National Grid recently made an impressive announcement indicating that it will transition all of its transmission substations to digital technology as part of one extended undertaking (National Grid Advances Digital Substations). National Grid pointed to the need for a more flexible system and the control, reliability and automation advantages that result with the adoption of IEC 61850 standards, so the company decided to digitalize the process and station busses at all transmission substations. National Grid’s comprehensive approach is notable given the partial substation conversions and phased conversion to digitalization seen at many utilities.
National Grid believes a complete and comprehensive conversion will help reduce the costs and challenges for staff, processes and systems associated with the migration to IEC 61850 and digital systems. In addition, the company plans to use a dedicated transition team and top-down design standards. This approach is smart because IEC 61850 standards implementation and digital conversion is not always straightforward. An excellent whitepaper that outlines some of the implementation issues and some recommendations for addressing same can be found here.
This paper explores top-down versus bottom-up approaches to implementing IEC 61850. The authors suggest a bottom up approach using intelligent electronic device (IED) vender tools may be losing appeal relative to a top down implementation using vendor agnostic system configuration methods. One of the benefits of the later approach is the creation of a substation configuration description (SCD) early in the process. This file guides the design for all communications within the current and similar future substations. Reusable configuration templates can be employed to create fully compatible description and communication files. The authors point out some possible trouble spots to consider when working in multiple vendor environments using IED and system configuration tools. They also caution users of system configuration tools about avoiding inadvertent alterations to protective and logic settings contained in the substation configuration language (SCL) files of IEDs. Even if your company does not have the resources to dedicate to a comprehensive digital conversion, this article will provide useful tips for making incremental conversion projects more efficient and replicable.