LOADING
BUSHING FOR POWER TRANSFORMERS 0 pages
نسخه متنی
"BUSHINGS: GENERAL INFORMATION nn1.0 Electrical characteristics (Ir = rated current; Ur = rated voltage) 1.1Standard insulation levels Rated voltage Ur kV (r.m.s.) One minute power frequency withstand voltage wet and dry kV (r.m.s.) Dry lighting impulse withstand voltage dry (1,2/50 ms) kV 1 3,6 12 24 36 52 10 10 28 50 70 95 20 40 75 125 170 250 nn
1.2 Standard values of rated thermal short time current (Ith) 25 times the rated current (Ir) for 2 s ; for Ir equal or greater than 4000A, Ith is always 100kA 1.3 Overload conditions (IEC 354): Bushing selected with Ir not less than 120% of the rated current of the transformers are considered to be able to withstand the overload conditions according to IEC 354. 2.0 Mechanical characteristic 2.1 Cantilever operating load (bushing installed less than 30 from vertical) Ur Ir kV 800 A 1600 A 2500 A 3150 A 36 52 500 N 500 N 625 N 625 N 1000 N 1000 N 1575 N 1575 N
nn2.2 Cantilever operating load ( bushing installed more than 30а from vertical) Ur Ir kV 800 A 1600 A 2500 A 3150 A 36 52 300 N 300 N 375 N 375 N 600 N 600 N 945 N 945 N
nn2.3 Cantilever test load Ur Ir kV 800 A 1600 A 2500 A 3150 A 36 52 1000 N 1000 N 1250 N 1250 N 2000 N 2000 N 3150 N 3150 N 3.0 Tightening torque
nn(suggested values, +/- 10% depending on the quality of the tank cover surface) 3.1 On the central conductor LV/HV in brass or copper Size Torque Size Torque M8 M12 M20 M30x2 10 Nm 13 Nm 30 Nm 70 Nm M42x3 M48x3 M55x3 M75x3 110 Nm 180 Nm 250 Nm 250 NmFile : ISOL POT UNCONTROLLED COPY Rev. 3 dtd 10/10/08 >
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