Optimal location of static var compensator device for damping oscillations

Problem statement: Static Var Compensators (SVC) devices are used to improve voltage and reactive power conditions in AC systems. An additional task of SVC is to increase transmission capacity as result of power oscillation damping. The effectiveness of this controller depends on its optimal location and proper signal selection in the power system network. A residue factor had been proposed to find the optimal location of the SVC controllers to damp out the inter-area mode of oscillations. Approach: The proposed residue factor was based on the relative participation of the parameters of SVC controller to the critical mode. A simple approach of computing the residue factor had been proposed, which combined the linearized differential algebraic equation model of the power system and the SVC output equations. Input-output controllability analyses were used to assess the most appropriate input signals (stabilizing signal) for SVC device. Results: The placements of SVC controller had been obtained for the base case as well as for the critical contingency cases. Conclusion: The effectiveness of the proposed method was demonstrated on 25 bus of south Malaysian power system

Optimized Controller for Inverted Pendulum

Stability is require in any control system, most system require controller in order to be stable. Tuning is one of the major problems associated with most conventional controllers in existence today. This paper addressesd the difficulties associated with tunning by considering an effective optimized Controller on Inverted pendulum for the control of the angle position. Conventional PID controller was designed separately, to validate the proposed optimized controller. A MATLAB script for genetic algorithm was written with the aim of obtaining optimum PID parameters that would stabilized the pendulum angle at any desired inference inputs (i.e. returns the pendulum to a desire point as quick as possible). This would be achieved by minimizing an objective function (Integral time absolute error ITAE). On the other hand, a convention PID controller was designed using MATLAB/Simulink environment; the PID’s gains were manually tuned until an optimum response is achieved. The results obtained in both schemes shows that the optimized controller proves more effective as compared to ordinary conventional PID controller, as optimized controller gives settling time, percentage overshoot of 5.02 seconds and 3% respectively as compared with settling time of 70 seconds and overshoot of 5% for conventional PID controller. Therefore, the proposed optimized controller can serve as a valuable and an effective controller for the control of inverted pendulum

Determination of best location of UPFC device for damping oscillation

Unified Power Flow Controller (UPFC) is use for controlling the real and reactive power on the transmission line and the bus voltage simultaneously and independently. An additional task of UPFC is to increase transmission capacity as result of power oscillation damping. The effectiveness of this controller depends on its optimal location in the power system network. A residue factor has been proposed to find the optimal location of the UPFC controllers and Eigen value analyses are used to assess the most appropriate input signals (stabilizing signal) for supplementary damping control of UPFC to damp out the inter-area mode of oscillations. The proposed residue factor is based on the relative participation of the parameters of UPFC controller to the critical mode. A simple approach of computing the residue factor has been proposed, which combines the linearized differential algebraic equation model of the power system and the UPFC output equations. The placements of UPFC controllers have been obtained for the base case and for the dynamic critical contingences. The effectiveness of the proposed method of placement is demonstrated on practical network of 25 bus south Malaysian Power system

Thyristor control series capacitor ANFIS controller for damping oscillations

This study applies Adaptive Neuro Fuzzy Inference System (ANFIS)-based TCSC controller for damping oscillations. ANFIS which tunes the fuzzy inference system with a back propagation algorithm based on collection of input-output data makes fuzzy system to learn ANFIS controller is designed to damp out the low frequency local and inter-area oscillations of the Multimachine power system. Direct inverse control techniques are used in the design-of TCSC ANFIS controller which is derived directly from neural networks counterpart’s methodologies of the power system and the controller network to provide optimal damping. By applying this controller to the TCSC devices the damping of inter-area modes of oscillations in a multi-machine power system is handled properly. The effectiveness of the proposed TCSC ANFIS controller is demonstrated on two area four machine power system (Kundur system) which has provided a comprehensive evaluation of the learning control performance. Finally, several fault and load disturbance simulation results are presented to stress the effectiveness of the proposed TCSC controller in a multimachine power system and show that the proposed intelligent controls improve the dynamic performance of the TCSC devices and the associated power networ

