QM2 Explosion/Powerloss: “critical equipment must ‘fail safe’,

 Accident, Accident report, engine room, explosion, fire  Comments Off on QM2 Explosion/Powerloss: “critical equipment must ‘fail safe’,
Jan 182012
 

In its investigation of an explosion and loss of propulsion aboard the RMS Queen Mary 2 Britain’s Marine Accident Investigation Branch warns that protection systems for critical equipment must ‘fail safe’, and should be thoroughly tested at regular intervals to prove that all sub-components are functioning correctly. In particular, harmonic filters with current imbalance protection systems should be thoroughly checked by a competent person at the earliest opportunity.

Investigation of the catastrophic failure of a capacitor and explosion in the aft harmonic filter room  showed that the protection system for the harmonic filter did not work. As a result the vessel blacked out and was without steering or propulsion for 30 minutes. There were 3823 people on board.

Says MAIB: “there is a need to improve the awareness of the potential risks of high voltage harmonic distortion and arc flash… Awareness of the damaging effects of harmonic distortion needs to improve throughout the marine industry as the risks to equipment caused by harmonic distortion are likely to increase significantly as variable speed AC electric motors become more widely used in ships”.
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MAIB Cautions, Appeals After QM2 Capacitor Blast

 Accident, Accident report, explosion  Comments Off on MAIB Cautions, Appeals After QM2 Capacitor Blast
Dec 032010
 
image

Soot staining on the blown-out doors of the harmonic filter casing

Britain’s Marine Accident Investigation Branch, MAIB, has issued an urgent Safety Digest which recommends checks on vessels with electric propulsion which have large capacitors in harmonic filters and has appealed for information regrading similar events elsewhere. The bulletin follows the catastrophic failure of a capacitor and explosion in an 11kV harmonic filter on board the passenger cruise vessel RMS Queen Mary 2.

At 0426 (UTC+1) on 23 September 2010, the cruise liner RMS Queen Mary 2 was approaching Barcelona when one of 12 capacitors in a harmonic filter1 failed (Figure 1), accompanied by a loud explosion. The explosion resulted in extensive damage to the surrounding electric panels and caused the vessel to black out. There were no navigational hazards nearby, main power was restored at 0455 and the ship was able to get back underway at 0523.

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