Automatic Voltage Regulator Loop Research Articles

Dynamic Behavior and Stability Analysis of Automatic Voltage Regulator with Parameter Uncertainty

This research article describes a novel optimization technique called simulink design optimization (SDO) to compute the optimal PID coefficients for an automatic voltage regulator (AVR). The time-domain performance of the proposed controller was analyzed using MATLAB/Simulation, and its performance was compared with that of water cycle algorithm, genetic algorithm, and local unimodal sampling algorithm-based PID controllers. The robustness of the proposed controller was verified by applying the disturbances to the generator field voltage and the amplifier parameter uncertainty. The studies presented in literature were discussed the AVR loop stability using the Bode plot which will not give the minimum stability margins. This study proposes a novel stability analysis called disk-based stability analysis to authenticate the stability of the AVR loop which is obtained by the classical analysis. This stability was compared with the proposed stability analysis. The MATLAB results reveal that the SDO-PID controller regulates the terminal voltage of the generator precisely, is more robust to parameter uncertainty, and is more stable than the other controllers. The maximum allowable parameter uncertainty of the amplifier model was identified as 102% of its nominal parameters. The stability margins are recognized as DGM = 10.40 dB and DPM = 56.50° for the AVR stability.

Combined Voltage and Frequency Control of Multiarea Multisource System Using CPDN-PIDN Controller

This paper discusses a multiarea multi-source system in combined automatic load frequency control (ALFC) and an automatic voltage regulator (AVR) model. The multiarea system comprises thermal and wind in Area-1, thermal-geothermal in Area-2, and hydrothermal plant in Area-3. Appropriate nonlinearity constraints are provided for both hydro and thermal plants. A maiden attempt has been made to employ a cascade proportional-derivative (PD) with filter coefficient (N) and PID with filter coefficient (N) (CPDN-PIDN) as a secondary controller in the combined ALFC-AVR system and optimized controller gains using artificial flora algorithm (AFA). It is examined that the CPDN-PIDN controller yields better dynamics responses than the PI and PIDN controllers. Analyze reflects that the system performance enhanced in the presence of AVR loop. This paper discusses the effect of renewable sources like wind and geothermal on the system dynamics. Analysis reveals that the geothermal power plant is more reliable than the wind plant. The parameter variations of the temporary and permanent droop and hydro turbine time constant (HTTC) of the hydro plant are examined through system responses. System response deteriorates significantly as permanent droop and HTTC are reduced. Peak overshoot and undershoot are reduced considerably as the temporary droop value is increased. Sensitivity analysis reveals that the AFA optimized CPDN-PIDN controller parameters obtained under the nominal condition are resilient enough and need not be reset with the system's substantial random variation. An experimental justification has been provided of the investigated system using a real-time simulation with the OPAL-RT OP4510 real-time setup.

Optimal Coordinated Frequency and Voltage Control of CCGT-Thermal Plants with TIDF Controller

This paper deals with unified method of voltage and frequency control of an interconnected three unequal-area systems with the Automatic Load Frequency Control (ALFC) and Automatic Voltage Regulator (AVR) loop. Every area comprises a reheat thermal and the combined cycle gas turbine (CCGT) plant. Concerning the pragmatic system, adequate governor dead band (GDB), boiler system, and generation rate constraint (GRC) are considered in all individual plants. The Tilt-Integral-Derivative with Filter (TIDF) controller is considered in the ancillary controller of the ALFC loops, core controller of the AVR loops, and air-flow, temperature controller of the CCGT Plants. The optimized controller gains are realized through the metaheuristic algorithm called Harris Hawks Optimization algorithm along with the integral square error as a performance index considering a 1% step load perturbation in Area-1. The critical analysis shows that the performance of the TIDF controller is superlative to the classical controllers, such as PI and PID, concerning all time-domain indices. With the TIDF controller, the impacts of the AVR loop, boiler system, and the CCGT plants are analyzed on the unified ALFC and AVR study separately. Sensitivity analysis unveils the sturdiness of the TIDF controller against the change in magnitude of the step load perturbation in Area-1. Finally, the proposed unified ALFC and AVR system of three unequal-area CCGT-thermal plants is analyzed with the OPAL-RT hardware set-up for its real-time validation.

