Voltage control of a facts shunt compensator

1. A method for voltage control of a static synchronous compensator, STATCOM, or a static var compensator, SVC, the method being performed in a control device, the method comprising:

obtaining a synchronous condenser, SC, error;

obtaining a STATCOM or SVC voltage setpoint;

adjusting the obtained STATCOM or SVC voltage setpoint with the obtained SC error to a total STATCOM or SVC voltage reference; and

providing the total STATCOM or SVC voltage reference for voltage control of the STATCOM or SVC.

2. The method according to claim 1 , wherein the obtaining of an SC error comprises obtaining a difference between an SC voltage setpoint and a quantity equal to an SC voltage measurement plus a correction term slope*i SC or slope*Q SC .

3. The method according to claim 1 , further comprising:

obtaining a power oscillation damping voltage signal V POD ; and

adding the obtained V POD to the total STATCOM or SVC voltage reference.

4. The method according to claim 1 , further comprising:

obtaining a slow MVar control voltage signal; and

adding the obtained slow MVar control voltage signal to the total STATCOM or SVC voltage reference.

5. The method according to claim 1 , further comprising:

obtaining a slope adjusted VSC and filter current for the STATCOM; and

subtracting the obtained slope adjusted VSC and filter current for the STATCOM from the total STATCOM voltage reference.

6. The method according to claim 1 , further comprising:

obtaining a slope adjusted SVC current for the SVC; and

subtracting the obtained slope adjusted SVC current for the SVC from the total SVC voltage reference.

7. The method according to claim 1 , further comprising, after the adjusting and prior to the providing, limiting the total STATCOM or SVC voltage reference by a voltage maximum and a voltage minimum.

8. The method according to claim 7 , further comprising:

measuring a STATCOM or SVC voltage; and

subtracting the measured STATCOM or SVC voltage from the limited total STATCOM or SVC voltage reference.

9. The method according to claim 1 , wherein the control device is a STATCOM or SVC control device.

10. The method according to claim 1 , wherein the control device is a master control device, the master control device connected to a STATCOM or SVC control device and to a SC control device.

11. A control device for voltage control of a static synchronous compensator, STATCOM, or static var compensator, SVC, the control device comprising:

processing circuitry; and

a computer program product embodied on a non-transitory computer readable medium and storing instructions that, when executed by the processing circuitry, causes the control device to:

obtain a synchronous condenser, SC, error;

obtain a STATCOM or SVC voltage setpoint;

adjust the obtained STATCOM or SVC voltage setpoint with the obtained SC error to a total STATCOM or SVC voltage reference; and

provide the total STATCOM or SVC voltage reference for voltage control of the STATCOM or SVC.

12. The control device according to claim 11 , wherein the obtain an SC error comprises obtaining a difference between an SC voltage setpoint and a quantity equal to an SC voltage measurement plus a correction term slope*i SC or slope*Q SC .

13. The control device according to claim 11 , further caused to, after the adjust and prior to the provide, limit the total STATCOM or SVC voltage reference by a voltage maximum and a voltage minimum.

14. The control device according to claim 13 , further caused to:

measure a STATCOM or SVC voltage; and

subtract the measured STATCOM or SVC voltage from the limited total STATCOM or SVC voltage reference.

15. The control device according to claim 11 , wherein the control device is a STATCOM or SVC control device.

16. The control device according to claim 11 , wherein the control device is a master control device, the master control device connected to a STATCOM or SVC control device and to a SC control device.

17. A computer program embodied on a non-transitory computer readable medium for voltage control of a static synchronous compensator, STATCOM, or static var compensator, SVC, the computer program comprising computer program code which, when run in a control device, causes the control device to:

obtain a synchronous condenser, SC, error;

obtain a STATCOM or SVC voltage setpoint;

adjust the obtained STATCOM or SVC voltage setpoint with the obtained SC error to a total STATCOM or SVC voltage reference; and

provide the total STATCOM or SVC voltage reference for voltage control of the STATCOM or SVC.