A synchronous generator is connected to an infinite bus with excitatio...
Understanding the System
The synchronous generator is connected to an infinite bus, which means it can deliver power without affecting the bus voltage. Here, we are given:
- Excitation voltage (Ef) = 1.3 pu
- Synchronous reactance (Xs) = 1.1 pu
- Real power (P) = 0.6 pu
- Infinite bus voltage (V) = 1.0 pu
Calculating the Internal Voltage (E)
To find the reactive power (Q), we first need to determine the internal voltage E of the generator.
- The relationship between E, V, and the power angle (δ) can be expressed as:
E = V + jQ / (Xs)
In this case, we need to calculate Q before we can find δ.
Using Power Equations
The real power P is given by:
P = V * I * cos(δ)
Where I is the current flowing into the bus.
Next, the equation for reactive power Q is:
Q = V * I * sin(δ)
Combining these equations, we can express Q in terms of known values.
Current Calculation
Using the formula for P:
- I = P / V = 0.6 pu / 1.0 pu = 0.6 pu
Now, we can find the power factor angle (δ) using the relationship:
P = |E| * |V| / |Xs| * sin(δ)
From the equivalent circuit, we can calculate δ and subsequently Q.
Final Calculation of Q
Using the derived equations, we can compute Q:
- Q = (V^2 / Xs) - (P * tan(δ))
Substituting the values leads to:
- Q = 1.0^2 / 1.1 - 0.6 * tan(δ)
Solving this gives:
- Q ≈ 0.109 pu
Conclusion
The reactive power supplied by the generator to the bus under the given conditions is approximately 0.109 pu. This indicates that the generator is supplying a small amount of reactive power to maintain voltage levels at the bus.