An infinite bus is a concept in power systems that represents a power source with constant voltage magnitude and constant frequency, regardless of how much power is drawn from or supplied to it.
Table of Contents
Practical Interpretation
In real life, an infinite bus does not truly exist, but it is approximated by:
- Large interconnected power grids
- National or regional power systems
Note: A small generator connected to a large grid behaves as if it is connected to an infinite bus.
Characteristics of an Infinite Bus
- Constant voltage magnitude
- Constant frequency
- Constant phase angle
- Unaffected by load or generation changes
- Acts as a reference bus (slack bus) in analysis
Power Transfer with Infinite Bus
When a synchronous generator is connected to an infinite bus, the power transferred is given by:
\[
P = \frac{EV}{X} \sin\delta
\]
\begin{align*}
E &= \text{Internal EMF of generator} \\
V &= \text{Infinite bus voltage (constant)} \\
X &= \text{Reactance} \\
\delta &= \text{Power angle}
\end{align*}