A Methodology to Implement and Investigate Performance of Sampled Values for Wide-Area Protection

IEC 61850 has been widely introduced into substations with the intention of reducing the complexity of hard-wired connections and implementing ethernet communications in protection and control applications. This standard is primarily designed to work within a substation and provide reliable communication framework between substation control room to all connected bay level and process level equipment. With the introduction of technical reports IEC 61850-90-1 and IEC 61850-90-5, it is now possible to implement IEC 61850 in wide-area. This paper presents a methodology to transmit and receive process level measurements known as sampled values (Instantaneous voltage and current measurements with time-stamp) between two substations on different Ethernet networks. This is achieved by using a unique Virtual Local Area Network (VLAN) ID that is assigned to the data packets and a Layer 3 switch that allows these particular packets into the network. This paper presents the laboratory setup to route sampled values between two different networks with the help of Opal-RT simulator, Layer 2 and 3 switches and communication network emulator. The main objective of this laboratory setup is to investigate the performance of sampled value data in a wide-area network with the influence of delays caused by transmission, background traffic, physical distance between the substations and unintentional delays due to communication devices. In addition, this work also evaluates the communication performance effects on phasor estimation, which will be used extensively in protection and control applications.