Due to the bearing damage caused by accident, well bearing detection is of great urgency

The kansai electric power company to hainan power plant the kansai electric power company power plant capacity of 600 mw # 3 machine in June 1972 attacks destructive accidents in the test run. The accident in the grand vibration units attack within a very short time after the attack. Normally, the cause of the steam turbine generator vibration increase a lot, but in such a short period of time so the vibration of the grand, # 3 # 11 bearing ( Exciter) This time the cause of the accident damage. Because of # 11 bearing bearing cover and bearing assembly quality is not very good, in the test run, landing speed shaft vibration particularly big, wear and tear of the bolt screw thread; When speeding experiment ( Speed up to 3850 r/min) , # 11 bearing the axial vibration of a sudden increase, the bearing cover fixed bolt out, bush is shattered; With oil baffle ring and the bearing bush flew out, and are unable to provide smooth oil bearing lower half, # 11 a bearing dies. At this time, the oil film damping is reduced, cause land shaft critical speed, speed (close to the time of the practice 3850 r / min) , caused resonance, the resonance immediately invite exciter shaft present grand vibration ( See the figure) 。 In the grand vibration units attack after a very short period of time, more section of shaft fracture, spare parts, and cause a fire, especially big accident. Figure 3 is # 9 ~ # 10 generator bearing structure, figure 4 to # 11 bearing structure diagram. With the increase of generator capacity and the growth of the shaft, the vibration of steam turbine generator problem will become even more important, so in the construction, installation, commissioning should especially pay attention to all aspects. Clarified the experience of the accident, the bearing device and fixed must adopt a kind of abundant thought the device technology solution to the problem of the vibration. Balanced adjustment way to begin, in addition, we should improve the generator covers the whole shafting vibration exciter of calculation of inspection methods. Heilongjiang big bending axis accident of a certain power plant in heilongjiang province motor maintenance staff of a certain power plant in November 1993 # 2 machine disposal of exciter commutation carbon brush a blaze defect, due to the disposal process degree, technical level is not high, a ring of fire, from # 2 generator field loss, active load swing sharply, speed regulating valve is out of control, is buried under the accident disaster. When electrical attendant for control of generator out-of-step operation with synchronizer # 2 machine active load reduction, has adjusted is invalid, so break out the magnetic switch, column of the machine. After solution column # 2 machine, speed regulation valve cannot close, not only maintain the unit idle, and speed shock, provoke critical protector action, the main valve closed automatically. Defects, due to the main valve automatically the jamming are not locked, forming unit overspeed accident: the first is at the end of the turbine triple blade fracture damage, breakdown of low pressure cylinder and attacks the first explosion, intense vibration unit, string shaft, shaft stability destroyed, thus damage power secret seal tile; Leave behind, the hydrogen overflow gave birth to a second explosion and fire that ignites the turbine turbine oil and local cable at the same time; , then further instability of shafting and destroy all bearings, twisting spindle, make each activity turbo-generator set severe local touch grinding, impact, seriously damage the unit. Close the main steam pipe after electric main gate and total valve, to cut off their admission, complete rotor rotational power lost and suspension, the whole process of the time is short. Supercritical unit in one power plant in jiangsu shaft neck injury device of a certain power plant in jiangsu have 2 units of 600 mw supercritical unit. On March 3, 2006 C level maintenance smoke generator rotor is found that the generator excitation end bearing severe wear and shaft neck also serious wear and tear. Opened on March 8 # 8 bearing shell tiles, wazhou found # 8 axis neck middle severe wear, wear attack position among wazhou # 8 axle neck, the axial period of about 420 mm long axis, the wear depth ( Radius direction) 0. 1毫米~ 0。 80毫米。 The deepest about 1. 0mm。 Turned out after # 8 on the bearing shell tile, tile has minor scratches, # 8 journal is severely scratched, article 17 of the scar, the largest scar about 2 mm wide, deep about LMM, the scar is circular shape, from middle to both sides, in turn, densely spreading gradually at # 8 journal. Dig out # 8 bearing bush found that after the second half of the tile generator end jacking oil sac by wear or by wear and tear of tungsten gold filled and motor end badly worn appearance of tungsten gold, and the steam side tungsten gold appearance has serious phenomenon, hair, hair attached to a large number of fine wire. Mesh serious breakage form a large number of fine wire into smooth oil system: a large number of fine mesh wire with smooth oil pours into between shaft and bush. Damaged the oil film between shaft and tile, exacerbated by the friction between the shaft and tile. Accident occurs, the mother tube jacking oil pressure has dropped to 9 mpa, 12 mpa is lower than the design value. Under the pressure, # 8 journal cannot complete the jacking. As mother pipe jacking oil pressure to land, incur journal and bearing clearance is reduced, while the low pressure cylinder on both sides of the bearings with bearing affected by the condenser vacuum and single side bending, thus easily provoked bearing one tile burning.