Adaptive controller for forced oscillation suppression in the grid

1. A control system for an inverter based resource device in a power system comprising:

at least one inverter based resource device connected to an electrical power system, and a controller module;

the inverter based resource device comprising a reference power P ref , a combination module and an inverter transfer function; the inverter based resource injecting power into the power system;

the power system comprising a power transfer function, to receive a forced oscillation source; the power transfer function configured to generate an output; and

a controller module to provide supervisory control of the inverter based resource device, the controller module configured to suppress a forced oscillation detected in the power system transfer function.

2. The control system of claim 1 , wherein the controller module is further configured to:

detect the forced oscillation at a predetermined measurement point;

set a tuned frequency for a band-pass filter frequency H F and a control compensator value H c , in response to the detected forced oscillation having the tuned frequency;

tune the control compensator value to cancel a gain and phase of a measured power value; and

set a gain value K c of a gain module to generate a feedback signal c in response to the band-pass filter frequency H F and the control compensator value H c ;

wherein the feedback signal is transmitted to the combination module of the inverter based resource device transfer function to modulate a real-power output of the at least one inverter based resource device in response to the forced oscillation.

3. The control system of claim 2 , wherein the controller module is further configured to: modulate the gain module automatically wherein K c is gradually increased to a maximum value.

4. The control system of claim 2 , wherein the controller module is further configured to: shut down the feedback signal by switching a feedback control loop to the Off state at a first switching unit connected in series with the control compensator and the band-pass filter; and a second switching unit connected in series with a gain module for Kc.

5. The control system of claim 2 , wherein a control module continuously operates an oscillation detection mode and a control logic, the control logic configured to generate the feedback signal in response to a detected oscillation, generate a plurality of control settings, provide a trigger logic and set weight assignment parameters.

6. The control system of claim 2 , wherein the forced oscillation is measured by a measurement unit comprising a phasor measurement unit in communication with the power system, the phasor measurement unit being configured to detect an oscillatory behavior of the forced oscillation.

7. The control system of claim 1 , wherein the controller module is further configured to: monitor the power system and shut down the feedback signal in response to the forced oscillation being undetected.

8. The control system of claim 1 , wherein the power transfer function comprises a forced oscillation added to a first grid transfer function G1 of the synchronous power system to generate a second grid transfer function G2.

9. A method for controlling an inverter based resource device to suppress forced oscillation in a radial transmission system, the method comprising:

providing an inverter based resource device connected to an electrical power system,

suppressing a forced oscillation;

detecting the forced oscillation at a predetermined measurement point;

setting a tuned frequency of a band-pass filter frequency H F based on the forced oscillation frequency;

setting a control compensator value H c , in response to the detected forced oscillation having the tuned frequency;

tuning a control compensator value to cancel a gain and phase of a measured power value;

setting a gain value K c ;

generating a feedback signal c with the gain value in response to the band-pass filter frequency H F and the control compensator value H c ;

transmitting the feedback signal to the inverter based resource device; and

modulating a real-power output of the inverter based resource device in response to the forced oscillation.

10. The method of claim 9 , further comprising:

monitoring the power system; and

shutting down the feedback signal in response to the forced oscillation being undetected.

11. The method of claim 10 , wherein the step of shutting down the feedback signal further comprises:

switching a feedback control loop to the Off state at a first switching unit connected in series with the control compensator and the band-pass filter; and

switching to the Off position a second switching unit connected in series with a gain module for Kc.

12. The method of claim 10 , further comprising:

modulating the gain module automatically by gradually increasing gain value K c to a maximum value.

13. The method of claim 10 , further comprising:

generating a transfer function of the power system comprising a forced oscillation;

adding the forced oscillation to a first grid transfer function G 1 of the synchronous power system; and

generating a second grid transfer function G 2 .

14. The method of claim 10 , further comprising:

continuously operating an oscillation detection mode and a control logic,

generating the feedback signal in response to a detected oscillation;

generating a plurality of control settings;

providing a trigger logic; and

setting weight assignment parameters associated with an inverter based resource device.

15. The method of claim 9 , wherein the forced oscillation is measured by a measurement unit comprising a phasor measurement unit in communication with the radial transmission system, the phasor measurement unit being configured to detect an oscillatory behavior of the forced oscillation.

16. A control method for suppressing forced oscillation in a power system, comprising:

detecting a forced oscillation signal y;

passing the forced oscillation signal through a band-pass (BP) filter that focuses on the desired bandwidth for an oscillation detection;

passing the band-pass filtered signal through a squaring function and squaring the filtered signal;

passing the squared signal thru a low-pass filter;

estimating the moving mean of the squared signal y that is matched to the BP filter; and

generating a square root of the low-pass filtered signal y;

wherein an output signal is an RMS-value of the forced oscillation signal in the bandwidth of the band-pass filter.

17. The control method of claim 16 , further comprising:

providing a plurality of RMS energy filters; and

providing a distinct range of band-pass filter frequencies for each RMS energy filter.

18. The control method of claim 17 , further comprising:

a speed governor band-pass frequency range is 0.01 Hz to 0.15 Hz for a speed governor band;

an inter-area oscillation band-pass frequency range is 0.15 Hz to 1 Hz;

a local mode and controls band-pass frequency range is 1 Hz to 5 Hz; and

a high-frequency band-pass frequency range is 5 Hz to Nyquist.

19. The control method of claim 18 , further comprising:

generating an alarm in response to at least one RMS energy filter output exceeding a predetermined threshold value; and

conducting a Fast Fourier Transform (FFT) operation conducted on the measured parameter;

wherein a maximum FFT range in the bandwidth of the RMS filter corresponds to a fundamental frequency of the forced oscillation; and

setting a compensating frequency f c .

20. The control method of claim 18 , further comprising:

a loop transfer function L(jω c )=K c with f c =1 Hz;

the loop transfer function having margin points for a gain profile and a phase profile.