G. H. George

After several years of teaching an introduction to probability and statistics for engineering degree students, my attention has been captured by some variations on the familiar general addition law of probability. Network analysis of components connected in parallel is one of many applications.

This paper implements a novel wavelet-based multiresolution analysis power system stabilizer (WMRA-PSS) for a power system consisting of a synchronous generator connected to an infinite bus system through transmission lines. To overcome the drawbacks of the conventional power system stabilizers that have a design based on a linearized model of the power system, the WMRA-PSS is implemented to enhance the dynamic behaviour of the power system under different operating conditions using MATLAB Simulink. The results verify the efficiency and stability of the suggested WMRA-PSS under different operating conditions.

In this paper, a Grid Search Method (GSM) with a Field Oriented Control (FOC) is presented to determine the optimal Proportional-Integral (PI) controller gain parameters for the speed control of an induction motor. This technique is useful in finding the optimal controller gain (proportional and integral) in a closed loop system. The GSM is used to obtain gains required for the adaptive PI by seeking the optimal local minimum of a squared speed error function. The results show that the GSM is very efficient, and gives stable convergence characteristics. It has a good track record of robustness under load variation, fast dynamic response, and high precision in tracking desired speed. Furthermore, the control system, based on the GSM-PI algorithm in FOC for induction motors, can be readily implemented for occasions of frequent load changing, such as in industrial applications.

A novel Finite Element Controller Map (FECM) method for the speed control of a saturated induction motor (IM) drive is presented in this paper. The newly developed algorithm is based on approximate functions in finite elements, which are expressed according to the nodal values of output response of the IM drive. The map complexity depends on the nodes assigned within a discrete element. The proposed FECM improves dynamic responses, and is designed by assigning a simple shape function to avoid computational burden. The complete controller scheme incorporating the FECM algorithm for an IM drive is developed in MATLAB/Simulink. The proposed FECM algorithm is experimentally implemented in real time using a DSP-DS1104 control board for a laboratory induction motor. The simulated performances of the proposed FECM are found to be not very sensitive to parameter variations. These simulation results are investigated and compared with a conventional PI controller, when they are subjected to changes to command speed and parameters variation, particularly at low speeds. The simulation and experimental results are provided to verify the effectiveness of the proposed control strategy.

This paper describes a simple design of a Fuzzy Logic Controller (FLC) that is suitable for real-time applications and uses novel output membership functions, which do not include overlap. This increases controller rate speed convergence, allows for a significant reduction in computational burden, and lowers the execution time. A digital signal processor board is used to implement the FLC based Field Oriented Control (FOC) for an Induction Motor (IM) drive. The performance of the proposed controller is validated via simulation and experiments. Comparative tests with a conventional (PI) controller are provided to confirm the efficiency of the proposed algorithm.

In this paper, a simple artificial neural network power system stabilizer (SANN-PSS) is presented for a synchronous generator with IEEE type-1 excitation system connected to the infinite bus through a transmission line. Conventional design techniques use a linearized single machine infinite bus system to design a power system stabilizer (PSS) based on the transfer function between the automatic voltage regulator input and resultant developed electrical torque by the synchronous generator. Because the power system is highly nonlinear, with configurations and parameters that change with time, the conventional PSS cannot guarantee good performance in a realistic operational environment. Therefore, a SANN-PSS has been simulated to improve the system dynamics performance and to adapt the controller's parameters in real time due to any changes in operating conditions using MATLAB Simulink. The results validate the efficacy of the proposed SANN-PSS over a wide range of operating conditions.

In this paper, a simple artificial neural network power system stabilizer (SANN-PSS) is implemented using a reduced order power system. Knowledge of the high bus voltage of a transformer is employed to alter the Heffron-Phillips' method. Furthermore, a reduction technique is applied to change the power system's sequence, and increase the power system's stability by adjusting the controller's parameters in real time in response to modifications in the operating conditions. The simulation results confirm and enhance the power system's stability with the suggested SANN-PSS at altered operating conditions.

A new protection system for power transmission lines is presented based on a d-q wavelet hybrid technique (dqWPT). This hybrid technique is developed via the integration of the d-q axis transformation with the wavelet packet transform (WPT). In this proposed method, fault and transient current signals are obtained experimentally. The data compression analysis is carried out using wavelet decomposition and reconstruction based signal processing for the selection of the optimal number of levels of approximations (a) and details (d) for the selected kind of mother wavelets. For optimum choice and faster response of the protection system, the number of levels should be maintained at a minimum level. In order to select the best mother wavelet, the minimum description length (MDL) is used in this paper. The pertinent detailed analyses are briefly summarized in this paper. Sample simulations and measured results of a laboratory transmission line model for various kinds of faults are presented in order to validate the novelty of this new method. Finally, the optimal number of decomposition levels required for transmission line protection system is discussed.