Power systems
Esmaeel Rokrok; Saman Dehghaninejad; Amir Hossein Poursaeed
Abstract
Recent technical advances in Wide-Area Measurement Systems (WAMS) have made it possible to use a combination of measured signals from remote locations to design centralized control. However, the transmission delay of remote signals and changes in the power system operating point are significant issues ...
Read More
Recent technical advances in Wide-Area Measurement Systems (WAMS) have made it possible to use a combination of measured signals from remote locations to design centralized control. However, the transmission delay of remote signals and changes in the power system operating point are significant issues in the operation of the Wide-Area Damping Controller (WADC). Regarding issues and uncertainties in the power system, mixed H_2/H_∞ synthesis has been proposed for wide-area robust controller design. In this paper, an adaptive wide-area robust controller for Thyristor Controlled Series Capacitors (TCSC) is presented to improve the inter-area oscillation damping in multi-machine power systems in which the time-varying delays in feedback signal time are taken into account. So, an Adaptive Delay Compensator (ADC) is used to compensate for the delay of receiving remote signals. Despite the nonlinearity of the power system, the changes in the operating point, and the presence of time-varying delays, the proposed scheme shows robust performance in damping the low-frequency oscillations. The efficiency of the proposed control system in the presence of TCSC is shown through simulation results that show its superiority over the conventional control system. The simulation of the paper is carried out on the Four-Machine Two-Area test system and 10-machine, 39-bus New England power system.
Control
Salehe Afsharian; Hussein Eliasi
Abstract
This article aims to derive new sufficient conditions to guarantee the stability of piecewise affine systems with time-varying delay (PWA-TVD). The set of delay-dependent linear matrix inequality (LMI) describes the novel stability criteria. This approach considers the PWA-TVD system with a time-delayed ...
Read More
This article aims to derive new sufficient conditions to guarantee the stability of piecewise affine systems with time-varying delay (PWA-TVD). The set of delay-dependent linear matrix inequality (LMI) describes the novel stability criteria. This approach considers the PWA-TVD system with a time-delayed state-dependent switching signal. The newly suggested Lyapunov-Krasovskii functional (L-K-F) and improved estimation of its derivative have a crucial role in decreasing the complexity and conservatism of the proposed stability results. The suggested L-K-F belongs to the current and time-delayed states, the integral of the states over the time-varying delay, and time derivation of the states. A new inequality was used to obtain an upper bound (UB) for the time derivation of the Lyapunov functional. Then based on this UB, less conservative results are achieved. The theoretical results are applied to the numerical examples. The results confirm the effectiveness of the presented method. The conservative index is the maximum admissible UB of time delay.
