Discussion on ventilation of the hottest transform

2022-08-11
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Discussion on transformer ventilation

1 reasons for high transformer room temperature

the area of ventilation window in transformer room in national standard figure 88d264 (hereinafter referred to as national standard figure) is designed according to the conditions that the calculated temperature of ventilation in transformer room in summer is not more than +35 ℃ (calculated temperature of inlet air), the outlet temperature is 45 ℃, and the temperature difference between inlet and outlet air is not more than 15 ℃. The transformer manufacturer stipulates that the ambient air temperature of the transformer during normal use shall not exceed +40 ℃. The ventilation condition in the national standard drawing is 5 ℃ higher than the normal operating ambient temperature specified by the manufacturer. The transformer room designed according to the size of the transformer room in the national standard drawing does not meet the requirements of the transformer for continuous innovation of the surrounding air temperature. The highest temperature in summer is also the time of maximum electrical load. The air temperature around the transformer is high, the load is large, and the temperature rise of the transformer itself is too high, In case of transformer failure, it is difficult to strengthen and improve comprehensive utilization to avoid it

in the national standard drawing 88d264, the area of the ventilation window in the transformer room is given as the effective area, and the effective area coefficient of the ventilation window is less than 1. Some designs do not pay attention to the difference between the area and the effective area. During the design, conditions are proposed to the civil engineering according to the area required in the standard drawing, and the actual ventilation window area of the transformer room is discounted again. The area of ventilation window does not meet the requirements of transformer operation

clause 9 of article 6.0.1 of GB stipulates that "the indoor passage of power distribution device shall be unobstructed, no threshold shall be set, and there shall be no pipeline irrelevant to the power distribution device". In some areas, in order to prevent the entry of small rodents, a 0.6m-high rat gate, namely the threshold, is set at the gate of the transformer room. The upper and lower shutters of the transformer room door are screened, and a large area of the air inlet shutter at the lower part of the transformer room door is just blocked, which makes the effective area of the air inlet window of the transformer room smaller and the ventilation effect worse

the size of the transformer room in the new substation is limited by the column spacing of the whole building. Some transformer rooms are too deep. The transformer is located far away from the air inlet and outlet louvers on the substation wall, which reduces the ventilation effect around the transformer

when the newly-built transformer room is part of the built standard plant, the consumption of plastic shopping bags in China in 2007 has reached 1million tons. The design height of some transformer rooms is limited to a certain extent. For 1600KVA and 2000 KVA transformer rooms, some areas still require bench layout, which has poor ventilation effect

in order to improve the ground distance between the incoming and outgoing terminals of the transformer, the transformer is installed on the steel bench n) experimental report: the report can be prepared and printed according to the format required by the user;, The indoor temperature of the transformer varies with the height from the ground. The higher the height from the ground, the higher the temperature. When the transformer is installed on the steel bench, it is in a higher position from the ground, which makes the transformer in a disadvantageous position of higher indoor temperature

although an exhaust fan has been added next to the air outlet louver of the transformer room for forced ventilation, the efficiency of the exhaust fan has not been brought into full play due to the short circuit between the air flow of the exhaust fan and the air flow of the air outlet louver

the running loss of the transformer heats the indoor air, and the rise of the hot air forms a flow airflow channel with the inlet and outlet louvers. The larger the height difference of the inlet and outlet louvers, the higher the air flow speed, and the better the ventilation effect. Air inlet and outlet louvers are set at the lower part of the transformer room door and the wall surface of the top of the transformer room, but some transformer rooms also set louvers at the upper half of the transformer door, that is, in the middle of the upper and lower air inlet and outlet louvers, which reduces the ventilation effect of the louvers

the load supplied by the transformer increases year by year, and the transformer is overloaded, and the capacity of the transformer has not been increased in time. Fortunately, with the progress of science and technology and the improvement of transformer design and manufacturing technology, the loss of the transformer is decreasing, and the overload capacity is increasing, which alleviates the problems caused by the rise of room temperature of some transformers

however, some transformers still have the quality problem of high loss

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