Optimal location of FACTS devices for damping oscillations

Damping of electromechanical oscillations between interconnected synchronous generators is necessary for a secure system operation. While local oscillations involving one or more generators swinging against the rest of the system are mainly influenced by a restricted number of local system parameter- the behavior of low frequency inter-area oscillations is generally determined by global parameters of larger parts of the power system. Power System Stabilizers (PSSs) applied on selected generators can effectively damp local oscillation modes; their limited influence on inter-area modes, however, lead to the fact that they may not be considered as the only solution to damp interarea oscillations. Flexible AC Transmission Systems are being increasingly used to better utilize the capacity of existing transmission systems. Flexible AC Transmission System (FACTS) is a technology based solution to help the utility industry deal with changes in the power delivery business. A major thrust of FACTS technology is the development of power electric based systems that provide dynamic control of the power transfer parameters transmission voltage, line impedance and phase angle [1]. The static var compensator (SVC), which is a shunt device, provides dynamically variable shunt impedance to regulate the series compensator (TCSC), which is a Series FACTS controller, is used to change the effective reactance of the line dynamically, thereby controlling the real power flow in the lines. The unified power flow controller (UPFC) is used to control the real and reactive powers simultaneously in a line by injecting a series voltage across the line. It also injects a shunt reactive current at one of the line-end buses to maintain the bus voltage at a specified value [2, 3]. FACTS devices are provided with supplementary controllers for damping out small signal oscillations [4-8], and the effectiveness of damping the oscillations depends on the location of FACTS controllers. Several methods [2–4] have been proposed for the placement of FACTS controllers. Previous studies [9–10] considered only static criterion like improving power transfer, available transfer capability (ATC), loss minimizations and did not consider any dynamic criteria for the placement of the FACTS controllers. A sensitivity based approach has been developed in some researches for determining the optimal placement of FACTS devices in electricity market having pool and contractual dispatches [11-13]. [11] Shows that few locations of FACTS devices can be decided based on sensitivity factors and then optimal dispatch problem must solved for finding suitable placement of UPFC in a congested system. [15] Implements Genetic Algorithm to finding the best location for TCSC to maximizing total transfer capacity. Tuning of FACTS parameters has been proposed for improving damping of weakly damped inter-area modes. [16-17] proposed a method for selecting suitable feedback signal to FACTS controllers for improving the damping. Sadikovic and Korba [18] used residue, called location index for effective damping, to find suitable location for damping inter-area mode of oscillations, also in the work of [14] and [19], the method used only UPFC placement based on only single operating condition. No consideration of other FACTS devices

Determination of best location of FACTS devices for damping oscillations

This paper proposes a residue factor method to find the optimal location of the FACTS controllers. Three types of FACTS controllers have been considered, which include thyristor-controlled series compensator (TCSC), Static Var compensator (SVC) and unified power flow controller (UPFC). The effectiveness of this controller depends on its optimal location and proper signal selection in the power system network. The proposed residue factor is based on the relative participation of the parameters of FACTS controller to the critical mode. A simple approach of computing the residue factor has been proposed, which combines the linearised differential algebraic equation model of the power system and the FACTS input and output equations. The placements of FACTS controllers have been obtained for the base case and for the dynamic critical contingences. The effectiveness of the proposed method of placement is demonstrated on 11 bus system and New England 39 Bus system

Optimal location of TCSC device for damping oscillation

This paper proposes a residue factor method to obtain the optimal location of the Thyristor Controlled Series Capacitor (TCSC) device to damp out the inter-area mode of oscillations. The residue method is base on the facts that it is the product of the mode’s Observability and controllability index of TCSC controllers to the critical mode. The placements of TCSC controllers have been obtained for the base case and for the dynamic critical contingences. Eigen value analyses are used to assess the most appropriate input signals (stabilizing signal) for supplementary damping control of TCSC. The Right-Half Plane zeros (RHP-zeros) and Hankel Singular Value (HSV) is used as tools to select the most receptive signal to a mode of the Interarea oscillation. The effectiveness of the proposed method of placement is demonstrated on practical network of 25 bus south Malaysian Power system

