New Technology for Stator Windings of Generators in Dahua Hydropower Station

2 Abstract This paper describes the manufacturing technology of insulated coils of 15.75kV strip-type stator coils jointly developed by Shuangfu Company and Fuji Electric and applied to the capacity expansion project of Dahua Hydropower Station, and the test results of the test bars.

1 Overview There are 4 single 100MW 4MVA turbine generator sets installed in Dahua Hydropower Station on the Hongshui River in Guangxi. Since December 4th, 1983 to June 1985, four turbines have been put into operation successively, and the stator of turbine runner generator has exposed more defects12, which has seriously jeopardized the safe operation of the unit. Therefore, the owner decided to use The 4 units were reconstructed, and at the same time, the transformed units were able to reach their output. After participating in bidding, Shuangfu Company won the bid of the generator company.

The first Unit No. 2 that was reformed was shut down in October 1998 and was successfully rebuilt on May 26, 1999. The first unit that was transformed was put into production on May 4, 2000. The first stage of the transformation of the original generator for the existence of defects, as well as the requirements for capacity expansion, the company conducted a more comprehensive deep calculations and demonstrations. In the design and manufacture of the stator coils for the capacity expansion of Dahua Hydropower Station, new structures, new materials, and new processes have been used in recent years.

2 Stator winding insulation technology for generators Since the company was established in 1994, the company has introduced Fuji Electric's advanced management concept technology research methods, design, research, and manufacturing technologies for hydroelectric generating sets. At the same time, the company carried out comprehensive promotion of the major aspects of the quality of the machine environment in accordance with the theory of total quality management. Among them, selected technical personnel to operate the workers to Fuji Electric for training. Fuji Electric was invited to send instructors to the company for guidance. Advanced equipment, transform existing equipment, improve product production environment, entrust domestic insulation material manufacturers, develop new materials according to the technical requirements proposed by our company;

Through the above measures, the insulation of our company and the design and manufacturing technology of its related products have gradually approached and have basically reached the world advanced level.

Dahua Power Station Capacity Modification 15.7510 Bar Stator Coil 2.1 Insulation System for Stator Bars The stator coil insulation system used in our company is a prepreg insulation system. By heating and pressing the wrapped insulation layer, it is cured into a uniform dense insulation layer.

22 Insulation Structure of Stator Bars Since 1993, Fuji Electric has conducted a comprehensive test analysis of the insulation materials used in the plant. Immediately after the establishment of the company, the trial process was added. Based on the experimental analysis results, we commissioned domestic insulation material manufacturers to develop new materials and improve the insulating structure of the bar.

2.2.1 Insulation between Rows The row insulation used in the Fuchun River Hydroelectric Equipment General Plant is used to adjust the thickness of the poly(masticated mica) board and the amount of glue, etc., to improve the gelation of the wire rods. The flatness and the filling rate between the strands of the strands.

2.2.2 Transposition Insulation F-class DMD is used as transposition insulation. Because its surface is fiber non-woven, it has better resin permeability, and it can make a good combination with winding wire and transposition conformal packing.

2.2.3 Transposition Conformal packing uses a new transposition conformal packing. With reference to Fuji Electric's technical requirements, the United Nations internal insulation materials manufacturers have jointly developed a mica resin mixture board. Since the mica resin mixture plate is in the air gap 3 inside the stator bar, at the same time, due to the glue used in the conformal filler and the mica plate and the main insulation glue, there is no defect of poor compatibility with the main insulation, so that the line bar The insulation characteristics have reached a higher 2.2.4 main insulation thinning technology Thinning the main insulation thickness is a more effective method to improve the economic indicators of the unit. The motors manufactured by most famous foreign motor manufacturing companies are much thinner than the main insulation thickness of domestic motors. Therefore, our company and other large electric motor manufacturing companies in China have conducted research on main insulation thinning technology in order to ensure stator bar operations.

The means of reducing the thickness of the main insulation and at the same time ensuring the electrical performance of the stator bars is the use of a main internal pressure equalization layer.

Due to the complex structure of the transposition of the strand bar, the electric field distribution is extremely uneven. Using the main insulating internal pressure equalization layer, the corner field electric field distribution can be reduced by increasing the fillet radius of the gelled wire rod to reduce the electric field distortion rate and improve the voltage strength of the wire rod.

2.25 Technical Requirements for Primary Insulating Materials and Comprehensive Applicability Tests for the Powdered Mica Tapes to Selected Material Manufacturers.

2.3 Design and manufacture of large stator bar The technical features are to ensure that the thickness of the stator bar after the main insulation thickness is reduced, in addition to the use of the main insulation inner uniform voltage layer to improve the corner electric field distribution to reduce the electric field distortion rate to improve the bar In addition to the voltage withstand strength, our company has also made major improvements in the design and production environment of online sticks and equipment manufacturing technologies.

The design of the bar takes full account of the bending performance of the winding wire and the resilience making equipment and manufacturing process.

