Comparison of the Operational Speed of Hard-wired and IEC 61850 Standard-based Implementations of a Reverse Blocking Protection Scheme

This paper focuses on the reverse blocking busbar protection scheme with aim to improve the speed of its operation and at the same time to increase operational reliability, flexibility and stability of the protection during external and internal faults by implementation of the extended functionality provided by the IEC61850 standard-based protective Intelligent Electronic Devices (IEDs). The practical implementation of the scheme by the use of IEC 61850 standard communication protocol is investigated. The proposed scheme is designed for a radial type of a distribution network and is modeled and simulated in the DigSILENT software environment for various faults on the busbar and its outgoing feeders. A laboratory test bench is built using three ABB IEDs 670 series that are compliant with the IEC 61850 standard, CMC 356 Omicron test injection device, PC, MOXA switch, and a DC power supplier. Two types of the reverse blocking signals between the IEDs in the test bench are considered: hard wired and Ethernet communication by using IEC 61850 standard GOOSE messages. Comparative experimental study of the operational trip response speeds of the two implementations for various traffic conditions of the communication network shows that the performance of the protection scheme for the case of Ethernet IEC 61850 standard-based communication is better.