2 Summary Through the analysis of the cause of the 9200 Huaji 200 generator earthing accident, the stator stator core loading and loosening of the generator are discussed. 1 Overview The machine is manufactured by the Xunxinxin 200 large-scale steam turbine manufactured by a certain internal machinery factory. Tuning machine, the amount of 2351 hearts, set a fixed cable 15.75 wish, rated current 8 6254, water and hydrogen lean cooling and type. The aircraft was put into operation in January 1998. In the event of an accident, the average load rate of self-employment was 170.83 lbs., with a total of 37 starts and stops.
2 The accident was connected to the grid.
At 15:45, the generator stator ground signal was issued, and the relative earth voltage of the generator was 125kV. UB=10.5 cut, and the circuit had a grounding point. After the request, the load was reduced and the system was shut down at 16:21.
After the unit was shut down, a test was conducted on the generator outlet line, the arrester and the neutral point reactor, and no fault was found. On the 15th, the outlet line and the neutral line were disconnected, and 2500 pieces of insulation were shaken. , Drip, phase 390018, river, 8 and 38, 6, 17 pm open the upper end of the steam excitation at both ends of the end cap, using the capacitor discharge method, find out the fault point in the slot of the stator core 13 slot, extract the rotor After that, confirm that the grounding point is in the lower layer of the slot.
(3) Accidental damage situation The ventilation channel steel in the wind gap between the first segment and the first segment of the teeth between the first slot and the first slot is released. The length of the detachment was about the core, and the foreign material was found. The shape was ventilation channel steel, and the effective length was about 20mm. The upper surface of the wire rod of the first slot was damaged by insulation, and the damage was still there. Insulation; Insulation damage in the lower groove of the slot, insulation at the damage is zero; a lot of slamming marks in the stator core is about 7; the iron core is loose at the end of the stator core in the stator core, and the iron core is loose at the end of the ventilation channel. Core broken teeth.
4 reasons to analyze the report to check the situation of apricots. The initial accident of the accident is to be prayed for the loosening of the stator core tip end, with the finger gently pulling, there will be about 31 gaps in operation, the local mountain is now vibrating violently, causing ventilation, steel fatigue rupture solder joint rupture, causing damage After the ventilation channel steel part of the ventilation steel channel breaks into the air gap, it cooperates with the rotor ventilation channel steel and the core broken teeth to scratch the wire rod and cause the stator windings to be grounded; after the ventilation channel steel enters the air gap, it is determined. Between rotors. Caused Tuenji's rotor surface to be bumped. The direct cause of the accident was a partial looseness of the core end, which caused the looseness of the core end. What is the reason for the looseness of the core end? The punching film insulation film is thicker than the filling and the uneven thickness iron core pressure is not 3 The above 5 kinds of reasons will cause the iron core loose. Under normal conditions, the thickness of the core punchings should be measured before loading the cores. In the stacking process, thick flakes should be used to avoid loose cores caused by uneven thickness.
The film thickness of the punching film is not thick, and the thickness is not, especially the teeth of the punching sheet. The paint will cause the tooth to rise, and the unit will loosen in the thermo-mechanical vibration.
From the structure along. The core of the side section is the weak link of the core. The entire pressing force of the iron core is ultimately transmitted through the iron core of the pressing ring plate teeth. The rigidity angle of the tooth jade plate has a great influence on the tightness of the iron core on the side section. If the rigidity is not enough, the angle will cause iron to be skewed. The core is partially loose. Specially, it is a loose iron core in the side section. To avoid loosening of the iron core in the side section, multiple factories are now using special techniques to solve the problem. We use the steel sheet to bond the strands, and the scallops of the 12-segment cores on the sides are punched into pieces. Bonding, as a whole to strengthen the structural strength of the side iron core, to avoid local loosening.
The accident was due to the fact that the flight of the unit was short, the seriousness of the iron core loosened, and the damage caused. It is a relatively tight dumping all times to complete the whole escape heat pressure, heat the core to 9, about 24, after cooling. , One tightens the screw nut between the two ends of the tight excitation steam and presses the core tightly. The question lies in this last process, because the exciting end is under, the steam end is on, the working conditions of the steam end are better, the work surface is bright and bright, and the lower end of the excitation side is due to the support of the pier and other bearing supports, the working surface is narrow, Working conditions left, when tightening the tight end of the screw nut. Not tightened. The stator core 1 of the turbine generator has a long period of farm life. If the aircraft reaches 5.37, the friction between the core punching plate and the positioning ribs is large, and the pressure at the steam end will not be transmitted to the excitation end. Therefore, two The end tightly tightens the screw nut, in order to close the iron core. As a result, the 12-segment iron core of this exciting situation has become loose and round, and a total of 53 teeth have been added to the factory to form a thick phenolic cloth plate to plug the iron core.
5 Repair Situation The stator core vent channel steel is plugged with a thick phenolic release plate.
Defining the surface of the iron core with a special tool to separate the silicon steel pieces from the Kuanglu Road, insert 0., 1 thick epoxy glass cloth plate or 0.02 inml, L7XlfJt, replace the upper and lower damage bars with the spare bar. , DC leakage and withstand voltage of 0.7531 +3000 AC withstand voltage test, March 13 grid-connected power generation.
6 Preventive measures Combine with the crew for repairs. Check if the stator core, especially the side core, is loose and loose. Should be dealt with immediately, and the machine that pays for the new bid requires the manufacturer to use iron core adhesive to bond the iron on the side section to strengthen its integrity and avoid partial looseness. .
The person thinks. 5 Technology has been used for many years. Within the organization, there should be special seminars and discussions to summarize the experience of application design and debugging and seriously evaluate its application performance. Based on this, the technology application standard for the planting Tao Tao is formed. In the newly-established unit and the coordinated control of the thermal control of the old unit, it is used as the current bath technology program. At the same time, it is required to enter the power system, and the manufacturer develops and provides it. 8 Technology-specific software modules simplify configuration tasks and provide technical support for the successful application of 08 technology. In this way, the level of control of the motive power of a thermal power generating unit can be raised. 1 The Xi'an Thermal Power Research Institute of the Ministry of Energy. Thermotechnician's Handbook 5 Thermal Instruments and Naturalization. Beijing Water Power Press. 1992 2 Wang Zhixiang. Zhu Zutao. Thermal control design manual.
Beijing China Electric Power Press. 1995.
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