HHO-based Model Predictive Controller for Combined Voltage and Frequency Control Problem Including SMES

This paper discusses the modelling and control of a combined load frequency control (LFC) and automatic voltage regulator (AVR) system for a multi-area power system network with each generating area includes thermal, diesel, and solar thermal power plant. Superconducting magnetic energy storage is incorporated with the LFC loop to provide auxiliary control against instantaneous changes in active power demand. Model Predictive Controller (MPC) has been employed in this study to improve the performance of AVR and LFC loops, and controller weights are fine-tuned with the help of Harris Hawks Optimization (HHO) approach. The effectiveness of the proposed MPC-HHO algorithm has been examined by comparing its transient performance indices with that of conventional MPC, PID, FOPID, fuzzy PID, integral double derivative with derivative filter controller as well as Particle Swarm Optimization and Sine Cosine Algorithm based Model Predictive Controllers. The proposed MPC-HHO controller gives superior results than the above-mentioned controllers.

Utilization of electric vehicles in combined voltage‐frequency control of multi‐area thermal‐combined cycle gas turbine system using two degree of freedom tilt‐integral‐derivative controller

AbstractThis paper conveys the unified control pattern of frequency and voltage of interconnected multi‐area power system through the automatic load frequency control (ALFC) loop and automatic voltage regulator (AVR) loop. Each area includes a single‐stage reheat thermal plant, combined cycle gas turbine (CCGT) plant, and electric vehicles (EVs). Pertinent generation rate constraint for thermal and CCGT plant and governor dead band for the thermal plant is considered. A maiden attempt has been made to introduce the two degree of freedom tilt‐integral‐derivative (2DOFTID) controller for both the ALFC and AVR loops. In this study, a meta‐heuristic algorithm called Harris Hawks optimization (HHO) is implemented to optimize the controller parameters. Study divulges that performance of the 2DOFTID controller predominates when compared with TID and proportional‐integral‐derivative with filter (PIDF) controller apropos time‐domain indices. By juxtaposition, the superiority of the proposed algorithm and performance index is observed. Also, improved system dynamics were independently exhibited by the influence of the lumped EV model and AVR. For the predominance of the 2DOFTID controller, different patterns of disturbances such as random and sinusoidal varying load perturbation have been investigated. Eventually, the sensitivity studies were accomplished to determine the sturdiness of the proposed controller for substantial variations in the system parameters.

Development of Intelligent AVR for Synchronous Generator

The major part of an automatic voltage regulator (AVR) is to normalise the terminal voltage of synchronous generator. The structure modelled contains of the amplifier and generator. The AVR organisms are recycled usually in exciter control system. The part of an AVR is to grip the generator terminal voltage constant below standard operating surroundings at different load levels. The AVR loop of excitation mechanism preparation works terminal voltage error for adjusting the field voltage so as to mechanism the terminal voltage. The basic mechanisms of an exciter control system arrangement comprises of four leading components, namely amplifier, sensor, exciter and generator. The generator and amortisseurs systems state matrix are included, the system equations developed in that model includes one d-axis amortisseurs and two q-axis amortisseurs. This exertion targets to improve a simulation on steady state analysis of a power system with a controller established on fuzzy logic to maintain the terminal voltage.

Contribution of frequency linked pricing control on ALFC and AVR power system integrated with DFIG based wind farms

This research article presents the participation of frequency linked pricing control (FPC) scheme for frequency and voltage control ancillary services in multi-area power system having automatic load frequency control (ALFC) loop and automatic voltage regulator (AVR) loop and integrated with doubly fed induction generator (DFIG) based wind farms. Mutual coupling effects are shown between the two loops by extending linearised ALFC system to include excitation model using AVR loop. FPC based on availability based tariff (ABT) mechanism is used under small load perturbations in power system to provide secondary control to reset frequency and voltage to their nominal values. Dynamic participation of DFIG based wind farms is shown by using modified inertial control scheme to inject active power quickly into the power system, thereby arresting deviations in frequency and voltage during transient conditions. Results reveal that coordinated action of DFIG based wind farms under FPC environment provides better dynamic frequency and voltage responses by reducing their deviations from nominal values.

