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三相自耦变压器

Three-phase autoformer

▁ 产品概述 /Product overview

• 自耦变压器是输出和输入共用一组线圈的特殊变压器 . 升压和降压用不同的抽头来实现 . 比共用线圈少的部分抽头电压就降低 . 比共用线
圈多的部分抽头电压就升高 .
• 其实原理和普通变压器一样的，只不过他的原线圈就是它的副线圈一般的变压器是左边一个原线圈通过电磁感应，使右边的副线圈产生
电压，自耦变压器是自己影响自己。
• 自耦变压器是只有一个绕组的变压器，当作为降压变压器使用时，从绕组中抽出一部分线匝作为二次绕组；当作为升压变压器使用时，
外施电压只加在绕组的部分线匝上。通常把同时属于一次和二次的那部分绕组称为公共绕组，自耦变压器的其余部分称为串联绕组，同容
量的自耦变压器与普通变压器相比，不但尺寸小，而且效率高，并且变压器容量越大，电压越高．这个优点就越加突出。因此随着电力系
统的发展、电压等级的提高和输送容量的增大，自藕变压器由于其容量大、损耗小、造价低而得到广泛应用 .
• 由于自耦变压器的计算容量小于额定容量．所以在同样的额定容量下，自耦变压器的主要尺寸较小，有效材料 ( 硅钢片和导线 ) 和结构
材料 ( 钢材 ) 都相应减少，从而降低了成本。有效材料的减少使得铜耗和铁耗也相应减少，故自耦变压器的效率较高。同时由于主要尺寸
的缩小和质量的减小，可以在容许的运输条件下制造单台容量更大的变压器。但通常在自耦变压器中只有 k=2 时，上述优点才明显。
• 由于自耦变压器的短路阻抗标幺值比双绕组变压器小，故电压变化率较小，但短路电流较大。
• 由于自耦变压器一、二次之间有电的直接联系，当高压侧过电压时会引起低压侧严重过电压。为了避免这种危险，一、二次都必须装设
避雷器，不要认为一、二次绕组是串联的，一次已装、二次就可省略。
• 在一般变压器中。有载调压装置往往连接在接地的中性点上，这样调压装置的电压等级可以比在线端调压时低。而自耦变压器中性点调
压侧会带来所谓的相关调压问题。因此，要求自耦变压器有载调压时，只能采用线端调压方式。
• autotransformer is a special transformer in which the output and input share a set of coils. Voltage boost and voltage drop are achieved by
using different taps. The tap voltage of the part less than the common coil is reduced and the tap voltage of the part more than the common
coil is increased.
• in fact, the principle is the same as the ordinary transformer, except that its primary coil is its secondary coil. In general, the transformer
is a primary coil on the left, which generates voltage through electromagnetic induction to the secondary coil on the right, and the auto-
transformer influences itself.
• autotransformer is a transformer with only one winding. When used as a step-down transformer, part of the wire turns are drawn from the
winding as the secondary winding; When used as a booster transformer, the applied voltage is applied only to part of the winding turns.
Generally, the part of the winding that belongs to both primary and secondary is called the common winding, and the rest of the auto-
transformer is called the series winding. Compared with the ordinary transformer, the auto-transformer with the same capacity is not only
small in size, but also high in efficiency. Besides, the larger the transformer capacity is, the higher the voltage will be. This advantage is more
and more outstanding. Therefore, with the development of power system, the improvement of voltage level and the increase of transmission
capacity, lotus root transformer is widely used for its large capacity, small loss and low cost.
• the calculated capacity of the autotransformer is less than the rated capacity. Therefore, at the same rated capacity, the main size of the auto-
transformer is small, and the effective materials (silicon steel sheet and wire) and structural materials (steel) are reduced correspondingly, thus
reducing the cost. With the decrease of effective materials, copper and iron consumption are also reduced correspondingly, so the efficiency
of autotransformer is higher. At the same time, due to the reduction of main size and quality, a single transformer with larger capacity can
be manufactured under allowable transportation conditions. However, the above advantages are usually obvious only when k=2 in the 17
autotransformer.
• since the unit value of the short-circuit impedance of the autotransformer is smaller than that of the double-winding transformer, the voltage
change rate is smaller, but the short-circuit current is larger.
• since there is a direct electrical connection between the primary and secondary of the autotransformer, when the high voltage side
overvoltage will cause serious overvoltage on the low voltage side. In order to avoid this kind of danger, a, 2 times must install arrester, do not
think winding of 1, 2 times is series, already installed, 2 times can omit.
• in general transformers. On-load voltage regulator is usually connected to a grounded neutral point so that the voltage level of the
voltage regulator can be lower than that of the on-line terminal voltage regulator. The voltage regulating side of the neutral point of the
autotransformer will bring about the so-called related voltage regulating problem. Therefore, when the autotransformer is required to adjust
voltage on load, only the line-end voltage regulation mode can be adopted.