Design and construction was carried out jointly by General Electric and MIT . When first demonstrated in June 1929, the system had eight phase-shifting transformers to represent synchronous machines.
12.
In analysis of three-phase synchronous machines the transformation transfers three-phase stator and rotor quantities into a single rotating reference frame to eliminate the effect of time-varying inductances.
13.
The equation describing the relative motion is known as the swing equation, which is a non-linear second order differential equation that describes the swing of the rotor of synchronous machine.
14.
Because the squirrel cage winding is not large enough to dissipate the heat of continuous operation, large synchronous machines often have protective relays to detect when the machine has fallen out of synchronization with the supply voltage.
15.
The additional controllability gives many advantages, notably the ability to switch the IGBTs on and off many times per cycle in order to improve the harmonic performance, and the fact that ( being self-commutated ) the converter no longer relies on synchronous machines in the AC system for its operation.
16.
Power factor correction may be applied at a central substation, through the use of so-called " synchronous condensers " ( synchronous machines which act as condensers which are variable in VAR value, through the adjustment of machine excitation ) or adjacent to large loads, through the use of so-called " static condensers " ( condensers which are fixed in VAR value ).
