2 Synchronous Generators in parallel connection

In summary, the two 3-phase 60-hertz 35-kilovolt synchronous generators (G1 and G2) with synchronous reactances of j9 ohms per phase and negligible armature resistance are connected in parallel to supply a 36-megawatt load at a rated voltage and power factor of 0.90 lagging. G1 has an excitation voltage of 40 kilovolts line-to-line, while G2 is operating at unity power factor. The question asks for the real power dissipated by each generator. The equations for active and reactive power in terms of voltages and power angles of both machines can be used to find the current through G1, which is equal to the reactive power
  • #1
lonelypancreas
12
1

Homework Statement


Two 3-phase 60-hertz 35-kilovolt synchronous generators (G1 and G2) each have synchronous reactances of j9 ohms per phase with negligible armature resistance. They are connected in parallel to supply a 36-megawatt load at rated voltage and power factor of 0.90 lagging. G1 has an exci-tation voltage of 40 kilovolts line-to-line. G2 is operating at unity power factor. What is the real power dissipated by each generator

Homework Equations


Power Equations

The Attempt at a Solution


I have computed the reactive power of the load which is equal to that of g1 since g2 is in unity power factor. I originally planned to get the current through gen 1 to get its complex power ie S = VI* and V is given already. However further down the drain, I acquire a real power of purely Vars in form (it has an imaginary part only)
 
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  • #2
lonelypancreas said:
...negligible armature resistance...What is the real power dissipated...
 
  • #3
lonelypancreas said:
What is the real power dissipated by each generator
I believe they are asking for the real power supplied by each generator.

What is the load voltage (per phase)? What are the equations for active and reactive power in terms of voltages and power angles of both machines?
 
  • #4
lonelypancreas said:
exci-tation voltage of 40 kilovolts line-to-line.

Wow! That machine has some really great insulation!
 
  • #5
In my opinion, the equation E1-sqrt(3).I1.jXs=Vg and E2-sqrt(3).I2.jXs=Vg and Itot=I1+I2 it is sufficient in order to find I1=function(E1real+jE1imag) and put E1real^2+E1imag^2=40^2 you can find I1.Note: you have to take into consideration I1=I1.(cosfi-jsinfi).
 

1. What is the purpose of connecting two synchronous generators in parallel?

Connecting two synchronous generators in parallel allows for increased power output and improved system reliability. By sharing the load between the two generators, the overall power capacity is increased and in case one generator fails, the other can continue to supply power.

2. How are the two generators synchronized in parallel connection?

The two generators are synchronized by adjusting their speed and voltage levels to match each other. This is typically done using a synchronizing panel which monitors the frequency and voltage of both generators and ensures they are in phase with each other before connecting them.

3. What are some of the challenges in operating synchronous generators in parallel?

One challenge is ensuring that both generators are in sync and sharing the load evenly. Any differences in speed or voltage levels can cause issues such as power surges or instability. Additionally, maintaining proper excitation levels and reactive power balance is important for efficient operation.

4. Can different types of synchronous generators be connected in parallel?

Yes, it is possible to connect different types of synchronous generators in parallel as long as they have similar characteristics and can be synchronized properly. This can include generators of different sizes, manufacturers, or even different types (such as a steam turbine and a diesel generator).

5. What are some advantages of using synchronous generators in parallel connection?

Some advantages of using synchronous generators in parallel include increased power output, improved system reliability, and flexibility in operation. It also allows for maintenance and repairs to be done on one generator while the other continues to supply power, minimizing downtime. Additionally, by sharing the load, the generators can operate at more efficient levels, reducing fuel consumption and costs.

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