Research On Insulation Fault In Aviation Electrical System

With the development of aviation industry, electrical power system is becoming more complex and the security of aviation is more important. Aircraft power will be changed from initial 115V AC, 400 Hz to complex power source. The complexity of aviation power supply may lead to more electrical fault in aircraft. The wiring fault become a seriously threaten to aviation security in case of hundreds of kilometers cables buried in aircraft.A series of catastrophe and fault was proved to be related with fault-arcing in aviation electrical system. The insulation failure lead by cables deterioration or hurt by physical is the major reason of fault arc. So the problem of fault arc and the deterioration of cable insulation have been researched in this paper.The purpose of researching fault arc is to detect and distinguish fault-arcing signals from other similarly normal signals in aircraft, which provided theoretical reference for developing aircraft fault arc interrupter. Based on the analysis of several present typical arc model, stokes arc model is selected to simulink fault arc in aircraft. A simulink-model for arcing based on simulink platform of Matlab is developed and applied in aviation power system. In order to detect the current and voltage characters of the fault arc, a series of parameters were modified in the simulation circuit. The factors affecting the fault arc behaviour were analyzed and concluded.The deterioration of insulation material for aircraft cables is the main reason to lead fault arc in aircraft. In order to simulate the aircraft cables deterioration, an accelerating aging experiment was designed in this paper. The experiment has been performed at higher temperature to simulate the aging of aircraft wire. Parameters such as insulating resistance, leaking-current and dielectric loss of aged cables have been tested. Comparing the above insulation parameters under different temperature and under different time, the aging influence on the inaulation has been concluded. The results show that PTFE insulation has a better capability against the aging and high temperature than the other tested insulating materials.