2 Abstract Through the analysis of the cause of 9 grounding accidents of generator 200 generator, the stator core loading and loosening of the generator is discussed. 1 Overview The machine is manufactured by a certain machine factory in the 8th 200-type large steam turbine. Downtime, the amount of capacity 2351 heart, Lu Ding telegraph 15.75 wish, rated current 8 6254, water hydrogen lean cooling and style. The aircraft was put into operation in the month of 1998. In the event of an accident, the average load rate was 170.83 cubits, and 37 times were started and stopped.
2 The accident went through the grid.
At 15:45, the stator grounding signal of the generator is emitted. The relative ground voltage of the generator is 125kV.UB=10.5, and the grounding point exists in the loop. After the request, the load is reduced, and the system is shut down at 16:21.
After the unit was shut down, the generator outlet, 1 arrester and neutral point reactor were tested and no faults were found. On the 15th, the outlet and neutral points were disconnected and insulated with 2 500 shakes. , Drop, Into phase 390018, River, 8 and 38, 6, 17 afternoon, open the upper half of the upper end of the steam excitation, use the capacitor discharge method to find out the fault point in the slot part of the slot of the stator core 13 and extract the rotor After that, confirm that the grounding point is in the lower slot of the slot.
3 Accident damage situation The first part of the toothed groove between the first groove and the third groove and the ventilation groove steel in the air groove between the first core are removed. The length of the take-out is about the core, and the foreign matter is found. The shape is a ventilation channel steel, and the effective length is about 20 mm; the insulation of the upper layer of the upper layer of the first groove is damaged, and the damage is still there. Insulation; the insulation of the lower layer of the first groove is damaged, the insulation at the damage is zero; the smashing flaw in the inner surface of the stator core is about 7 pieces of the core of the stator core end of the stator core is loose, and the ventilation core is out of the place. Core broken teeth.
4 reasons analysis report according to the above inspection of apricot. Initially, the accidental flashing of the stator core is as follows. The end of the stator core is loose. With a finger, the gap is about 31. During the operation, the local mountain is now vibrating, causing ventilation, and the steel fatigue fracture joint is broken. Part of the ventilation channel steel exits the broken ventilation channel steel head into the air gap, and cooperates with the rotor ventilation channel steel and the core broken teeth to scratch the wire rod, causing the stator winding to be grounded; after the ventilation channel steel enters the air gap, it is determined Movement between the rotors. Caused by multiple impacts on the rotor surface of the machine, the direct cause of the accident is the partial looseness of the core end, which causes the partial looseness of the core end, and the thickness of the core iron fan is uneven; The insulating film of the punching film is relatively filled and the thickness is uneven. The iron core pressing process is not 3. The above five reasons will cause the iron core to loosen. Under normal conditions, before the core is pressed, the thickness of the core punching piece should be measured. In the stacking process, thick sheets are matched to avoid looseness of the core caused by uneven thickness.
The film thickness of the punching film is thick, and the thickness is not high, especially the teeth of the punching piece, the tooth is caused by the paint, and the vibration of the thermomechanical machine is loosened by the unit.
From the structure along. The core of the edge is the weak link of the core. The entire pressing force of the iron core is finally transmitted through the iron core of the pressing plate and the edge of the pressing piece. The rigidity angle of the toothed jade piece has a great influence on the jade tightness of the side core. If the rigidity is not enough, the angle will cause iron. The core is partially loose. In particular, the core of the edge is loose. In order to avoid the looseness of the core, the multi-factory is now solved by a special process. The steel is bonded to the strands, and the 12-segment core of the side is cut into pieces. Bonding, to become a structural strength of the core reinforcement core, to avoid partial looseness.
In this accident, the unit was shipped, the short period between them, the looseness of the core reinforcement, and the damage caused. It is one of the more severe pressures, and all the escapes are completed. The heating core is heated to 9, around, and the heat is kept. , 1 tighten the screw nut at both ends of the tight excitation steam and press the iron core. The question is that in the last process, because the excitation end is at the bottom, the steam end is on the upper end, the working condition of the steam end is better, the working surface is spacious and bright, and the lower side excitation side has a load-bearing support such as a buttress, and the working surface is narrow. Working conditions are left, when tightening the screw nut at the tight end. Not tightened. The steam turbine generator stator core shaft 1 has a long degree of agronomy. If the machine reaches 5.37, the friction between the core punching piece and the positioning rib is large, and the pressing force of the steam end will not be transmitted to the excitation end. Therefore, two The end tightens the screw nut to tighten the core of the core. As a result, the current stage of the 12-segment core is loose, and the entire circle of 53 teeth is added to the factory as a thick phenolic cloth to tighten the core.
5 repair situation Stator core ventilation channel steel out of the place with a thick phenol waking board plug.
Separate the core surface of the iron plate with a special tool to separate the silicon steel sheet of the road, and insert it into 0., 1 thick epoxy glass cloth board or 0.02inml, L7XlfJt, the upper and lower damage bars of the first groove are replaced with spare wire rods. , DC leakage and withstand voltage 0.7531 + 3000 AC withstand voltage test, connected to the grid on March 13th.
6 Precautionary measures combined with the crew repair, check whether the stator core, especially the core of the side, is loose, if it is loose. It should be dealt with immediately. The machine that pays the new bidding requires the manufacturer to bond the iron to the edge of the iron core to strengthen its integrity and avoid partial loosening. Male, Yunshang 4 Mingren, engaged in high voltage technology test research .
The latter believes. 5 technology has been applied for many years. The organization should organize special discussions and exchanges, summarize the application design and debugging experience, and carefully evaluate its application performance. On this basis, the technical application standard of the species is completed. In the coordinated control of the new unit and the old unit thermal control transformation, as the current bath technology program is promoted and applied at the same time, it is required to enter the power system 0, and the manufacturer develops and adopts it. 8 technology dedicated software module, simplifying the configuration work, providing technical support for the successful application of 08 technology. In this way, you can make the face of the high-powered fire-fighting generator moxibustion control level, 1 Xi'an Thermal Power Research Institute of the Ministry of Energy. Thermal Technology Handbook 5 Thermal Instruments and Naturalization. Beijing Water Power Press. 1992 2 Wang Zhixiang. Zhu Zutao. Thermal control design design manual.
Beijing China Electric Power Press. 1995.
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