Generator bearing bushing high temperature shaft accident case

Generator bearing bushing temperature rise high 2018 - axial channeling accident cases 11 - 21 a, the occurrence of the incident and processing on October 25, 2017 # 7 units ready to stop working at a factory, 35 minutes and 56 seconds 17 when operators start communication lubricating oil pump, oil pressure of 0. 123 mpa, 4 # 5 watts jacking oil pressure. 48 mpa, lubricating oil temperature of 39. 7 ℃, # 5-5 bearing 2 metal temperature of 68. 4℃。 17 when 36 minutes 47 seconds to 0 # 7 unit load brake down, rotor to idle away, when 17 40 minutes and 54 seconds in # 7 units idle speed to 1606 r/min, # 5 bearing axial hydraulic top 1. 67 mpa, 5 - 2 metal temperature rapidly from 71. 9 ℃ to 157 ℃, 7 - running personnel immediately started 1 and 7 2 jacking oil pump and dc # 7 machine lubrication oil pump, 54 points by 17 # 5 bearing 5-09 seconds 2 metal highest temperature rise to 181. 3℃。 In 17 minutes and 39 seconds 54 units droop to 525 r/min, 5 - # 5 bearing 2 metal temperature starts to drop, 18 unit 15 minutes 33 seconds when droop to '0', # 5-5 bearing 2 metal temperature of 93. 6 ℃, turning normal. Analysis curve of the two, cause analysis, # 5 bearing 5 - # 7 machine 2 metal temperature rising rapidly, after which he points and 14 seconds at the top of the points to which he slew both points and 14 seconds shaft oil continues to decline, the axial displacement curve has obvious fluctuations, by - 0. 16 mm to - 0. 15 mm, then down to - 0. Rose - 17 mm later 0. 13mm。 The whole process of machine stop lubricating oil pressure and oil temperature has no obvious change, tile in the process of high temperature operation personnel to start jacking oil pump, jacking oil pressure rise, # 5 bearing bushing temperature by a brief decline, thus can eliminate oil system failure and improper operation cause # 5 bearing bushing high temperature rising. Based on the analysis of the above phenomenon, for the unit brake rotor appear in the process of small front axle, double tile when measured by the unit # 5 watts bearing about 36 tons of gravity, the power of the axial channeling will through the oil film is passed on to the bearing shell, prompted a synchronous or slightly lagging behind the front axle of bearing, bearing bush and slightly tilted, after bearing tilt in the jacking oil capsule is hydraulic uninstalled, big oil film between shaft and bush are destroyed, the dry friction, and thus lead to 5 - 2 watts temperature rise quickly. Analysis from the aspects of equipment, economic plant for the bearing bush of relying only on the motion of the bearing pad iron line to maintain the position of the bearing, self-aligning ability is poor. Comprehensive analysis from the above two aspects, immobilized idler rotor axial channeling occurred in the process of moving, from oil film transfer to bearing, due to the self-aligning bearing ability is poor, lead to bearing and rotor is not parallel, big oil film between shaft and bush are destroyed, eventually lead to dry friction burn. Three, to formulate the preventive measures and implementation effect of the event 1, immobilized before load reduction, strict according to the requirements of the operation rules, communicate the steam turbine lubricating oil pump, lubricating oil pump start and interconnection test, dc dc lubricating oil pump should also be hard hit start-stop test and in situ, barring in-place start the test, to ensure that the oil pump, the turning test is normal, if there is a problem should contact maintenance for processing, in front of the untreated normal defects, prohibit to shut down the unit operation, and make relevant accident forecast. Unit 2, in the process of stoppage adjust steam turbine lube oil temperature, oil temperature at 35 45 ℃, should not be too high or too low, more than a specified value, in the process of the unit load down if you find any support bearing temperature turbo generator thrust bearing temperature of 110 ℃ or 110 ℃, should immediately stop manually, if any of the steam turbine generator in the unit idle away support bearing temperature of 110 ℃ or thrust bearing temperature of 110 ℃, should add lubricating oil pump, immediately start ahead of jacking oil pump, vacuum unit idle away time, reduce the damage degree of the bearing. The normal bearing return oil temperature < 65 ℃, if abnormal check reason analysis and processing. 3, unit load drop to zero before the brake, early start and a jacking oil pump, unit to droop to 2300 r/min and second jacking oil pump, check the jacking oil pressure is normal, closely monitor unit each tile temperature changes and the axial vibration, found that exception handling in advance. On March 16, 2018 # 7 units start the operation again, according to these measures, in the process of start up and stop idle away 2300 r/min, 3000 r/min to start or stop a jacking oil pump, ensure the generator bearing oil film stability before and after the test all the bearing parameters such as temperature, vibration stability has no obvious change. Experience, if four, epilogue experience, and summed up the experience and lessons, hope that through this event can be used to be used for reference in jinan generator brother unit, according to the characteristics of their units units to develop the corresponding preventive measures and precautions.