Low frequency electromechanical oscillations can pose a threat to the stability of power systems if not properly addressed. This paper proposes a novel methodology to damp these inter-area oscillations using loads, the demand side of the system. In the proposed methodology, loads are assigned to an aggregated cluster whose demand is modulated for oscillation damping. The load cluster control action is obtained from an optimal output feedback control (OOFC) strategy. The paper presents an extension to the regular OOFC formulation by imposing a constraint on the sum of the rows in the optimal gain matrix. This constraint is useful when the feedback signals are generator speeds. In this case, the sum of the rows of the optimal gain matrix is the droop gain of each load actuator. Time-domain simulations of a large-scale power system are used to demonstrate the efficacy of the proposed control algorithm. Two different cases are considered: a power imbalance and a line fault. The simulation results show that the proposed controllers successfully damp inter-area oscillations under different operating conditions and with different clustering for the events considered. In addition, the simulations illustrate the benefit of the proposed extension to the OOFC that enable load to provide a combination of droop control and small signal stability augmentation.

%B IEEE Transactions on Power Systems %V 35 %P 2024 - 2036 %8 05/2020 %G eng %U http://xplorestaging.ieee.org/ielx7/59/9070029/08876651.pdf?arnumber=8876651 %N 3 %! IEEE Trans. Power Syst. %R 10.1109/TPWRS.5910.1109/TPWRS.2019.2948116 %0 Journal Article %J IEEE Transactions on Power Systems %D 2020 %T Damping of Inter-Area Oscillations via Modulation of Aggregated Loads %A Wilches-Bernal, Felipe %A Byrne, Raymond H. %A Lian, Jianming %K AA14-006 %XLow frequency electromechanical oscillations can pose a threat to the stability of power systems if not properly addressed. This paper proposes a novel methodology to damp these inter-area oscillations using loads, the demand side of the system. In the proposed methodology, loads are assigned to an aggregated cluster whose demand is modulated for oscillation damping. The load cluster control action is obtained from an optimal output feedback control (OOFC) strategy. The paper presents an extension to the regular OOFC formulation by imposing a constraint on the sum of the rows in the optimal gain matrix. This constraint is useful when the feedback signals are generator speeds. In this case, the sum of the rows of the optimal gain matrix is the droop gain of each load actuator. Time-domain simulations of a large-scale power system are used to demonstrate the efficacy of the proposed control algorithm. Two different cases are considered: a power imbalance and a line fault. The simulation results show that the proposed controllers successfully damp inter-area oscillations under different operating conditions and with different clustering for the events considered. In addition, the simulations illustrate the benefit of the proposed extension to the OOFC that enable load to provide a combination of droop control and small signal stability augmentation.

%B IEEE Transactions on Power Systems %V 35 %P 2024 - 2036 %8 05/2020 %G eng %U http://xplorestaging.ieee.org/ielx7/59/9070029/08876651.pdf?arnumber=8876651 %N 3 %! IEEE Trans. Power Syst. %R 10.1109/TPWRS.5910.1109/TPWRS.2019.2948116 %0 Journal Article %J IEEE Transactions on Power Systems %D 2018 %T Interarea Oscillation Damping Control Using High-Voltage DC Transmission: A Survey %A Elizondo, Marcelo A. %A Fan, Rui %A Kirkham, Harold %A Ghosal, Malini %A Wilches-Bernal, Felipe %A Schoenwald, David %A Lian, Jianming %K AA14-006 %XHigh-voltage direct current (HVDC) transmission lines are increasingly being installed in power systems around the world, and this trend is expected to continue with advancements in power electronics technology. These advancements are also bringing multiterminal direct current (MTDC) systems closer to practical application. In addition, the continued deployment of phasor measurement units makes dynamic information about a large power system readily available for highly controllable components, such as HVDC lines. All these trends have increased the appeal of modulating HVDC lines and MTDC systems to provide grid services in addition to bulk power transfers. This paper provides a literature survey of HVDC and MTDC damping controllers for interarea oscillations in large interconnected power systems. The literature shows a progression from theoretical research to practical applications. There are already practical implementations of HVDC modulation for lines in point-to-point configuration, although the modulation of MTDC systems is still in the research stage. As a conclusion, this paper identifies and summarizes open questions that remain to be tackled by researchers and engineers.

%B IEEE Transactions on Power Systems %V 33 %P 6915 - 6923 %8 11/2018 %G eng %U https://ieeexplore.ieee.org/ielaam/59/8496918/8353481-aam.pdf %N 6 %! IEEE Trans. Power Syst. %R 10.1109/TPWRS.2018.2832227 %0 Journal Article %J IEEE Transactions on Power Systems %D 2018 %T Interarea Oscillation Damping Control Using High-Voltage DC Transmission: A Survey %A Elizondo, Marcelo A. %A Fan, Rui %A Kirkham, Harold %A Ghosal, Malini %A Wilches-Bernal, Felipe %A Schoenwald, David %A Lian, Jianming %K AA14-006 %XHigh-voltage direct current (HVDC) transmission lines are increasingly being installed in power systems around the world, and this trend is expected to continue with advancements in power electronics technology. These advancements are also bringing multiterminal direct current (MTDC) systems closer to practical application. In addition, the continued deployment of phasor measurement units makes dynamic information about a large power system readily available for highly controllable components, such as HVDC lines. All these trends have increased the appeal of modulating HVDC lines and MTDC systems to provide grid services in addition to bulk power transfers. This paper provides a literature survey of HVDC and MTDC damping controllers for interarea oscillations in large interconnected power systems. The literature shows a progression from theoretical research to practical applications. There are already practical implementations of HVDC modulation for lines in point-to-point configuration, although the modulation of MTDC systems is still in the research stage. As a conclusion, this paper identifies and summarizes open questions that remain to be tackled by researchers and engineers.

%B IEEE Transactions on Power Systems %V 33 %P 6915 - 6923 %8 11/2018 %G eng %U https://ieeexplore.ieee.org/ielaam/59/8496918/8353481-aam.pdf %N 6 %! IEEE Trans. Power Syst. %R 10.1109/TPWRS.2018.2832227