Major Power Outage 18 September 2018

Much has been said about the blackout on Tuesday morning. Thus far, these are the official findings

  • Disruption lasted for about 38 minutes, between 1:18AM and 01:56AM on the 18 September 2018.
  • 19 areas in Singapore were affected: Boon Lay, Choa Chu Kang, Clementi, Jurong, Pandan Loop, Aljunied, Geylang, Tanjong Rhu, Mountbatten, Kembangan, Bedok, East Coast, Ang Mo Kio, Bishan, Thomson, Mandai, Admiralty, Sembawang and Woodlands (~146,000 customers).
  • Caused by the tripping of power generation units belonging to Sembcorp Cogen and Senoko Energy.
  • Dubbed the worst major power outage since 2004.
  • Previous major blackout (albeit much smaller scale than this incident) was on 1 June this year confined to the CBD area.

We had one advanced energy logger on-site (an office in Cecil Street – CBD area), doing harmonics compliance measurement during the incident. Here, the trending graphs showed that frequency ‘dipped’ down to as low as 48.83 Hz. The journal logs showed that it returned to its normal operating range (49.5 Hz to 50.5Hz) in about 18 seconds. Unfortunately, we did not use our higher-end equipment here (Dranetz HDPQ for instance). Hence the limited information (eg. Waveforms, detailed rms trends, etc could not be shown).

This particular office was not affected by the blackout.

Voltage & Frequency Trend

Power Quality Development in Singapore

I was invited to a talk by my former Deputy Managing Director, Mr. Chang Swee Tong at SP Group HQ.
It was a like a walk down memory lane, as he went thru various PQ-related initiatives that he led while at the helm.
Got to meet some old friends and mentors too.

Thanks again to SP Alumni Secretariat for the invitation.

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A paper on the same topic by Mr. Chang and the seniors of my old section can be found here.

PQSynergy International Conference and Exhibition 2017

PQSynergy 2017 Day 3 – Final day

The third and final day of PQSynergy 2017 ends with a sharing session by PQT’s Terry Chandler and Mirus’ Tony Hoevenaars on the topic of harmonics.

It has been another fruitful conference, with a good mix of local and international speakers. Thomas Pua’s (PSL) presentation on synchrophasors was particularly interesting and Bill Howe’s (EPRI) insights on the proactive use of PQ data is a welcome change for the industry.

I always look forward to these sharing sessions with fellow practitioners, something not common back home for me, especially in power quality.

This year, I shared some common and simple day-to-day PQ related cases encountered back in Singapore. The presented slides will soon be available for download at www.pqsynergy.com

Mr. Flicker II

A technical report regarding voltage fluctuations was recently published by Cigre. The working WG C4.111 was set up to look into the possible changes to existing voltage fluctuation compatibility levels. This is mainly due to the widespread opinion (myself included) that modern lighting are less susceptible to voltage fluctuations as compared to the traditional 60W incandescent light bulb which formed the basis for the Pst (Short Term Flicker) concept.

In summary, it was found that it was not definitive (at this time) to confirm this widespread opinion. While many of the modern lamp technologies tested were less sensitive, there were some that were tested to be more sensitive. It is thus concluded that the existing limits or compatibility levels for voltage fluctuation remain for the time being.

The full technical report (Review of LV and MV compatibility levels for voltage fluctuations) can be found at www.e-cigre.org

PQSynergy International Conference and Exhibition 2016

My 2nd year presenting a topic in PQSynergy. It has been an enjoyable 2-day conference.
Made new friends and learnt new things from fellow practitioners. Glad to have met the guys from Sonel too.
Will definitely take a closer look at some of your instruments.

And congratulations to Terry Chandler and his Power Quality Thailand on another successful conference.
Happy 30th anniversary, PQT. Many more good years ahead.

PQSynergy 2016
PQSynergy 2016
Friends from PEA
Friends from PEA

Voltage Dip 27-02-2016 1005hrs

Just a while ago, the following waveforms were captured from monitors in Jurong East and in the River Valley area, indicating a transmission fault, likely to be originating from the South block of Singapore. Waveforms captured in the River Valley area indicated a single-phase fault on L1 (Red) at 230kV transmission voltage.

Captured at LV (West area)
Captured at LV (West area)
Captured at 22kV (South)
Captured at 22kV (South area)

Added the following screenshots obtained from a PQUBE, being monitored in South of Singapore, at Low Voltage. Thanks James!

PQUBE Waveforms - EcoXplore
PQUBE Waveforms – EcoXplore
PQUBE RMS Plot - EcoXplore
PQUBE RMS Plot – EcoXplore

“Back to back” Voltage Dips

Earlier this afternoon in the midst of the year-end festive mood, you might have seen your office lights flickered twice in an hour: two transmission-level faults occurred. Tell-tale signs were from the nature of the waveforms and that in general, everyone in Singapore ‘felt’ it, with 1/4 of the island getting the ‘worst-magnitudes’.

One at around 1:46pm and the other at 2:36 PM. The following were captured from an office in Jurong East and in Bedok area (at low voltage).

At 1:46PM, it can be seen that the dips were fairly shallow.  Hence it can be deduced that the origin of the fault were neither in the 230kV blocks that these two sites are located. From the RMS trend of the waveforms captured at Site 2, it can be inferred that it was likely a single-phase 230kV fault on Phase L1 (Red).

Site1 Jurong East 1346hrs
Fig1: Site1 Jurong East 1346hrs
Site2: Bedok 1346hrs
Fig2: Site2 Bedok 1346hrs

At 2:36PM, the dips were much more pronounced at Site 1, suggesting that it resides in the same 230kV block as the fault. Here it is very clear that the 230kV fault was on the Phase L3 (Blue). At the second site at Bedok, the dips were again shallow. These are characteristics of a 230kV transmission level fault in Singapore. Only 1/4 of the island will be most affected with dip magnitudes in the range of 40 to 50% (dip by).

Fig3: Site1 1436hrs
Fig3: Site1 1436hrs
Fig4: Site 2 1436hrs
Fig4: Site 2 1436hrs

 

Localized Voltage Dip 26-09-2015 0736hrs

Earlier in the morning today, there was a localized voltage dip (dip by ~ 80%) in the Jurong East area. From the waveforms captured, it can be inferred that there was a 22kV L3-L1 fault.
Sensitive equipment was likely to be affected, especially those sensitive single phase LV control circuits taking in on Phase L3.

Localized Dip - Monitored at LV
Localized Dip – Monitored at LV

Islandwide voltage dip 9/5/2015 2:25PM

Earlier at 2:25PM, there were voltage dips reported all over the island.
This is the waveform captured at low voltage in Jurong East, typical of a 230kV transmission level fault.
This small dip in voltage here suggests that the transmission fault did not originate from this particular 230kV block, where this PQ monitoring device is located.

voltage dip 09-05-2015 225pm