The aim of study is designed of Power System Stabilizer (PSS) based on H4 approach for power system stabilization. The uncertainties in power system modeling and operations are considered at designing of H4 PSS. The bounds of power system parameters are determined over a wide range of low frequency operating conditions. These bounds are used to design a robust H4 PSS. A sample power system composed a synchronous generator connected to infinite bus through transmission line is simulated. The digital H4 PSS can achieve good performance over a wide range of operating conditions. A comparison between power system responses at variety of operating conditions using the proposed H4 PSS and Linear Quadratic Regulator LQR control have been done. H2 PSS is designed and compared with the proposed controller.

A position control of DC motor servo drive based on the Sliding Mode (SM) approach is presented. The modeling and analysis of the servo DC motor are obtained. The Sliding Mode Controller (SMC) design changes such that its performance is substantially improved. To improve the controller performance in steady stat (zero error) the Integral Sliding Mode Controller (ISMC) is used. Since the main drawback of SMC is a phenomenon, the so-called chattering, resulting from discontinuous controllers. A ISMC with switched gains is used for chattering reduction and controller robustness. For comparison, the proposed ISM with switched gains is compared with that of a PID controller. Experiments and simulations have been carried out in order to validate the effectiveness of the proposed scheme. The proposed controller offers very good tracking; it is highly robust, reaches the final position very fast. Furthermore the application of the SM ensures reduction of the system order by one. Also, quick recovery from matched disturbance in addition to good tracking ability. Moreover, this scheme is robust against the parameters variations and eliminate the influence of modeling.

The present study investigates the power system stabilizer based on neural predictive control for improving power system dynamic performance over a wide range of operating conditions. In this study a design and application of the Neural Network Model Predictive Controller (NN-MPC) on a simple power system composed of a synchronous generator connected to an infinite bus through a transmission line is proposed. The synchronous machine is represented in detail, taking into account the effect of the machine saliency and the damper winding. Neural network model predictive control combines reliable prediction of neural network model with excellent performance of model predictive control using nonlinear Levenberg-Marquardt optimization. This control system is used the rotor speed deviation as a feedback signal. Furthermore, the using performance system of the proposed controller is compared with the system performance using conventional one (PID controller) through simulation studies. Digital simulation has been carried out in order to validate the effectiveness proposed NN-MPC power system stabilizer for achieving excellent performance. The results demonstrate that the effectiveness and superiority of the proposed controller in terms of fast response and small settling time.

Design of power system stabilizer for enhancement power system stability is proposed. The effect of the proposed PSS on the synchronizing and damping torque coefficients is proved. To study the effectiveness of the proposed linear quadratic regulator (LQR) power system stabilizer, a sample power system in a linearized model is simulated and subjected to different operating conditions. The Linear Quadratic Gaussian (LQG) power system stabilizer is proposed. The power system dynamic responses after applying a variety of operating points with the proposed LQG-PSS stabilizer are plotted. The output of such stabilizer is fed directly to the automatic voltage regulator (AVR) of the synchronous machine. The input to such stabilizer are four state variables, two are accessible which are the deviation of the speed (Δω) and rotor angle (Δδ ). The other two inaccessible states that are the deviation of the Voltage proportional to q-axis flux linkage. ( ' q ΔE ) and the Generator field voltage ( fd ΔE ). An observer has been designed to access the two inaccessible states. Further, the effect of connecting the proposed power system stabilizer on synchronizing and damping torque coefficients is tabulated. A comparison between the effect of the power system stabilizer based on either LQR approach, the proposed LQG stabilizer in terms of either power system responses or its eigenvalues due to different load condition is reported.

The present paper investigates the design of Load-Frequency Control ( LFC) system for improving power system dynamic performance over a wide range of operating conditions based on model predtictive control MPC technique. The objectives of load frequency control (LFC) are to minimize the transient deviations in area frequency and tie-line power interchange variables . Also steady state error of the above variaables forced to be zeros. The two control schems namely Fuzzy logic control and proposed model predictive control are designed. Both the two controllers empoly the local frequency deviation signal as input signal. The dynamic model of two-area power system under study is estabilished . To validate the effectiveness of the proposed MPC controller, two-area power system is simulated over a wide range of operating conditions. Further, comparative studies between the fuzzy logic controller (FLC), and the proposed MPC load frequency control are evaluated.

