Sarat Chandra Swain

Design and analysis of SSSC-based supplementary damping controller

Abstract Power-system stability improvement by a static synchronous series compensator (SSSC)-based damping controller is thoroughly investigated in this paper. The design problem of the proposed controller is formulated as an optimization problem, and real coded genetic algorithm (RCGA) is employed to search for the optimal controller parameters. Both local and remote signals with associated time delays are considered in the present study and a comparison has been made between the two signals. The performances of the proposed controllers are evaluated under different disturbances for both single-machine infinite-bus power system and multi-machine power system. Simulation results are presented and compared with a recently published modern heuristic optimization technique under various disturbances to show the effectiveness and robustness of the proposed approach.

A Harmony Search-Firefly Algorithm Based Controller for Damping Power Oscillations

This paper analysed the power oscillations of a transmission system when subjected to disturbance. When a power system is followed by a fault the transmission line power as well as the rotor angle deviates from its steady state value leading to system instability. A HS-FA based damping controller used to damp out the power oscillations along with a static synchronous series compensator. The lead lag structure of the damping controller improves the stability of the system by injecting a compensating voltage through series compensator. A harmony search -- firefly hybrid optimizing technique is used to tune the controller parameters. Integral of squared error (ISE) of the rotor speed deviation is considered for analysing the controller performance. Different disturbance conditions are analysed for verifying performance of the controller to damp out the power oscillations.

SSSC-based controller design employing a multi-objective optimisation technique

This paper presents a multi-objective optimisation technique for the design of a static synchronous series compensator (SSSC)-based controller. The design objective is to improve the transient performance of a power system subjected to a severe disturbance by minimising the power angle, terminal voltage and power flow time trajectory deviations with respect to a post-contingency equilibrium point for a power system installed with a SSSC. A genetic algorithm (GA)-based solution technique is applied to generate a Pareto set of global optimal solutions to the given multi-objective optimisation problem in power systems. The optimal gain and time constant values for the proposed SSSC-based controller are determined in a generator-infinite-bus test system. Simulation results show the effectiveness and robustness of the proposed approach in improving transient performance of the example power system.

Performance evaluation of photovoltaic system based on solar cell modelling

This paper describes about the solar photovoltaic cell and its different modelling phenomena. In solar cell modelling generally curve fitting is adopted to calculate or extract the parameter. However for better calculation of error it is not recommended to adopt the curve fitting. the objective behind this paper is to find a suitable optimization technique so that it can be applied to all other models for curve fittings. The reference parameter for evaluating the performance of the grid is taken from the data sheet provided by the manufacturer. two distinct point like zero current voltage point, maximum current voltage point has been chosen for evaluating the best performance. The simulation is performed with a commercially available multicrystalline solar PV cell for simplicity purpose and then it is compared with the reference PV characteristic to check the compatibility of the system. The paper has been organised with three parts, like the 1st part contain some basic part of solar cell modelling and followed by characteristics and model verification. Finally the parameters are extracted from the curve.

Differential evolution algorithm for simultaneous tuning of excitation and FACTS-based controller

This paper investigates the application of recently developed bio-inspired optimisation technique known as differential evolution (DE) optimisation technique for the simultaneous tuning of excitation and a flexible AC transmission systems (FACTS)-based controller. The design objective is to improve the stability of a power system subjected to a disturbance. The design problem is transformed as an optimisation problem and DE optimisation technique is employed to simultaneously tune the excitation and FACTS-based controller parameters. Non-linear simulation results are presented at various loading conditions and disturbances to show the effectiveness and robustness of the proposed approach. It is observed that the proposed controllers improve greatly the system damping and are robust to variation in operating conditions and type of disturbance.

Control of active and reactive power of a three phase grid connected photovoltaic system

Electrical transmission system is a very complex structure. To provide quality power to the end user customer. It is required to control the power by avoiding the congestion effect. To meet the quality power distributed generation may be adopted at different location nearer to the load. This paper investigate the performance of a renewable energy based grid connected system through load voltage ride through capability. The main objective of the paper is to enhance the quality of power by implementing suitable control strategy.

Design and analysis of bacteria foraging optimised TCSC-based controller for power system stability improvement

This paper presents a simple but accurate continuous-time, large-signal dynamic models of a power system installed with a thyristor-controlled series capacitor-based (TCSC) controller which is suitable for carrying out power system stability studies. The synchronous generator is represented by one field circuit and one equivalent damper on q-axis known as the model 1.1, so as to evaluate the impact of TCSC on power system stability more reasonably. The design problem of the proposed controller is formulated as an optimisation problem and bacteria foraging optimisation algorithm (BFOA), is employed to search for optimal controller parameters. A detailed analysis on the selection of control signals (both local and remote signals) on the effectiveness of the TCSC controller is carried out and simulation results are presented. The dynamic performance of proposed TCSC controller under various loading and disturbance conditions are analysed and compared with recently published modern heuristic optimisation techniques such as GA, PSO and DE.

Analysis of voltage and loss profile using various FACTS devices

The Aim of this paper is the study of models and procedures with which we assess the steady-state operation of electrical power systems at the fundamental frequency. The improvement of stability will be achieved by controlling the reactive power flow in the line [3]. The Flexible Alternating Current Transmission System (FACTS) devices have been proposed to control the power flow in transmission lines & to regulate the bus voltages in electrical power systems resulting in an increased power transfer capability, less system losses and improved stability[8]. This summary presents the implication of adding various FACTS controllers such as a Static Var Compensator SVC, TCSC(thyristor controlled series capacitor) and UPFC(Unified power flow controller) etc. So a power flow program using MATLAB finds the steady voltage and angle at each bus and corresponding for a given system and finds the load ability margin of power system with FACTS devices. A 2 machine 5 bus system is considered for performance analysis[9]. This paper states the implementation of FACTS in a Newton raphson load flow(NRLF) method.

Performance prediction of a grid interfaced PV system through Matlab modelling - part-II

This paper discuss the modelling of a solar photovoltaic grid interconnected system to predict the behaviour of system under different grid condition. Moreover the detail power quality control strategies are described with a simple solar photovoltaic circuit. Standard data are used to simulate the system under different solar insolation condition. Power conditioning circuits are described with all its associated features to predict the transient behaviour of the system under different loading and fault condition. The system has been simulated with Matlab. Different types of step size are used in the system to evaluate the transient present in the system.

A DWT based differential relaying scheme of SVC compensated line

This paper discusses the fault classification and detection applying Discrete Wavelet transform (DWT) approach of differential relaying based SVC (Static Var Compensator) compensated transmission line. The SVC is located at middle part of transmission line. Fast detection of faults and fault classification helps restoration of supply, which enhances the economy and reliability of the power supply. SVC integrated line helps to improve reactive power compensation in transmission line. The current signals are retrieved from both end of the transmission line synchronously through CTs and processed with the help of DWT approach to compute Spectral Energy (SE) of each phase from both sending and receiving end of the transmission line. Then the Differential Spectral Energy(DSE) of each phase current signals are computed by subtracting the SE current signals obtained at sending end and the SE current signals obtained at receiving end of the transmission line. The evaluated DSE value of each phase current signifies the fault pattern identification and detection.