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Ventilation of the transformer

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Update time : 2018-06-04 15:00:48
With the progress of society, the degree of electrification continues to increase, power capacity, with substation equipment showed insufficient capacity or transformer overheating phenomenon more frequently. Play the greatest role of existing equipment, reduce equipment failure rate, high quality, stable, continuous, reliable power supply, is the obligatory responsibility of the power system. According to a district substation transformer fault investigation statistics; transformer fault 79 times, the transformer temperature is too high, causing 53 faults, accounting for 67.09% of the total fault. , Discuss the transformer room temperature, ventilation, ventilation, the correct design of the transformer room ventilation system, to reduce the indoor distribution transformer failure rate is of great significance. The company is located in:
National standard Figure 88D264 (hereinafter referred to as the national standard) in the transformer room ventilation window area, according to the transformer room summer ventilation temperature does not exceed +35 ℃ (inlet calculation temperature), the outlet temperature of 45 ℃, the difference between the inlet and outlet air temperature does not exceed 15 ℃ conditions, the design of the transformer room ventilation window area. The transformer manufacturer regulations, the transformer normally used ambient air temperature does not exceed +40 ℃. National standard ventilation conditions than the manufacturer's normal use of ambient temperature 5 ℃, according to the national standard transformer room size transformer room design, transformer does not meet the requirements of ambient air temperature, summer maximum temperature is the maximum electrical load, Transformer around the air temperature is high, the load, the transformer itself temperature is too high, the transformer failure is difficult to avoid. The company is located in:
National Standard Figure 88D264, given the transformer room ventilation window area for the effective area, the effective area coefficient of the ventilation window is less than 1, part of the design did not notice the difference between the area and the effective area, the design requirements of the standard area required to civil construction conditions , The actual transformer room ventilation window area was once again discounted. Ventilation window area does not meet the transformer operation requirements. The company is located in:
GB 50060-92 Section 6.0.1 of the ninth paragraph provides that "indoor distribution channels should be unimpeded access, without setting a threshold, and should not have a power distribution line has nothing to do." Some areas for the rodent-like animals to enter the transformer room door set a 0.6m high ratchet barrier that the upper and lower transformer room door blinds plus screen, the lower part of the transformer room door a large inlet louvers area just to be blocked so that Transformer room into the windshield effective area smaller, poor ventilation.
The size of the transformer room in the new substation is limited by the column spacing of the entire building. Some of the transformer rooms are deeply deepened. The transformer is located far away from the wall of the substation to enter the wind blind and the ventilation effect around the transformer is discounted .
When a new transformer room is part of a standard factory building, some transformer room designs have a limited height. In some 1600 kVA and 2000 kVA transformer rooms, some areas still require a gantry arrangement with poor ventilation. The company is located in:
In order to improve the transformer terminal access to the distance, the transformer is installed on the steel bench, the transformer room temperature varies with the distance from the surface height, the higher the height, the higher the temperature, the transformer is installed on steel bench in the distance from the surface High, the transformer in the indoor temperature is higher disadvantageous position.
Exhaust fans have been installed next to the windshield window of the transformer room to force ventilation. However, the exhaust fan airflow and the outlet airflow close to each other are short-circuited, resulting in that the exhaust fan efficiency is not fully utilized. The company is located in:
The lower part of the transformer room door and the wall of the top of the transformer room opened into the wind window, part of the transformer room transformer door also opened the upper half of the blinds, that is, up and down into the middle of the wind blinds, louboutin pas cher, which reduces blind ventilation effect. The company is located in:
Transformer for the load increase year by year, the transformer overload operation, the transformer is also not timely capacity, good science and technology, transformer design and manufacturing technology, transformer losses decreased, overload increased, easing some of the transformer room temperature problems . The company is located in:
2 transformer temperature rise and heat treatment methods
For the transformer temperature rise and cooling the above reasons, we suggest to take some measures to enhance the transformer heat, reducing the transformer temperature rise.
