January 21, 2022

Optimization Research on Insulation Structure of Ertan Hydrogenerator

The structure has been optimized, and the results of the optimized research have been applied to the actual situation, and good results have been obtained. This paper mainly focuses on the stator core insulated Roebel bar insulation structure, the main insulation structure stator groove fixed structure, and the rotor inter-turn insulation structure. And the optimization of the insulation structure of the body and the like, so that the entire insulation structure meets or exceeds the requirements of the Canadian company GE, reaching the world advanced level.

1 Stator core insulation According to the requirements of GE Canada, the silicon steel sheet paint for Ertan stator core must meet the following conditions: The performance of semi-inorganic silicon steel sheet paint is shown in Table 1. Other properties and comparisons are shown in Table 2. 1 Table 2 can be seen that this paint has two significant advantages: one is to overcome the shortcomings of the current organic paint and inorganic paint, can better meet the requirements of the Franklin burn test, even at least thin film thickness The Franklin test can also meet the requirements of the Franklin test; the second is to make up for the shortcomings of the current semi-inorganic paint cross-section (which limits the application) and can be applied to any product.

Table 1CGE company performance requirements and measured results Performance standards measured Franklin test current (A) ft15 (maximum 0.6) 0 bending test film does not crack, does not fall off without cracking, does not fall off Franklin burned 0.5V (DC) conditions measured The average leakage current is not more than 0.15A, and the maximum value is not more than 0. Bending test: After the sample is bent on a rod with a diameter of 38 mm, the paint film does not crack and does not fall off.

Department of Electrical Engineering. Mainly engaged in the research and development of high-voltage motor insulation (Tel 2 stator winding insulation stator winding insulation mainly focuses on winding magnet wire, Roebel bar and main insulation structure. The Roebel bar is studied in two aspects: one is Roebel The most important material of the wire rod is the electromagnetic wire, and the second is the optimization of the Roebel wire rod insulation structure.

In the case of the electromagnetic wire, the thickness of the insulation should be as thin as possible, so that it is beneficial to the heat conduction and is also beneficial to the improvement of the groove utilization. The conventionally used electromagnetic wire is a double glass wire covered with an insulation thickness of 0.4 mm. The disadvantage is that the insulation is thick, and the flexibility and heat resistance are both poor. A new type of electromagnetic wire-one-polyester glass fiber lacquer-free sintering line has been newly developed. The performance requirements and measured data are shown in Table 3.

