The power system is prone to many emergency conditions which may lead to emergency state of operation with decay in the system frequency. The dramatic change in the frequency can result in cascaded failure of the syst...The power system is prone to many emergency conditions which may lead to emergency state of operation with decay in the system frequency. The dramatic change in the frequency can result in cascaded failure of the system. In order to avoid power system collapse, load shedding （LS） schemes are adopted with the optimal amount of load shed. This paper proposed a methodology in a two-area thermal-thermal system for finding the required amount of load to be shed for setting the frequency of the system within minimum allowable limits. The LS steps have been obtained based on the rate of change of frequency with the increase in load in steps. A systematic study has been conducted for three scenarios： the scheme with a conventional integral controller; the scheme with a linear quadratic regulator （LQR）; and the scheme with an LQR and superconducting magnetic energy storage devices （SMES）. A comparison of the results has been presented on the two-area system.展开更多
This paper introduces a technique based on linear quadratic regulator （LQR） to control the output voltage at the load point versus load variation from a stand- alone proton exchange membrane （PEM） fuel cell power ...This paper introduces a technique based on linear quadratic regulator （LQR） to control the output voltage at the load point versus load variation from a stand- alone proton exchange membrane （PEM） fuel cell power plant （FCPP） for a group housing use. The controller modifies the optimal gains ki by minimizing a cost function, and the phase angle of the AC output voltage to control the active and reactive power output from an FCPP to match the terminal load. The control actions are based on feedback signals from the terminal load, output voltage and fuel cell feedback current. The topology chosen for the simulation consists of a 45 kW proton exchange membrane fuel cell （PEMFC）, boost type DC/ DC converter, a three-phase DC/AC inverter followed by an LC filter. Simulation results show that the proposed control strategy operated at low commutation frequency （2 kHz） offers good performances versus load variations with low total harmonic distortions （THD）, which is very useful for high power applications.展开更多
文摘The power system is prone to many emergency conditions which may lead to emergency state of operation with decay in the system frequency. The dramatic change in the frequency can result in cascaded failure of the system. In order to avoid power system collapse, load shedding （LS） schemes are adopted with the optimal amount of load shed. This paper proposed a methodology in a two-area thermal-thermal system for finding the required amount of load to be shed for setting the frequency of the system within minimum allowable limits. The LS steps have been obtained based on the rate of change of frequency with the increase in load in steps. A systematic study has been conducted for three scenarios： the scheme with a conventional integral controller; the scheme with a linear quadratic regulator （LQR）; and the scheme with an LQR and superconducting magnetic energy storage devices （SMES）. A comparison of the results has been presented on the two-area system.
文摘This paper introduces a technique based on linear quadratic regulator （LQR） to control the output voltage at the load point versus load variation from a stand- alone proton exchange membrane （PEM） fuel cell power plant （FCPP） for a group housing use. The controller modifies the optimal gains ki by minimizing a cost function, and the phase angle of the AC output voltage to control the active and reactive power output from an FCPP to match the terminal load. The control actions are based on feedback signals from the terminal load, output voltage and fuel cell feedback current. The topology chosen for the simulation consists of a 45 kW proton exchange membrane fuel cell （PEMFC）, boost type DC/ DC converter, a three-phase DC/AC inverter followed by an LC filter. Simulation results show that the proposed control strategy operated at low commutation frequency （2 kHz） offers good performances versus load variations with low total harmonic distortions （THD）, which is very useful for high power applications.
