Effects Of Governor Dead Band Research Articles

Improvement of Automatic Generation Control Behavior of Two Interconnected Areas Using SMES and TCSC

In this paper, an attempt has been made to enhance the dynamic behaviour of Automatic Generation Control (AGC) of two areas two units using both Thyristor Controlled Series Compensator (TCSC) placed in the tie-line and Superconducting Magnetic Energy Storage (SMES) units are considered in both areas. For more realistic study, the effects of Governor Dead Band (GDB) and Generation Rate Constraints (GRCs) are taken into account for both areas. However, to conduct the system to better dynamic responses, we have implemented a PI-PD cascade controller. After that, a well-known and powerful optimisation algorithm named Firefly Algorithm (FA) is employed by evaluating the Integral of the Squared Error (ISE). From the obtained results, the implemented methods prove its efficiency from different view of points such as: minimisation of Overshoot and Undershoot Peaks (PO), (PU) and Settling Time (ST).

An intelligent coordinator design for GCSC and AGC in a two-area hybrid power system

This study addresses the design procedure of an optimized fuzzy fine-tuning (OFFT) approach as an intelligent coordinator for gate controlled series capacitors (GCSC) and automatic generation control (AGC) in hybrid multi-area power system. To do so, a detailed mathematical formulation for the participation of GCSC in tie-line power flow exchange is presented. The proposed OFFT approach is intended for valid adjustment of proportional–integral controller gains in GCSC structure and integral gain of secondary control loop in the AGC structure. Unlike the conventional classic controllers with constant gains that are generally designed for fixed operating conditions, the outlined approach demonstrates robust performance in load disturbances with adapting the gains of classic controllers. The parameters are adjusted in an online manner via the fuzzy logic method in which the sine cosine algorithm subjoined to optimize the fuzzy logic. To prove the scalability of the proposed approach, the design has also been implemented on a hybrid interconnected two-area power system with nonlinearity effect of governor dead band and generation rate constraint. Success of the proposed OFFT approach is established in three scenarios by comparing the dynamic performance of concerned power system with several optimization algorithms including artificial bee colony algorithm, genetic algorithm, improved particle swarm optimization algorithm, ant colony optimization algorithm and sine cosine algorithm.

Modified group search optimisation‐based comparative performance evaluation of thyristor controlled series capacitor‐based fractional order damping controllers to improve load frequency control performance in restructured environment

This study compares fractional order phase lead-lag controller, fractional order proportional-integral-derivative (FOPID), and tilt-integral-derivative controllers as thyristor controlled series capacitor (TCSC)-based damping controller to improve load frequency control (LFC) performance in a restructured power system. To prepare an efficient ancillary service, a precise formulation for participation of TCSC in tie-line power flow exchange is presented which is compared with the earlier Taylor-based approximated model. The controller parameters are adjusted by employing different evolutionary algorithms. To obtain realistic results under a competitive environment, a diverse-GENCOs multi-DISCOs power system with the generation rate constraint and governor dead-band effects, communication time delay, bilateral contracts, and pool-co transactions is taken into account. Non-linear time-domain simulations demonstrate that the FOPID-based TCSC damping controller in coordination with an integral-type simple LFC can most effectively suppress the area frequency and tie-line power oscillations. Further investigations are performed for uncontracted higher order step and random load demands treated as contract violation scenarios to confirm the superiority of the proposed fractional order controllers-based TCSC–LFC over the Taylor-based TCSC–LFC. The sensitivity analysis is done for a wide range of loading condition and system parameters to compare the robustness of the considered controllers.

Load Frequency Control of Power Systems with Governor Deadband (GDB) Non-linearity

Load frequency control of power systems with a governor deadband (GDB) is studied in the paper. The effects of GDB on the linear active disturbance rejection controller (LADRC) are analyzed first. It is shown that the limit cycle can be avoided by reducing the controller and/or observer bandwidth. However, the disturbance rejection performance will be degraded. To maintain the performance of the original LADRC controller, two anti-GDB schemes are proposed. One is based on the observer structure of active disturbance rejection control, which utilizes the output of the governor to reconstruct the input to the system in order to correctly estimate the controller states. Another is based on the error between the realistic output of the governor and its ideal value which is fed back and added to the output of the original LADRC. Simulation results on a single-area and a two-area power system with the GDB show that the two schemes are effective in reducing the limit cycle caused by the GDB. The observer-based anti-GDB has some limitations in practical implementation and performance, while the error-compensation-based scheme is simple to implement and can approximate the disturbance rejection performance of the original LADRC.

