Electricians don’t know all their lives, many people don’t know,
1. The apparent power calculation formula is S=UI.
2. Apparent power refers to the capacity of AC electrical equipment. Equal to the product of the effective value of the voltage and the effective value of the current. It is multiplied by the power factor to equal the active power. The unit is volt-ampere and kilovolt-ampere. For example, when designing a single-phase transformer, the rated voltage is 220
, The current is 10 A, then the value is 2200 VA. It is equivalent to the maximum active power that can be obtained under a given voltage and current.
Three-phase In fact, the three-phase apparent power calculation formula and the three-phase electric power calculation formula belong to the knowledge recorded in the books. It may be forgotten because of too many years of graduation or not often used in work. Explain the calculation formulas and solutions of these two powers.

　　 Three-phase apparent power calculation formula

　　 There are three types of power, active power P, reactive power Q and apparent power S.

The cosine of the phase difference (Φ) between voltage and current is called power factor, which is represented by the symbol cosΦ. In terms of value, power factor is the ratio of active power to apparent power, that is, cosΦ=P/S three powers and power factors cosΦ is a right angle power triangle relationship:

　　 The two right-angle sides are active power and reactive power, and the hypotenuse is the apparent power.

　　 Active power square + reactive power square = apparent power square.

　　 In a three-phase load, these three types of power always exist at the same time:

　　 Apparent power S=1.732UI

　　 Active power P=1.732UIcosΦ

　　 Reactive power Q=1.732UIsinΦ

　　Power factor cosΦ=P/SsinΦ=Q/S

　　When the three-phase load is balanced:

　　P=3*U phase*I phase*cosφ=√3*U line*I line*cosφ

　　 When the three-phase load is unbalanced:

　　 calculate the power of each phase separately, and then sum up,

　　P=P1+P2+P3=U1*I1*cosφ1+U2*I2*cosφ2+U3*I3*cosφ3

　　 Three-phase electric power calculation method

　　 Three-phase electric power is divided into active power and reactive power, and the addition is the apparent power, which are all different algorithms.

　　 Active power P=1.732 (I can’t hit the root number 3) UICosφ

　　 Reactive power Q=1.722UISinφ

　　 Apparent power S=1.722UI

　　Power factor Cosφ=P/S Sinφ=Q/S

　　 Little knowledge popular science:

　　 Why should the three-phase total apparent power be multiplied by three in the calculation formula?

　　Because: This is clearly stated in the book, three-phase total apparent power = phase voltage * current * 3, line voltage = phase voltage * root number 3. Therefore, three-phase apparent power = line voltage * current * root number 3