Combined voltage and frequency control of a multi‐area multisource system incorporating dish‐Stirling solar thermal and HVDC link

This study highlights the significance of dish-Stirling solar thermal system (DSTS) and high voltage direct current (HVDC) link in the combined automatic load frequency control (ALFC) and automatic voltage regulator (AVR) model of the multi-area thermal-diesel plant. Appropriate generation rate constraints and governor dead band for the thermal plant are considered. A maiden attempt has been made to apply fractional order integral double derivative controller with derivative filter (FOIDDF) as a secondary controller for both ALFC and AVR loops. The performance of the FOIDDF controller is compared with some commonly used classical controllers. The lightning search algorithm is implemented for simultaneous optimisation of the controller parameters. The comparison shows the better performance of FOIDDF than others. The effect of the AVR loop on the ALFC loop is also analysed for the first time in the combined model. The investigation of the effect of DSTS and HVDC links reveals that their inclusion improves the system dynamics. The superiority of the proposed controller has been established for variable insolation of the DSTS. The rigorous sensitivity analysis of the different position and magnitude of disturbance, change in tie-line synchronising coefficient and different condition of the DSTS reflects the robustness of the proposed controller parameters obtained at the nominal condition.

Automatic Voltage Generation Control for Two Area Power System Based on Particle Swarm Optimization

<p>This article presentes a PID controller for two area power system equipped with both automatic generation control and automatic voltage regulator loops. The research has been done to control two area power systems with PSO optimized self-tuning PID controller. The comparison between different controllers and the suggested PSO based controller illustrates that the proposed controller can generate the best dynamic response for a step load change. For this purpose, MATLAB-Simulink software is used. The obtained results are promising.</p>

Reduction of Damping Oscillations of Power Systems with Combinational Operation of LFC & AVR in Single Area

The main aim of this paper is to reduce the damping oscillations. In this paper a new model is proposed to show the interaction between load frequency oscillations and automatic voltage regulator loops and to achieve more accuracy in dynamic and steady state response. The major problem arising from large scale electric power system interconnection is the low frequency oscillation of interconnected system. In order to maintain all the scheduled power transactions to the constant value, automatic generation control of a power system with closed loop feedback is used. By using the data acquisition system which conducts the actual operating conditions of the systems and the errors are computed. In ordered to maintain the level of voltage and frequency automatic generation control method through LFC loops is used.

A Fuzzy Approach of Autonomous Power Generating Systems

In this paper,an fuzzy approach for determining the optimal values for the proportional-integral(PI) controller parameters of load frequency control(LFC) Automatic voltage regulator(AVR) system for single area power system using the Fuzzy Gain Scheduled proportional-integral controller (FGSPIC) techniques is presented. The LFC loop controls real power and frequency and AVR loop controls reactive power and voltage. Due to rising and falling power demand, the real and reactive power balance is harmed, hence frequency and voltage get deviated from nominal value. This necessitates designing of an accurate and fast controller to maintain the system parameters at nominal value.atahe main purpose of system generation control is to balance the system generation against the load and losses so that the desired frequency and power interchange between neighbouring systems are maintained.This work demonstrates the application of fuzzy method to search efficiently optimal PI controller parameters of LFC and AVR system. The proposed method had superior features like, stable convergence characteristics, easy implementation and good computational efficiency. The simulation results demonstrate the effectiveness of the designed system in terms of reducing settling time, overshoot and oscilllations.This results are compared with conventional Integral. PI,PID and fuzzy based controller.

Application of capacitive energy storage for transient performance improvement of power system

In this paper, a comparative transient performance of two types of single machine power system is analyzed. The two types of system configurations are viz. (i) automatic voltage regulator (AVR) loop with single input conventional power system stabilizer (CPSS) combined with automatic generation control (AGC) loop, (ii) AVR with CPSS combined with capacitive energy storage (CES) unit-based AGC loop. For AGC loop both thermal unit and hydro unit are individually considered. The thermal unit is considered with either single or double stage reheat turbine, hydro unit is considered with mechanical or electric governor. Integral controller is provided in the AGC loop. It is shown that the CES-based integral controlled AGC loop along with CPSS assists in the best transient performance of the power system in all cases under different operating conditions. Parameters of the CPSS installed in AVR loop, gains of the integral controller in AGC loop are optimized with the help of a novel particle swarm optimization, developed by the authors, called as craziness-based particle swarm optimization (CRPSO). Transient performance is carried out with 1% step perturbation in either reference voltage or load torque.