1. Brief Description
The seasonal variation, personal mobility, and the difference of power consumption of residents at different time periods of day and night lead to big load fluctuation of power distribution network of China, the capacity of distribution transformer doesn’t match the power demands, the specific transformers of general enterprises run at no load or at light load in over 70% of the time, and the common transformers of residents run at no load or at light load in over 80% of the time, resulting in high loss of transformer. To address such situation, the Company develops the high-overload oil-immersed transformer. The insulating material of this new transformer reaches the standard of insulation class B and higher. On the basis of normal temperature rise requirements, this new transformer satisfies staged continuous operation for 6h at 1.5 multiples of rated capacity (3h respectively at load rising and dropping stages), 3h at 1.75 multiples of rated capacity (1.5h respectively at load rising and dropping stages), and 1h at 2.0 multiples of rated capacity, without affecting the normal service life of transformer. The temperature rise of high-overload distribution transformer satisfies class-F insulation limit value, and the current applying process curve of temperature rise test is shown by Fig. 1. Meanwhile, according to the core material, this new transformer can be classified into the high-overload oil-immersed transformer with amorphous alloy core and the high-overload oil-immersed transformer with the core made of silicon steel sheet.
2. Application Scope
The product has been widely applied in new and reconstruction projects of urban and rural power grids, and is especially suitable for the areas where the seasonable fluctuation of power consumption is big, the difference of power consumption at day and night is big and the daily maintenance is difficult. As the transformer adopts fully sealed structure and avoids contact with the air, it may run in the humid environment and is the ideal power distribution equipment for urban and rural power distribution network.
3. Model Description
GB1094.1, GB1094.2, GB1094.3, GB1094.5,
IEC 60076-1:2000, IEC 60076-2:1993, IEC 60076-3:2000, IEC 60076-5:2006,
GB/T 6451, etc
5. Normal Service Conditions
Height above sea level: Not greater than 1,000m;
Ambient temperature: Maximum temperature: +40℃;
Maximum daily average temperature: +30℃;
Maximum annual average temperature: +20℃;
Minimum outdoor temperature: -25℃;
Installation environment: ground acceleration caused by earthquake: ag<2m/s
1. The product may overload at double the rated capacity for 1h, at 1.75 multiples of rated capacity for 3h and 1.5 multiples of rated capacity for 6h while ensuring normal service life of the transformer.
2. The low voltage adopts foil winding, thus enhancing the ability of the transformer to withstand the sudden short circuit; as the low voltage adopts copper foil winding, the electric field distribution of transformer is uniform. The low-voltage inner frame adopts formed hard paper tube, while the high-voltage outer half lap is wound with tasteless glass adhesive tape layer by layer. The compression pad adopts the laminated wood, thus enhancing the mechanical strength of the transformer. The transformer uses vacuum oil filling, which may totally eliminate the bubble in the coil, so as to improve the overall ability of the transformer to withstand the sudden short circuit.
3. The tank rim adopts stainless steel bolts, with beautiful appearance.
4. The oil tank adopts the fully sealed tank, thus isolating the transformer oil from the air, and slowing down the aging of transformer oil. The sealing elements adopt formed parts, with the sealing reliability of the transformer enhanced.