Excitation Control Of Synchronous Generator Research Articles

Predictive Controller Based on Paraconsistent Annotated Logic for Synchronous Generator Excitation Control

This study presents a new Model Predictive Controller (MPC), built with algorithms based on Paraconsistent Annotated Logic (PAL), with application examples in the excitation control of a synchronous generator. PAL is a non-classical evidential and propositional logic that is associated with a Hasse lattice, and which presents the property of accepting the contradiction in its foundations. In this research, the algorithm was constructed with a version of the PAL that works with two information signals in the degrees of evidence format and, therefore, is called Paraconsistent Annotated Logic with annotation of two values (PAL2v). For the validation of the algorithmic structure, the computational tool MATLAB® Release 2012b, The MathWorks, Inc., Natick, MA, United States was used. Simulations were performed which compared the results obtained with PPC-PAL2v to those obtained in essays with the AVR (Automatic Voltage Regulator) controls in conjunction with the PSS (Power System Stabilizer) and the conventional MPC of fixed weights. The comparative results showed the PPC-PAL2v to display superior performance in the action of the excitation control of the synchronous generator, with a great efficiency in response to small signals.

Study and Application of the Advanced Frequency Control Techniques H∞ in the Voltage Automatic Regulator of Powerful Synchronous Generators (Application under Gui/Matlab)

This article presents a study of of the advanced frequency control techniques based on loop-shaping H∞ optimization method applied on automatic excitation control of powerful synchronous generators (AVR and PSS), to improve transient stability and its robustness of a single machine- infinite bus system (SMIB).The computer simulation results (static and dynamic stability), with test of robustness against machine parameters uncertainty (electric and mechanic), have proved that good dynamic performances, showing a stable system responses almost insensitive to large parameters variations, and more robustness using the robust H-infinity controller, in comparison with the classical Russian PID power system stabilizer . Our present study was performed using a GUI realized under MATLAB in our work.

Synchronous Generator Excitation System for a Ship Based on Active Disturbance Rejection Control

To solve synchronous generator oscillations in marine power systems which cannot be effectively suppressed, according to the nonlinearity and time variability of the ship power system, a method of synchronous generator excitation control for a ship based on active disturbance rejection control (ADRC) is proposed. Under different working conditions, three methods are automatic voltage regulator (AVR), automatic voltage regulator with power system stabilizer (PSS), and ADRC methods, which are applied to the two-generator parallel-running excitation system of a ship in simulations. The simulation results show that the excitation control system based on ADRC is faster and has better anti-interference ability and has a better restraining effect on synchronous generator oscillation.

Сильное регулирование возбуждения и стабилизация режимов в многомашинной энергосистеме

In the previously published papers: «Features of Strong Excitation Control of Synchronous Generators in a Complex Power System» (magazine Electric Power Plants, 2019, No. 7) and «Improving Power System Stabilization in Response to Grid Disturbances» (magazine Electricity, 2020, No. 5 ) the author, on the basis of experimental data, showed that the standard method of stabilizing modes in the case of disturbances in a modern complex power system, adopted in the Unified Energy System of Russia, is not always effective. Automatic excitation regulators (AER) rely on the deviation and derivative of the voltage frequency at the terminals of the generators. In oscillatory transient modes, these signals differ significantly in phase from the deviation and derivative of the generator rotation frequency. Instead of reducing the resulting vibrations, this can cause vibration amplitude and duration increase. The author suggested an alternative method based on comparing frequency of rotation of generator to frequency on the busbars of the power plant along with derivative of the difference. Results of full-scale tests, confirming effectiveness of the proposed method, were presented. Effectiveness of the proposed method was also verified in the discussion in the Electric Power Plants magazine, after the publication of the above articles. This publication offers physical perspective of the difference between the proposed method of stabilization versus the standard method, and illuminates why it’s effective in modern complex power systems. Previously unpublished oscillograms of transient processes are also presented.

