POWER FLOW AND LOSS ALLOCATION IN DEREGULATED TRANSMISSION SYSTEMS

Abstract

In present times, deregulated transmission section in power system in power systems are of major research in electricity market. The three major parts of a power system, generation, transmission and distribution are separately handled by separate companies. So, it is necessary for unbundling these three sections, and this unbundled transmission section is called deregulated transmission system. In this work, the method that is utilized is based on circuit theories and orthogonal projection so as to determine the loss allocated for the generators. Optimal re-dispatch to alleviate transmission congestion has been modeled as a nonlinear optimization program. A hyperbolic tangent function in the index of performance permits the dispatch of reactive power based on bids. Power Flow is done with the help of one of the conventional power flow methods. During power flow evaluation, the slack-bus, the generator buses, and the load buses are considered separately. Then, loss allocation is evaluated by a method which utilizes circuit theories and orthogonal projection [3]. By this method, a programme is coded in MATLAB Version 7.6.0.324 (R2008a) in a general manner, and the transmission loss allocation for each transmission lines is evaluated by taking the results from it, each time running it from different results samples, and then feeding these results to a hybrid neural network programme using MATLAB 7 so as to compare the results with the ones obtained by the previous programme. Also with the results obtained from power flow, the minimization of congestion cost is done by an optimization procedure mentioned in Chapter 6 [9]. By this method, the active power and the reactive power that is to be generated by each generator are evaluated, and the voltages and load angles of each bus are also evaluated, so as to have minimum congestion. The constraints that are used are the Load flow Equations, upper and lower bounds on bus-voltages, upper and lower bounds on apparent Power of generator buses, and upper and lower bounds on Apparent Power Flow through each lines For these evaluations, AMPL software along with snopt solver (version 7.0.0) is used. iii AMPL is optimization software useful for large-scale optimization and evaluation of mathematical programming problems in production, distribution, .blending, scheduling, and many other applications. Combining familiar algebraic notation and a powerful interactive command environment, AMPL makes it easy to create models, use a wide variety of solvers, and examine solutions. Though flexible and convenient for rapid prototyping and development of models, AMPL also offers the speed and generality needed for repeated large-scale production units. To solve the problem, snopt solver is used by the AMPL software.