Dynamic Performance Enhancement of Synchronous Generator Excitation via Nonlinear Backstepping Control

Author(s):  
Haitham Saad Mohamed Ramadan ◽  
Mohamed Becherif

Abstract This paper addresses the transient stability problem in power systems of nonlinear character. A recursive nonlinear backstepping controller for improving the single machine infinite bus system’s dynamic behavior is proposed for the system global stabilization considering the network transfer conductances. Despite parameters uncertainties, nonlinear dynamics and/or disturbances, the feedback laws based on the backstepping approach are explicitly derived and the conservatism of the stability property is guaranteed for both lossy and lossless power system representations. Simulation results, via MATLAB™-Simulink, reveal that the proposed backstepping technique can be feasibly designed to ensure significant dynamic performance enhancements.

2021 ◽  
Author(s):  
THIAGO FIGUEIREDO DO NASCIMENTO ◽  
ANDRES ORTIZ SALAZAR

The integration of distributed generation (DG) systems based on renewable energy sources (RES) by using power converters is an emerging technology in modern power systems. Among the control strategies applied to this new configuration, the virtual synchronous generator (VSG) approach has proven to be an attractive solution due providing suitable dynamic performance. Thus, this paper presents a dynamic analysis of gridtied converters controlled by using VSG concept. This analysis is based on a dynamic model that describes the DG power flow transient characteristics. Based on this model, the grid impedance parameters variation effects on the VSG controllers dynamic performance are discussed. Simulation results are presented to evaluate the effectiveness of the theoretical analysis performed.


2020 ◽  
Vol 20 (4) ◽  
pp. 103-113

A synchronous generator is one of the key elements of any power system, having a significant impact on the stability and reliability of consumers’ power supply. Nowadays, the power systems emergency and operational control issues are being solved using computational models, the parameters whereof are determined using the reference data, or the data obtained during testing. High dependence of the models’ parameters on various external factors leads to a significant decrease in the accuracy of solving the issues of emergency and operational control. Identification based on the traditional telemetry systems or synchrophasor measurements is used to improve the accuracy of parameters of the power systems’ computational models. The purpose of this research lies in a meta-analysis of the available studies aimed at developing a methodology for determining parameters of a synchronous generator on the basis of measurement data. Russian and foreign studies were analyzed and grouped to achieve this goal. After that, for each group, advantages, disadvantages, and the area of application were identified. As a result, it is shown that the existing methods for determining parameters of synchronous generators based on measurement data cannot adapt to the source dataset and also require significant computing power. As a way to overcome these shortcomings, an adaptive model of a synchronous machine is proposed.


Author(s):  
Salah Eddine Rhaili Et. al.

Variable structure strategies have shown an efficient performance in controlling nonlinear electrical power systems by reason of its strength to handle perfectly the unmodeled system dynamics. In this study, with the exponent reaching law, a robust enhancement method of sliding mode controller (SMC) based on a nonlinear fractional order sliding surface that consists of both fractional differentiation and integration is proposed and applied to control a high-power multiphase permanent magnet synchronous generator based direct-driven Wind Energy Conversion System (WECS), in order to improve the energy efficiency and reduce the produced chattering phenomenon of conventional SMC . Moreover, a new smooth and derivable nonlinear switching control function is applied to replace the traditional non-derivable nonlinear control law, to improve dynamic performance, static performance, and robustness of the system. The proposed strategy stability is investigated under Lyapunov theory. A comparative simulation of the new proposed approach with the conventional SMC and PI controller display the excellent performance, stability and high robustness of FOSMC, by improving the system efficiency up to 98.66%, compared to conventional SMC with 91,14%, while the PI control achieves 86, 2%.


2014 ◽  
Vol 573 ◽  
pp. 328-333
Author(s):  
R. Ramya ◽  
K. Selvi ◽  
M. Tamilvanan

This paper deals with the design and evaluation of robust excitation controller for a single-machine infinite-bus power system. The design of the regulator guarantees the stability of the closed loop system and ensures the output voltage is maintained within an acceptable threshold. In addition, it damps out local mode oscillations for small signal disturbances. The designed robust controller is also analyzed under change in step input and disturbance, which limits the heavy oscillations on the speed ω and voltage. Glover-McFarlane loop shaping algorithm is applied in designing the robust excitation controller. Two different techniques such as Optimal control and mixed sensitivity approach is used in this paper. The performance of the AVR was analyzed and compared with IEEE type2 Exciter.


2013 ◽  
Vol 732-733 ◽  
pp. 719-725 ◽  
Author(s):  
Jian Tao Liu ◽  
Chen Long Li ◽  
Ke Wang

Emergency HVDC power support (EDCPS) can be used for improving the transient stability of AC/DC power systems, but the effect is directly determined by the quantity, the starting time, the speed and other factors of the power support. In this article, the dynamic characteristics of AC/DC power systems after a fault are analyzed, generalized dynamical models of the AC/DC power system are established, the relationship between the duration and the quantity of the EDCPS and the dynamic characteristics of the system are established based on the impulse theorem, then the EDCPS strategy besed on the principles of the generalized dynamics is proposed. At last, it is verified by examples of simulation that the strategy can effectively improve the stability of the AC/DC power systems after a fault.


2022 ◽  
Vol 12 (2) ◽  
pp. 589
Author(s):  
Abdul Waheed Khawaja ◽  
Nor Azwan Mohamed Kamari ◽  
Muhammad Ammirrul Atiqi Mohd Zainuri

Low frequency oscillations in large power systems may result in system instability under large disturbances. Power system stabilisers (PSS) play an effective role in damping these low frequency oscillations by injecting a modulating signal in the excitation loop of a synchronous machine. A new metaheuristic optimisation algorithm termed the sine cosine algorithm (SCA) was proposed for optimising PSS controller parameters to obtain an optimal solution with the damping ratio as an objective function. The SCA technique was examined on a single machine infinite bus (SMIB) system under distinct loading situations and matched with a moth flame optimisation technique and evolutionary programming to design a robust controller of PSS. The simulation was accomplished using a linearised mathematical model of the SMIB. The performance of a designed lead lag-controller of PSS was demonstrated using eigenvalue analysis with simulations, showing promising results. The dynamic performance was validated with respect to the damping ratio, the eigenvalue’s location in the s-plane and rotor angle deviation response to demonstrate system stability.


2020 ◽  
pp. 0309524X2097546
Author(s):  
Abdul Waheed Kumar ◽  
Mairaj ud din Mufti ◽  
Mubashar Yaqoob Zargar

This paper reports the modeling and dynamic performance of a wind penetrated multi-area power system incorporating a Singular Virtual Synchronous Generator (SVSG)/Distributed Virtual Synchronous Generator (DVSG). The active and reactive power controls are achieved by using Superconducting Magnetic Energy Storage (SMES) as Virtual Synchronous Generator (VSG). SMES based VSG control parameters are tuned offline using genetic algorithm (GA). Two topologies of VSGs are considered in this paper: SVSG at lowest inertia generator bus (SVSGGENBUS), SVSG at load bus (SVSGLOADBUS) and DVSG of comparatively smaller rating at three lowest inertia generator buses. A modified 18 machine, 70-bus power system is simulated in MATLAB/Simulink environment. System performance is assessed for two different types of disturbances: step wind disturbance and three-phase fault. The simulation results show that rate of change of frequency (ROCOF), deviations in frequency and voltage are minimized with DVSG. Transient stability measured in terms of critical clearing time (CCT) verifies that CCT is increased by DVSG topology.


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