ASimulationModelforCrowbarringThyristorDevices.docVIP

A Simulation Model for Crowbarring Thyristor Devices Devender Kasturi, BE Thesis Prepared for the Degree of MASTER OF SCIENCE UNIVERSITY OF NORTH TEXAS December 2003 APPROVED Dr. Albert B. Grubbs, Major Advisor Dr. Monty Smith, Committee member Dr. Vijay Vaidyanathan, Committee member Mr. Phillip Havens, Committee member Dr. C. Neal Tate, Dean of the Robert B. Toulouse School of Graduate Studies. Introduction Surges from lightning, induction, and electrostatic discharge are based on the laws of physics and are known to cause problems (circuit burning out, some or most of the components not functioning properly) to many electronic devices, especially communications devices. The types of surges seen by these devices are as following: Lightning: - Over voltage surge is the most common cause of surge damage. Lightning strikes, near or far from an electronic device, can generate a surge, which travels through aerial or buried cable to the equipment. Power Line Cross: - Accidental crossing of power lines with telecommunication lines causes this over current surge. Conductive Spikes: - Voltage surges caused by the momentary contact between a power and telecommunications lines. Inductive Spikes: - Induced voltage/current surges caused by electromagnetic fields of high energy switching equipment or surges in cables near communications cables. Communications equipment can be subjected to over voltage surges, over current surges or both. Over voltages destroy sensitive semiconductors in microprocessor based PBX/KSU systems, as well as CPUs in PCs or workstations. Over current events can generate enough heat to cause a building wiring fire. There are devices that prevent the potential destruction caused by these surges. A SIDACtor? product is one such device. SIDACtor components are solid-state devices designed to protect telecommunications equipment during hazardous transient conditions. Compared with surge suppression devices using other tech