Description of baseline simulation

Electrical systems perform various functions in a nuclear power plant (NPP), and they are required for the operation of many safety systems. In normal operation, all electrical systems are connected together at the high voltage level, which creates the potential for common cause failures due to faults in the plant internal or external power system. In fact, several such incidents have been reported. This report reviews literature related to NPP electrical system reliability and electrical disturbances. Three particularly relevant conditions (power frequency overvoltages, open phase conditions and subsynchronous oscillations) are selected for in-depth analysis. Based on the literature review and analyses, this report makes recommendations about simulating these conditions in COSI project. COSI is a research project which aims to develop a co-simulation platform for simulating the electrical system and NPP process systems together. This report notes that existing electrical simulation studies have not considered process system feedback effects and other transient dynamics in much detail, and that COSI could provide insight into their effects on nuclear safety. The challenge of building the architecture of the COSI co-simulation platform covers the data exchange layout among simulators, data exchange Intervals, time step handling and the protocol of data exchange between simulators. Here, an update on the challenges of data exchange layout is added and also, a discussion about initialising of simulators is expressed.