Sawan Sen

Alleviation of line congestion using Multiobjective Particle Swarm Optimization

This paper presents a methodology based on Particle Swarm Optimization technique for rescheduling of generation patterns to manage congestion in contingent power networks. In deregulated systems, line congestion attract additional penalties which add on to the overall operational cost to be incurred by the Independent System Operators (ISO), apart from causing limit violations, and stability problems. Thus, limiting the congestion level of lines and restricting power flows within the safe limits is important from stability as well as economy point of view. The algorithm proposed in the present paper uses a Standard Sensitivity Index to identify the congested zone(s) in a large power network and then adopt corrective actions for limiting line congestion at the cost of a nominal rescheduling cost without any load curtailment and installation of FACTS devices. It has been demonstrated that the proposed method can reduce congestion even below the minimum level obtained from the conventional cost optimization results. It has been depicted that the methodology on application can provide better operating conditions in respect of improvement of bus voltage profile. The efficiency of the proposed methodology has been tested on a IEEE 30 bus benchmark system and the results look promising.

Genetic Algorithm based transmission loss optimization under deregulated environment

This paper proposes a systematic method for reactive loss optimization using Genetic Algorithm (GA) and load flow analysis for deregulated transmission systems. Due to nonlinear nature of power flow, tracing the loss and power flow through the mesh network becomes more complicated. In this paper, in genetic algorithm, the loss optimization using equivalent optimal power flow model has been treated as fitness function where conventional power balance equation is considered as constraint. On second level, the accuracy has been further improved using ac load flow by changing the tap position of the existing transformer in the system. The proposed methodology depicts the information related to the optimization status of total system loss with or without installing external device to minimize the investment cost under deregulated environment. IEEE 30 bus system is used to demonstrate the effectiveness of the method.

Genetic algorithm based spot pricing of electricity in deregulated environment for consumer welfare

This paper proposes a systematic method for evaluation of optimal spot prices using genetic algorithm as well as classical method. Spot pricing of electricity in a power system was proposed during early eighties considering unit generation and consumer usage as decision variables. With restructuring followed by deregulation, a number of players have started participating in the competitive power market leading optimal spot pricing to a complicated level. This paper presents a novel method using genetic algorithm (GA) for optimal allocation of generated power with minimal cost so that spot price can be optimised under stressed condition. This method has been extended by using load flow analysis to minimize the operating loss keeping the spot price within predefined limit, so that ISO can choose any one of techniques considering the consumers welfare. This proposed algorithm has been successfully tested with standard IEEE 30 bus system to produce remarkable optimal solution.

A multi-objective optimisation algorithm with swarm intelligence for contingency surveillance

This paper proposes a new multi-objective optimization model to minimize congestion cost, load curtailment and generation cost simultaneously to restore the equilibrium of operating point of the system under contingency. The solution algorithms of the proposed method are based on the Particle Swarm Optimization (PSO) in which load curtailment and generation cost have been optimized without breaching line flow constraints for congestion management. The significance of the proposed method has been presented in this paper by a comparative study with the conventional cost optimization method in terms of operating cost considering VOLL (Value of lost load) and two more proposed analytical indices namely Value of Congestion Cost (VOCC) and Value of Excess Loss (VOEL) in contingent states of power system. It has been depicted that the proposed method effectively reduces the operating cost volatility in spot power market with respect to the conventional methods. The applicability of the developed method has been tested on the IEEE 30 bus system.

An evolutionary algorithm for consumer welfare optimisation of a contingent power network

An evolutionary optimization technique based methodology has been proposed in this paper to sustain the total generation cost even in contingent states of a power network for consumer welfare. The alteration of generation cost during contingency is quite evident which makes the consumers suffer economically due to rise of the level of congestion and price of electricity. The aim of this proposed methodology is to minimize the deviations of generation cost, during contingency, from a preferred value by re-allocation of generation schedule with a controlled load curtailment technique and hence relieving the lines from overloading for congestion management. It has been demonstrated that, on application, the proposed methodology can improve the operating conditions of the system apart from optimizing the price volatility of electrical power market. The methodology has been tested on a standard benchmark system and the comprehensive simulation results looked promising.

Impacts of FACTS and HVDC interconnecting link in a deregulated power system with contingency and heavily loaded condition

This paper focuses on the effective utilization of Flexible AC Transmission System (FACTS) and High Voltage Direct Current (HVDC) interconnection link for the improvement of voltage profile, stability and loss allocation in heavily loaded as well as contingent conditions of the network. The weakest bus interconnection has been replaced by FACTS and HVDC link and a study has been carried out to prove their effectiveness in an interconnecting network under deregulated environment. The IEEE 14 bus system, operating with common loads and generators is used to demonstrate the usefulness of FACTS and HVDC link. A new voltage stability index (VSI) has been proposed in this paper for stability analysis with HVDC and FACTS. A comparative analysis between FACTS and HVDC has also been presented in this paper, for their comparison, in field of power quality and cost efficiency.