Performance evaluation of a process bus architecture in a zone substation based on IEC 61850-9-2

Ethernet communication has been the back bone of high speed communication in digital substations from protection relaying, control and automation perspective. Major substation manufacturers have been constantly upgrading softwares and adding new features in their Intelligent Electronic Devices (IED’s) to carry out multiple functions in process bus devices. This paper presents simulation results with respect to the delay in packets transfer in an Ethernet environment. Understanding the delay in packet transfer of Generic Object Oriented Substation Event (GOOSE) and Sampled Values (SV) shall assist the user in understanding the substation automation, control and protection of substation primary plants such as current transformers (CT’s), voltage transformers (VT’s), circuit breakers etc. connected in the network during a fault condition Conventional substation uses Merging Units (MU’s) to communicate with the IED’s featuring IEC 61850-9-2 standard. This standard exhibits transparency and standardization of data communication while addressing issues related to reliability, packet sharing, and maintainability, etc. However, process bus architecture is yet to be widely accepted in the industry and needs further validation due to lack of confidence. This paper evaluates the performance of a digital protection scheme in a zone substation operating at 132kV, featuring IEC 61850-9-2 IED’s and using an optimized network engineering tool (OPNET) simulator. Understanding the delay in receiving time critical GOOSE and sampled value SV messages from protection perspective is critical as loss of data could cause mal-function in the protection jeopardizing vital substation plants.