This research tracks the abnormal system operating conditions of the city of Asyut water supply network over an extended period. EPANET software was used to perform hydraulic and water quality analysis. Firstly, the effect of roughness variation with time on pressure head distribution and water quality through the network is simulated. Secondly, leakage due to failure of some pipes on the flow, pressure heads and water quality are investigated. Also the effect of closing some pipes in the network on pressure head and chlorine distributions is taken into consideration. Finally, the effect of changing the source of chlorine disinfection on water quality in the network is studied. The results indicate the following: (1) The increasing roughness of pipes can significantly increase the head losses through the network and consequently decrease the head at the end of network below the minimum limit. The variability in nodal pressures also has a significant effect on chlorine decay if the bulk wall reaction coefficient is taken to be dependent on the roughness of the pipe. (2) The failure of some pipes in the networks not only increases the consumed discharge in the network and decreases the pressure head but also changes the flow directions in some pipes through the network. (3) Closing a pipeline increases pressure in a region and decreases it at another and also changes the direction of flow in the network. This may affect the chlorine distribution through the network. (4) Chlorine disinfection from one source can significantly decrease the residual concentrations under the minimum limit in part of the network, while it can increase variability in nodal concentrations.

Nearly all water supply systems for high-rise buildings in Egypt include storage cisterns to feed the upper floors with cold water for different uses. Although these cisterns are the most important component in the distribution system, they are generally the least understood in terms of their effect on water quality. In this study, chlorine residual, algae genus and concentration, and pH value were measured before and after storage cisterns that exist above a 12-floor building in Assiut City, Egypt, to check their effect on water potability, through 48 h of observation. EPANET quality model is applied to simulate the chlorine residual and water age in the distribution system and storage cisterns through extended period simulations. The model is used to study the influence of the storage cisterns size and the turnover depth on residual chlorine decay and water age in the tanks. Results indicated that oversized storage cisterns can have negative impacts on water quality, including increased water age, reduced disinfectant residuals, and increased growth of disinfectant by-products (DBPs). However, there are other key roles that storage plays in the distribution system, e.g., security of supply during supply interruption and reserve storage for firefighting. Some of the microbiological and chemical effects of the cisterns on water quality have been investigated. DOI: 10 .1061/(ASCE)WR.1943-5452.0000132. © 2011 American Society of Civil Engineers.

Nearly all water supply systems for high-rise buildings in Egypt include storage cisterns to feed the upper floors with cold water for different uses. Although these cisterns are the most important component in the distribution system, they are generally the least understood in terms of their effect on water quality. In this study, chlorine residual, algae genus and concentration, and pH value were measured before and after storage cisterns that exist above a 12-floor building in Assiut City, Egypt, to check their effect on water potability, through 48 h of observation. EPANET quality model is applied to simulate the chlorine residual and water age in the distribution system and storage cisterns through extended period simulations. The model is used to study the influence of the storage cisterns size and the turnover depth on residual chlorine decay and water age in the tanks. Results indicated that oversized storage cisterns can have negative impacts on water quality, including increased water age, reduced disinfectant residuals, and increased growth of disinfectant by-products (DBPs). However, there are other key roles that storage plays in the distribution system, e.g., security of supply during supply interruption and reserve storage for firefighting. Some of the microbiological and chemical effects of the cisterns on water quality have been investigated. DOI: 10 .1061/(ASCE)WR.1943-5452.0000132. © 2011 American Society of Civil Engineers.

This research tracks the abnormal system operating conditions of the city of Asyut water supply network over an extended period. EPANET software was used to perform hydraulic and water quality analysis. Firstly, the effect of roughness variation with time on pressure head distribution and water quality through the network is simulated. Secondly, leakage due to failure of some pipes on the flow, pressure heads and water quality are investigated. Also the effect of closing some pipes in the network on pressure head and chlorine distributions is taken into consideration. Finally, the effect of changing the source of chlorine disinfection on water quality in the network is studied. The results indicate the following: (1) The increasing roughness of pipes can significantly increase the head losses through the network and consequently decrease the head at the end of network below the minimum limit. The variability in nodal pressures also has a significant effect on chlorine decay if the bulk wall reaction coefficient is taken to be dependent on the roughness of the pipe. (2) The failure of some pipes in the networks not only increases the consumed discharge in the network and decreases the pressure head but also changes the flow directions in some pipes through the network. (3) Closing a pipeline increases pressure in a region and decreases it at another and also changes the direction of flow in the network. This may affect the chlorine distribution through the network. (4) Chlorine disinfection from one source can significantly decrease the residual concentrations under the minimum limit in part of the network, while it can increase variability in nodal concentrations.