It is recommended to increase the transformer room room with a hundred sheets of electrical door and ratchet baffle distance> 0.2 ㎝, in order to increase the inlet area of the transformer room. Can also be outside the transformer room door, near the surface of about 40cm below the wall to open more than one intake window to increase the inlet area. The company is located in:
Try to install the transformer into the air outlet and outlet air circulation between the position, enhance the ventilation of the transformer. The company is located in:
Large-capacity transformers will be installed down, using fences or masking, for security, to prevent personnel access to the transformer live parts. In this way, the transformer is placed in the indoor lower temperature region, enhance the transformer cooling effect.
Exhaust fan installation position should be far above the outlet of the transformer room to leave and to ensure that the exhaust fan and air inlet path between the effective convection path transformer to increase the transformer cooling effect. The company is located in:
The transformer room room door above 100 canceled, increasing indoor effective convection.
As far as possible the use of low-loss transformers, or heat sink with better heat dissipation transformer.
Conditional production units, transformers can be installed indoors large-scale industrial fan air conditioning, cooling room to achieve the transformer room to increase cooling effect. The company is located in:
3 transformer room ventilation window area and ventilation
Transformer room temperature may be one of the many reasons for the above. However, after analysis, we think the most important reason is that the problem of poor ventilation is concentrated. However, poor ventilation has much to do with the ventilation area. , The following transformer room ventilation window area and ventilation for calculation and analysis.
According to the room temperature of the transformer room is 45 ℃ and 40 ℃, calculate the area of the inlet and outlet of the transformer room by the formula of "Installation and Commissioning Technology of Building Electrical Equipment" and compare it with the area of the outlet window of the national standard figure 88D264. The results are as follows: The new S11 transformer is used to calculate the loss of the new S11 transformer. When the temperature difference between the inlet and outlet of the transformer room is 5 ℃, 10 ℃ and 15 ℃, the calculated window area is slightly smaller than the standard area of 88D264 in China, which is in line with the normal conditions. The company is located in:
The following calculations based on the above, the transformer room temperature difference between the ventilation needs. The company is located in:
(1) "Concise Ventilation Design Manual" Formula (3-1), G1 = 3600Q / [(tp - tj) Cb] Calculate the hourly ventilation weight. The company is located in:
(2) Divide the result of the above formula by the density of air, and weigh the hourly ventilation weight to the hourly ventilation volume, that is, G2 = G1 / r. Check the "Concise and Draft Design Manual", Table 1-3, dry air 100kPa pressure The density r = 1.11kg / m3 when the dry air temperature is 35 ℃; the density r = 1.092kg / m3 at 40 ℃; the density r = 1.056kg / m3 at 50 ℃; 1.056) / 2 = 1.074 kg / m3. Into the formula, to different capacity transformer temperature difference between the natural ventilation data. The company is located in:
4 draft fan selection and configuration
From the calculation results, the transformer room into and out of the wind when the temperature difference is 15 ℃, 1600kVA and below the transformer, the inlet and outlet temperature difference is 10 ℃, 1000kVA and below the transformer, the inlet and outlet temperature difference is 5 ℃, 630kVA and below transformer transformer room Natural access to the window area is relatively easy to meet, there is no difficulty. The company is located in:
Transformer room naturally difficult to access the windshield Transformer room additional mechanical exhaust. Mechanical exhaust G4 = G2 × (1-k), G4 mechanical exhaust volume, G2 total exhaust volume, k for the transformer room natural window area of the total area ratio. Standard drawing out of the window area ratio to take the largest 1: 1.5, additional mechanical exhaust only to compensate for the amount of exhaust, into the windshield area is not compensated, out of the windshield area ratio can be 1: 2, you can find the mechanical exhaust air intake and exhaust Window blinds plus mechanical exhaust to work together to complete the transformer room ventilation tasks. When it reaches summer and the transformer load is full, the exhaust fan needs to be put into operation. Inlet air temperature is 25 ℃ and below or transformer oil surface temperature 90 ℃ and below, exhaust fan can be out of service. Fan selection DGF-type fan, transformer room or install the highest point on both sides of the wall, outdoor pipe and wall perpendicular to the outer wall, with no more than 10 × 10mm2 hole stainless steel mesh. Calculations show that different temperature transformers with different temperature, the use of different numbers of suction fan to meet the needs of ventilation and cooling.