Subhransu Sekhar Dash

Particle Swarm Optimization Algorithm to Find the Location of Facts Controllers for a Transmission Line

The main purpose of this project is to find the optimal location of FACTS controllers in a multi machine power system using particle swarm optimization (PSO). Using the proposed method, the location of FACTS controller, their type and rated values are optimized simultaneously. Among the various FACTS controllers, Thyristor Controlled Series Compensator (TCSC) and Unified Power Flow Controller (UPFC) are considered. The proposed algorithm is an effective method for finding the optimal choice and location of FACTS controller and also minimizing the overall system cost, which comprises of generation cost and the investment cost of the FACTS controller using PSO and conventional Newton Raphsons power flow method. A MATLAB coding is developed for Enhanced Genetic Algorithm. In order to verify the effectiveness of the proposed method, IEEE 14- bus system is used.

Multicarrier pulse width modulation methods based three phase cascaded multilevel inverter including over modulation and low modulation indices

The multilevel inverter utilization have been increased since the last decade. These new type of inverters are suitable in various high voltage & high power application due to their ability to synthesize waveforms with better harmonic spectrum and faithful output. This paper presents, two proposed scheme adopting the multicarrier Pulse width modulation concept. The multicarrier pulse width modulation Cascaded multilevel inverter strategy enhances the fundamental output voltage and reduced total harmonic distortion. The multilevel inverter circuit analysis and selection of proper references discussed based on the formulation switching patterns. A Three phase five level cascaded inverter is used to explain the methods. The methods can be easily extended to a n-level inverter. The cascaded inverter is subjected to a new modulation scheme, which uses multiple modulating signals with a single carrier. From the modulation scheme, mathematical equations that define the pulse width modulation switching instants are derived. In order to justify the merits of the proposed modulation scheme, harmonic analysis for and measured Total harmonic distortion and output voltages are compared and discussed. The method can be confirmed by experimental results obtained using a three phase cascaded five level inverter.

Stability Index Based Voltage Collapse Prediction and Contingency Analysis

Voltage instability is a phenomenon that could occur in power systems due to stressed conditions. The result would be an occurrence of voltage collapse leading to total blackout of the system. Therefore, voltage collapse prediction is an important part of power system planning and operation, and can help ensure that voltage collapse due to voltage instability is avoided. Line outages in power systems may also cause voltage collapse, thereby implying the contingency in the system. Contingency problems caused by line outages have been identified as one of the main causes of voltage instability in power systems. This paper presents a new technique for contingency ranking based on voltage stability conditions in power systems. A new line stability index was formulated and used to identify the critical line outages and sensitive lines in the system. Line outage contingency ranking was performed on several loading conditions in order to identify the effect of an increase in loading to critical line outages. Correlation studies on the results obtained from contingency ranking and voltage stability analysis were also conducted, and it was found that line outages in weak lines would cause voltage instability conditions in a system. Subsequently, using the results from the contingency ranking, weak areas in the system can be identified. The proposed contingency ranking technique was tested on the IEEE reliability test system.

Grid Voltage Stability Enhancement Using Photovoltaic Based Static Synchronous Compensator

Today, we are mostly dependent on non renewable energy that have been and will continue to be a major cause of pollution and other environmental degradat ion. Because of these problems and our dwindling supply of petroleum, finding sustainable alternativ es is becoming increasingly urgent. Perhaps, the gr eatest challenge is in devising a sustainable future, whic h relies on integration and control of renewable en ergy sources in grid distributed generation. This study presents the usage of utilizing Photovoltaic (PV) S olar Farm (SF) during idle conditions as Static Synchron ous Compensator (STATCOM), to regulate the point of common coupling voltage when the wind farm supply the power to the grid. The proposed control will enable increased connections of WECS to the grid. MATLAB/Simulink based simulation results are presented for validation of the system. The PV-STATCOM increase the stability of the grid with interconnected wind farm system without any use of additional compensator.

Design of Unified Power Quality conditioner (UPQC) to improve the power quality problems by using P-Q theory

In this paper presents a Design of a Unified Power Quality conditioner (UPQC) connected to three phase four wire system (3P4W). The neutral of series transformer used in the fourth wire for the 3P4W system. The neutral current that may flow toward transformer neutral point is compensated by using a four-leg voltage source inverter topology for shunt part. The series transformer neutral will be at virtual zero potential during all operating conditions. In this simulation we observe the power quality problems such as unbalanced voltage and current, harmonics by connecting non linear load to 3P4W system with Unified Power Quality conditioner. A new control strategy such as unit vector template is used to design the series APF to balance the unbalanced current present in the load currents by expanding the concept of single phase P-Q theory. The P-Q theory applied for balanced three phase system. And also be used for each phase of unbalanced system independently. The MATLAB/Simulink based simulations are provided the functionality of the UPQC.

