Nonlinear disturbance observer based adaptive super twisting sliding mode load frequency control for nonlinear interconnected power network

Abstract

This article revisits the study of load frequency control (LFC) problem in an interconnected nonlinear power network under mismatched disturbance.Unlike previous works, a more realistic interconnected power network with nonlinear coupling between control areas and also including nonlinearities like generation rate constraint (GRC) and governor dead band (GDB) is under study. An adaptive super twisting sliding mode controller (ST-SMC) is designed based on system states and estimated disturbance. The nonlinear disturbance observer (NDO) estimates the mismatch between the electrical and mechanical power and then the estimated value is employed in the controller design to compensate the disturbance. The proposed control scheme ensures faster frequency and tie-line power stabilization compared with techniques existing in the literature. The robustness of the proposed design is validated under random varying step load disturbance and with two area four machine Kundur's test system. The closed loop system stability is theoretically proved using the Lyapunov function. Simulation results confirm the effectiveness of the proposed design in a two-area interconnected power network.

Designing of 2‐degree of freedom load frequency controller for power system using novel improved pole clustering and genetic method of reduced‐order modelling

“…There are some commonly noticed nonlinearities such as backlash or governor dead band, 47 time delay 48 and generation rate constraint 49 that may occurred at any instant of time and these may deteriorate the performance of the power system. So, these nonlinearities are necessary to tackle while implementing LFC.…”

Decentralized Robust Disturbance-Observer Based LFC of Interconnected Systems

“…Therefore, instead of considering the pre-know upper limit of external disturbance inputs, in several control approaches, disturbance inputs are estimated and then compensated by an adaptive disturbance-observer-based control scheme. Although a disturbance-observer can be incorporated with several advanced control methods [21]- [23], for the secondary LFC issue, mainly it is merged with the sliding mode control [24]- [27]. Though, using sliding mode control provides a discontinuous control input law with chattering.…”

Frequency Regulation of Nonlinear Power Systems using Neural Network Observer-Based Optimized Resilient Controller

“…A disturbance-observer based SMLFC is discussed in references [20,21]. Considering the abovesaid troubled situation, the SMC's performance has been improved by integrating linear/nonlinear disturbance observers [21,22]. Sliding mode observer-based SMLFC has been presented in reference [23].…”