K. McCarthy, B. P. Loop, PC Krause and Associates, Inc. Charles Singer, Naval Air Systems Command
The primary objective of this effort was to enable rapid evaluation of under voltage conditions resulting from arc faulting onboard naval aircraft. This faulting reduces the main bus voltage and, if not cleared fast enough, will result in loss of power to mission-critical loads. Hardware fault tests were used to develop and validate a system-level model including a Naval aircraft generator, cabling, arc faulting behavior, and thermal and arc fault circuit breakers. Specifically, a genetic algorithm-based optimization technique was used to identify parameter values for the generator, exciter system, and arc fault models such that the error between the behavior predicted by the model and the true hardware response was minimized. A graphical user interface for the model was then developed to facilitate rapid deployment of fault studies. The model is capable of simulating single, multiple simultaneous, or multiple sequential faults. Additionally, the base loading, power factor, cable lengths and gauges, fault location and duration, and circuit breaker ratings and trip curve characteristics can all be altered to evaluate the faulting effects under different system configurations.
Several fault studies were performed with the model encompassing different combinations of base loading and circuit breaker ratings. The time required to clear the faults were recorded for each study, and these results were compared to military standards for power quality to determine the success of the protection system. The modeling work performed under this effort is a first step toward quantifying the performance of one part of the electric power protection system. The behavior of the system is very complex; however, efforts were taken to ensure the accuracy of the model by conducting extensive comparisons to hardware data. With such a model, advanced fault mitigation strategies can be implemented and tested in a virtual environment under worst-case scenarios in an effort to prevent catastrophic failures in the field.
Propulsion – Safety and Affordable Readiness (P-SAR) Conference, March 24-26, 2009, Myrtle Beach, SC. Proceedings not available. Contact information: loop@pcka.com