The entire process of bar production is performed in a dust-proof room with constant temperature and humidity, eliminating the adverse environmental impact on the performance of the bar.

The bar is primarily insulated and molded on computer-controlled fully-automatic stator bar molding equipment imported from Austria 13001.

Because the molding equipment has the following characteristics, it is determined that the molded bar has high stability and the main insulation layer is compact. The molding of the bar is implemented by program management, and a special molding process is adopted to fully eliminate the remaining powder. The gas between the mica tapes, when molding the bar. The pressure on the bar surface is increased by 3 times.

The wire rod gelation process is performed by using grooves and ends, respectively. That is, the straight portion is gelatinized to form the rear end portion of the body, and then the end portion is gelated. The implementation of this method makes the size of the linear part of the bar very stable.

The molding die end gel mold of the bar also considers the resilience of the winding wire.

The above improvements in many aspects ensure the correct geometrical dimensions of the molded bar and the uniformity of the main insulation thickness of the main insulation, ensuring the manufacturing quality of the stator bar.

2.4 The electrical characteristics of the stator windings of the large-scale stator test cable 2.4.1 Initial characteristics data of the initial characteristics 1.

The initial characteristics through the domestic insulation materials manufacturers to submit higher than the national standard test project characteristics of the project test results and other products excellent products Remarks No requirements No requirements No requirements No requirements No requirements Breakdown voltage = 5 boost speed, no requirements breakdown field According to the calculation of the main insulation thickness, Yuan Ying, 24.2 resistance to cold and hot cycle characteristics 180, N a little impatient 00 claws, and then use about 120,1 for cooling. The residual breakdown voltage after 100 cycles is 12 let.

2.4.3 withstand voltage life test withstand voltage test life line number n = 5X2 in normal temperature oil, according to 4.3, the experimental data projections. 1 life under voltage at 1081! the above.

2. Small 4 heat resistance test was carried out, in which the wire rod was continuously placed 1000 and then the residual breakdown voltage was measured. The result was 8 so that the mechanical properties of the 2.5-gauge stator test rod passed through the test rod bending test wire rod number The elastic modulus E test was performed on a dedicated bending test apparatus, and the test rod was placed on the apparatus.

The two fulcrums on the lower side of the test bar can be vertically raised and lowered so that the test bar can be bent upwards with respect to the fulcrum on the upper side of the test bar, and the test can be performed step-by-step. At the same time, the deflection is 8141618 2,22mm. On the rod, a voltage withstand test of 4% of the power frequency of 2+3 was performed, and the test ended when the test rod was broken down.

3 Conclusion Since the establishment of the dual-rich company, through joint research and development with Fuji Electric, so that the stator coil design and manufacturing technology has gradually approached and basically reached the world advanced level.

We should make progress to promote the development of new products such as domestic powder mica tapes, and improve our processes so that our products can fully reach the world's advanced level.

Nie Qirong. Increasing Capacity of Hydraulic Turbines in Dahua Hydropower Station . Hydraulic machinery information network, technical experience exchange conference proceedings. 2000, 9 Dahua Hydropower Station Generator Capacity Expansion Renovation Contract Document.

Advances in design and manufacturing technology of stator coils for hydro-generator strips of Chengde Minghuang Shuangfu Company. Motor Technology, 2000, 5 Received the Editor's Edition 20010321 Editor Guo Shijie Shen Ziping! Water conservancy and hydropower installation industry held in Beijing Old Comrade Tea Party I! On the eve of the National Day celebration of the 5.2th anniversary of the founding of the People's Republic of China, the 50th anniversary of the birth of the electromechanical installation industry for hydropower in China was welcomed. China Water Conservancy and Hydroelectric Engineering Corporation asked the old leader and old leader of the Beijing area nearly 7 people, more than people, held a hydropower electromechanical Installation industry in Beijing Old Comrade Tea Party. China Water Resources and Hydropower Corporation Fu Yuanhao’s deputy general manager first paid tribute to the senior leaders and old experts who had made pioneering contributions to the installation of hydroelectric and electrical equipment by General Manager Guo Jiantang and 120,000 hydropower workers. The speeches of the brief report on the reform and development of the hydropower electromechanical installation industry. In his speech, he reviewed the achievements and achievements of hydropower and electromechanical installation passengers for five years. At the same time, he put forward concrete prospects and implications for the reform and development of the hydropower electromechanical installation industry. The old leader of the hydropower industry, Lin Hanxiong and Zhang Tiexi and Shen Xinxiang, attended the meeting and delivered warm and enthusiastic speeches. Everyone was greatly inspired by the old comrades of the hydroelectric and electromechanical installation in the Beijing area. They talked about the achievements of the past 50 years and recalled the past years. Summarizing the feelings of colleagues in the friendship development between the comrades and the comrades in the past, everyone is in a state of excitement and joy. At the same time, we are grateful to the Hydropower Engineering Corporation for providing such rare gatherings to the old comrades. We all wish our country's hydropower! The construction business continues to take off and creates a brighter development prospect. !

Wang Mante