Ming-Tong Tsay

Nonconvex Economic Dispatch by Integrated Artificial Intelligence

This paper presents a new algorithm by integrating evolutionary programming (EP), tabu search (TS), and quadratic programming (QP) methods to solve the nonconvex economic dispatch problem (NED). A hybrid EP and TS were used for quality control and the Fletchers quadratic programming technique was used for solving. EP and TS determine the segment of a cost curve used, which is piecewise quadratic natured. Operation constraints are modeled as linear equality or inequality equations, resulting in a typical QP problem. Fletchers QP was chosen to enhance the performance. The fitness function is constructed from priorities without penalty terms. Numerical results show that the proposed method is more effective than other previously developed evolutionary computation algorithms.

A Fault Classification Method by RBF Neural Network with OLS Learning Procedure

This paper presents a new approach to identify fault types and phases. A transmission line fault classification method based on a radial basis function (RBF) neural network with orthogonal-least-square (OLS) learning procedure was used to identify various patterns of associated voltages and currents. The RBF neural network was also compared with the back-propagation (BP) neural network in this paper. It is shown that the RBF approach can provide a fast and precise operation for various faults. The simulation results also show that the proposed approach can be used as an effective tool for high speed relaying.

Applying the multi-objective approach for operation strategy of cogeneration systems under environmental constraints

This paper presents a multi-objective approach based on evolutionary programming to solve the economical operation of cogeneration system under emission constraints. A multi-objective function including the minimization of cost and multi-emission is formulated in this paper. The cost model includes fuels cost and tie-line energy. The emissions with CO2, SOx, and NOx were derived as a function of fuel enthalpy. All constraints including fuel mix, operational constraints, and emission constraints must be met in the optimization process. The steam output, fuel mix, and power generations will be found by considering the time-of-use dispatch between cogeneration systems and utility companies. Data of an industrial cogeneration system was used to illustrate the effectiveness of the proposed method.

Multiple-frequency three-phase load flow for harmonic analysis

A multiple-frequency three-phase load-flow model was developed in this paper. There are two new submodels including the fundamental power flow (FPF) and harmonic frequency power-flow (HPF) model. In FPF, models of electrical elements and PV buses were treated in the form of current injections in a transmission system. The standard Fourier analysis was used to deal with the harmonic loads to get injection currents. With harmonic currents as equivalent current sources, the HPF can be derived. Besides, the decoupled fast version of FPF and HPF, called DFPF and DHPF, were also proposed in this paper. Test results show that the proposed general-purpose methods are better performers than conventional power-flow solutions and are very robust.

Application of evolutionary programming to optimal operational strategy cogeneration system under time-of-use rates

Abstract This paper presents the application of Evolutionary Programming (EP) to optimal operational strategy of cogeneration systems under Time-of-Use (TOU) rate. The fuel consumption and steam generation will first be measured and the Input–Output (I/O) curve derived using the regression method. The operational model developed also considers the connection of the cogeneration system with the utility company in terms of TOU rate and various fuel consumptions. EP was adopted to decide the optimal fuel dispatch, steam output of boiler, and generation output subjective to satisfying all the operation constraints. The Newton–Raphson based method has been implemented to show that EP does have the tendency of getting the global optimum. The proposed methodology could provide a practical model for both the utility company and the cogeneration industry to follow.

Application of evolutionary programming for economic dispatch of cogeneration systems under emission constraints

Abstract This paper studies the economical operation of cogeneration systems under emission control with NOx and SOx from fossil-fueled thermal generation. The emission model is formulated as a function of fuel enthalpy dependent on the emission factor. The objective function includes fuel cost, emission cost, and tie-line energy cost, subject to the use of mixed fuels, operational limits, and emission constraints. An evolutionary programming was adopted to solve this problem. The steams, fuel mix, and generations will be found by considering the time-of-use dispatch between cogeneration systems and utility companies. A real cogeneration system is given to illustrate the proposed method.

Genetic algorithm for optimal distribution system planning

This paper is concerned with application of the genetic algorithm (GA) to the optimal distribution system planning (DSP). GA was used to solve the optimization of DSP problem which includes the discrete nature of substation installation and feeder routing. Several search procedures including coding and encoding the chromosome, fitness evaluated, reproduction, crossover, and mutation are examined in detail. A simple example has been implemented with the proposed method. All results show that GA can obtain a better solution.

Improvement in system unbalance and loss reduction of distribution feeders using transformer phase rearrangement and load diversity

This paper proposes two techniques for improving the system unbalance and loss reduction by means of transformer load management. First technique, a computer algorithm with linear programming, was used to derive the optimal load diversity among the various load types. Second technique, in regard to transformer phase rearrangement, dynamic programming (DP) with forward and backward procedure is employed to find out the optimal phase assignment of transformer for a feeder. Finally, a three-phase load flow program was used to compute the system losses and system unbalance on a practical feeder in cases of transformer rearrangement, optimal load diversity, and mixed-type. At last, both of the proposed techniques are verified to be valid and available.

Operation strategy of cogeneration systems under environmental constraints

This paper studies the economical operation of cogeneration systems under emission constraints. It attempts to control the production of atmospheric emissions such as NO/sub x/ and SO/sub x/ caused by the operation of fossil-fueled thermal generation. The objective of this paper includes fuel cost, population cost and tie-line energy cost, subject to fuel mix ratios in a boiler, operational constraints and emission condition. Evolutionary programming was adopted to solve this problem. The steam and fuel ratios of boilers and generation output will be obtained by considering the time-of-use (TOU) dispatch between cogeneration systems and utility companies. With the introduction of optimization methods, one can explore the potential for operational changes in unit commitment and dispatching to achieve minimal cost while complying with environmental standards.

The operational strategy of cogeneration plants in a competitive market

This paper presented an operational strategy for cogeneration plants under a deregulated market. The objective of this paper includes fuel cost, population cost, and electricity wheeling cost, subjective to the use of mixed fuels, operational limits, emissions constraints, and transmission line flow constraints. Enhanced immune algorithm (EIA) was proposed by an improved crossover and mutation mechanism with a competition and auto-adjust scheme to avoid prematurity. Results verify that EIA can offer an efficient way for cogeneration plants to solve the problem of economic dispatch, environmental protection, and electricity wheeling.