As can be seen from the performance of Table 3, the insulation thickness of this wire is much thinner than the traditional double glass wire (0.4mm), and the heat resistance and flexibility of the performance of the pregnancy 2 paint performance comparison standard organic paint semi-inorganic paint New semi-inorganic paint film hardness paint film adhesion level 1 temperature index section coverage good difference good minimum film thickness lm) bending does not break off table 3 electromagnetic line performance requirements and measured results measured results serial number project test method CGE standard requirements Wire gauge insulation thickness Insulation bond with knife edge cut 50mm long firmly attached does not warp qualified insulation adhesion stretch 20% does not loosen qualified turn 4a bend does not crack qualified electrical strength steel ball method high temperature performance does not crack qualified heat aging firm not warping The non-cracking qualification is conducive to the improvement of heat conduction and the improvement of the tank utilization rate. At present, the electromagnetic insulation insulation, the transposition insulation and the inter-row insulation of the Roeble rod of the company are still relatively thick, and there is still a certain gap compared with foreign companies. As shown in Table 4, the gap between the company and the advanced companies is reduced. The electromagnetic wire is made of double-polyester glass and lacquer-free sintered wire. The transposition insulation is made of soft mica plate. The insulation thickness of other parts is also set. Reduced, the final optimization results are shown in Table 5. It can be seen that the Roebel wire rod insulation structure of the company has reached the level of Canadian GE company, and the Roebel wire rod made according to this structure has good integrity, no short circuit phenomenon is generated through optimization, Roebel wire rod section insulation Occupancy (insulation area crowbar area) can be reduced by 38% ~ 39%, groove utilization can be increased by 3% ~ 5% Table 4 Roebel wire rod insulation thickness parameter comparison (mm) project Shuikou (the company) Ming Tombs (ELIN company ) Ertan Lubuge Company) Three Gorges Wide Height, Height, Height, Height, Height, Height, Height, High Electromagnetic Line, Swelling Capacity, Interchanging Table, Table 5Roebel Bar, Insulation Structure, Material, CGE Structure Thickness (mm), Company Structure Thickness (mm) ) Electromagnetic wire double-polyester glass, no paint line, expansion amount, transposition, insulation, soft mica board, row insulation, multi-gel mica board. It can be seen from equation (1) that the electric field non-uniformity coefficient fm decreases with the decrease of d/r. That is, reducing d and or large r can reduce fm. Therefore, in order to improve the electric field distribution, it is necessary to reduce d/r 0.8mm, the conductor fillet radius r = 2mm, the insulation thickness d = 3.5mm, and the calculation electric field unevenness coefficient is listed in the table. 6 Table 6 electric field unevenness coefficient calculation results can be seen Under the same conditions, the maximum field strength can be reduced to the original when the fillet radius is from 08mm to 20mm (E'm 8 (%, the breakdown field strength can be increased by 25%. The visible effect is obviously based on the above analysis). The electric aging life can be estimated by the following formula: the general n is 6) is a constant, then T / r = (EWEm) = (1.25) 6 = 3.8, that is, in the range of n constant The internal rapid aging life can be increased by 3.8 times, and the effect is extremely obvious. From the above analysis, the effect of increasing the fillet radius to 2 good electric field distribution is remarkable. However, the structure for achieving this goal can be various. Through argumentation analysis, it is optimal to take measures on the narrow side of the Roebel bar.

5毫米的密度耗系数 The thickness of the main insulation is 3. 5mm dielectric loss factor. The thickness of the main insulation is 3. 5mm dielectric loss factor. The thickness of the main insulation is 3. 5mm dielectric loss factor. The relationship with temperature (1) and voltage (U) is plotted as curve (eg 3). It can be seen from 3: (1) The initial value of dielectric loss tanS is between 0.4% and 1.1%, and there is no significant difference between the optimized structure and the common structure ( 2) The dielectric loss tanS does not increase with the voltage and the large dielectric loss tanS and the temperature curve appear peak near 90C, which is consistent with the common structure. This shows that the optimized structure of the semiconductor table 7 line bar breakdown test results number optimization structure bar Ordinary structure bar average breakdown voltage kV Table 8 bar fast electrical aging test results (field strength 35kV/3.5mm) sample number optimization structure bar common structure bar (1985 Tongma mica tape bar) life time ( h) It can be seen from Table 7 that the optimized structure of 137. 75kV is 1555h longer than the normal value, and the median life of 743h is longer than the regular structure. The 112kV of the near structure is increased by 23%, that is, the field strength is increased by 23%, and the field strength is 1.1 times. Compared with the theoretical calculation of 28 times The 25% calculation of the recent theory is quite consistent. It can be seen from Table 8 that at the same time, eight rods with an insulation thickness of 4.4 mm were fabricated according to the optimized structure, and the results were as high as shown in Table 9. The median life is 1620h, far exceeding the 600h gauge breakdown voltage average of 151kV, field strength 34. Table 9 line bar breakdown and aging results (44kV / 4. test line knot number breakdown test electric aging test breakdown voltage kV electric aging life time (h) In summary, the optimized structure improves the electric field distribution, which can effectively improve the breakdown field strength of the coil and prolong the electric aging life.

