A new wide area damping controller design method considering signal transmission delay to damp interarea oscillations in power system

Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damping performance of WADC designed by the conventional method may deteriorate or even has no effect when signal transmission delay is beyond delay margin, an index that denotes delay endurance degree of power system. Therefore, a new design method for WADC under the condition of expected damping factor and required signal transmission delay is presented in this work. An improved delay margin with less conservatism is derived by adopting a new Lyapunov-Krasovskii function and more compact bounding technique on the derivative of Lyapunov-Krasovskii functional. The improved delay margin, which constructs the correlation of damping factor and signal transmission delay, can be used to design WADC. WADC designed by the proposed method can ensure that power system satisfies expected damping factor when WADC input signal is delayed within delay margin. Satisfactory test results demonstrate the effectiveness of the proposed method.

A Delay-dependent Dynamic Wide Area Damping Controller for Renewable Energy Integrated Power System Resilient to Communication Failure

Integration of renewable energy sources(RES)with a conventional power system has a detrimental effect on interarea oscillation.Most popular RESs are solar photovoltaic(PV)and wind energy conversion systems(WECS).Both solar PV power generation and WECS are integrated with power systems using a power electronic converter.Increasing the amount of RES generation lead towards reduction of system damping,which leads towards inter-area oscillation.Also,the intermittent behavior of a RES reduces the effectiveness of damping controllers.A dynamic controller based wide area damping controller(WADC)is proposed in this paper to increase small signal stability of a RES integrated power system.The WADC is designed for contemplating delay in a communication channel,communication failure and saturation.An anti-windup compensator is developed to overcome the effect of actuator saturation.However,the gain of the anti-windup compensator is calculated using LyapunovKrasovskii functional(LKF)in terms of linear matrix inequality(LMI).The actuator considered in this paper is a unified power flow controller(UPFC).Efficacy of PV and wind power integration on power system is also observed.The efficacy of the developed dynamic controller is verified using IEEE 39 bus and 68 bus power system.