Turbine Operation Issues.pptx
- 1. TURBINE OPERATION ISSUES Presented By: TAHOOR ALAM KHAN Dy. Manager-Operations RattanIndia Power Limited
- 2. EHA OIL SYSTEM • Loss of EHA oil pressure resulting into closing of control valves & stop valves due to any of the following reasons: • Oil line leakage. • Malfunctioning pump. • Malfunctioning Pilot Valve or TSV. • EHA filter chocking.
- 3. TURBINE BEARING ISSUES • Rise in turbine bearing metal temperature due to excessive loading. • Turbine bearing worn out due to higher MI contents in oil. • In adequate lube oil pressure can cause insufficient lubrication of bearings. • High moisture contents in MOT oil causing inadequate cooling of bearings. • Hindrance in formation of oil film inside bearing due to changes in oil quality.
- 4. TURBINE VIBRATIONS • Sudden changes in turbine load. • Wear & Tear of turbine bearings. • Wear & Tear of thrust pads of thrust bearing. • High difference in upper and lower casing temperatures. • Damaged moving or stationary blades. • Sudden changes in seal steam pressure or temperature.
- 5. HIGH TEMPERATURE ISSUES • Due to issues with DMCW cooling water system, following issues by occur: • Exciter hot air temperature increases. • MOT lube oil temperature increase causing increase in turbine bearing temperatures. • Generator cold gas temperature will increase due to inadequate cooling in hydrogen coolers.
- 6. SEAL STEAM ISSUES • Seal steam can cause issues in following ways: • Reduction in seal steam pressure causing drop in condenser vacuum. • Closure of seal steam supply valve or opening of leak off valve causing drop in seal steam header pressure. • Drop in seal steam inlet temperature below 280 deg. C causing closing of inlet valve. • High seal steam pressure may causing leakage of seal steam into atmosphere and can also result into increase in MOT moisture.
- 7. GEN COOLING VALVE ISSUE • Due to malfunctioning of generator gas cooling valve, the cold gas temperature will increase causing outage of unit. • Malfunctioning may due to issues related to supply module or command problem.
- 8. CONDENSER VACUUM • Loss is vacuum can be due to any of the following reasons: • Tripping of vacuum pump. • Inadequate seal steam pressure. • Malfunctioning of seal steam supply valve or leak-off valve. • Tripping of CW pumps. • Opening of Vacuum Breaker.
- 9. SEAL OIL SYSTEM • Seal oil is provided to avoid hydrogen to escape from generator from clearances between gen shaft and gen casing. But failure of seal oil system can result into unit outage. • Due failure in maintaining seal oil pressure due to any of the following reason, hydrogen purging need to be done along with turbine tripping • Tripping of AC seal oil pumps and DC seal oil pump failure to start. • DPR malfunction. • VOT level low. • Leakage in seal oil carrying line.
- 10. MEASUREMENT ISSUES • Issues with parameter measurement includes: • False temperature of turbine bearing, cold gas temp, hot exciter air temp or HP exhaust temperature. • False axial shift of turbine. • False vibrations of shaft or bearing. • False lube oil pressure, seal oil pressure etc. • False main steam temperature. • Malfunctioning of turbine overspeed trip channel.
- 11. HPBP/LPBP SYSTEM • Sudden opening of HPBP or LPBP system due to any of the following reason: • HPBP valve opening due to loss of pressure due to leakage or pump tripping. • HPBP valves fail to open due to loss of vacuum. • LPBP valves fail to open due to condenser wall temperature high.
- 12. THANK YOU