3. Design of voltage source converter stations

3.1 General diagram

A Voltage Sourced Converter (VSC) connected to the grid behaves like an inertial-free alternator. It exchanges active and reactive power with the AC network, depending on the phase and amplitude of the AC voltage it generates. Any exchange of active power from the converter to the AC network will result in an equivalent exchange from the converter to the DC network.

AC voltage synthesis by the converter requires forced switching at high frequency (1 to 2 kHz), which generates more losses than AC/DC conversion in a thyristor converter.

Controlling the reactive power exchanged with the grid not only makes it possible to dispense with capacity banks, but also to sustain grid voltage at the point of connection....