Muhammad Ahmad Choudhry

Preparation and characterization of EPDM-silica nano/micro composites for high voltage insulation applications

Abstract The rising market for substitute materials in high voltage insulation components is stimulated largely by the need to reduce overall costs. In this respect, polymer insulators offer significant advantages over old traditional materials. In the present research, efforts have been made to quantify the effect of silica (having different particle size nano, micro and hybrid) loading on the mechanical and thermal behaviors of Ethylene-Propylene-Diene Monomer (EPDM) based high voltage electrical insulations. The fabricated composites were subjected to mechanical, thermal and electrical properties measurements. The results of dielectric strength, surface and volume resistivities showed that all composites had insulator properties, while their mechanical and thermal properties improved considerably. EPDM was compounded with different types of silica in a two roll mill using sulphur cure system. The outcome achieved from the comparative study revealed that the EPDM nanocomposites had enhanced mechanical, thermal and electrical properties even at 5 % loadings.

A generic procedure for troubleshooting of PLC based control systems

This paper describes the problems generally faced with PLC based control systems and a general procedure to solve them. Flowcharts for troubleshooting of power supply faults, internal and external problems of PLC has been included in the paper. The approach mentioned for troubleshooting is general and can be applied on any type of PLC based control system. A case study is included to validate the developed general procedure for the trouble shooting of PLC based controlled system.

A generalized higher order neural network for aircraft recognition in a video docking system

In modern world of today where air traffic is continuously increasing and available space at the airports remains finite, there is a problem of safe docking of aircraft. The problem needs to be solved to ensure safe and smooth movement of aircraft, passengers and crew while making optimum utilization of available ground space. Without such systems having in place, accidents keep occurring due to human judgment errors. These accidents are causing loss of material costs and human injury. The importance of Video-based Docking Systems is continuously increasing due to the challenges of current and upcoming traffic demands of future. This paper evaluates two neural networks architectures for recognition of civil airliners in a Video docking system. The networks compared are feedforward neural network and probabilistic neural network. The results are compared by presenting data to neural networks while deforming the shape, adding noise and partly occluding the shape and presenting those angles for which network was not trained.

Modeling and Control of Cartesian Robot Manipulator

To analyze qualitatively the dynamical responses of a manipulator various factors are to be considered. In this paper we have developed kinematics and dynamics model for a cartesian robot manipulator (CRM). A 3-axis controller was designed, developed and interfaced with the manipulator. The developed model and controller were programmed in C++ language and the tests results were plotted in Microsoft Excel. Various tests were performed on system to evaluate performance of the model and the controller. The results that were obtained from these tests were plotted and have been discussed. An application for drilling purpose was also developed

A Systematic Approach to Develop PLC Program for Automation of a Backwash Water Treatment Plant

Programmable logic controllers (PLCs) are type of process control computers, which are small but relatively inexpensive, environmentally hardened, and easy to program, operate, maintain and repair. The process control computers primarily control devices such as motors, solenoids, pumps, valves, lights and heaters etc. These computers, which number in millions, are the control elements in the virtually all modern factory operations. The programmability of PLC allows for fast and easy changes in relay ladder logic to meet the changing needs of the process or driven equipment without the need for expensive and time consuming rewiring. In this paper a target to develop, simulate and implement PLC software for automation of a water treatment plant is achieved. The algorithm developed in this paper may be used to develop PLC based software for any control process

Performance analysis of static transfer switch using MATLAB/Simulink

Many industrial loads suffer from various power quality problems like voltage sag and swell, service outages etc. Due to these power quality issues industrial customer bears huge financial loss. So in this situation static transfer switch can be the most cost effective solution to avoid from these problems. Thyristor based Static transfer switch is used to protect industrial load from these power quality problems by transferring sensitive load from one source to another within minimum transfer time. This paper investigates the performance of thyristor switches based STS system by improving the power quality of a sensitive three-phase industrial load. Extensive simulations are carried out to validate the use of thyristor switches in medium voltage systems to achieve a lesser transfer time in network reconfiguration. Performance analysis of thyristor based STS system is carried out under various faults/disturbance conditions. Simulation results obtained from MATLAB/Simulink verifies the performance of static transfer switch.

Voltage Control Measures by Using STATCON through PSS/E in WAPDA Power System

Water and Power Development Authority (WAPDA) Pakistan has lack of reactive power reserves. The station which needs reactive power to boost the voltage during under voltage problem also requires some source to absorb reactive power to overcome over voltage problem. In this research work, the behavior of static Voltage control through STATCON has been reviewed and real data of WAPDA 500/220 kV power system regarding extreme cases of voltage control has been simulated on power system simulator PSS/E. Different rating of simulated STATCON has been proposed at various locations to overcome voltage stability problem, increase steady state, dynamic state and transient stability. Due to practical nature of the research work, it would be effectively utilized for resolving issues and bottlenecks related to WAPDA primary transmission line.

Network simulation with STATCON devices to avoid voltage collapse in the interconnected system

In this paper reactive power control with the help of STATCON has been simulated. Converter operation and switching sequence has been briefed. Real data of Wapda 500/220 kV power system regarding extreme cases of voltage control has been simulated on power system simulator PSS/E. Different rating of simulated STATCON has been suggested at various stations to overcome voltage collapse problem, increase steady state, dynamic and transient stability.