Robust Adaptive Backstepping Excitation Controller Design for Higher-Order Models of Synchronous Generators in Multimachine Power Systems

A robust adaptive backstepping approach is considered in this paper to design excitation controllers for synchronous generators in power systems. The higher-order dynamical models of synchronous generators are considered to design the proposed excitation controller. Since the parameters appearing within these dynamical models (especially the parameters related to the synchronous generators and excitation systems) significantly affect the stability of power systems, these parameters are considered as completely unknown during the proposed controller design process. The parameter adaptation laws are used in this paper to estimate the unknown parameters while maintaining the overall stability of power systems. The effects of external disturbances are also considered in this paper to incorporate the model accuracies and measurement noises, which in turn ensure the robustness of the proposed control scheme. The control Lyapunov functions are used to analyze the stability of the whole system through the negative semi-definiteness of their derivatives. Simulation studies are carried out on an IEEE standard power system, the New England 10-machine 39-bus power system, to further validate the performance of the proposed scheme under different operating conditions. Comparisons are also made with different existing nonlinear excitation controllers sliding mode controller and robust partial feedback linearizing controller, which are designed based on the higher order models as well as with the robust adaptive controller, which is designed based on the traditional one-axis model. Simulations results, under different operating conditions, demonstrate the superiority of the proposed control scheme over all these existing nonlinear excitation controllers.

Power System Stabilization Using Energy-Dissipating Hybrid Control

A new energy-dissipating hybrid control framework is proposed in this paper. The proposed framework incorporates a plant with continuous dynamics connected in parallel with a hybrid controller that combines logical switches with continuous dynamics. The overall closed-loop system can be described as a hybrid impulsive dynamical system in which the redundant energy preserved in the plant can be damped quickly and continuously due to the enhanced dissipativity of the closed-loop system. The proposed framework is applied to design decentralized nonlinear excitation controllers for synchronous generators in a multimachine system to improve its transient stability, in which the synchronous generators are modeled as port-controlled Hamiltonian systems. Simulation studies on the IEEE 10-generator, 39-bus New England power system are carried out to verify the effectiveness of the proposed energy-dissipating hybrid excitation control to improve the transient stability and dissipativity of the interconnected power system under various fault conditions.

Decentralized Voltage and Power Control of Multi-Machine Power Systems With Global Asymptotic Stability

Maintaining power system stability is becoming urgent due to the large-scale interconnection of power grids and the high penetration of uncertain renewable energy sources. The excitation control and governor control of synchronous generators have been considered as two crucial measures for enhancing the power system stability. However, a major challenge is to simultaneously achieve global asymptotic stability (GAS), voltage regulation (VR), and power regulation (PR) in the excitation and governor control. In this paper, a Lyapunov-based decentralized control (LBC) is proposed to address this challenge. The time-derivative of the Lyapunov function is designed by the feedback control of synchronous generators in order to guarantee GAS. VR and PR are ensured by considering voltage and power deviations as the feedback variables. The simulation results on the New-England ten-machine power system validate the effectiveness of the proposed LBC in improving power system transient stability and simultaneously achieving VR and PR. Although the proportional-integral- and power system stabilizer-based control can also perform VR and PR, the proposed control has much better dynamic performance and can more significantly improve the system transient stability.

An improved Backstepping technique using sliding mode control for transient stability enhancement and voltage regulation of SMIB power system

The problem of transient stability and voltage regulation for a single machine infinite bus (SMIB) system is addressed in this paper. An improved Backstepping design method for transient stability enhancement and voltage regulation of power systems is discussed beginning with the classical Backstepping to designing the nonlinear excitation control of synchronous generator. Then a more refined version of this technique will be suggested incorporating the sliding mode control to enhance voltage regulation and transient stability. The proposed method is based on a standard third-order model of a synchronous generator connected to the grid (SMIB system). It is basically implemented on the excitation side of the synchronous generator and compared to the classical Backstepping controller as well as the conventional controllers which are the automatic voltage regulator and the power system stabiliser. Simulation results prove the effectiveness of the proposed method which ameliorates to a great extent the transient stability compared to the other methods.

Interconnection and damping assignment automatic voltage regulator for synchronous generators

In this paper a new nonlinear regulation for synchronous generator excitation control is presented. This method comprises the nonlinear Interconnection and Damping Assignment (IDA) method together with the generator voltage feedback giving a nonlinear Automatic Voltage Regulator (AVR). First, the IDA excitation control is introduced in the third order salient pole synchronous generator mathematical model represented as a Port Controlled Hamiltonian (PCH) system. Thereafter, a generator voltage feedback signal is added. It is proven that adding the feedback to IDA control preserves a PCH structure of a system and the system is therefore passive. In the paper it is also proven that the gained system is stable and that the reference operating point corresponds to the minimal energy point of the system. Finally, the gained IDA AVR is tested with seventh order synchronous generator model and compared to classical generator excitation controllers. The simulations show the efficient tracking of generator voltage reference value, as well as the maintenance of stability in case of grid-side short-circuit occurrence. The main advantages of the proposed controller are efficiently generator voltage tracking and attenuation of electromechanical oscillations in case of a large disturbance, such as grid-side short-circuit.

