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ISLAMABAD: Managing Director, Genco Holding Company Limited (GHCL), Muhammad Imran has sent inquiry report of Guddu ST-16 fire incident to the Board of CPGCL (Genco-II) for action against seven employees responsible for the mishap.
The inquiry report, available with Business Recorder, says that Steam Turbine Generator (ST-16) installed at 747 MW Combined Cycle Power Plant (CCPP) Guddu tripped on differential protection at 01:15:31 hrs on July 10, 2022.
At the instant of tripping, hydrogen leakage detectors installed at ST-Generator detected the leakage of hydrogen, which presumably resulted in fire incident at star point of Generator. After tripping of Generator Circuit Breaker (GCB), excitation breaker remained in contact and tripped at 01:15:34 AM under no-load for additional 3 seconds.
Excitation current remained greater than 1353 Amp (which was the excitation current at 210MW condition) which indicates the possible short circuit/ spark condition at rubbed/ loose contact carbon brushes and the presence of hydrogen in the area might have caused sudden explosion damaging generator’s rocker assembly, 20 KV Bus bar neutral point, bus bar CTs and PTs fire fighting system was not operational which caused delay in timely extinguishing of fire.
According to the report, at 0245 hours the fire was completely extinguished however, it caused severe damage to STG rocker assembly, generator output terminals and star point.
The fire eruption also damaged the overhead crane, associated power cables and panel.
An inquiry committee was constituted comprising Sabeeh-uz-Zaman Faruqui, Chief Executive Officer NPGCL, Convener, Haseeb Saqib, Chief Engineer, Representative NESPAK (Member), Muhammad Akram Sheikh, Additional Plant Manager, NPGCL Muzaffargarh (Member), and Jameel Hassan, Additional Director, NPGCL Muzaffargarh (Member).
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Terms of Reference (ToRs) of the committee were as follows: (i) the events, in chronological order, which led to the fire incident of ST-16; (ii) why the operation field team failed to identify any abnormality in the machine or in case of heavy rain, what remedial measure were taken;(iii) recommend action plan for early restoration of ST-16;(iv) fix responsibility in case of negligence or poor maintenance or poor operations; and (iv) recommended way forward to avoid such incident in future.
The inquiry report states that 747 MW CCPP has an ill-fated history. It has a history of “availability” and “reliability” issues. In recent past the plant suffered a lot, technically and financially.
The events in its chronology, which led to the fire incident: (i) Sequence of Events (SoE) function of Distributed Control System (DCS) is always quite helpful in fault diagnosis. This feature is part of the DCS (Ovation-Oc-4000 Emerson) of ST-16 of 747 MW but unfortunately it is not currently available due to some unknown reasons.