happened in the recent past, they affect different parts, components, for which the OEMs are still looking at it. So, until investigations are complete, I will not draw any premature conclusions to say that there is a trend linking all these different equipment and different components together.