Electrical Dielectric Breakdown of Insulators Used in High Energy Pulsed Power Systems
Abstract
The US Navy has been actively researching electromagnetic launch (EML) systems for well over a decade now. Considerable progress has been made toward reducing the size of the prime power/pulsed power supply, increasing barrel life, improving armature performance, and developing a projectile that can survive the harsh electromagnetic/acceleration loads of a railgun bore. Electrical insulators are among the most critical of components utilized within nearly every sub-system of the EML. Significant demands are placed on them to ensure proper operation of the power supply, pulsed current transfer (PCT), and to maintain the bore structure throughout its usable life. Considerable R&D resources have been invested toward improving the structural strength of the insulators, such as those developed by IAP for example, allowing them to better survive the harsh in-bore environment. A tremendous amount of energy is stored in the EML pulsed power system and could result in dangerous conditions and costly repairs if flashover was to occur. However, size and weight is at a premium so simply over-engineering the insulators is not an option either. Insulator designs that achieve all of the intended goals are critical. Though these insulator advancements have been shown to improve bore life/structure, there is a heavy shortfall in the examination and characterization of their high voltage surface flashover tendency when deployed in electrical/environmental conditions similar to a shipboard platform. Though electrical standards have been written as a guide to prevent insulator surface flashover, such as UL 840, they are not directly applicable to the Navy’s EML program. The design of experiments within UL 840 is vague, it does not consider a harsh sea environment, and it is written with the electric power utilities in mind rather than shipboard pulsed power systems. These shortfalls call for significant research to be performed to validate UL 840’s limited results and to expand upon them further for use as a more accurate reference manual that the EML pulsed power team can use to ensure surface flashover will not occur. This proposal requests funds for the UT Arlington Pulsed Power and Energy Laboratory (PPEL) team, led by Dr. David Wetz, to study the flashover dielectric strength of insulator technologies of interest to the Navy’s EML team. As a baseline, UL 840 [1], as well as the other standards referenced within UL 840 [2,3], will be utilized to evaluate the flashover of EML insulator materials at voltages and electrode separation distances expected in a fielded system. A test plan will be developed in collaboration with NSWC Dahlgren that characterizes relative materials in operational scenarios that all components of the Navy’s EML system will have to withstand when fielded on a shipboard platform. Dr. Wetz has over fifteen years of experience in the pulsed power field, over twelve of those years have been spent assisting the Navy’s EML team with various aspects of EML technology. The PPEL team will utilize pulsed power supplies previously donated as GFE by NSWC Dahlgren to UTA. A small portion of the funding will be utilized to complete the standing up of that equipment. The UTA team will work with the NSWC-Dahlgren to identify insulators of interest and to develop a test plan that ensures all possible operational scenarios are considered and studied.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 29, 2020
- Source ID
- N001741910030
Entities
People
- David A. Wetz Jr.
Organizations
- United States Navy
- University of Texas at Arlington