IEC 61850 – What It Can and Cannot Offer to Traditional Protection Schemes

As the latest standard that is quickly gaining popularity in power substation automation, IEC 61850 offers self-descriptive object data models, standardized configurability with Substation Configuration Language (SCL), the promise of interoperations among intelligent electronic devices (IEDs) from different manufacturers, and lower integration installation costs. The IEC 61850 standard initially focused on communications between IEDs within a single power substation. However, the working groups of IEC Technical Committee TC57 are preparing IEC 61850 for communications between substations and between substations and control centers. Most existing papers regarding IEC 61850 concentrate on the standard, communication, and automation. In this paper, from a protection engineer’s point of view, we examine what the standard can and cannot offer to traditional protection schemes that require communications assistance. These protection schemes include fast bus tripping, breaker failure, directional comparison blocking (DCB), permissive overreaching transfer trip (POTT), and others. We review the Generic Object-Oriented Substation Event (GOOSE) control mode mechanism of the standard: its generation, mapping, communication over local-area and wide-area networks, and timing aspects. With this knowledge, we compare the use of GOOSE messages with traditional protection schemes in terms of feasibility, speed, and dependability.