A Mechanism and Operation Characteristics of Electrical Hazard Factors in LVDC Distribution System

The DC distribution system has been considered as one of the alternatives to improve the hosting capacity of renewable energy sources in the existing AC distribution system. However, researches on the worker safety and equipment protection from various electrical hazards in DC distribution system are being required due to the lack of technical guidelines of electrical facilities standards and safety operation procedures compared to the existing AC distribution system. Therefore, this paper presents systematic mechanisms of electrical hazards in LVDC distribution system such as fault current, CMV, leakage current, circuit current and surge, and also performs the modeling of electrical hazards using PSCAD/EMTDC S/W. Moreover, this paper implements a test device for the electrical hazards based on the proposed modeling, which is composed of AC source, main and section converters and generator device of electrical hazards. From the simulation and test results based on the proposed modeling and test device, it is found that electrical hazards such as fault current, leakage current, circuit current and surge may have a negative impact on the safety and stable operation in LVDC distribution system, and that it is a practical and effective tool to evaluate the electrical hazards in LVDC distribution system as the operation characteristics of simulation modeling is nearly identical as one of the test device.