N. Subrahmanyam

New approach with muller method for profit based unit commitment

This paper presents a new approach with Muller method for solving profit based unit commitment (PBUC). In deregulated environment, the generation companies (GENCOs) schedule their generators to maximize their profit rather than satisfying the power demand. While solving the PBUC problem, the information of forecasted price at the given predicted power demand is known. The PBUC problem is solved by the proposed approach in two stages. Initially, committed units table obtains information of the committed units and finally the non linear programming sub problem of economic dispatch is solved by Muller method. The proposed approach has been tested on a power system with 3 and 10 generating units. Simulation results of the proposed approach have been compared with existing methods and also with the traditional unit commitment. It is observed from the simulation results that the proposed algorithm provides maximum profit with less computational time compare to existing methods.

Improved Pre-prepared Power Demand Table and Muller's Method to Solve the Profit Based Unit Commitment Problem

This paper presents the Improved Pre-prepared Power Demand (IPPD) table and Muller’s method as a means of solving the Profit Based Unit Commitment (PBUC) problem. In a deregulated environment, generation companies (GENCOs) schedule their generators to maximize profits rather than to satisfy power demand. The PBUC problem is solved by the proposed approach in two stages. Initially, information concerning committed units is obtained by the IPPD table and then the subproblem of Economic Dispatch (ED) is solved using Muller’s method. The proposed approach has been tested on a power system with 3 and 10 generating units. Simulation results of the proposed approach have been compared with existing methods and also with traditional unit commitment. It is observed from the simulation results that the proposed algorithm provides maximum profit with less computational time compared to existing methods.

New approach with Muller method for Solving Profit Based Unit Commitment

This paper presents a new approach with Muller method for solving profit based unit commitment (PBUC). In deregulated environment, the generation companies (GENCOs) schedule their generators to maximize their profit rather than satisfying the power demand. The PBUC problem is solved by the proposed approach in two stages. Initially, the information of committed units is obtained by a simple approach and finally non linear programming sub problem of economic dispatch is solved by Muller method. The proposed approach has been tested on a power system with 3 and 10 generating units. Simulation results of the proposed approach have been compared with existing methods and also with traditional unit commitment. It is observed from the simulation results that the proposed algorithm provides maximum profit with less computational time compared to existing methods.

Brent method for Dynamic Economic Dispatch with transmission losses

This paper presents application of Brent method to solve dynamic economic dispatch (DED) problem with transmission losses. The algorithm involves the selection of incremental fuel costs (lambda values) and then the optimal lambda is evaluated from the power balance equation by Brent method at predicted power demand. In real time operation, thermal gradients inside the turbine should be kept within safe limits to avoid shortening the life of generating units. This mechanical constraint is translated into a limit on the rate of increase and decreases of the output power during the variation in the power demand and is known as ramp rate limits. The constraint of ramp rate limits distinguishes the DED problem from the traditional static economic dispatch (ED) problem. Due to ramp rate limits, DED problem cannot be solved for a single value of the power demand. The main objective is to determine the optimal schedule of output powers of online generating units with predicted power demands over a certain period of time to meet power demands at minimum operating cost. The proposed method has been tested on a power system having 6 and 15 generating units. The results of the proposed algorithm are compared with the conventional lambda iterative method in terms of solution quality and computational time. It is observed from the case studies that the Brent method provides qualitative solution with less computational time compare to lambda iterative method.

Secant method combined with PSO for Economic Dispatch with prohibited operating zones

This paper describes secant method combined with particle swarm optimization for solving Economic Dispatch (ED) problem with prohibited operating zones. Two stages are involved in the proposed approach to solve the ED problem with prohibited operating zones. First, the range of output powers near to the global optimal solution is determined by secant method without considering prohibited zones and then the evaluation of the final optimal solution is done by particle swarm optimization. The proposed algorithm has been tested on a power system having 4, 15 and 40 units with prohibited zones. Simulation results of the proposed approach were compared in terms of solution quality, convergence characteristics and computation efficiency with existing algorithms. From the different case studies, it is observed that the proposed approach provides qualitative solution with less computational time compared to various methods available in the literature survey.