Application of Type 2 Fuzzy for Maximum Power Point Tracker for Photovoltaic System

Photovoltaic systems (PV) are becoming more popular as a way to make electricity because they offer so many benefits, such as free solar irradiation to harvest and low maintenance costs. Moreover, the system is environmentally friendly because it neither emits noxious gases nor generates environmental noise. Consequently, during the operation of a PV system, the working environment is free of all types of pollution. Despite the aforementioned advantages, a photovoltaic (PV) system’s performance is significantly impacted by the fluctuation in electrical charges from the panel, such as shading conditions (PSC), weather conditions, and others, which significantly lowers the system’s efficiency. To operate the PV modules at their peak power, maximum-power point tracking (MPPT) is employed. As a result of the various peaks present during fluctuating irradiance, the P-V curves become complex. Traditional methods, such as Perturb and Observe (P and O) have also failed to monitor the Global Maximum Power Point (GMPP), therefore they usually live in the Local Maximum Power Point (LMPP), which drastically lowers the efficiency of the PV systems. This study compares type 2 fuzzy logic (T2-FLC) with the traditional Perturb and Observe Method (P and O) in three different scenarios of irradiance, temperature, and environmental factors, in order to track the maximum power point of photovoltaics. Type 1 fuzzy logic (T1-FLC) is not appropriate for systems with a high level of uncertainty (complex and non-linear systems). By modelling the vagueness and unreliability of information, type 2 fuzzy logic is better equipped to deal with linguistic uncertainties, thereby reducing the ambiguity in a system. The result for three conditions in terms of four variables; efficiency, settling time, tracking time, and overshoot, proves that this strategy offers high efficiency, dependability, and resilience. The performance of the proposed algorithm is further validated and compared to the other three tracking techniques, which include the Perturb and Observe methods (P and O). The particle swarm algorithm (PSO) and incremental conductance method results show that type 2 fuzzy (IT2FLC) is better than the three methods mentioned above

Application of FACTS devices for damping out power systems oscillations using model techniques

Variable impedance devices using power electronic technology, such as Static VAR Compensators (SVCs) Thyristor-Controlled Series Capacitors (TCSC) and Unified Power Flow Controller (UPFC) have the potential to increase power control and system damping [1, 2]. The allocation of these devices to get the most effective stabilisation of system modes is a complex problem that requires consideration of many factors. Major design considerations include the identification of busbars and branches in which to locate the system controllers and the choice of suitable feedback signals to be used as input to a stabilising control function [3-6]. Several analytical criteria for placement of damping controllers have been proposed in the literature. Specifically, modal analysis techniques based on the calculation of participation factors, transfer function residues and controllability and observability indices have been used to identify optimal locations for SVCs, TCSC, UPFC and power system stabilisers [2, 7-11]. The computation of controllability and observability measures is of particular interest as it provides valuable information about system dynamic characteristics and the ability of system controllers to enhance damping. This work presents an efficient analysis and design method to place variable impedance devices for enhancement of small signal stability in complex power systems. Controllability is first explored to allocate damping controllers in those busbars and system branches in which they are more effective to enhance damping of a given subset of critical oscillation modes. Observability indices are, in turn, taken to assess supplementary signals that are to be used in a given controller and which are required to “show” the oscillation mode. In this approach, the computation of controllability and observability is based on a measure of the distance of a state representation from the nearest uncontrollable system [12, 13]. This method is numerically stable and can be used to assess the numerical rank and other properties of state models. The study of inter-area oscillations and placement of controllers is done using modal analysis of a linearised model of the power system that includes a detailed representation of variable impedance controllers. The devices presently considered in this research include SVC, TCSC and UPFC. A reduced order equivalent of the interconnected New England test system (NETS) and New York power system (NYPS) is used to illustrate the proposed algorithms