Electrical Equipment Safety Risk Assessment Method in LVDC System

Abstract

The safety of electrical equipment is one of important advantages in low voltage direct current (LVDC) system. If the safety is assessed quantitively, the application of LVDC system will be promoted quickly. With the combination of electrical safety factors and the characteristics of LVDC system, this paper proposed a 5-level safety risk assessment model for the electrical equipment in LVDC system. The model defined three parameters to describe the injury severity, the danger exposure and the user restriction. The parameter of injury severity is determined by the value and duration of ventricular fibrillation current. The parameter of danger was obtained by the defined exposure coefficient and occurrence coefficient. The parameter of user restriction is obtained by the types of users. The assessment model mapped the three parameters into the 5-level safety with a decision tree model. The effectiveness of the proposed method was verified by 48V and 375V DC outlets in a practical LVDC system. The proposed method can be used to analyze the electrical safety of equipment quantitatively in LVDC system with different grounding types and different voltage levels.