Event report for the accident occurred on 10th June 2014 -
TRC ordered Electric Transfer Company Ltd. to repair the bushing of load break switch no. LBS2, during power stoppage on 10 June 2014. As per the shut down plan power supply to LBS2 made off and allowed contractor to start work. Contractor confirmed no power supply with voltage detector and started the job at about 8 am.
As per the work sequence made by TRC Electrical dept team, power supply to substation 2 & 3 was stopped and next activity was planned for changeover of substation 4. During this period process dept. requested to do the changeover of substation 4, after completing the power up activity of sub 2. This change in the plan was communicated by Mr. Mittal to Mr. Prayoon personally at substation 2 & Mr. Sutee on walkie-talkie, as it was not affecting the other changeover activities.
Mr. Sutee, who was supervising power changeover activities at 115 KV switchyard thought that he need to start power of substation 2. He checked the single line diagram and informed substation 2 team about starting of power supply from TCB 22 KV feeder HE5, from LBS 4 on walkie-talkie. As per the plan LBS2 job was to be completed before switching on power from LBS 4 but he missed to ensure job completion and went to LBS4 for switching ON. Power supply from LBS 4 was connected to LBS 2 breaker also, which caused spark at bushing of LBS2 and injured the person working there.
Power supply from LBS4 was immediately switched OFF and after confirmation of no power supply; injured person was taken down from pole & shifted to Angthong hospital by TRC emergency van. After initial treatment & checking, he was transferred to Paolo Hospital Bangkok, for further treatment.