Apparatus and method for regulating a power line using frequency domain self-synchronization control

A static VAR compensator, comprising:

• a power line output node for connection to a power line carrying a power signal;
• a parameter measurement circuit to continuously sample said power signal and obtain a measured power signal;
• a plurality of compensating capacitors, with associated increment VAR values;
• a compensating inductor;
• a plurality of thyristor strings each of said thyristor strings connecting a selected compensating capacitor of said plurality of compensating capacitors to said power line output node to provide capacitive reactive power conditioning to said power signal, one of said plurality of thyristor strings connecting said compensating inductor to said power line output node to provide inductive reactive power conditioning to said power signal;
• a plurality of gate drive circuits corresponding to said plurality of thyristor strings to fire said plurality of thyristor strings;
• and
• an SVC controller that assesses the voltage level of said measured power signal and in response thereto selectively executes either
• a high voltage coarse line conditioning strategy,
• a high voltage fine line conditioning strategy,
• a low voltage coarse line conditioning strategy, or
• a low voltage fine line conditioning strategy, each of said line condition strategies including a corresponding set of gate drive signals that are applied to selected gate drive circuits of said plurality of gate drive circuits to accomplish selective reactive power conditioning of said power signal.

A static VAR compensator, comprising:

• a power line output node for connection to a power line carrying a power signal;
• a parameter measurement circuit to continuously sample said power signal and obtain a measured power signal;
• a plurality of compensating capacitors, with associated increment VAR values;
• a compensating inductor;
• a plurality of thyristor strings each of said thyristor strings connecting a selected compensating capacitor of said plurality of compensating capacitors to said power line output node to provide capacitive reactive power conditioning to said power signal, one of said plurality of thyristor strings connecting said compensating inductor to said power line output node to provide inductive reactive power conditioning to said power signal;
• a plurality of gate drive circuits corresponding to said plurality of thyristor strings to fire said plurality of thyristor strings;
• and
• a self-synchronizing SVC controller connected to said parameter measurement circuit and said plurality of gate drive circuits to analyze said measured power signal in the frequency domain to identify a frequency domain firing angle and to convert said frequency domain firing angle to a time-domain firing signal command to be applied to selected gate drive circuits of said plurality of gate drive circuits to selectively execute either
• a high voltage coarse line conditioning strategy,
• a high voltage fine line conditioning strategy,
• a low voltage coarse line conditioning strategy, or
• a low voltage fine line conditioning strategy, to accomplish selective reactive power conditioning for said power signal.