A novel fuzzy logic controller for STATCOM to improve power system stability

This paper presents the application of Fuzzy Logic Controller (FLC) for Thyristor Controlled Series Capacitor (TCSC) to enhance over all stability of electric power systems. The proposed hybrid controller combines the advantages of FLC and a conventional PI controller. In this work, we consider Single Machine Infinite Bus (SMIB) system installed with Power System Stabilizer (PSS) and Fuzzy-PI based TCSC Controller. In order to test effectiveness of these controllers, simulations are carried out in different loading conditions under a symmetrical three-phase short circuit fault at generator terminals. The response of Fuzzy-PI controller is compared with that of the PI controller. The simulation result shows that the Fuzzy-PI controller has outstanding operation in fast damping of power system oscillations.

This paper presents the application of a fuzzy logic controlled Static Compensator (STATCOM) to improve stability of power system. The nonlinear fuzzy logic controller is used to overcome the problems generated by different uncertainties exist in power systems. Different input variables are used to design the controller. Parameters of the proposed controller are adjusted by means of Neural Network techniques to improve performance of the system. Proposed controller is implemented on a single machine infinite bus system to confirm the performance of the controller through simulation results.

Underwater Remotely Operated Vehicle (ROV) is important to substitute human in doing underwater task. In marine industries, ROV is used to do underwater surveillance or observation. Due uncertainty of underwater environment and dynamic of ROV itself, depth trajectory control of ROV is difficult. Lambda tuning single input fuzzy logic (SIFLC) controller was implemented to the ROV to control the depth trajectory of the ROV. Performance analysis of Lambda SIFLC had been conducted for open frame and close frame ROV. The close frame ROV model is first order system while the open frame ROV is second order system. The transient responds analysis had been made using MATLAB Simulink. The implementation of the Lambda SIFLC shows significant improvement in the transient responds of the system.

A simplified approach to design fuzzy logic controller for an underwater vehicle

This paper describes the application of the Single Input Fuzzy Logic Controllers (SIFLC) to regulate the output voltage of a Boost (step-up) DC to DC power converter. The SIFLC is derived from the Signed Distance Method which reduces the multi-input Fuzzy Logic Controller (FLC) with Toeplitz rule table structure to a single input FLC. Effectively, it allows for the rule table to be approximated to a one dimensional piecewise liner control surface. To validate the effectiveness of the SIFLC compared to the Conventional FLC, MATLAB is simulation carried out. Controller is implemented in digital using FPGA and experimental results are exhibited.

This text proposes the design of the integer order IOPID Controller as Power System Stabilizer (PSS) on a SMIB System with AVR excitation and compare the performance by replacing it with fractional order FOPID controller as PSS on the same system. The performance and conduct of the controller adopted are differentiated and evaluated on a Single Machine Infinite Bus (SMIB) system under various distinct loading condition for which Heffron Phillip Model is adopted. The PSS is designed on the basis of its frequency responses by inspecting the system robustness by analyzing sensitivity function, gain margin (GM) and phase margin (PM). This paper first utilizes the IOPID as PSS and then its non-integer form is taken up and designed. It is seen that the performance achieved by using FOPID controller as PSS is better compared to IOPID controller.

Single machine infinite bus (SMIB) power system and multi-machine power system (MMPS) stability improvement by tuning of static var compensator (SVC) based controller parameters are investigated in the proposed method. The design problem is formulated as an optimization problem with a time-domain simulation-based objective function and real-coded genetic algorithm is used for searching optimal controller parameters. SMIB power system and MMPS models are developed using MATLAB’s SIMULINK which incorporates SVC controller. A fault is created on the transmission line. The simulation results of SMIB power system and MMPS without SVC controller and with SVC controller are presented. The simulation results are analyzed which show that the power system becomes unstable on the occurrence of the fault if SVC controller is not used. This paper proves the effectiveness of the proposed design. Thus the proposed method enhances the power system stability.

Optimal tuning of power system stabilizer (PSS) parameters using genetic algorithm with single objective function is presented in this paper. A Single Machine Infinite Bus (SMIB) system is considered. The main objective of this research paper is to investigate the suitability of genetic algorithm for effective tuning of parameters of the power system stabilizer in a single machine infinite bus system. A conventional speed based lead‐lag PSS is used. A simple and effective method of tuning the parameters of PSS is proposed which is posed as an optimization formulation by maximizing the damping of modes of oscillations of the SMIB system over a wide range of loading conditions and different system configurations. It is found that GA based PSS with single objective design shows improved dynamic performance over Conventional PSS over a wide range of operating conditions and different system parameters.

