performance evaluation of evolutionary designed conventional AGC controllers for interconnected electric power system studies in a deregulated market environment

Abstract

Electric power industry is currently in transition from vertically integrated utilities to an industry that will incorporate competitive companies. This increases the complexity of the load frequency issue and calls for more insight and research. In this context, the tuning of a multi-area automatic generation control (AGC) system after deregulation and furthermore, the effect of reheat turbines dynamics in the power system performance, are not yet discussed in depth and are studied in this work. The effect of bilateral contracts on the dynamics of the system is taken into account and the concept of DISCO participation matrix for these bilateral contracts is simulated. Genetic algorithms are adopted in order to obtain the optimal parameters of the loadfrequency controllers as well as of the frequency biases of thermal systems with reheat turbines. Also, since the optimum parameter values of the classical AGC have been obtained in the literature by minimizing the popular integral of the squared errors criterion (ISE) only, an effort is made in this study to show that this criterion does not give always the best system performance especially in a deregulated environment. In this work, we investigate the optimum adjustment of the load frequency controllers using a set of performance indices which are various functions of error and time. In this way, someone can observe the various performances that such a kind of power system might have when a different performance index is used. It should be noted that to the extent of the authors' knowledge, this kind of optimization has not been done yet in the literature. The performances of the tuned two-area AGC system are obtained using appropriate Matlab/Simulink models. Finally, it is envisaged that the synthesis procedure highlighted in this paper could be of practical significance for tuning conventional AGC controllers for an interconnected thermal-electric power system in a deregulated environment.

Regulation of ancillary services with integrated GAS power plant in a hydro-thermal deretulated power system

“…The electrical industry over the years has been dominated by an overall authority known as vertical integrated utility having authority over generation, transmission and distribution of power within its domain of operation [1]- [2], [7], [8]. With the emerging or various independent power producers in the power market motivates the necessity of deregulation of the power system were the power can be sold at a competitive price performing all functions involved in generation, transmission, distribution and retail sales.…”

“…The concept of DISCO Participation Matrix (DPM) [1], [2], [7], [8] is introduced to express these possible contracts in the generalized model. DPM is a matrix with the number of rows equal to the number of GENCOs and the number of columns equal to the number of DISCOs in the overall system.…”

“…The objective here is to minimize the deviation in the frequency and the deviation in the tie line power flows and these variations are weighted together as a single variable called the ACE. The fitness function is taken as the Integral of time multiplied absolute value (ITAE) of ACE [1], [2]. An optional penalty term is added to take care of the transient response specifications viz.…”

Differential evolutionary algorithm based structure preserving controller in three area deregulated environment

“…In restructured power systems, load frequency control is intricate to predict and hence, received increased attention and need to identify automatic generation or load frequency control as an auxiliary service that must be provided by generation companies. A traditional power system has been dominated by an authorized administrator Vertical Integrated Utility (VIU) having authority over generation, transmission and distribution of power within its operating boundaries [1][2][3][4][5]. In a deregulated environment, the ancillary services are provided and managed to meet the power system requirements and market objectives.…”