Impact of IEC 61850-9-2 Standard-Based Process Bus on the Operating Performance of Protection IEDS: Comparative Study

IEC 61850-9-2 is an international substation automation standard that proposes a Process Bus communication network between process level equipment and bay level Intelligent Electronic Devices (IEDs) used for power systems protection and control. This paper considers the drive towards the use of IEC 61850-9-2 Process Bus in substations. The impact of the IEC 61850-9-2 standard on the operating performance of protection IEDs in terms of dependability, security, and operating speed is considered. A lab-scale hardware-in-the-loop experiment involving the Real-Time Digital Simulator (RTDS), IEC 61850-9-2 protection IED based on Sampled Values (SV) inputs, conventional hardwired protection IED, GPS satellite clock, and industrial network switches is implemented and used for the investigations. The experiments are directed towards the comparison of the performance of the distance protection function of the two protection IEDs when subjected to various fault types at various fault locations, fault resistances, and fault inception angles, with different Source Impedance Ratios (SIRs). Furthermore, the possible impact of random noise/delay on the protection functions of the IEC 61850-9-2 Process Bus based protection IED is investigated. The stability and security of the protection function of the protection IED based on SVs generated from the GTNET-SV card of the RTDS is investigated and compared to that of the IED based on conventional hardwired CTs and VTs.