Research on the safety analysis method of power supply conversion of aircraft AC system based on STPA

Abstract

The aircraft AC power generation system is the main source of power for the whole aircraft, so a complete safety analysis is required. Traditionally safety analysis pays less attention to the security problems caused by nonlinear interaction between system components. Especially when the support data of the developed model is insufficient, there is a risk of analysis omission. According to the basic characteristics of the power supply conversion process of AC power generation system, this paper constructs a safety control structure chart and identify unsafe control action(UCA) based on the STPA method, and introduces the failure model and effect analysis(FMEA) of similar system to analyse the UCA cause factor and cause scenario. Using formal tool of timed automata theory, the system modeling and verification are carried out. The correctness of this methods is confirmed by expert evaluation and accident comparison. The result shows that the introduction of STPA based on traditional safety analysis methods can effectively identify unsafety control action and the causes of accident, which can be an effective supplement to the traditional method.

Keywords

• ac power system of aircraft
• stpa
• uca
• the theory of timed automata