Quasi-oppositional symbiotic organism search algorithm applied to load frequency control

Abstract The present work approaches a relatively new optimization scheme called “quasi-oppositional symbiotic organism search (QOSOS) algorithm”, for the first time, to find an optimal and effective solution for load frequency control (LFC) problem of the power system. The symbiotic organism search (SOS) algorithm works on the effect of symbiotic interaction strategies adopted by an organism to survive and propagate in the ecosystem. To avoid the suboptimal solution and to accelerate the convergence speed, the theory of quasi-oppositional based learning (Q-OBL) is integrated with original SOS and used to solve the LFC problem. To demonstrate the effectiveness of QOSOS algorithm, two-area interconnected power system with nonlinearity effect of governor dead band and generation rate constraint is considered at the first instant, followed by the four-area power system showing the consequence of load perturbation. The structural simplicity, robust performance and acceptability of well-popular proportional-integral-derivative (PID) controller enforce to implement it as a secondary controller for the present analysis. The success of QOSOS algorithm is established by comparing the dynamic performances of concerned power system with those obtained by some recently published algorithms available in the literature. Furthermore, the robustness and sensitivity are analyzed for the concerned power system to judge the efficacy of the proposed QOSOS approach.

Quasi-oppositional differential search algorithm applied to load frequency control

In this article, quasi-oppositional differential search algorithm (QODSA) is proposed for finding an optimal and effective solution for load frequency control (LFC) problem in the power system. Initially, original DSA is employed for fine-tuning of the secondary controller of LFC system and then, quasi-oppositional based learning (Q-OBL) mechanism is integrated into the original DSA to enhance the convergence speed and to find a better solution of LFC problem. To validate the effectiveness of proposed QODSA, four widely used interconnected power system networks are designed and analyzed. The superiority of the proposed method is established by an extensive comparative analysis with other existing evolutionary algorithm’s (EA) using transient analysis method. A critical investigation of simulation results reveals that the proposed QODSA gives simple and better solution compared to original DSA and other reported algorithms. To study the robustness of QODSA, two different random load patterns are projected and results confirm the robustness of the designed controllers. To add some degree of nonlinearity, generation rate constraint and governor dead band effects are considered and their consequence on the system dynamics has been examined. Finally, sensitivity analysis is performed with a wide variation of system parameters.

Automatic generation control of power system using a novel quasi-oppositional harmony search algorithm

Abstract The present work approaches a novel quasi-oppositional harmony search (QOHS) algorithm, as an optimization technique, for its optimum performance in the subject area of automatic generation control (AGC) of power system. The proposed QOHS algorithm is applied with an aim to converge rapidly towards the optimal solution(s) that houses both the characters of two guesses, i.e. opposite-point and quasi-opposite point. The area of concern of this study is to discuss the multi-objective problems of an interconnected power system for the benefits of AGC. The proposed QOHS algorithm is, individually, applied to single-area, precede to two-area considering the non-linearity effects of governor dead band and generation rate constraint and, finally, extended to four-area power system showing the consequences of multiple load disturbances. A case of robustness and stability analysis are also investigated for the studied two-area power system model. The control strategy, for the dynamic power system model, is based on area control error. The simplicity of the structure and acceptability responses of the well-known proportional–integral–derivative controller enforces to implement as a controller in this work. The comparative evaluation of the proposed QOHS algorithm is carried out by the way of comparing the dynamic performances of the studied power system model with those offered by other algorithms reported in the recent state-of-the-art literature. The simulation works, presented in the paper, reveal that the proposed QOHS algorithm may be effectively utilized for the purpose of AGC study of power system having varying degrees of complexities and non-linearities. Moreover, the proposed QOHS based control strategy adopted in this work provides a robust and stable speed control mechanism.

Sampled Data Automatic Generation Control Analysis with Reheat Steam Turbines and Governor Dead-Band Effects

In this paper a systematic method of choosing the frequency bias parameter and the integrator gain of the sampled data supplementary control is presented by using the discrete version of the Lyapunov technique. The reheat effect of the steam turbines is considered in the state space model. The effect of governor dead-band nonlinearity is considered by using the describing function approach and including the linearized equations in the state space model. It is shown that the governor dead-band nonlinearity has a destabilizing effect on the transient response with deterministic and random load disturbances for purely integral ACE control. However, this destabilizing effect is reduced by proportional feedback of ACE.

Sampled Data Automatic Generation Control Analysis with Reheat Steam Turbines and Governor Dead-Band Effects

Sampled Data Automatic Generation Control Analysis with Reheat Steam Turbines and Governor Dead-Band Effects