The three-phase chain represents the main type of electrical circuit which is actively used today by production of electrical energy, its transfer and distribution. It is special case of symmetric multiphase network. But correctly to build three-phase network, it is necessary to calculate for a start its power and other parameters.
- - personal computer with access to global network;
- - basic data.
1. Set inquiry of "formula for calculation of power of three-phase chain" in search string of the browser. In the offered list of answers choose in detail painted management for performance of calculations.
2. Calculate the active power of three-phase network. Remember that on condition of asymmetrical loading, the active power of three-phase chain will be equal to the sum of active capacities of separate phases. That is P = Pa + Pb + Pc. The formula for calculation of power of separate phase looks so: P = UIcos φ, where U-phase tension; I – current intensity; φ– the angle of shift of phases between tension and current. Substitute basic data and calculate the active power of separate phases, and then summarize the received results.
3. Count the reactive power of three-phase network. This size is equal to the sum of reactive capacities of separate phases. In other words, Q = Qa + Qb + Qc. For calculation of reactive power on each separate phase use the following formula: Q = UIc sin φ, in which value U - indicator of phase tension; I – current intensity; φ– the angle of shift of phases between tension and current. Substitute basic data in formula. After you recognize reactive power by each separate phase, find the sum of the received results.
4. Execute calculation of ultimate power of three-phase network. Ultimate power of separate phase is on formula: S = UI, where U - phase tension, and I – current intensity.
5. Counting the power of three-phase network, you remember that at the symmetric system of tension the indicator of phase tension on each certain site is equal among themselves. Moreover, at symmetrical load the current intensity on three certain sites is equal and also the identical angle of shift of phases between tension and the operating current. So, active power can be determined on formula: P = 3UF IF cos φ. For calculation of reactive power use formula: Q = 3 UF IF cos φ. And carry out calculation of ultimate power on formula: S = 3 UF IF.