Multi-Objective Differential Evolution for Voltage Security Constrained Optimal Power Flow in Deregulated Power Systems

Abstract Voltage stability is an important issue in the planning and operation of deregulated power systems. The voltage stability problems is a most challenging one for the system operators in deregulated power systems because of the intense use of transmission line capabilities and poor regulation in market environment. This article addresses the congestion management problem avoiding offline transmission capacity limits related to voltage stability by considering Voltage Security Constrained Optimal Power Flow (VSCOPF) problem in deregulated environment. This article presents the application of Multi Objective Differential Evolution (MODE) algorithm to solve the VSCOPF problem in new competitive power systems. The maximum of L-index of the load buses is taken as the indicator of voltage stability and is incorporated in the Optimal Power Flow (OPF) problem. The proposed method in hybrid power market which also gives solutions to voltage stability problems by considering the generation rescheduling cost and load shedding cost which relieves the congestion problem in deregulated environment. The buses for load shedding are selected based on the minimum eigen value of Jacobian with respect to the load shed. In the proposed approach, real power settings of generators in base case and contingency cases, generator bus voltage magnitudes, real and reactive power demands of selected load buses using sensitivity analysis are taken as the control variables and are represented as the combination of floating point numbers and integers. DE/randSF/1/bin strategy scheme of differential evolution with self-tuned parameter which employs binomial crossover and difference vector based mutation is used for the VSCOPF problem. A fuzzy based mechanism is employed to get the best compromise solution from the pareto front to aid the decision maker. The proposed VSCOPF planning model is implemented on IEEE 30-bus system, IEEE 57 bus practical system and IEEE 118 bus system. The pareto optimal front obtained from MODE is compared with reference pareto front and the best compromise solution for all the cases are obtained from fuzzy decision making strategy. The performance measures of proposed MODE in two test systems are calculated using suitable performance metrices. The simulation results show that the proposed approach provides considerable improvement in the congestion management by generation rescheduling and load shedding while enhancing the voltage stability in deregulated power system.

A new maximum power tracking in PV system during partially shaded conditions based on shuffled frog leap algorithm

Abstract Maximum Power Point Trackers (MPPTs) are power electronic conditioners used in photovoltaic (PV) system to ensure that PV structures feed maximum power for the given ambient temperature and sun’s irradiation. When the PV panels are shaded by a fraction due to any environment hindrances then, conventional MPPT trackers may fail in tracking the appropriate peak power as there will be multi power peaks. In this work, a shuffled frog leap algorithm (SFLA) is proposed and it successfully identifies the global maximum power point among other local maxima. The SFLA MPPT is compared with a well-entrenched conventional perturb and observe (P&O) MPPT algorithm and a global search particle swarm optimisation (PSO) MPPT. The simulation results reveal that the proposed algorithm is highly advantageous than P&O, as it tracks nearly 30% more power for a given shading pattern. The credible nature of the proposed SFLA is ensured when it outplays PSO MPPT in convergence. The whole system is realised in MATLAB/Simulink environment.

Zero-one Integer Programming Approach to Determine the Minimum Break Point Set in Multi-loop and Parallel Networks

The current study presents a zero-one integer programming approach to determine the minimum break point set for the coordination of directional relays. First, the network is reduced if there are any parallel lines or three-end nodes. Second, all the directed loops are enumerated to reduce the iteration. Finally, the problem is formulated as a set-covering problem, and the break point set is determined using the zero-one integer programming technique. Arbitrary starting relay locations and the arbitrary consideration of relay sequence to set and coordinate relays result in navigating the loops many times and futile attempts to achieve system-wide relay coordination. These algorithms are compared with the existing methods, and the results are presented. The problem is formulated as a setcovering problem solved by the zero-one integer programming approach using LINGO 12, an optimization modeling software.

Artificial Intelligence and Evolutionary Computations in Engineering Systems

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Simulation of Half Bridge Series Resonant PFC DC to DC converter

price are net prices, subject to local VAT. Prices indicated with * include VAT for books; the €(D) includes 7% for Germany, the €(A) includes 10% for Austria. Prices indicated with ** include VAT for electronic products; 19% for Germany, 20% for Austria. All prices exclusive of carriage charges. Prices and other details are subject to change without notice. All errors and omissions excepted. S.S. Dash, M.A. Bhaskar, B.K. Panigrahi, S. Das (Eds.) Artificial Intelligence and Evolutionary Computations in Engineering Systems