An interval type-2 fuzzy logic controller (IT2FLC) is proposed in this paper for the design of power system stabilizer (PSS) of a single machine infinite bus (SMIB) and multi machine infinite bus (MMIB) system incorporated with an AC1A exciter. For controller design, memberships of system variables are represented using interval value fuzzy sets. Fuzzy logic based on interval value sets is capable of modeling the uncertainty and imprecision in a better way. The proposed controller performance is compared with the optimal lead lag and optimal type-1 fuzzy logic controller respectively reference to damp the oscillations of both SMIB and MMIB system. Simulation results reveal the superior performance of the proposed controller and also it is robust with respect to system parameter variation and at different disturbances.

This paper presents a control scheme that provides an efficient and a simple way to design a Fuzzy Logic Controller (FLC) for the autonomous underwater vehicle (AUV). The proposed method, known as the Single Input Fuzzy Logic Controller (SIFLC), condenses the conventional two-input FLC (CFLC) to a single input single output (SISO) controller. The SIFLC significantly reduces the rules and simplifies the tuning of control parameters. Practically, it can be easily implemented by a look-up table using a low cost microprocessor due to its piecewise linear control surface. To verify the effectiveness of the designed controller, the control algorithm is simulated using the Marine Systems Simulator (MSS) on the Matlab/Simulink® platform. The result clearly indicates that both the SIFLC and CFLC give almost identical response to the same input sets. However SIFLC requires very minimum tuning effort and its execution time is in the orders of two magnitudes less than CFLC.

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.

<span>This paper presents the capability of a fuzzy logic based stabilizer used for generating the supplementary control signal to voltage regulator of static VAR compensator (SVC) for improving damping oscillations in power systems. Generator speed deviation and line active power were chosen as input signals for the fuzzy logic controller (FLC). The quantity of reactive power supplied/absorbed by SVC is determined based on the two input signal and deviation of terminal voltage at each sampling time. The effectiveness and feasibility of the proposed control is demonstrated with Single Machine Infinite Bus (SMIB) system and multi machine system which show improvement over the use of a fixed parameter controller. It has been observed that a robust controller is obtained with fuzzy logic controller.</span>

Remotely Operated Vehicle (ROV) is an important vehicle to do underwater task. The uncertainty environment of underwater make it harder for ROV to maneuver and hold position at certain depth. Research on ROV controller for holding position had been conducted. Proportional, Integral and Derivative (PID), Fuzzy Logic Controller (FLC) and Single Input Fuzzy Logic Controller (SIFLC) was designed and compared. This paper discusses the modelling of developed ROV and tuning the SIFLC to get the best transient response. Steady state error (SSE), percent overshoot (%OS), time rise (Tr) and settling time (Ts) were analyzed to select the best controller.

Low-frequency oscillation is associated with dynamic power system stability. In this paper, the ability of power system to damp low-frequency oscillation is compared between the conventional system with PSS and system installed with Unified Power Flow Controller (UPFC) based on Fuzzy Logic Power System Stabilizer (FLPSS). Both models are developed using linearized model of Phillips-Heffron Single Machine Infinite Bus (SMIB) and simulated in Matlab Simulink. UPFC controller based on boosting modulation index converter (m b ) and excitation modulation index converter (m e ) have been designed using Single in Single Out (SISO) method. The change of rotor speed, rotor angle and electrical power is investigated when power system is being perturbed by small disturbance. The results of this study shown the improvement of dynamic power system stability using the designed model by damping low-frequency oscillation with less overshoot and shorter settling time.

Power Systems are playing a vital role in the energy development and energy transmission in a most efficient and useful ways. Need of power transmission requires huge series capacitors to bring in the stability of massive amount of electrical energy. However, there are practical scenarios where these series capacitors are not capable of being synchronous with the turbine generators and thus causing Subsynchronous resonance (SSR). Though we have Flexible AC transmission systems (FACTS), we still have no control on the SSR. Therefore, Mitigation of SSR as a focus on TCSC controlled power system had been introduced with constant and enhanced power control methodologies and developed. Still there is room for improvement and hence we have introduced a GCSC controlled power transmission system. This paper proposes an approach for Subsynchronous resonance mitigation in Single Machine Infinite Bus System (SMIB) System Using GCSC and TCSC with Conventional and Fuzzy Logic Controllers compared. We have adopted the First IEEE benchmark a so-called SMIB system and used MATLAB/SIMULINK to witness the controllability on SSR. To evaluate performance of both devices, we have taken three different ratings of GCSC. We have projected a detailed analysis of comparing TCSC designed with conventional methods are inadequate to control the dynamic torsional oscillations when compared to the proposed GCSC ratings. Results and analysis proves that our Proposed design of GCSC controlled power system has the better performance results with inclusion of Takagi Sugeno fuzzy logic controller over the proportional(P) controller with respective of all the proposed Ratings Considered in the design. We are able to damp the dynamic power Oscillations and SSR with this method.