Robust H2-PSS design based on LQG control optimized by genetic algorithms

This paper proposes a genetic algorithms (GA) optimization technique applied to power system stabilizer (PSS) for adapt a robust H2 control based on linear quadratic controller (LQ) and Kalman Filter applied on automatic excitation control of powerful synchronous generators, to improve stability and robustness of power system type single machine connected to an infinite bus system (SMIB). Adaptation technique proposed of the robust H2 control with the various electrical and mechanical parametric variations based on the optimization of the PSS parameters. The genetic algorithms is a search technique based on the mechanisms of natural selection of a genetic and evolution. This optimization technique is more used in the field of control for solve optimal choice problem of regulators parameters. The integration of GA to robust H2 control with robustness test (electrical and mechanical parameters variations of the synchronous machine) show considerable improvements in dynamics performances, robustness stability and good adaptation of the robust H2-PSS parameters under uncertain constraints. This present study was performed using our realized Graphical User Interface (GUI) developed under MATLAB.

Influence of Load in Performance of the Static Excitation Control of Synchronous Generator

This paper has as its prime objective to analyze the performance of a static excitation system in function of the type of load applied to the synchronous generator. This is seen through how the magnitude, the power factor and the load variation rate influence the working of the excitation system in the restoration of the generator's terminal voltage. Also shown is the influence of the non-linear load in this type of excitation system.

A Fuzzy Predictive PID Control Scheme for the Excitation System of Synchronous Generator

With the rapid development of the process control theories in the electrical engineering, new control strategies which lead to better performances are urgently demanded for the excitation control of synchronous generators. For the sake of improving the convergence rate of the terminal voltage and covering the weakness in the adaptability of operational conditions of conventional controls in disturbances, a fuzzy predictive PID excitation control method is proposed in this paper. This control scheme can be divided into three steps in every sample interval: PID parameter adaptation, rolling state prediction and real-time control movement integration. Numerical simulations have been conducted under different operational conditions with the proposed method as well as the conventional ones, respectively. Experimental comparisons indicate the superiority in voltage regulation performance of the proposed method.

An Advanced Robust AVR-PSS Based H2 and H∞ Frequency Approachs Simulated Under a Realized GUI

This article present a comparative study between two advanced robust frequency control strategies and their implementation using our realised Graphical User Interface ‘GUI’ under MATLAB software: the first method based on loop-shaping H∞ optimization technique and the second on robust H2 control method (LQG controller associated with KALMAN filter), and applied on automatic excitation control of synchronous generators, to improve transient stability and robustness of a single machine- infinite bus (SMIB) system operating in different several conditions. The computer simulation results (static and dynamic stability), with test of robustness against machine parameters uncertainty (electric and mechanic), have proved that good dynamic performances, showing a stable system responses almost insensitive to large parameters variations, and more robustness using robust H∞ controller in comparison with H2 approach by exploiting our developed GUI interface in this work.

An Advanced Robust AVR-PSS Based H2 and H∞ Frequency Approachs Simulated Under a Realized GUI

This article present a comparative study between two advanced robust frequency control strategies and their implementation using our realised Graphical User Interface ‘GUI’ under MATLAB software: the first method based on loop-shaping H∞ optimization technique and the second on robust H2 control method (LQG controller associated with KALMAN filter), and applied on automatic excitation control of synchronous generators, to improve transient stability and robustness of a single machine- infinite bus (SMIB) system operating in different several conditions. The computer simulation results (static and dynamic stability), with test of robustness against machine parameters uncertainty (electric and mechanic), have proved that good dynamic performances, showing a stable system responses almost insensitive to large parameters variations, and more robustness using robust H∞ controller in comparison with H2 approach by exploiting our developed GUI interface in this work.

