Wide-area Damping Controller Design Strategy For Power System Inter-area Oscillations Considering Communication Time Delays And Actuator Saturation Based On Parametric Lyapunov Theory

With the development of the Wide Area Measurement System(WAMS),the use of remote feedback signals can effectively dampen the low-frequency oscillations in the interval,but the resulting delay in the transmission of the feedback signal becomes the main reason that affects the controller’s effect and even the stability of the system.A key problem that is inevitable for large-scale grid dynamic safety and stability analysis and control.The time delay of different wide-area control loops in real power systems is not the same,and the time delay of any control loop will change randomly with time.The background of the controller is designed with multiple time-delay correlation conditions.On the other hand,actuator saturation is a ubiquitous phenomenon because the output of the control actuator is limited.In fact,most power system control modules are subject to saturation limitations,such as PSS and excitation control.Output limit,etc.,once the output signal reaches the upper and lower limits,the actuator can not meet the control command,resulting in deterioration of the controller performance and even threatening system stability.The actuator output limit may not only encounter passive physical limitations,but in the design of the wide-area damping controller(WADC),in order to avoid excessive interference from the main voltage regulator,it is necessary to actively limit the output of the WADC.Therefore,the controller design of the saturated system and its stability analysis need to be studied in depth.And because the communication time delay and actuator saturation will affect the damping controller effect,while the controller design problem considering saturation and time delay is not a simple superposition of the controller outputs with time delay and saturation separately,they are a pair of mutual coupling.Mutual influence factors,therefore,it is necessary to study the unified design method of wide-area damping controllers that consider both power system time delay and actuator saturation.Considering the above problems,this paper deals with wide-area time-delay damping control strategy,wide-area damping control strategy considering controller saturation,wide-area damping coordinated control strategy considering multiple time delays,and wide-area damping coordination considering multi-controller time-delay and saturation.The controller has been thoroughly studied in four aspects,as follows:(1)Considering the time delay problem faced by wide-area damping controllers,the control law and control parameters of wide-area time-delay damping controller for power system based on parametric Lypunov theory are derived.The wide-area power system considering single-delay is designed.The stagnation controller is characterized in that the obtained control law and control parameters are significantly correlated with the time delay parameters,so that the controller can achieve satisfactory control effects under fixed time delay and time varying time delay conditions,overcoming the general The parameter tuning of time-delay compensation controller and the adaptability problem to time-varying delay are designed based on the original energy function of the system and its stability definition.Compared with the LMI-based time-delay robust controller,it is less conservative.The controller is essentially "minimum energy control with convergence rate guarantee",which theoretically ensures that the dynamic response performance of the controller proposed in this paper is better,and the time required for the controller to stabilize the closed-loop system can also be guaranteed;The simulation verification on the four-machine two-zone system and the ten-machine thirty-nine node system confirms the effectiveness of the proposed controller and verifies the wide-area time based on the parametric Lyapunov theory.The above characteristics and advantages of the snubber controller and the control effect of the traditional LMI method design wide-area time-delay damper controller method illustrate the superiority of the proposed method.(2)Considering the time delay problem faced by the wide-area damping controller at the same time,and the controller output limit may not only encounter physical constraints such as materials and environment,but also the controller design of the special-purpose controller in the wide-area damping controller(WADC).In order to avoid excessive interference of the main voltage regulator,it is necessary to actively limit the output of WADC,which is the output limitation problem of wide-area damping controller,and derive the power system output based on the parameter Lypunov theory.The control law and control parameters of the constrained wide-area time-delay unified controller are designed.The unified power system wide-area damping controller considering controller saturation(output limitation)and communication time-delay is designed.The method is based on the original energy of the system.The function and its stability definition are designed to be less conservative in theory;the controller designed is ―minimum energy control with convergence rate guarantee‖,and the saturation characteristics of the actuator are considered in the closed-loop system modeling.Effectively avoid saturation of the actuator,thus ensuring that the designed controller has multiple communication time delays and actuators at the same time.When has better performance.It is "the minimum energy control with convergence rate guarantee",which theoretically guarantees that the dynamic response performance of the controller proposed in this paper is better,and the time required for the controller to stabilize the closed-loop system can also be guaranteed;The simulations on the node and the 16-node 68-node system verify the effectiveness of the proposed controller.The above characteristics and advantages of the wide-area time-delayed controller based on the parameter Lyapunov theory are verified.The wide-angle time delay is designed with the traditional LMI method.The comparison of the control effects of the damping controller method illustrates the superiority of the proposed method.(3)Consider that there are many different wide-area control loops in the actual power system,and the time delays of these control loops are not the same.The time delay of any control loop will change randomly with time.This paper deduces the power system.The multi-control damper controller multi-control loop multi-delay condition coordinating design control law and the mathematical form of controller parameters,designing a wide-area multi-delay coordinated damping controller with time-delay correlation,and giving control related to multi-delay parameters Law and controller parameters,transform the power system state equation matrix,so that the proposed control method can be applied to the design process of wide-area multi-delay coordinated damping controller to ensure that the controller has fixed multiple time delays and time-varying multiple time delays.It has good adaptability;it is "minimum energy control with convergence rate guarantee",which theoretically guarantees that the dynamic response performance of the controller proposed in this paper is better,and the time required for the controller to stabilize the closed-loop system can also be obtained.Guarantee.The simulation verification on the four-machine two-zone system shows the effectiveness of the wide-area multi-delay coordinated controller based on the parameter Lyapunov theory method,and the comparison of the control effects of the separate design of each time-delay controller based on the same parameter Lyapunov theory method.The necessity of multi-delay coordinated control is compared with the control effect of wide-area multi-delay damping coordination controller based on LMI method.The superiority of the proposed controller design method is verified.(4)Considering the problem that multi-control loops of multi-control damper controllers have multiple time delays and saturation limits at the same time,the coordinated design control law and controller parameters of multi-control loops of multi-control loops of power system with multiple time delays and saturation constraints are derived.In mathematical form,the anti-saturation wide-area multi-delay coordinated damping controller related to multi-time delay and multi-controller saturation limit is designed,and the power system state equation matrix is transformed,so that the proposed control method can be applied to the power system wide area.In the design process of multi-delay coordinated damping controller,the designed controller has good control effect and dynamic performance for multi-controller multi-delay multi-saturation limitation.The simulation verification on the four-machine two-area system and the control effect of the controller based on the LMI method verify the effectiveness and superiority of the proposed controller design method.