Self adaptive harmony search algorithm for optimal capacitor placement on radial distribution systems

Optimal capacitor placement is a complex combinatorial optimization process aimed at finding the location and size of capacitors on a radial distribution network that minimizes the system power and energy loss, deviation of node voltages and increases the available capacity of the feeders. A Harmony Search algorithm (HSA) is a recently developed algorithm which is conceptualized using the musical process of searching for a perfect state of harmony. It uses a stochastic search instead of a gradient search. In this paper, a Self Adaptive Harmony Search algorithm (SAHSA) is proposed to solve the optimal capacitor placement in order to minimize the power loss. Forward/Backward sweep power flow method is used to solve the radial distribution system. The proposed approach is tested on standard IEEE 33bus and IEEE 69-bus radial distribution systems. The results are compared with Particle Swarm Optimization (PSO) algorithm, and plant growth simulation algorithm (PGSA) and it is observed that the proposed method performed well in terms of the quality of solution.

Secant Method for Economic Dispatch with Generator Constraints and Transmission Losses

This paper describes the secant method for solving the economic dispatch (ED) problem with generator constraints and transmission losses. The ED problem is an important optimization problem in the economic operation of a power system. The proposed algorithm involves selection of minimum and maximum incremental costs (lambda values) and then the evaluation of optimal lambda at required power demand is done by secant method. The proposed algorithm has been tested on a power system having 6, 15, and 40 generating units. Studies have been made on the proposed method to solve the ED problem by taking 120 and 200 units with generator constraints. Simulation results of the proposed approach were compared in terms of solution quality, convergence characteristics, and computation efficiency with conventional methods such as lambda iterative method, heuristic methods such as genetic algorithm, and meta-heuristic methods like particle swarm optimization. It is observed from different case studies that the proposed method provides qualitative solutions with less computational time compared to various methods available in the literature.

Improved Music Based Harmony Search algorithm for Optimal Network Reconfiguration

Distribution network reconfiguration is a complex combinatorial optimization process aimed at finding a radial operating structure that minimizes the system power loss, deviation of node voltages and service restoration while satisfying operating constraints. A Music Based Harmony Search algorithm (MBHS) is a recently developed algorithm which is conceptualized using the musical process of searching for a perfect state of harmony. It uses a stochastic search instead of a gradient search. In this paper, an Improved Music Based Harmony Search (IMBHS) algorithm is proposed to solve the network reconfiguration problem in order to minimize the power loss. Constant Complex Matrix Power Flow method is used to solve the radial distribution system. The proposed approach is tested on standard IEEE 33-bus system. The results are compared with MBHS algorithm and it is observed that the proposed method performed well in terms of the quality of solution.

Secant method with PSO for economic dispatch with valve point loading

This paper describes Secant method with Particle Swarm Optimization (PSO) for solving the Economic Dispatch (ED) problem with valve point loading. The ED problem is solved in two stages. The range of output powers near the global optimal solution is determined by the Secant method and then the final optimal solution is obtained by PSO. The proposed algorithm has been tested on 3-, 13- and 40-units. Simulation results of the proposed approach are compared with existing algorithms. From the different case studies, it is observed that the proposed approach provides qualitative solution with less computational time compared to various methods available in the literature.

Control strategies of a fuzzy controlled grid connected hybrid PV/PEMFC/battery distributed generation system

This paper describes the power control strategies of a fuzzy controlled grid connected hybrid photovoltaic and proton exchange membrane fuel cell distributed generation system with battery as energy storage device. The primary source of energy for the hybrid distributed generation system is from photovoltaic cell and proton exchange membrane fuel cell and the battery acts as a complementary source of energy. The hybrid distributed generation system is connected to a grid through power electronic interfacing devices. A Matlab/Simulink model is developed for the grid connected hybrid distributed generation system, fuzzy controlled power electronic DC/DC and DC/AC converters to control the flow of power on both sides. Simulation results illustrate the performance of the hybrid system following the load demand and operating the system near unity power factor.