Solve 3 Phase Total Power Problems

In summary, the student has encountered difficulty in understanding the equations for 3 phase systems. They have shared their attempt at the solution and included links to online resources. After discussing with another person, they have realized that their calculation was correct and that the difference lies in the calculation of line currents versus load branch currents.
  • #1
billyray
58
1

Homework Statement


I have included the problems attached below. I have looked at a recent post and the equations made sense to me but I am very new to 3 phase systems basically know only what I have learned from trying to answer my questions. i feel my attempt is wrong from what I have seen online as total power equation in 3 phase system. I have included link. I am not sure which equation to use now I think mine is wrong.[/B]

Homework Equations


https://www.physicsforums.com/threads/delta-and-star-transformation-ac-circuits.791979/
and online 3 phase power solution
https://www.electricaltechnology.org/2014/09/delta-connection-power-voltage-current.html

The Attempt at a Solution


I have attached all my workings[/B]
 

Attachments

  • 3 phase problem.PNG
    3 phase problem.PNG
    23.2 KB · Views: 366
  • 3 phase.pdf
    350.3 KB · Views: 199
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  • #2
Your calculations look okay to me. You might want to trim the significant figures in your final power value, maybe express it in kW.
 
  • #3
hi gneill
thanks again.
Did you see the online link to P = √3 x VL x IL x CosФ for a balanced system delta. is that not different from mine.
 
  • #4
billyray said:
Did you see the online link to P = √3 x VL x IL x CosФ for a balanced system delta. is that not different from mine.
Yes. Note that in this instance you have not calculated the Line currents (##I_L##), but rather the separate load branch currents for the Delta load. This makes a difference because the Line currents are made up of combinations of currents of load branches (which have different relative phases). Now, if you directly calculate the real power for each branch of the load as you've done, then you can simply sum those real powers.
 
  • #5
thanks gneill
 

Related to Solve 3 Phase Total Power Problems

1. What are the three phases in a 3 phase total power system?

The three phases in a 3 phase total power system are known as phase A, phase B, and phase C. These phases are used to distribute power in a balanced way, allowing for more efficient transmission of electricity.

2. How do you calculate total power in a 3 phase system?

To calculate total power in a 3 phase system, you can use the formula P = √3 * V * I * cos(θ), where P is the total power, V is the line voltage, I is the line current, and cos(θ) is the power factor.

3. What is the significance of power factor in 3 phase systems?

Power factor is a measure of how efficiently a system uses electricity. In 3 phase systems, it is important to have a high power factor in order to reduce energy losses and improve the overall efficiency of the system.

4. How do you determine the power factor in a 3 phase system?

The power factor in a 3 phase system can be determined by dividing the real power (in watts) by the apparent power (in volt-amperes). This will give you a decimal value between 0 and 1, with 1 being a perfect power factor.

5. What are some common problems that can occur in 3 phase total power systems?

Some common problems that can occur in 3 phase total power systems include unbalanced loads, voltage fluctuations, and power factor issues. These problems can lead to inefficiency, equipment damage, and power outages if not addressed properly.

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