A Developed Graphical User Interface for Power System Stability and Robustness Studies

This paper present the realization and development of a graphical user interface (GUI) to studied the stability and robustness of power systems (analysis and synthesis), using Conventional Power System Stabilizers (CPSS - realized on PID scheme) or advanced controllers (based on adaptive and robust control), and applied on automatic excitation control of powerful synchronous generators, to improve dynamic performances and robustness. The GUI is a useful average to facilitate stability study of power system with the analysis and synthesis of regulators, and resolution of the compromise: results precision / calculation speed. The obtained Simulation results exploiting our developed GUI realized under MATLAB shown considerable improvements in static and dynamic performances, a great stability and enhancing the robustness of power system, with best precision and minimum operating time. This study was performed for different types of powerful synchronous generators.

A Developed Graphical User Interface for Power System Stability and Robustness Studies

This paper present the realization and development of a graphical user interface (GUI) to studied the stability and robustness of power systems (analysis and synthesis), using Conventional Power System Stabilizers (CPSS - realized on PID scheme) or advanced controllers (based on adaptive and robust control), and applied on automatic excitation control of powerful synchronous generators, to improve dynamic performances and robustness. The GUI is a useful average to facilitate stability study of power system with the analysis and synthesis of regulators, and resolution of the compromise: results precision / calculation speed. The obtained Simulation results exploiting our developed GUI realized under MATLAB shown considerable improvements in static and dynamic performances, a great stability and enhancing the robustness of power system, with best precision and minimum operating time. This study was performed for different types of powerful synchronous generators.

Improved synergetic excitation control for transient stability enhancement and voltage regulation of power systems

Abstract This paper proposes decentralized improved synergetic excitation controllers (ISEC) for synchronous generators to enhance transient stability and obtain satisfactory voltage regulation performance of power systems. Each generator is considered as a subsystem, for which an ISEC is designed. According to the control objectives, a manifold, which is a linear combination of the deviation of generator terminal voltage, rotor speed and active power, is chosen for the design of ISEC. Compared with the conventional synergetic excitation controller (CSEC), a parameter adaptation scheme is proposed for updating the controller parameter online in order to improve the transient stability and voltage regulation performance simultaneously under various operating conditions. Case studies are undertaken on a single-machine infinite-bus power system and a two-area four-machine power system, respectively. Simulation results show the ISEC can provide better damping and voltage regulation performance, compared with the CSEC without parameter adaptation scheme and the conventional power system stabilizer.

Performance of PSS to Damp Power Oscillations Caused by an HVDC Link in AC-DC Power System

HVDC (High Voltage Direct Current) systems are increasingly being applied to improve power system operation and controllability. However, inappropriate setting of HVDC controller may have a detriment effect on the system performance. Generally, PSS (Power System Stabilizer) is known as a simple concept, easy to perform, and computationally effective to enhance damping of power system oscillations through excitation control of synchronous generator. This paper examines the effectiveness of the PSS to enhance the dynamic performance of AC-DC power systems and to compensate the negative damping of HVDC system. The dynamic performance is evaluated by examining the system response to various disturbances. In order to ensure the reliability of the simulation test results as well as the performance of the PSS, detailed HVDC modeling is adopted using SimPowerSystems toolbox in the MATLAB, and some important conclusions are drawn.

Predictive Synchronous Generator Excitation Control Based on Laguerre Model

In this paper the synchronous generator excitation control is designed using the model reference control approach and its predictive extension. The control objective is to satisfy requirements on the synchronous generator performances imposed by the transmission system operator. The structure of both controllers is expressed in the form of modified Laguerre network. The efficiency of the proposed control design procedure is illustrated by simulation of the 259 MVA synchronous generator of the nuclear power plant Mochovce in Slovakia.

A Comparison between Conventional and Optimal Power System Stabilizers for a Single Machine to an Infinite Bus Power System

The excitation control of synchronous generator in a single machine to an infinite bus (SMIB) power system is very important to improve the stability modes of power system. In addition to the usual or conventional excitation control techniques and speed governors, other devices proved its effectiveness to enhance better system stability like power system stabilizers (PSS) and static VAR compensators (SVC). In this paper, the PSS is used as an additional device to improve the SMIB power system stability. Two out of different control strategies were used; a conventional control technique (PI controller) and a linear optimal controller (LOC). A comparison between both types of PSSs was stated. The contribution of this paper is the design and application of an optimal-PSS and a PI-PSS to a synchronous generator connected to an infinite bus power system. KeywordsSingle machine to an infinite bus, power system stabilizer, excitation control, PI controller, linear optimal controller.