Flexible AC Transmission System - Theory

Theory

In the case of a no-loss line, voltage magnitude at the receiving end is the same as voltage magnitude at the sending end: Vs = Vr=V. Transmission results in a phase lag that depends on line reactance X.

\begin{align}
\underline{V_s}&=V \cos\left(\frac{\delta}{2}\right) +jV \sin\left(\frac{\delta}{2}\right)\\
\underline{V_r}&=V \cos\left(\frac{\delta}{2}\right)-jV \sin\left(\frac{\delta}{2}\right)\\
\underline{I}&=\frac{\underline{V_s}-\underline{V_r}}{jX}=\frac{2V\sin{\left(\frac{\delta}{2}\right)}}{X}
\end{align}

As it is a no-loss line, active power P is the same at any point of the line:

Reactive power at sending end is the opposite of reactive power at receiving end:

As is very small, active power mainly depends on whereas reactive power mainly depends on voltage magnitude.

Read more about this topic:  Flexible AC Transmission System

Famous quotes containing the word theory:

    No theory is good unless it permits, not rest, but the greatest work. No theory is good except on condition that one use it to go on beyond.
    André Gide (1869–1951)

    The great tragedy of science—the slaying of a beautiful theory by an ugly fact.
    Thomas Henry Huxley (1825–1895)

    We have our little theory on all human and divine things. Poetry, the workings of genius itself, which, in all times, with one or another meaning, has been called Inspiration, and held to be mysterious and inscrutable, is no longer without its scientific exposition. The building of the lofty rhyme is like any other masonry or bricklaying: we have theories of its rise, height, decline and fall—which latter, it would seem, is now near, among all people.
    Thomas Carlyle (1795–1881)