Prior to the incident Unit #5, STPS was running with restricted load at 175 MW due to TG bearing vibration high. Four mills operation had been carried out & no secondary fuel oil support was required at that time.
At around 21:00 hrs during routine check-up by the operating personnel, it was observed that the huge smoke was coming out from turbine aquastic encloser. Control Engineers along with operating personnel were rushed to the affected area and observed a big fire hazard occurred at the vertical portion of LHS turbine inlet MS pipe. Immediately they tried to extinguish the fire. By the collective effort of STPS people, fire was extinguished at around 21:50 hrs.
Then it was found that there was a huge turbine oil leakage from orifice/ throttle valve flange joint of MOP/ AOP common discharge header. Temporary measure at the leakage point was taken to minimize the quantity of leakage.