STATCOM arrangement without phase reactors
A STATCOM arrangement includes an MMC and a transformer arrangement arranged to be an interface between the MMC and an AC grid. The MMC is connected in a wye topology with a plurality of converter arms, one for each phase of the AC grid, each arm including a plurality of chain-linked converter cells. The transformer arrangement is arranged to interface each of the arms of the MMC with a respective phase of the grid, and arranged to for each of the converter arms produce leakage reactance resulting in reactance in series with the arm which obviates the need for a phase reactor connected in series with said arm.
1. A static synchronous compensator (STATCOM) station comprising:
a STATCOM arrangement comprising a Modular Multilevel Chain-Link Converter (MMC) and a transformer arrangement arranged to be an interface between the MMC and an alternating current (AC) grid;
wherein the MMC is connected in a wye topology with a plurality of converter arms, one converter arm for each phase of the AC grid, each arm comprising a plurality of chain-linked converter cells;
wherein the transformer arrangement is arranged to interface each of the arms of the MMC with a respective phase of the AC grid;
wherein the transformer arrangement is arranged to, for each of the converter arms, produce leakage reactance resulting in reactance in series with the arm, thereby obviating a need for a phase reactor connected in series with the arm;
wherein there is no phase reactor connected in series with any of the converter arms; and
wherein the STATCOM station further comprises:
a valve hall enclosing the MMC;
a transformer tank enclosing the transformer arrangement; and
a bushing for a conductor electrically connecting the MMC with the transformer arrangement, the same bushing directly passing through both a wall of the valve hall and a wall of the transformer tank.
2. The STATCOM station of claim 1 , wherein the wall of the valve hall and the wall of the transformer tank are positioned at a distance from each other of at most 10 meters.
3. The STATCOM station of claim 2 , wherein the wye connected MMC comprises three converter arms for a three-phase AC grid.
4. The STATCOM station of claim 2 , wherein the transformer arrangement comprises a phase transformer per phase of the AC grid, wherein the phase transformers are wye connected on an MMC side thereof.
5. The STATCOM station of claim 2 , wherein the transformer arrangement comprises a phase transformer per phase of the AC grid, wherein the phase transformers are delta connected on an MMC side thereof.
6. The STATCOM station of claim 5 , wherein the wye connected MMC comprises three converter arms for a three-phase AC grid.
7. The STATCOM station of claim 1 , wherein the transformer arrangement comprises a phase transformer per phase of the AC grid, wherein the phase transformers are delta connected on an MMC side thereof.
8. The STATCOM station of claim 7 , wherein the wye connected MMC comprises three converter arms for a three-phase AC grid.
9. The STATCOM station of claim 1 , wherein the wye connected MMC comprises three converter arms for a three-phase AC grid.
10. The STATCOM station of claim 1 , wherein the wall of the valve hall and the wall of the transformer tank are positioned at a distance from each other within a range of 1-5 meters.
11. The STATCOM station of claim 1 , wherein the transformer arrangement comprises a phase transformer per phase of the AC grid, wherein the phase transformers are wye connected on an MMC side thereof.