Diagnostic Analysis Method of Direct Air Cooling Unit Limited Output Based on Pressure Ratio

Abstract Given the limited output of a 600MW direct air cooling steam turbine unit, through thermal performance test, historical operation data extraction, and comparative analysis combined with after latest overhaul, it is found that extraction pressure first section high-pressure cylinder began to appear over-pressure in recent two years. After further calculating ratio HP flow passage stage group, exhaust Section I has increased by nearly 4% last years, indicating area part this group become smaller serious salt deposition occurred, resulting reduction capacity ultimate limitation whole unit. The uncovering inspection results verify correctness diagnosis. diagnosis method simple suitable for fault actual passage.