The Hidden Regression: Risks of Embedding Protection and Control Functions in IEC 61850 Merging Units

Busbar protection is a critical component in maintaining the stability and reliability of highvoltage power systems. While traditional distributed protection schemes have proven robust and relatively simple, their vendor-specific architectures present serious knowledge management challenges. These include difficulties in system upgrades, limited or no interoperability, and increased dependence on proprietary tools, hardware, and undocumented logic and knowledge, making it hard for utilities to retain institutional knowledge and adapt efficiently to changing operational needs. Even minor upgrades, such as adding a bay, often require costly re-engineering due to vendor lock-in and incompatibility among equipment from different manufacturers.