Static var compensator apparatus
View Patent ↗A one-phase static var compensator apparatus includes a compensator string consisting of a first static var compensator connected serially to a thyristor valve. The compensator string is arranged to be connected on its first end to one phase of a transmission grid of a rated voltage exceeding 69 kV. Moreover, the thyristor valve includes a plurality of thyristors connected serially and the compensator string is arranged to be directly connected to the transmission grid. A corresponding three phase apparatus is also presented.
1. A single phase static var compensator system used in connection with a transmission grid, the compensator system comprising:
a compensator string having a first end and a second end including:
a static var compensator having a first end and a second end;
a plurality of serially connected thyristors forming a thyristor group, said thyristor group having a first end and a second end;
a capacitor having a first end and a second end;
said first and second ends of said compensator string directly galvanically connected across the transmission grid;
said first end of said capacitor directly galvanically connected to said first end of said thyristor group and said second end of said capacitor directly galvanically connected to said second end of said thyristor group;
said transmission grid having a rated voltage exceeding 69 kV.
2. The single phase static var compensator system according to claim 1 wherein said plurality of serially connected thyristors includes at least one hundred thyristors connected serially.
3. The single phase static var compensator system according to claim 1 wherein said plurality of serially connected thyristors comprises bidirectional controlled thyristors.
4. The single phase static var compensator system according to claim 1 wherein said static var compensator comprises an inductor.
5. The single phase static var compensator system according to claim 1 wherein said static var compensator comprises a first static var compensator, and said compensator string further includes:
a second static var compensator, and
said plurality of serially connected thyristors are connected on a first end thereof to said first static var compensator and said plurality of serially connected thyristors are connected on a second end thereof to said second static var compensator.
6. The single phase static var compensator system according to claim 5 wherein said first static var compensator and said second static var compensator each comprise an inductor.
7. The single phase static var compensator system according to claim 5 wherein said first static var compensator comprises an inductor and said second static var compensator comprises a capacitor.
8. A three phase static var compensator system used in connection with a three phase transmission grid, the three phase static var compensator system comprising:
three compensator strings, each compensator string directly galvanically connected to one phase of the three phase transmission grid, each compensator string including:
a static var compensator having a first end and a second end;
a plurality of serially connected thyristors forming a thyristor group, said thyristor group having a first end and a second end;
a capacitor having a first end and a second end;
said first end of one of said compensator strings directly galvanically connected to one phase of the transmission grid and said second end of said one of said compensator strings directly galvanically connected to a second phase of the transmission grid;
said first end of said capacitor directly galvanically connected to said first end of said thyristor group and said second end of said capacitor directly galvanically connected to said second end of said thyristor group;
said transmission grid having a rated voltage exceeding 69 kV.
9. The three phase static var compensator system according to claim 8 wherein said plurality of serially connected thyristors comprises bidirectional controlled thyristors.
10. The three phase static var compensator system according to claim 8 wherein said static var compensator comprises an inductor.
11. The three phase static var compensator system according to claim 8 wherein said static var compensator comprises a first static var compensator, and said compensator string further includes:
a second static var compensator, and
said plurality of serially connected thyristors are connected on a first end thereof to said first static var compensator and said plurality of serially connected thyristors are connected on a second end thereof to said second static var compensator.
12. The three phase static var compensator system according to claim 11 wherein said first static var compensator and said second static var compensator each comprise an inductor.
13. The three phase static var compensator system according to claim 11 wherein said first static var compensator comprises an inductor and said second static var compensator comprises a capacitor.
14. The three phase static var compensator apparatus according to claim 8 , wherein said compensator string is connected on a first end thereof to said respective phase and on a second end thereof to a transmission grid associated with a different phase than said respective phase, thus forming a delta connection.
15. The three phase static var compensator apparatus according to claim 8 , wherein said compensator string is arranged to be connected on a first end thereof to said respective phase and on a second end thereof to a neutral point, thus forming a wye connection.
16. The three phase static var compensator apparatus according to claim 15 , wherein said neutral point is connected to a transmission grid.
17. The three phase static var compensator apparatus according to claim 15 , wherein said neutral is provided using an artificial neutral from a z-transformer connected to the three respective phases.