Performance and reliability assessment of protection system in IEC 61850-based smart substation

The architecture and performance between substation protection system based on IEC 61850 and conventional system are quite different. The advanced protection system presented in this paper incorporates the Rogowski-coil current sensors and performs over a communication network. Transient characteristics of transformers are researched to analyze its impacts on protective relayings. It is revealed that the measuring error of fault current mainly depends on the decay time constant of aperiodic component and the parameters of integrator. The dynamic performance of communication network is discussed by modeling technique using the OPNET Modeler. It could be observed that the IEC61850 substation communication system based on Ethernet has shown sufficient performance to satisfy the time critical demand of protection system. Finally, typical protection system architecture is modeled and numerically analyzed based on the reliability block diagram. Some interesting results are found by sensitivity analysis.