由两部分组成：
-与电源电压同相的有功分量IR与输出直接相关（因此与转换的电能部分直接相关）
转化为不同类型的能量，通常是具有不同特性的电能，
机械、光和/或热）；
-与电压正交的无功分量IQ用于产生
通过电或磁转换功率所需的流量
领域没有这一点，就不可能有权力流动，例如在一个
变压器或电机的气隙中。
在常见的情况下，在存在欧姆感应型负载的情况下
与有功分量IR相比，总电流（I）滞后。
在电气装置中，有必要生成和传输，而不是
有功功率P，某个无功功率Q，对转换至关重要
电能，但用户无法使用。权力的情结
发电和输电构成视在功率S。
功率因数（cosν）定义为有源元件IR之间的比率
和电流l的总值；ν是电压之间的相移
U和电流l。
结果如下：
无功需求系数（tanñ）是无功功率之间的关系
有功功率：
3.1一般方面
ABB |电气设备423
3功率因数校正
负载cosƍtanƍ
功率因数无功需求因数
变压器（空载条件）0.1÷0.15 9.9÷6.6
电机（满载）0.7÷0.85 1.0÷0.62
电机（空载）0.15 6.6
金属加工设备：
-电弧焊0.35÷0.6 2.7÷1.3
-电弧焊补偿0.7÷0.8 1.0÷0.75
-电阻焊：0.4÷0.6 2.3÷1.3
-电弧炉0.75÷0.9 0.9÷0.5
荧光灯
-补偿0.9 0.5
-未补偿0.4÷0.6 2.3÷1.3
汞蒸气灯0.5 1.7
钠蒸汽灯0.65÷0.75 1.2÷0.9
交直流变流器0.6÷0.95 1.3÷0.3
直流驱动器0.4÷0.75 2.3÷0.9
交流驱动器0.95÷0.97 0.33÷0.25
电阻负载1 0
表1：典型功率因数
功率因数校正是在特定情况下增加功率因数的动作
通过本地提供必要的无功功率，
从而将电流值降低到所需功率的等效值，以及
因此，从上游侧吸收的总功率。因此，供应
线路、发电机和变压器的尺寸可以降低视在电压
负载所需的功率值。
具体来说，如图1和图2所示，增加
负载：
-降低每单位传输有功功率的相对压降urp；
-另一方面，增加可传输有功功率并减少损耗
尺寸标注参数保持相等。

sented by two components: - the active component IR, in phase with the supply voltage, is directly correlated to the output (and therefore to the part of electrical energy transformed into energy of a different type, usually electrical with different characteristics, mechanical, light and/or thermal); - the reactive component IQ, in quadrature to the voltage, is used to produce the flow necessary for the conversion of powers through the electric or magnetic field. Without this, there could be no flow of power, such as in the core of a transformer or in the air gap of a motor. In the most common case, in the presence of ohmic-inductive type loads, the total current (I) lags in comparison with the active component IR. In an electrical installation, it is necessary to generate and transmit, other than the active power P, a certain reactive power Q, which is essential for the conversion of electrical energy, but not available to the user. The complex of the power generated and transmitted constitutes the apparent power S. Power factor (cosϕ) is defined as the ratio between the active component IR and the total value of the current l; ϕ is the phase shifting between the voltage U and the current l. It results: The reactive demand factor (tanϕ) is the relationship between the reactive power and the active power: 3.1 General aspects ABB | Electrical devices 423 3 Power factor correction Load cosϕ tanϕ power factor reactive demand factor Transformers (no load condition) 0.1÷0.15 9.9÷6.6 Motor (full load) 0.7÷0.85 1.0÷0.62 Motor (no load) 0.15 6.6 Metal working apparatuses: - Arc welding 0.35÷0.6 2.7÷1.3 - Arc welding compensated 0.7÷0.8 1.0÷0.75 - Resistance welding: 0.4÷0.6 2.3÷1.3 - Arc melting furnace 0.75÷0.9 0.9÷0.5 Fluorescent lamps - compensated 0.9 0.5 - uncompensated 0.4÷0.6 2.3÷1.3 Mercury vapour lamps 0.5 1.7 Sodium vapour lamp 0.65÷0.75 1.2÷0.9 AC DC converters 0.6÷0.95 1.3÷0.3 DC drives 0.4÷0.75 2.3÷0.9 AC drives 0.95÷0.97 0.33÷0.25 Resistive load 1 0 Table 1: Typical power factor The power factor correction is the action increasing the power factor in a specific section of the installation by locally supplying the necessary reactive power, so as to reduce the current value to the equivalent of the power required, and therefore the total power absorbed from the upstream side. Thus, the supply lines, the generator and the transformers can be sized for a lower apparent power value required by the load. In detail, as shown by Figure 1 and Figure 2, increasing the power factor of the load: - decreases the relative voltage drop urp per unit of active power transmitted; - increases the transmittable active power and decreases the losses, the other dimensioning parameters remaining equal.