site analysis report
DESCRIPTION
This is how to prepare defects report.TRANSCRIPT
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DONGFANG ELECTRIC CORPORATION LIMITED 333 Shuhan Road, Chengdu, Sichuan, 610036, P.R. China Tel: (+86-28) 87583501-3509, Fax: (+86-28) 87583652 http://www.dec-ltd.cn, E-Mail: [email protected]
Our Ref: DEC-E-001 Date: June 8, 2015
No. Defected Equipment Name Status Remark
1 #142CB Circuit Breaker Close Coil burned 2 I/O Card of #142CB Circuit Breaker Protection Panel burned
EVENT DESCRIPTION
On June 5, 2015, DECL was doing the protection transmission inspection for #4 Steam Generator protection panel.
After initialize the close command to close the #142 circuit breaker, the breaker fail to close.
On June 6, 2015, DECL found one close coil of breaker burned.
On June 7, 2015, DECL found one I/O Card of #142CB Circuit Breaker Protection Panel burned.
ANALYSIS AND CONCLUSION
When the 132KV circuit breaker close command initialed by interposing relay device in Circuit Breaker Protection Panel, it will energize one close contactor in breaker control box first, then the contactor will charge the close coil of breaker for a very short time, accordingly close the breaker. After that it will discharge the coil. One close operation loop completed.
After checking, we observe that the operation mechanism is working smoothly and no abnormality so far, but internal status of the operation mechanism can not be checked.
According to the site inspection, we believe that the close contactor may work not properly due to long-term storage and cause above said failure.
If above said contactor can not return to the original poison (open position) after contactor discharge, it will charge the close coil of breaker continuously, then burn the coil and I/O card finally.
CONTRACTOR SUGGESTION
1 Replace all electrical components. 2 Purchase some I/O card as spare parts.
REMARK
425 MW Combined Cycle Power Plant Nandipur
Site Analysis Report