Development Of Mica Tape Of Application On Three Gorge Hydrogenerator

Attracting worldwide attention, the Changjiang River Three Gorges power station dress up machine totally 26 covers with the rated voltage for 20kV, the unilateral main insulation thickness for 4.6mm and the unit capacity for 700MW. As the first times, it is made in our country for the highest rated voltage, the thinnest unilateral main insulation and the biggest unit capacity. Its manufacturing success signifies that main insulation of hydrogenerator in our country has achieved the world standard.The mica tape used in Three Gorges hydrogenerator unit(Three Gorges tape)is maded by mica from Xinjiang Mine. The property of mica tape is outstanding by adulterated aperture, especially the dielectric strength is improved to 33.6MV/m from30.2 MV/m. The thermal mechanical properties of cured adhesives is improved and the flexural strength is improved to 65.2Mpa from 54.2 MPa for adulterating JF resin. The flexural strength of mica tape maed by adhesive achieves 78.5Mpa. At the same time, the excellent JC accelerant for dielectric properties of adhesive is selected by epoxy curing mechanism and adhesive is fabricated. The mica tape used in Three Gorges hydrogenerator unit is maded by appropriate process and E-glass fabric used for reinforcing materials. Its capability was superior to JB/T6488.3-1992 mica tape. The dielectric strength before curing is improved from 40 MV/m to 45MV/m. The normal dielectric loss factor and hot dielectric loss factor for stator bar insulation of Three Gorges tape is decreased from 2% and 5% to 1% and 3% respectively. The hot transverse bending strength and vertical bending strength of Three Gorges tape is improved from 40 Mpa and 30 MPa to 70Mpa and 40 MPa respectively. The mica tape and stator bar insulation which was made by Three Gorges tape have excellent insulation properties by the performance test, particularly outstanding dielectric properties. Its average dielectric dissipation factor is 0.732% andΔtgδis 0.19%. Its average breakdown voltage is163.4 kv, electric life is 3466h at 40kv and more than 4438h at 32 kv. All performances of the mica tape and the main insulation of stator bar used in Three Gorges hydrogenerator have reached the requirement of ALSTOM company and Changjiang River Three Gorges developments head company examination contracts, and has passed through examinations of Changjiang River Three Gorges developments head company. The Three Gorges mica tape has applied in the main insulation of the Three Gorges hydrogerator successfully. Up to the present, Three Gorges mica tape are taken more than 150 tons.