23.4 Structural application The application optimization structure on the Ertan unit was first applied to the rated voltage of the Ertan unit at 18kV and the insulation thickness of 4. 6mm. The dielectric loss and breakdown test results of the coil are shown in Table 10 as shown in Table 10. , dielectric loss and dielectric loss are very small, the breakdown field strength is higher than that of similar products. Table 10 dielectric loss and breakdown test result rated voltage multiple bar insulation dielectric loss, normal state (% dielectric loss, thermal state (% Breakdown voltage (kV) electrical strength (MV/m) (41.5kV/4.6mmA20C) aging test. The results are shown in Table 11, the lowest one of which is 1309h, which is much larger than the 400h standard specified by CGE. Send to CGE for hot and cold cycle test after 500 cycles, (a) dielectric loss measurement; (b) dimensional measurement; (c) air measurement; (d) partial discharge measurement. CGE company concluded: meet the requirements At the same time, CGE carried out additional electric aging (33kV/4.6mm) test on the wire rods after 4 hot and cold cycle tests. The results are shown in Table 12. It can be seen that the test results of CGE Company are much higher than the 250h table. Coil electricity Heat aging life time coil number heat aging life (h) target life (h) breakdown of the damaged part of the straight part, the corner is not broken down Table 12 electric aging life result number life time (h) target life (h) remarks Wear unbreakable table 13 electric aging life test results line bar number stress level life time (h) remarks heat aging treatment average value minimum life expectancy average minimum life expectancy 23.4.2 in the Three Gorges test line bar application for the Three Gorges The manufacturing rights of the stator coil, Harbin Electric Machinery Co., Ltd. produced six test wire rods to ABB for comprehensive performance test, the six wire rods used optimized structure. The most critical test items, one electrical aging test results are shown in Table 13. The life shown at 6U (32kV) is 7889h, and both bars are not broken down. The average life of 2040h at 2U (40kV) is more than four times the expected life of 500h.

At the same time, this optimized structure has been applied to the Wanjiazhai hydropower generating unit and has achieved good results.

24 stator winding groove fixed structure groove is fixed by the use of insulated corrugated board and RTV / CRTV fixed structure.

24.1 Corrugated plate adopts a radially fixed structure in the groove, and an elastic insulating corrugated plate is added between the groove wedge and the coil. The advantage is that the corrugated plate is in a compressed state after the lower wire, and a prestress is generated in the radial direction to ensure the coil. In the radial direction, the semiconductor laminate is used to fix the side of the coil, and it is segmented. It is actually in point contact with the coil and the groove wall. There are many disadvantages. The RTV/CRTV structure uses room temperature vulcanized silicone rubber (RTV). And the semiconductor silicone rubber (CRTV) is applied to both sides of the coil and solidified. Because RTV/CRTV has better elasticity after curing, the contact with the groove wall after the lower wire is in surface contact, so it is tight, which overcomes the traditional fixed structure. Disadvantages, make mechanical fixing more secure, will not cause vibration and wear, and greatly improve heat conduction, especially to effectively reduce the slot potential (groove resistance). 3 Rotor insulation structure Rotor insulation structure is mainly interturn insulation and polar insulation 3.1 Rotor winding inter-turn insulation The traditional inter-turn insulation is made of epoxy glass cloth. The biggest disadvantage is the large thickness (0.4mm) and electrical and mechanical properties. It is also inferior. The paper uses the glued Nomex paper as the inter-turn insulation. It is also a material commonly used by the world's leading companies. The thickness is only 0.26mm, so that the inter-turn insulation thickness is reduced from 0.4mm to 0.2mm, and the electromechanical performance is also large. Improve and reach the world's advanced level.

3.2 Rotor body insulation The traditional pole insulation is made of epoxy glass laminate with a thickness of 4mm. At the same time, additional insulation is needed to prevent creepage. The wide mica tape is wound around the surface of the pole and hot pressed to form a continuous closed. The overall insulation, no gap between the pole and the body, the thickness is only 1.3mm. Its advantage is that the thickness is small, the overall continuous type is not easy to generate creepage, and no additional insulation is required. 4 Conclusion The Ertan unit adopts advanced and reliable insulation materials and structures. A number of technologies have filled the domestic gap and reached the world's advanced level.

The research and application of double polyester glass lacquer-free sintered electromagnetic wire, Roebel bar optimized structure main insulation optimization structure and new semi-inorganic lacquer is another leap in the research application and structural design level of materials in this field, which will promote the domestic motor insulation technology. The overall level of improvement.

Most of the results of this project have been fully promoted and applied in domestic water and thermal power units, and achieved good results and benefits.

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