S N Shivani

Here four mathematical models are modelled in ATPdraw. User defined model library block is programed to represent circuit breaker in ATPdraw. Circuit breaker model output is observed in diversified conditions. All four models are compared for conclusion.

With the growing of demand of electric power, the distribution system is expanding continuously. This results in the high level of short-circuit currents. Therefore, the electric distribution cost such as devices, installation, operation and maintenance increases gradually. Moreover, the high level of short circuit current becomes the serious problem. It may damage the electric devices or effect on machine operation. Continuity of power supply systems is very low because operations of protective devices under faulted conditions. Mechanical circuit breakers in power distribution systems give a safe handling of short-circuits under limited short-circuit power of the grid. Using delayed turn-off times, the circuit breakers can be coordinated with some other protective equipment. Hence, a high availability of the grid can be expected. However, when the short circuit event occurs in a medium-voltage distribution feeder, voltages along the feeder line are suddenly sagged. Sensitive loads ...

Modeling of a wind diesel hybrid system (WDHS) is done to perform under varying wind and load conditions on MATLAB Simulink platform. The hybrid system is design in such a way that under low wind conditions, a diesel generator feeds required power to the load. A load flow controller is designed for WDIS to control the load flow depending on the load condition. The power controller reduces the fuel consumption and running costs of generating of hybrid system. The frequency of the system is also monitored. The models of the generation units, the power system and frequency-power control are developed and simulation studies have been performed under various conditions using Mat lab/Simulink. It has been demonstrated that this system can provide reliable and good quality power to the customers in WDIS systems.

Abstract: This paper represents the active modeling and simulation results of a renewable energy based hybrid power system. The various energy sources such as wind, PV and FC are modeled individually and latterly integrated to form a hybrid system. The simulation model of stand-alone system is developed from mathematical models of solar photovoltaic system, wind turbines and fuel cell. The simulation includes all practical components of the system, in this thesis power delivered by the Combine system component is compared with each other and various conclusions are drawn. A comparative study of hybrid model of solar /wind and fuel cells system has been made. This paper describe of solar-wind hybrid system for supplying electricity to power grid. Work principle and specific working condition are presented in this paper.

AC traction scheme is implemented in 1957 by Indian railway board. It was simple 25kV, 50 Hz single phase system. Mainly AC traction employed for economy purpose in OHE, substations and locomotives because it reduces the cost of supporting structures. Various elements of AC traction system are explained in detail in this paper. Also different types of faults are also explained. It also contains an Introduction to out-of-phase short circuit fault which is new type of fault in AC traction and various issues in power quality of AC traction system and techniques to mitigate the issues and improve power quality.